Initialize boot-time tracing in core_initcall_sync instead of
fs_initcall, and initialize required tracers (kprobes and synth)
in core_initcall. This will allow the boot-time tracing to trace
__init code from the beginning of postcore_initcall stage.
Link: https://lkml.kernel.org/r/159974155727.478751.7486926132902849578.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Enable creating new trace_array instance in early boot stage.
If the instances directory is not created, postpone it until
the tracefs is initialized.
Link: https://lkml.kernel.org/r/159974154763.478751.6289753509587233103.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Split the event fields initialization from creating new event directory.
This allows the boot-time tracing to define dynamic events before
initializing events directory on tracefs.
Link: https://lkml.kernel.org/r/159974153790.478751.3475515065034825374.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Define event fields at early stage so that boot-time tracing can
access the event fields (like per-event filter setting).
Link: https://lkml.kernel.org/r/159974152862.478751.2023768466808361350.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Init kprobes feature in early_initcall as same as jump_label and
dynamic_debug does, so that we can use kprobes events in earlier
boot stage.
Link: https://lkml.kernel.org/r/159974151897.478751.8342374158615496628.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Support perf-style return probe ("SYMBOL%return") for kprobe events.
This will allow boot-time tracing user to define a return probe event.
Link: https://lkml.kernel.org/r/159972813535.428528.4437029657208468954.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add per-instance tracing_on option, which will be useful with
traceon/traceoff event trigger actions. For example, if we
disable tracing_on by default and set traceon and traceoff on
a pair of events, we can trace functions between the pair of
events.
Link: https://lkml.kernel.org/r/159972811538.428528.2561315102284268611.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
It seems that alloc_retstack_tasklist() can also take a lockless
approach for scanning the tasklist, instead of using the big global
tasklist_lock. For this we also kill another deprecated and rcu-unsafe
tsk->thread_group user replacing it with for_each_process_thread(),
maintaining semantics.
Here tasklist_lock does not protect anything other than the list
against concurrent fork/exit. And considering that the whole thing
is capped by FTRACE_RETSTACK_ALLOC_SIZE (32), it should not be a
problem to have a pontentially stale, yet stable, list. The task cannot
go away either, so we don't risk racing with ftrace_graph_exit_task()
which clears the retstack.
The tsk->ret_stack management is not protected by tasklist_lock, being
serialized with the corresponding publish/subscribe barriers against
concurrent ftrace_push_return_trace(). In addition this plays nicer
with cachelines by avoiding two atomic ops in the uncontended case.
Link: https://lkml.kernel.org/r/20200907013326.9870-1-dave@stgolabs.net
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The "tr" is a stack variable so setting it to NULL before a return is
a no-op. Delete the assignment.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
It is advised to use module_name() macro instead of dereferencing mod->name
directly. This makes sense for consistencys sake and also it prevents a
hard dependency to CONFIG_MODULES.
Link: https://lkml.kernel.org/r/20200818050857.117998-1-jarkko.sakkinen@linux.intel.com
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-mm@kvack.org
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Some kernels builds might inline vfs_getattr call within fstat
syscall code path, so fentry/vfs_getattr trampoline is not called.
Add security_inode_getattr to allowlist and switch the d_path test stat
trampoline to security_inode_getattr.
Keeping dentry_open and filp_close, because they are in their own
files, so unlikely to be inlined, but in case they are, adding
security_file_open.
Adding flags that indicate trampolines were called and failing
the test if any of them got missed, so it's easier to identify
the issue next time.
Fixes: e4d1af4b16 ("selftests/bpf: Add test for d_path helper")
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200918112338.2618444-1-jolsa@kernel.org
The mapping between bpf_arg_type and bpf_reg_type is encoded in a big
hairy if statement that is hard to follow. The debug output also leaves
to be desired: if a reg_type doesn't match we only print one of the
options, instead printing all the valid ones.
Convert the if statement into a table which is then used to drive type
checking. If none of the reg_types match we print all options, e.g.:
R2 type=rdonly_buf expected=fp, pkt, pkt_meta, map_value
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-12-lmb@cloudflare.com
check_func_arg has a plethora of weird if statements with empty branches.
They work around the fact that *_OR_NULL argument types should accept a
SCALAR_VALUE register, as long as it's value is 0. These statements make
it difficult to reason about the type checking logic.
Instead, skip more detailed type checking logic iff the register is 0,
and the function expects a nullable type. This allows simplifying the type
checking itself.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-11-lmb@cloudflare.com
Move the check for PTR_TO_MAP_VALUE to check_func_arg, where all other
checking is done as well. Move the invocation of process_spin_lock away
from the register type checking, to allow a future refactoring.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-10-lmb@cloudflare.com
If we encounter a pointer to memory, we set meta->raw_mode depending
on the type of memory we point at. What isn't obvious is that this
information is only used when the next memory size argument is
encountered.
Move the assignment closer to where it's used, and add a comment that
explains what is going on.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-9-lmb@cloudflare.com
Always check context access if the register we're operating on is
PTR_TO_CTX, rather than relying on ARG_PTR_TO_CTX. This allows
simplifying the arg_type checking section of the function.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-8-lmb@cloudflare.com
Instead of dealing with reg->ref_obj_id individually for every arg type that
needs it, rely on the fact that ref_obj_id is zero if the register is not
reference tracked.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-7-lmb@cloudflare.com
Perform BTF type checks if the register we're working on contains a BTF
pointer, rather than if the argument is for a BTF pointer. This is easier
to understand, and allows removing the code from the arg_type checking
section of the function.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-6-lmb@cloudflare.com
Function prototypes using ARG_PTR_TO_BTF_ID currently use two ways to signal
which BTF IDs are acceptable. First, bpf_func_proto.btf_id is an array of
IDs, one for each argument. This array is only accessed up to the highest
numbered argument that uses ARG_PTR_TO_BTF_ID and may therefore be less than
five arguments long. It usually points at a BTF_ID_LIST. Second, check_btf_id
is a function pointer that is called by the verifier if present. It gets the
actual BTF ID of the register, and the argument number we're currently checking.
It turns out that the only user check_arg_btf_id ignores the argument, and is
simply used to check whether the BTF ID has a struct sock_common at it's start.
Replace both of these mechanisms with an explicit BTF ID for each argument
in a function proto. Thanks to btf_struct_ids_match this is very flexible:
check_arg_btf_id can be replaced by requiring struct sock_common.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-5-lmb@cloudflare.com
Move the check for a NULL or zero register to check_helper_mem_access. This
makes check_stack_boundary easier to understand.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-3-lmb@cloudflare.com
bsearch doesn't modify the contents of the array, so we can take a const pointer.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200921121227.255763-2-lmb@cloudflare.com
Pull RCU fix from Paul McKenney:
"This contains a single commit that fixes a bug that was introduced in
the last merge window. This bug causes a compiler warning complaining
about show_rcu_tasks_classic_gp_kthread() being an unused static
function in !SMP kernels.
The fix is straightforward, just adding an 'inline' to make this a
static inline function, thus avoiding the warning.
This bug was reported by Laurent Pinchart, who would like it fixed
sooner rather than later"
* 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
rcu-tasks: Prevent complaints of unused show_rcu_tasks_classic_gp_kthread()
The in_atomic() macro cannot always detect atomic context, in particular,
it cannot know about held spinlocks in non-preemptible kernels. Although,
there is no user call bpf_link_put() with holding spinlock now, be on the
safe side, so we can avoid this in the future.
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200917074453.20621-1-songmuchun@bytedance.com
Fix this link error:
ERROR: modpost: "rcu_idle_enter" [drivers/acpi/processor.ko] undefined!
ERROR: modpost: "rcu_idle_exit" [drivers/acpi/processor.ko] undefined!
when CONFIG_ACPI_PROCESSOR is built as module. PeterZ says that in light
of ARM needing those soon too, they should simply be exported.
Fixes: 1fecfdbb7a ("ACPI: processor: Take over RCU-idle for C3-BM idle")
Reported-by: Sven Joachim <svenjoac@gmx.de>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Paul E. McKenney <paulmckrcu@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
rewritten syscall number, from Kees Cook.
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Merge tag 'core_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull syscall tracing fix from Borislav Petkov:
"Fix the seccomp syscall rewriting so that trace and audit see the
rewritten syscall number, from Kees Cook"
* tag 'core_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
core/entry: Report syscall correctly for trace and audit
Zijlstra.
* Make percpu-rwsem operations on the semaphore's ->read_count IRQ-safe
because it can be used in an IRQ context, from Hou Tao.
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Merge tag 'locking_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Borislav Petkov:
"Two fixes from the locking/urgent pile:
- Fix lockdep's detection of "USED" <- "IN-NMI" inversions (Peter
Zijlstra)
- Make percpu-rwsem operations on the semaphore's ->read_count
IRQ-safe because it can be used in an IRQ context (Hou Tao)"
* tag 'locking_urgent_for_v5.9_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/percpu-rwsem: Use this_cpu_{inc,dec}() for read_count
locking/lockdep: Fix "USED" <- "IN-NMI" inversions
Merge fixes from Andrew Morton:
"15 patches.
Subsystems affected by this patch series: mailmap, mm/hotfixes,
mm/thp, mm/memory-hotplug, misc, kcsan"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
kcsan: kconfig: move to menu 'Generic Kernel Debugging Instruments'
fs/fs-writeback.c: adjust dirtytime_interval_handler definition to match prototype
stackleak: let stack_erasing_sysctl take a kernel pointer buffer
ftrace: let ftrace_enable_sysctl take a kernel pointer buffer
mm/memory_hotplug: drain per-cpu pages again during memory offline
selftests/vm: fix display of page size in map_hugetlb
mm/thp: fix __split_huge_pmd_locked() for migration PMD
kprobes: fix kill kprobe which has been marked as gone
tmpfs: restore functionality of nr_inodes=0
mlock: fix unevictable_pgs event counts on THP
mm: fix check_move_unevictable_pages() on THP
mm: migration of hugetlbfs page skip memcg
ksm: reinstate memcg charge on copied pages
mailmap: add older email addresses for Kees Cook
Commit 32927393dc ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer. Adjust the
signature of stack_erasing_sysctl to match ctl_table.proc_handler which
fixes the following sparse warning:
kernel/stackleak.c:31:50: warning: incorrect type in argument 3 (different address spaces)
kernel/stackleak.c:31:50: expected void *
kernel/stackleak.c:31:50: got void [noderef] __user *buffer
Fixes: 32927393dc ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200907093253.13656-1-tklauser@distanz.ch
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 32927393dc ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer. Adjust the
signature of ftrace_enable_sysctl to match ctl_table.proc_handler which
fixes the following sparse warning:
kernel/trace/ftrace.c:7544:43: warning: incorrect type in argument 3 (different address spaces)
kernel/trace/ftrace.c:7544:43: expected void *
kernel/trace/ftrace.c:7544:43: got void [noderef] __user *buffer
Fixes: 32927393dc ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200907093207.13540-1-tklauser@distanz.ch
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a kprobe is marked as gone, we should not kill it again. Otherwise, we
can disarm the kprobe more than once. In that case, the statistics of
kprobe_ftrace_enabled can unbalance which can lead to that kprobe do not
work.
Fixes: e8386a0cb2 ("kprobes: support probing module __exit function")
Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Song Liu <songliubraving@fb.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20200822030055.32383-1-songmuchun@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current tracing_init_dentry() return a d_entry pointer, while is not
necessary. This function returns NULL on success or error on failure,
which means there is no valid d_entry pointer return.
Let's return 0 on success and negative value for error.
Link: https://lkml.kernel.org/r/20200712011036.70948-5-richard.weiyang@linux.alibaba.com
Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Currently we have following call flow:
tracer_init_tracefs()
tracing_init_dentry()
event_trace_init()
tracing_init_dentry()
This shows tracing_init_dentry() is called twice in this flow and this
is not necessary.
Let's remove the second one when it is for sure be properly initialized.
Link: https://lkml.kernel.org/r/20200712011036.70948-4-richard.weiyang@linux.alibaba.com
Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
- Fix order in trace_hardirqs_off_caller() to make locking state
consistent even if the IRQ tracer calls into lockdep again.
Touches common code. Acked-by Peter Zijlstra.
- Correctly handle secure storage violation exception to avoid kernel
panic triggered by user space misbehaviour.
- Switch the idle->seqcount over to using raw_write_*() to avoid
"suspicious RCU usage".
- Fix memory leaks on hard unplug in pci code.
- Use kvmalloc instead of kmalloc for larger allocations in zcrypt.
- Add few missing __init annotations to static functions to avoid section
mismatch complains when functions are not inlined.
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Merge tag 's390-5.9-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Vasily Gorbik:
- Fix order in trace_hardirqs_off_caller() to make locking state
consistent even if the IRQ tracer calls into lockdep again. Touches
common code. Acked-by Peter Zijlstra.
- Correctly handle secure storage violation exception to avoid kernel
panic triggered by user space misbehaviour.
- Switch the idle->seqcount over to using raw_write_*() to avoid
"suspicious RCU usage".
- Fix memory leaks on hard unplug in pci code.
- Use kvmalloc instead of kmalloc for larger allocations in zcrypt.
- Add few missing __init annotations to static functions to avoid
section mismatch complains when functions are not inlined.
* tag 's390-5.9-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390: add 3f program exception handler
lockdep: fix order in trace_hardirqs_off_caller()
s390/pci: fix leak of DMA tables on hard unplug
s390/init: add missing __init annotations
s390/zcrypt: fix kmalloc 256k failure
s390/idle: fix suspicious RCU usage
The local_storage->list will be traversed by rcu reader in parallel.
Thus, hlist_add_head_rcu() is needed in bpf_selem_link_storage_nolock().
This patch fixes it.
This part of the code has recently been refactored in bpf-next
and this patch makes changes to the new file "bpf_local_storage.c".
Instead of using the original offending commit in the Fixes tag,
the commit that created the file "bpf_local_storage.c" is used.
A separate fix has been provided to the bpf tree.
Fixes: 450af8d0f6 ("bpf: Split bpf_local_storage to bpf_sk_storage")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200916204453.2003915-1-kafai@fb.com
Since kprobe_event= cmdline option allows user to put kprobes on the
functions in initmem, kprobe has to make such probes gone after boot.
Currently the probes on the init functions in modules will be handled
by module callback, but the kernel init text isn't handled.
Without this, kprobes may access non-exist text area to disable or
remove it.
Link: https://lkml.kernel.org/r/159972810544.428528.1839307531600646955.stgit@devnote2
Fixes: 970988e19e ("tracing/kprobe: Add kprobe_event= boot parameter")
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
clang static analyzer reports this problem
trace_events_hist.c:3824:3: warning: Attempt to free
released memory
kfree(hist_data->attrs->var_defs.name[i]);
In parse_var_defs() if there is a problem allocating
var_defs.expr, the earlier var_defs.name is freed.
This free is duplicated by free_var_defs() which frees
the rest of the list.
Because free_var_defs() has to run anyway, remove the
second free fom parse_var_defs().
Link: https://lkml.kernel.org/r/20200907135845.15804-1-trix@redhat.com
Cc: stable@vger.kernel.org
Fixes: 30350d65ac ("tracing: Add variable support to hist triggers")
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Commit 32927393dc ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer. Adjust the
signature of ftrace_enable_sysctl to match ctl_table.proc_handler which
fixes the following sparse warning:
kernel/trace/ftrace.c:7544:43: warning: incorrect type in argument 3 (different address spaces)
kernel/trace/ftrace.c:7544:43: expected void *
kernel/trace/ftrace.c:7544:43: got void [noderef] __user *buffer
Link: https://lkml.kernel.org/r/20200907093207.13540-1-tklauser@distanz.ch
Fixes: 32927393dc ("sysctl: pass kernel pointers to ->proc_handler")
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
For 64bit CONFIG_BASE_SMALL=0 systems PID_MAX_LIMIT is set by default to
4194304. During boot the kernel sets a new value based on number of CPUs
but no lower than 32768. It is 1024 per CPU so with 128 CPUs the default
becomes 131072 which needs six digits.
This value can be increased during run time but must not exceed the
initial upper limit.
Systemd sometime after v241 sets it to the upper limit during boot. The
result is that when the pid exceeds five digits, the trace output is a
little hard to read because it is no longer properly padded (same like
on big iron with 98+ CPUs).
Increase the pid padding to seven digits.
Link: https://lkml.kernel.org/r/20200904082331.dcdkrr3bkn3e4qlg@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Add synchronize_rcu() after list_del_rcu() in
ftrace_remove_trampoline_from_kallsyms() to protect readers of
ftrace_ops_trampoline_list (in ftrace_get_trampoline_kallsym)
which is used when kallsyms is read.
Link: https://lkml.kernel.org/r/20200901091617.31837-1-adrian.hunter@intel.com
Fixes: fc0ea795f5 ("ftrace: Add symbols for ftrace trampolines")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Commit fc0ea795f5 ("ftrace: Add symbols for ftrace trampolines")
missed to remove ops from new ftrace_ops_trampoline_list in
ftrace_startup() if ftrace_hash_ipmodify_enable() fails there. It may
lead to BUG if such ops come from a module which may be removed.
Moreover, the trampoline itself is not freed in this case.
Fix it by calling ftrace_trampoline_free() during the rollback.
Link: https://lkml.kernel.org/r/20200831122631.28057-1-mbenes@suse.cz
Fixes: fc0ea795f5 ("ftrace: Add symbols for ftrace trampolines")
Fixes: f8b8be8a31 ("ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict")
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Currently the callback passed to arch_stack_walk() has an argument called
reliable passed to it to indicate if the stack entry is reliable, a comment
says that this is used by some printk() consumers. However in the current
kernel none of the arch_stack_walk() implementations ever set this flag to
true and the only callback implementation we have is in the generic
stacktrace code which ignores the flag. It therefore appears that this
flag is redundant so we can simplify and clarify things by removing it.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/20200914153409.25097-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
LD_[ABS|IND] instructions may return from the function early. bpf_tail_call
pseudo instruction is either fallthrough or return. Allow them in the
subprograms only when subprograms are BTF annotated and have scalar return
types. Allow ld_abs and tail_call in the main program even if it calls into
subprograms. In the past that was not ok to do for ld_abs, since it was JITed
with special exit sequence. Since bpf_gen_ld_abs() was introduced the ld_abs
looks like normal exit insn from JIT point of view, so it's safe to allow them
in the main program.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Relax verifier's restriction that was meant to forbid tailcall usage
when subprog count was higher than 1.
Also, do not max out the stack depth of program that utilizes tailcalls.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit serves two things:
1) it optimizes BPF prologue/epilogue generation
2) it makes possible to have tailcalls within BPF subprogram
Both points are related to each other since without 1), 2) could not be
achieved.
In [1], Alexei says:
"The prologue will look like:
nop5
xor eax,eax // two new bytes if bpf_tail_call() is used in this
// function
push rbp
mov rbp, rsp
sub rsp, rounded_stack_depth
push rax // zero init tail_call counter
variable number of push rbx,r13,r14,r15
Then bpf_tail_call will pop variable number rbx,..
and final 'pop rax'
Then 'add rsp, size_of_current_stack_frame'
jmp to next function and skip over 'nop5; xor eax,eax; push rpb; mov
rbp, rsp'
This way new function will set its own stack size and will init tail
call
counter with whatever value the parent had.
If next function doesn't use bpf_tail_call it won't have 'xor eax,eax'.
Instead it would need to have 'nop2' in there."
Implement that suggestion.
Since the layout of stack is changed, tail call counter handling can not
rely anymore on popping it to rbx just like it have been handled for
constant prologue case and later overwrite of rbx with actual value of
rbx pushed to stack. Therefore, let's use one of the register (%rcx) that
is considered to be volatile/caller-saved and pop the value of tail call
counter in there in the epilogue.
Drop the BUILD_BUG_ON in emit_prologue and in
emit_bpf_tail_call_indirect where instruction layout is not constant
anymore.
Introduce new poke target, 'tailcall_bypass' to poke descriptor that is
dedicated for skipping the register pops and stack unwind that are
generated right before the actual jump to target program.
For case when the target program is not present, BPF program will skip
the pop instructions and nop5 dedicated for jmpq $target. An example of
such state when only R6 of callee saved registers is used by program:
ffffffffc0513aa1: e9 0e 00 00 00 jmpq 0xffffffffc0513ab4
ffffffffc0513aa6: 5b pop %rbx
ffffffffc0513aa7: 58 pop %rax
ffffffffc0513aa8: 48 81 c4 00 00 00 00 add $0x0,%rsp
ffffffffc0513aaf: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
ffffffffc0513ab4: 48 89 df mov %rbx,%rdi
When target program is inserted, the jump that was there to skip
pops/nop5 will become the nop5, so CPU will go over pops and do the
actual tailcall.
One might ask why there simply can not be pushes after the nop5?
In the following example snippet:
ffffffffc037030c: 48 89 fb mov %rdi,%rbx
(...)
ffffffffc0370332: 5b pop %rbx
ffffffffc0370333: 58 pop %rax
ffffffffc0370334: 48 81 c4 00 00 00 00 add $0x0,%rsp
ffffffffc037033b: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1)
ffffffffc0370340: 48 81 ec 00 00 00 00 sub $0x0,%rsp
ffffffffc0370347: 50 push %rax
ffffffffc0370348: 53 push %rbx
ffffffffc0370349: 48 89 df mov %rbx,%rdi
ffffffffc037034c: e8 f7 21 00 00 callq 0xffffffffc0372548
There is the bpf2bpf call (at ffffffffc037034c) right after the tailcall
and jump target is not present. ctx is in %rbx register and BPF
subprogram that we will call into on ffffffffc037034c is relying on it,
e.g. it will pick ctx from there. Such code layout is therefore broken
as we would overwrite the content of %rbx with the value that was pushed
on the prologue. That is the reason for the 'bypass' approach.
Special care needs to be taken during the install/update/remove of
tailcall target. In case when target program is not present, the CPU
must not execute the pop instructions that precede the tailcall.
To address that, the following states can be defined:
A nop, unwind, nop
B nop, unwind, tail
C skip, unwind, nop
D skip, unwind, tail
A is forbidden (lead to incorrectness). The state transitions between
tailcall install/update/remove will work as follows:
First install tail call f: C->D->B(f)
* poke the tailcall, after that get rid of the skip
Update tail call f to f': B(f)->B(f')
* poke the tailcall (poke->tailcall_target) and do NOT touch the
poke->tailcall_bypass
Remove tail call: B(f')->C(f')
* poke->tailcall_bypass is poked back to jump, then we wait the RCU
grace period so that other programs will finish its execution and
after that we are safe to remove the poke->tailcall_target
Install new tail call (f''): C(f')->D(f'')->B(f'').
* same as first step
This way CPU can never be exposed to "unwind, tail" state.
Last but not least, when tailcalls get mixed with bpf2bpf calls, it
would be possible to encounter the endless loop due to clearing the
tailcall counter if for example we would use the tailcall3-like from BPF
selftests program that would be subprogram-based, meaning the tailcall
would be present within the BPF subprogram.
This test, broken down to particular steps, would do:
entry -> set tailcall counter to 0, bump it by 1, tailcall to func0
func0 -> call subprog_tail
(we are NOT skipping the first 11 bytes of prologue and this subprogram
has a tailcall, therefore we clear the counter...)
subprog -> do the same thing as entry
and then loop forever.
To address this, the idea is to go through the call chain of bpf2bpf progs
and look for a tailcall presence throughout whole chain. If we saw a single
tail call then each node in this call chain needs to be marked as a subprog
that can reach the tailcall. We would later feed the JIT with this info
and:
- set eax to 0 only when tailcall is reachable and this is the entry prog
- if tailcall is reachable but there's no tailcall in insns of currently
JITed prog then push rax anyway, so that it will be possible to
propagate further down the call chain
- finally if tailcall is reachable, then we need to precede the 'call'
insn with mov rax, [rbp - (stack_depth + 8)]
Tail call related cases from test_verifier kselftest are also working
fine. Sample BPF programs that utilize tail calls (sockex3, tracex5)
work properly as well.
[1]: https://lore.kernel.org/bpf/20200517043227.2gpq22ifoq37ogst@ast-mbp.dhcp.thefacebook.com/
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Protect against potential stack overflow that might happen when bpf2bpf
calls get combined with tailcalls. Limit the caller's stack depth for
such case down to 256 so that the worst case scenario would result in 8k
stack size (32 which is tailcall limit * 256 = 8k).
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reflect the actual purpose of poke->ip and rename it to
poke->tailcall_target so that it will not the be confused with another
poke target that will be introduced in next commit.
While at it, do the same thing with poke->ip_stable - rename it to
poke->tailcall_target_stable.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Previously, there was no need for poke descriptors being present in
subprogram's bpf_prog_aux struct since tailcalls were simply not allowed
in them. Each subprog is JITed independently so in order to enable
JITing subprograms that use tailcalls, do the following:
- in fixup_bpf_calls() store the index of tailcall insn onto the generated
poke descriptor,
- in case when insn patching occurs, adjust the tailcall insn idx from
bpf_patch_insn_data,
- then in jit_subprogs() check whether the given poke descriptor belongs
to the current subprog by checking if that previously stored absolute
index of tail call insn is in the scope of the insns of given subprog,
- update the insn->imm with new poke descriptor slot so that while JITing
the proper poke descriptor will be grabbed
This way each of the main program's poke descriptors are distributed
across the subprograms poke descriptor array, so main program's
descriptors can be untracked out of the prog array map.
Add also subprog's aux struct to the BPF map poke_progs list by calling
on it map_poke_track().
In case of any error, call the map_poke_untrack() on subprog's aux
structs that have already been registered to prog array map.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit 2a9127fcf2 ("mm: rewrite wait_on_page_bit_common() logic") made
the page locking entirely fair, in that if a waiter came in while the
lock was held, the lock would be transferred to the lockers strictly in
order.
That was intended to finally get rid of the long-reported watchdog
failures that involved the page lock under extreme load, where a process
could end up waiting essentially forever, as other page lockers stole
the lock from under it.
It also improved some benchmarks, but it ended up causing huge
performance regressions on others, simply because fair lock behavior
doesn't end up giving out the lock as aggressively, causing better
worst-case latency, but potentially much worse average latencies and
throughput.
Instead of reverting that change entirely, this introduces a controlled
amount of unfairness, with a sysctl knob to tune it if somebody needs
to. But the default value should hopefully be good for any normal load,
allowing a few rounds of lock stealing, but enforcing the strict
ordering before the lock has been stolen too many times.
There is also a hint from Matthieu Baerts that the fair page coloring
may end up exposing an ABBA deadlock that is hidden by the usual
optimistic lock stealing, and while the unfairness doesn't fix the
fundamental issue (and I'm still looking at that), it avoids it in
practice.
The amount of unfairness can be modified by writing a new value to the
'sysctl_page_lock_unfairness' variable (default value of 5, exposed
through /proc/sys/vm/page_lock_unfairness), but that is hopefully
something we'd use mainly for debugging rather than being necessary for
any deep system tuning.
This whole issue has exposed just how critical the page lock can be, and
how contended it gets under certain locks. And the main contention
doesn't really seem to be anything related to IO (which was the origin
of this lock), but for things like just verifying that the page file
mapping is stable while faulting in the page into a page table.
Link: https://lore.kernel.org/linux-fsdevel/ed8442fd-6f54-dd84-cd4a-941e8b7ee603@MichaelLarabel.com/
Link: https://www.phoronix.com/scan.php?page=article&item=linux-50-59&num=1
Link: https://lore.kernel.org/linux-fsdevel/c560a38d-8313-51fb-b1ec-e904bd8836bc@tessares.net/
Reported-and-tested-by: Michael Larabel <Michael@michaellarabel.com>
Tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Chris Mason <clm@fb.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fold the misaligned u64 workarounds into the main quotactl flow instead
of implementing a separate compat syscall handler.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The new field 'dma_range_map' in struct device is used to facilitate the
use of single or multiple offsets between mapping regions of cpu addrs and
dma addrs. It subsumes the role of "dev->dma_pfn_offset" which was only
capable of holding a single uniform offset and had no region bounds
checking.
The function of_dma_get_range() has been modified so that it takes a single
argument -- the device node -- and returns a map, NULL, or an error code.
The map is an array that holds the information regarding the DMA regions.
Each range entry contains the address offset, the cpu_start address, the
dma_start address, and the size of the region.
of_dma_configure() is the typical manner to set range offsets but there are
a number of ad hoc assignments to "dev->dma_pfn_offset" in the kernel
driver code. These cases now invoke the function
dma_direct_set_offset(dev, cpu_addr, dma_addr, size).
Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
[hch: various interface cleanups]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
When booting the kernel v5.9-rc4 on a VM, the kernel would panic when
printing a warning message in swiotlb_map(). The dev->dma_mask must not
be a NULL pointer when calling the dma mapping layer. A NULL pointer
check can potentially avoid the panic.
Signed-off-by: Thomas Tai <thomas.tai@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The rcu_tasks_trace_postgp() function uses for_each_process_thread()
to scan the task list without the benefit of RCU read-side protection,
which can result in use-after-free errors on task_struct structures.
This error was missed because the TRACE01 rcutorture scenario enables
lockdep, but also builds with CONFIG_PREEMPT_NONE=y. In this situation,
preemption is disabled everywhere, so lockdep thinks everywhere can
be a legitimate RCU reader. This commit therefore adds the needed
rcu_read_lock() and rcu_read_unlock().
Note that this bug can occur only after an RCU Tasks Trace CPU stall
warning, which by default only happens after a grace period has extended
for ten minutes (yes, not a typo, minutes).
Fixes: 4593e772b5 ("rcu-tasks: Add stall warnings for RCU Tasks Trace")
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: <bpf@vger.kernel.org>
Cc: <stable@vger.kernel.org> # 5.7.x
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
When rcu_tasks_trace_postgp() function detects an RCU Tasks Trace
CPU stall, it adds all tasks blocking the current grace period to
a list, invoking get_task_struct() on each to prevent them from
being freed while on the list. It then traverses that list,
printing stall-warning messages for each one that is still blocking
the current grace period and removing it from the list. The list
removal invokes the matching put_task_struct().
This of course means that in the admittedly unlikely event that some
task executes its outermost rcu_read_unlock_trace() in the meantime, it
won't be removed from the list and put_task_struct() won't be executing,
resulting in a task_struct leak. This commit therefore makes the list
removal and put_task_struct() unconditional, stopping the leak.
Note further that this bug can occur only after an RCU Tasks Trace CPU
stall warning, which by default only happens after a grace period has
extended for ten minutes (yes, not a typo, minutes).
Fixes: 4593e772b5 ("rcu-tasks: Add stall warnings for RCU Tasks Trace")
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: <bpf@vger.kernel.org>
Cc: <stable@vger.kernel.org> # 5.7.x
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The more intense grace-period processing resulting from the 50x RCU
Tasks Trace grace-period speedups exposed the following race condition:
o Task A running on CPU 0 executes rcu_read_lock_trace(),
entering a read-side critical section.
o When Task A eventually invokes rcu_read_unlock_trace()
to exit its read-side critical section, this function
notes that the ->trc_reader_special.s flag is zero and
and therefore invoke wil set ->trc_reader_nesting to zero
using WRITE_ONCE(). But before that happens...
o The RCU Tasks Trace grace-period kthread running on some other
CPU interrogates Task A, but this fails because this task is
currently running. This kthread therefore sends an IPI to CPU 0.
o CPU 0 receives the IPI, and thus invokes trc_read_check_handler().
Because Task A has not yet cleared its ->trc_reader_nesting
counter, this function sees that Task A is still within its
read-side critical section. This function therefore sets the
->trc_reader_nesting.b.need_qs flag, AKA the .need_qs flag.
Except that Task A has already checked the .need_qs flag, which
is part of the ->trc_reader_special.s flag. The .need_qs flag
therefore remains set until Task A's next rcu_read_unlock_trace().
o Task A now invokes synchronize_rcu_tasks_trace(), which cannot
start a new grace period until the current grace period completes.
And thus cannot return until after that time.
But Task A's .need_qs flag is still set, which prevents the current
grace period from completing. And because Task A is blocked, it
will never execute rcu_read_unlock_trace() until its call to
synchronize_rcu_tasks_trace() returns.
We are therefore deadlocked.
This race is improbable, but 80 hours of rcutorture made it happen twice.
The race was possible before the grace-period speedup, but roughly 50x
less probable. Several thousand hours of rcutorture would have been
necessary to have a reasonable chance of making this happen before this
50x speedup.
This commit therefore eliminates this deadlock by setting
->trc_reader_nesting to a large negative number before checking the
.need_qs and zeroing (or decrementing with respect to its initial
value) ->trc_reader_nesting. For its part, the IPI handler's
trc_read_check_handler() function adds a check for negative values,
deferring evaluation of the task in this case. Taken together, these
changes avoid this deadlock scenario.
Fixes: 276c410448 ("rcu-tasks: Split ->trc_reader_need_end")
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: <bpf@vger.kernel.org>
Cc: <stable@vger.kernel.org> # 5.7.x
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The various RCU tasks flavors currently wait 100 milliseconds between each
grace period in order to prevent CPU-bound loops and to favor efficiency
over latency. However, RCU Tasks Trace needs to have a grace-period
latency of roughly 25 milliseconds, which is completely infeasible given
the 100-millisecond per-grace-period sleep. This commit therefore reduces
this sleep duration to 5 milliseconds (or one jiffy, whichever is longer)
in kernels built with CONFIG_TASKS_TRACE_RCU_READ_MB=y.
Link: https://lore.kernel.org/bpf/CAADnVQK_AiX+S_L_A4CQWT11XyveppBbQSQgH_qWGyzu_E8Yeg@mail.gmail.com/
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: <bpf@vger.kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Many workloads are quite sensitive to IPIs, and such workloads should
build kernels with CONFIG_TASKS_TRACE_RCU_READ_MB=y to prevent RCU
Tasks Trace from using them under normal conditions. However, other
workloads are quite happy to permit more IPIs if doing so makes BPF
program updates go faster. This commit therefore sets the default
value for the rcupdate.rcu_task_ipi_delay kernel parameter to zero for
kernels that have been built with CONFIG_TASKS_TRACE_RCU_READ_MB=n,
while retaining the old default of (HZ / 10) for kernels that have
indicated an aversion to IPIs via CONFIG_TASKS_TRACE_RCU_READ_MB=y.
Link: https://lore.kernel.org/bpf/CAADnVQK_AiX+S_L_A4CQWT11XyveppBbQSQgH_qWGyzu_E8Yeg@mail.gmail.com/
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: <bpf@vger.kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Commit 8344496e8b ("rcu-tasks: Conditionally compile
show_rcu_tasks_gp_kthreads()") introduced conditional
compilation of several functions, but forgot one occurrence of
show_rcu_tasks_classic_gp_kthread() that causes the compiler to warn of
an unused static function. This commit uses "static inline" to avoid
these complaints and possibly also to avoid emitting an actual definition
of this function.
Fixes: 8344496e8b ("rcu-tasks: Conditionally compile show_rcu_tasks_gp_kthreads()")
Cc: <stable@vger.kernel.org> # 5.8.x
Reported-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The RCU Tasks Trace grace periods are too slow, as in 40x slower than
those of RCU Tasks. This is due to my having assumed a one-second grace
period was OK, and thus not having optimized any further. This commit
provides the first step in this optimization process, namely by allowing
the task_list scan backoff interval to be specified on a per-flavor basis,
and then speeding up the scans for RCU Tasks Trace. However, kernels
built with CONFIG_TASKS_TRACE_RCU_READ_MB=y continue to use the old slower
backoff, consistent with that Kconfig option's goal of reducing IPIs.
Link: https://lore.kernel.org/bpf/CAADnVQK_AiX+S_L_A4CQWT11XyveppBbQSQgH_qWGyzu_E8Yeg@mail.gmail.com/
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: <bpf@vger.kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The n_heavy_reader_attempts, n_heavy_reader_updates, and
n_heavy_reader_ofl_updates variables are not used outside of their
translation unit, so this commit marks them static.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
To support MSI irq domains which do not fit at all into the regular MSI
irqdomain scheme, like the XEN MSI interrupt management for PV/HVM/DOM0,
it's necessary to allow to override the alloc/free implementation.
This is a preperatory step to switch X86 away from arch_*_msi_irqs() and
store the irq domain pointer right in struct device.
No functional change for existing MSI irq domain users.
Aside of the evil XEN wrapper this is also useful for special MSI domains
which need to do extra alloc/free work before/after calling the generic
core function. Work like allocating/freeing MSI descriptors, MSI storage
space etc.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200826112333.526797548@linutronix.de
PCI devices behind a VMD bus are not subject to interrupt remapping, but
the irq domain for VMD MSI cannot be distinguished from a regular PCI/MSI
irq domain.
Add a new domain bus token and allow it in the bus token check in
msi_check_reservation_mode() to keep the functionality the same once VMD
uses this token.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Jon Derrick <jonathan.derrick@intel.com>
Link: https://lore.kernel.org/r/20200826112332.954409970@linutronix.de
pci_msi_get_hwirq() and pci_msi_set_desc are not longer special. Enable the
generic MSI domain ops in the core and PCI MSI code unconditionally and get
rid of the x86 specific implementations in the X86 MSI code and in the
hyperv PCI driver.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200826112332.564274859@linutronix.de
The documentation of irq_chip_compose_msi_msg() claims that with
hierarchical irq domains the first chip in the hierarchy which has an
irq_compose_msi_msg() callback is chosen. But the code just keeps
iterating after it finds a chip with a compose callback.
The x86 HPET MSI implementation relies on that behaviour, but that does not
make it more correct.
The message should always be composed at the domain which manages the
underlying resource (e.g. APIC or remap table) because that domain knows
about the required layout of the message.
On X86 the following hierarchies exist:
1) vector -------- PCI/MSI
2) vector -- IR -- PCI/MSI
The vector domain has a different message format than the IR (remapping)
domain. So obviously the PCI/MSI domain can't compose the message without
having knowledge about the parent domain, which is exactly the opposite of
what hierarchical domains want to achieve.
X86 actually has two different PCI/MSI chips where #1 has a compose
callback and #2 does not. #2 delegates the composition to the remap domain
where it belongs, but #1 does it at the PCI/MSI level.
For the upcoming device MSI support it's necessary to change this and just
let the first domain which can compose the message take care of it. That
way the top level chip does not have to worry about it and the device MSI
code does not need special knowledge about topologies. It just sets the
compose callback to NULL and lets the hierarchy pick the first chip which
has one.
Due to that the attempt to move the compose callback from the direct
delivery PCI/MSI domain to the vector domain made the system fail to boot
with interrupt remapping enabled because in the remapping case
irq_chip_compose_msi_msg() keeps iterating and choses the compose callback
of the vector domain which obviously creates the wrong format for the remap
table.
Break out of the loop when the first irq chip with a compose callback is
found and fixup the HPET code temporarily. That workaround will be removed
once the direct delivery compose callback is moved to the place where it
belongs in the vector domain.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200826112331.047917603@linutronix.de
The __this_cpu*() accessors are (in general) IRQ-unsafe which, given
that percpu-rwsem is a blocking primitive, should be just fine.
However, file_end_write() is used from IRQ context and will cause
load-store issues on architectures where the per-cpu accessors are not
natively irq-safe.
Fix it by using the IRQ-safe this_cpu_*() for operations on
read_count. This will generate more expensive code on a number of
platforms, which might cause a performance regression for some of the
other percpu-rwsem users.
If any such is reported, we can consider alternative solutions.
Fixes: 70fe2f4815 ("aio: fix freeze protection of aio writes")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20200915140750.137881-1-houtao1@huawei.com
__raise_softirq_irqoff() must be called with interrupts disabled to protect
the per CPU softirq pending state update against an interrupt and soft
interrupt handling on return from interrupt.
Add a lockdep assertion to validate the calling convention.
[ tglx: Massaged changelog ]
Signed-off-by: Jiafei Pan <Jiafei.Pan@nxp.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200814045522.45719-1-Jiafei.Pan@nxp.com
Alexei Starovoitov says:
====================
pull-request: bpf 2020-09-15
The following pull-request contains BPF updates for your *net* tree.
We've added 12 non-merge commits during the last 19 day(s) which contain
a total of 10 files changed, 47 insertions(+), 38 deletions(-).
The main changes are:
1) docs/bpf fixes, from Andrii.
2) ld_abs fix, from Daniel.
3) socket casting helpers fix, from Martin.
4) hash iterator fixes, from Yonghong.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This syscall binds a map to a program. Returns success if the map is
already bound to the program.
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Link: https://lore.kernel.org/bpf/20200915234543.3220146-3-sdf@google.com
To support modifying the used_maps array, we use a mutex to protect
the use of the counter and the array. The mutex is initialized right
after the prog aux is allocated, and destroyed right before prog
aux is freed. This way we guarantee it's initialized for both cBPF
and eBPF.
Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Link: https://lore.kernel.org/bpf/20200915234543.3220146-2-sdf@google.com
Use the record extending feature of the ringbuffer to implement
continuous messages. This preserves the existing continuous message
behavior.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914123354.832-7-john.ogness@linutronix.de
Add support for extending the newest data block. For this, introduce
a new finalization state (desc_finalized) denoting a committed
descriptor that cannot be extended.
Until a record is finalized, a writer can reopen that record to
append new data. Reopening a record means transitioning from the
desc_committed state back to the desc_reserved state.
A writer can explicitly finalize a record if there is no intention
of extending it. Also, records are automatically finalized when a
new record is reserved. This relieves writers of needing to
explicitly finalize while also making such records available to
readers sooner. (Readers can only traverse finalized records.)
Four new memory barrier pairs are introduced. Two of them are
insignificant additions (data_realloc:A/desc_read:D and
data_realloc:A/data_push_tail:B) because they are alternate path
memory barriers that exactly match the purpose, pairing, and
context of the two existing memory barrier pairs they provide an
alternate path for. The other two new memory barrier pairs are
significant additions:
desc_reopen_last:A / _prb_commit:B - When reopening a descriptor,
ensure the state transitions back to desc_reserved before
fully trusting the descriptor data.
_prb_commit:B / desc_reserve:D - When committing a descriptor,
ensure the state transitions to desc_committed before checking
the head ID to see if the descriptor needs to be finalized.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914123354.832-6-john.ogness@linutronix.de
Rather than deriving the state by evaluating bits within the flags
area of the state variable, assign the states explicit values and
set those values in the flags area. Introduce macros to make it
simple to read and write state values for the state variable.
Although the functionality is preserved, the binary representation
for the states is changed.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914123354.832-5-john.ogness@linutronix.de
prb_reserve() will set some meta data values and leave others
uninitialized (or rather, containing the values of the previous
wrap). Simplify the API by always clearing out all the fields.
Only the sequence number is filled in. The caller is now
responsible for filling in the rest of the meta data fields.
In particular, for correctly filling in text and dict lengths.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914123354.832-4-john.ogness@linutronix.de
Rather than continually needing to explicitly check @begin and @next
to identify a dataless block, introduce and use a BLK_DATALESS()
macro.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914123354.832-3-john.ogness@linutronix.de
Move the internal get_data() function as-is above prb_reserve() so
that a later change can make use of the static function.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914123354.832-2-john.ogness@linutronix.de
@state_var is copied as part of the descriptor copying via
memcpy(). This is not allowed because @state_var is an atomic type,
which in some implementations may contain a spinlock.
Avoid using memcpy() with @state_var by explicitly copying the other
fields of the descriptor. @state_var is set using atomic set
operator before returning.
Fixes: b6cf8b3f33 ("printk: add lockless ringbuffer")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914094803.27365-2-john.ogness@linutronix.de
It is expected that desc_read() will always set at least the
@state_var field. However, if the descriptor is in an inconsistent
state, no fields are set.
Also, the second load of @state_var is not stored in @desc_out and
so might not match the state value that is returned.
Always set the last loaded @state_var into @desc_out, regardless of
the descriptor consistency.
Fixes: b6cf8b3f33 ("printk: add lockless ringbuffer")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200914094803.27365-1-john.ogness@linutronix.de
On v5.8 when doing seccomp syscall rewrites (e.g. getpid into getppid
as seen in the seccomp selftests), trace (and audit) correctly see the
rewritten syscall on entry and exit:
seccomp_bpf-1307 [000] .... 22974.874393: sys_enter: NR 110 (...
seccomp_bpf-1307 [000] .N.. 22974.874401: sys_exit: NR 110 = 1304
With mainline we see a mismatched enter and exit (the original syscall
is incorrectly visible on entry):
seccomp_bpf-1030 [000] .... 21.806766: sys_enter: NR 39 (...
seccomp_bpf-1030 [000] .... 21.806767: sys_exit: NR 110 = 1027
When ptrace or seccomp change the syscall, this needs to be visible to
trace and audit at that time as well. Update the syscall earlier so they
see the correct value.
Fixes: d88d59b64c ("core/entry: Respect syscall number rewrites")
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200912005826.586171-1-keescook@chromium.org
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Merge v5.9-rc5 into drm-next
Paul needs 1a21e5b930 ("drm/ingenic: Fix leak of device_node
pointer") and 3b5b005ef7 ("drm/ingenic: Fix driver not probing when
IPU port is missing") from -fixes to be able to merge further ingenic
patches into -next.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Commit:
0cb2f1372b ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler")
fixed one bug but the underlying bugs are not completely fixed yet.
If we run a kprobe_module.tc of ftracetest, a warning triggers:
# ./ftracetest test.d/kprobe/kprobe_module.tc
=== Ftrace unit tests ===
[1] Kprobe dynamic event - probing module
...
------------[ cut here ]------------
Failed to disarm kprobe-ftrace at trace_printk_irq_work+0x0/0x7e [trace_printk] (-2)
WARNING: CPU: 7 PID: 200 at kernel/kprobes.c:1091 __disarm_kprobe_ftrace.isra.0+0x7e/0xa0
This is because the kill_kprobe() calls disarm_kprobe_ftrace() even
if the given probe is not enabled. In that case, ftrace_set_filter_ip()
fails because the given probe point is not registered to ftrace.
Fix to check the given (going) probe is enabled before invoking
disarm_kprobe_ftrace().
Fixes: 0cb2f1372b ("kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/159888672694.1411785.5987998076694782591.stgit@devnote2
Switch order so that locking state is consistent even
if the IRQ tracer calls into lockdep again.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
A number of architectures implement IPI statistics directly,
duplicating the core kstat_irqs accounting. As we move IPIs to
being actual IRQs, we would end-up with a confusing display
in /proc/interrupts (where the IPIs would appear twice).
In order to solve this, allow interrupts to be flagged as
"hidden", which excludes them from /proc/interrupts.
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
For irqchips using the fasteoi flow, IPIs are a bit special.
They need to be EOI'd early (before calling the handler), as
funny things may happen in the handler (they do not necessarily
behave like a normal interrupt).
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
- Fix memory resource leak of user_notif under TSYNC race (Tycho Andersen)
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Merge tag 'seccomp-v5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull seccomp fixes from Kees Cook:
"This fixes a rare race condition in seccomp when using TSYNC and
USER_NOTIF together where a memory allocation would not get freed
(found by syzkaller, fixed by Tycho).
Additionally updates Tycho's MAINTAINERS and .mailmap entries for his
new address"
* tag 'seccomp-v5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
seccomp: don't leave dangling ->notif if file allocation fails
mailmap, MAINTAINERS: move to tycho.pizza
seccomp: don't leak memory when filter install races
Using gcov to collect coverage data for kernels compiled with GCC 10.1
causes random malfunctions and kernel crashes. This is the result of a
changed GCOV_COUNTERS value in GCC 10.1 that causes a mismatch between
the layout of the gcov_info structure created by GCC profiling code and
the related structure used by the kernel.
Fix this by updating the in-kernel GCOV_COUNTERS value. Also re-enable
config GCOV_KERNEL for use with GCC 10.
Reported-by: Colin Ian King <colin.king@canonical.com>
Reported-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Tested-by: Leon Romanovsky <leonro@nvidia.com>
Tested-and-Acked-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dma_declare_coherent_memory should not be in a DMA API guide aimed
at driver writers (that is consumers of the API). Move it to a comment
near the function instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Add a new file that contains helpers for misc DMA ops, which is only
built when CONFIG_DMA_OPS is set.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
The __phys_to_dma vs phys_to_dma distinction isn't exactly obvious. Try
to improve the situation by renaming __phys_to_dma to
phys_to_dma_unencryped, and not forcing architectures that want to
override phys_to_dma to actually provide __phys_to_dma.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
There is no harm in just always clearing the SME encryption bit, while
significantly simplifying the interface.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Move the detailed gfp_t setup from __dma_direct_alloc_pages into the
caller to clean things up a little.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Just merge these helpers into the main dma_direct_{alloc,free} routines,
as the additional checks are always false for the two callers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Add back a hook to optimize dcache flushing after reading executable
code using DMA. This gets ia64 out of the business of pretending to
be dma incoherent just for this optimization.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Driver that select DMA_OPS need to depend on HAS_DMA support to
work. The vop driver was missing that dependency, so add it, and also
add a another depends in DMA_OPS itself. That won't fix the issue due
to how the Kconfig dependencies work, but at least produce a warning
about unmet dependencies.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Now that the main dma mapping entry points are out of line most of the
symbols in dma-debug.c can only be called from built-in code. Remove
the unused exports.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
dma_dummy_ops is only used by the ACPI code, which can't be modular.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Header frame.h is getting more code annotations to help objtool analyze
object files.
Rename the file to objtool.h.
[ jpoimboe: add objtool.h to MAINTAINERS ]
Signed-off-by: Julien Thierry <jthierry@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Sparse is not happy about max_segment declaration:
CHECK kernel/dma/swiotlb.c
kernel/dma/swiotlb.c:96:14: warning: symbol 'max_segment' was not declared. Should it be static?
Mark it static as suggested.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
There is an extension to a %p to print phys_addr_t type of variables.
Use it here.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
The pmu::sched_task() is a context switch callback. It passes the
cpuctx->task_ctx as a parameter to the lower code. To find the
cpuctx->task_ctx, the current code iterates a cpuctx list.
The same context will iterated in perf_event_context_sched_out() soon.
Share the cpuctx->task_ctx can avoid the unnecessary iteration of the
cpuctx list.
The pmu::sched_task() is also required for the optimization case for
equivalent contexts.
The task_ctx_sched_out() will eventually disable and reenable the PMU
when schedule out events. Add perf_pmu_disable() and perf_pmu_enable()
around task_ctx_sched_out() don't break anything.
Drop the cpuctx->ctx.lock for the pmu::sched_task(). The lock is for
per-CPU context, which is not necessary for the per-task context
schedule.
No one uses sched_cb_entry, perf_sched_cb_usages, sched_cb_list, and
perf_pmu_sched_task() any more.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200821195754.20159-2-kan.liang@linux.intel.com
The pmu::sched_task() is a context switch callback. It passes the
cpuctx->task_ctx as a parameter to the lower code. To find the
cpuctx->task_ctx, the current code iterates a cpuctx list.
The same context was just iterated in perf_event_context_sched_in(),
which is invoked right before the pmu::sched_task().
Reuse the cpuctx->task_ctx from perf_event_context_sched_in() can avoid
the unnecessary iteration of the cpuctx list.
Both pmu::sched_task and perf_event_context_sched_in() have to disable
PMU. Pull the pmu::sched_task into perf_event_context_sched_in() can
also save the overhead from the PMU disable and reenable.
The new and old tasks may have equivalent contexts. The current code
optimize this case by swapping the context, which avoids the scheduling.
For this case, pmu::sched_task() is still required, e.g., restore the
LBR content.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200821195754.20159-1-kan.liang@linux.intel.com
Latch sequence counters are a multiversion concurrency control mechanism
where the seqcount_t counter even/odd value is used to switch between
two data storage copies. This allows the seqcount_t read path to safely
interrupt its write side critical section (e.g. from NMIs).
Initially, latch sequence counters were implemented as a single write
function, raw_write_seqcount_latch(), above plain seqcount_t. The read
path was expected to use plain seqcount_t raw_read_seqcount().
A specialized read function was later added, raw_read_seqcount_latch(),
and became the standardized way for latch read paths. Having unique read
and write APIs meant that latch sequence counters are basically a data
type of their own -- just inappropriately overloading plain seqcount_t.
The seqcount_latch_t data type was thus introduced at seqlock.h.
Use that new data type instead of seqcount_raw_spinlock_t. This ensures
that only latch-safe APIs are to be used with the sequence counter.
Note that the use of seqcount_raw_spinlock_t was not very useful in the
first place. Only the "raw_" subset of seqcount_t APIs were used at
timekeeping.c. This subset was created for contexts where lockdep cannot
be used. seqcount_LOCKTYPE_t's raison d'être -- verifying that the
seqcount_t writer serialization lock is held -- cannot thus be done.
References: 0c3351d451 ("seqlock: Use raw_ prefix instead of _no_lockdep")
References: 55f3560df9 ("seqlock: Extend seqcount API with associated locks")
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200827114044.11173-6-a.darwish@linutronix.de
Latch sequence counters have unique read and write APIs, and thus
seqcount_latch_t was recently introduced at seqlock.h.
Use that new data type instead of plain seqcount_t. This adds the
necessary type-safety and ensures only latching-safe seqcount APIs are
to be used.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200827114044.11173-5-a.darwish@linutronix.de
sched_clock uses seqcount_t latching to switch between two storage
places protected by the sequence counter. This allows it to have
interruptible, NMI-safe, seqcount_t write side critical sections.
Since 7fc26327b7 ("seqlock: Introduce raw_read_seqcount_latch()"),
raw_read_seqcount_latch() became the standardized way for seqcount_t
latch read paths. Due to the dependent load, it has one read memory
barrier less than the currently used raw_read_seqcount() API.
Use raw_read_seqcount_latch() for the suspend path.
Commit aadd6e5caa ("time/sched_clock: Use raw_read_seqcount_latch()")
missed changing that instance of raw_read_seqcount().
References: 1809bfa44e ("timers, sched/clock: Avoid deadlock during read from NMI")
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200715092345.GA231464@debian-buster-darwi.lab.linutronix.de
Pull crypto fix from Herbert Xu:
"This fixes a regression in padata"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
padata: fix possible padata_works_lock deadlock
The last sd_flag_debug shuffle inadvertently moved its definition within
an #ifdef CONFIG_SYSCTL region. While CONFIG_SYSCTL is indeed required to
produce the sched domain ctl interface (which uses sd_flag_debug to output
flag names), it isn't required to run any assertion on the sched_domain
hierarchy itself.
Move the definition of sd_flag_debug to a CONFIG_SCHED_DEBUG region of
topology.c.
Now at long last we have:
- sd_flag_debug declared in include/linux/sched/topology.h iff
CONFIG_SCHED_DEBUG=y
- sd_flag_debug defined in kernel/sched/topology.c, conditioned by:
- CONFIG_SCHED_DEBUG, with an explicit #ifdef block
- CONFIG_SMP, as a requirement to compile topology.c
With this change, all symbols pertaining to SD flag metadata (with the
exception of __SD_FLAG_CNT) are now defined exclusively within topology.c
Fixes: 8fca9494d4 ("sched/topology: Move sd_flag_debug out of linux/sched/topology.h")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200908184956.23369-1-valentin.schneider@arm.com
Using the read_iter/write_iter interfaces allows for in-kernel users
to set sysctls without using set_fs(). Also, the buffer is a string,
so give it the real type of 'char *', not void *.
[AV: Christoph's fixup folded in]
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit 41c48f3a98 ("bpf: Support access
to bpf map fields") added support to access map fields
with CORE support. For example,
struct bpf_map {
__u32 max_entries;
} __attribute__((preserve_access_index));
struct bpf_array {
struct bpf_map map;
__u32 elem_size;
} __attribute__((preserve_access_index));
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 4);
__type(key, __u32);
__type(value, __u32);
} m_array SEC(".maps");
SEC("cgroup_skb/egress")
int cg_skb(void *ctx)
{
struct bpf_array *array = (struct bpf_array *)&m_array;
/* .. array->map.max_entries .. */
}
In kernel, bpf_htab has similar structure,
struct bpf_htab {
struct bpf_map map;
...
}
In the above cg_skb(), to access array->map.max_entries, with CORE, the clang will
generate two builtin's.
base = &m_array;
/* access array.map */
map_addr = __builtin_preserve_struct_access_info(base, 0, 0);
/* access array.map.max_entries */
max_entries_addr = __builtin_preserve_struct_access_info(map_addr, 0, 0);
max_entries = *max_entries_addr;
In the current llvm, if two builtin's are in the same function or
in the same function after inlining, the compiler is smart enough to chain
them together and generates like below:
base = &m_array;
max_entries = *(base + reloc_offset); /* reloc_offset = 0 in this case */
and we are fine.
But if we force no inlining for one of functions in test_map_ptr() selftest, e.g.,
check_default(), the above two __builtin_preserve_* will be in two different
functions. In this case, we will have code like:
func check_hash():
reloc_offset_map = 0;
base = &m_array;
map_base = base + reloc_offset_map;
check_default(map_base, ...)
func check_default(map_base, ...):
max_entries = *(map_base + reloc_offset_max_entries);
In kernel, map_ptr (CONST_PTR_TO_MAP) does not allow any arithmetic.
The above "map_base = base + reloc_offset_map" will trigger a verifier failure.
; VERIFY(check_default(&hash->map, map));
0: (18) r7 = 0xffffb4fe8018a004
2: (b4) w1 = 110
3: (63) *(u32 *)(r7 +0) = r1
R1_w=invP110 R7_w=map_value(id=0,off=4,ks=4,vs=8,imm=0) R10=fp0
; VERIFY_TYPE(BPF_MAP_TYPE_HASH, check_hash);
4: (18) r1 = 0xffffb4fe8018a000
6: (b4) w2 = 1
7: (63) *(u32 *)(r1 +0) = r2
R1_w=map_value(id=0,off=0,ks=4,vs=8,imm=0) R2_w=invP1 R7_w=map_value(id=0,off=4,ks=4,vs=8,imm=0) R10=fp0
8: (b7) r2 = 0
9: (18) r8 = 0xffff90bcb500c000
11: (18) r1 = 0xffff90bcb500c000
13: (0f) r1 += r2
R1 pointer arithmetic on map_ptr prohibited
To fix the issue, let us permit map_ptr + 0 arithmetic which will
result in exactly the same map_ptr.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200908175702.2463625-1-yhs@fb.com
As described in commit a3460a5974 ("new helper: current_pt_regs()"):
- arch versions are "optimized versions".
- some architectures have task_pt_regs() working only for traced tasks
blocked on signal delivery. current_pt_regs() needs to work for *all*
processes.
In preparation for adding a coccinelle rule for using current_*(), instead
of raw accesses to current members, modify seccomp_do_user_notification(),
__seccomp_filter(), __secure_computing() to use current_pt_regs().
Signed-off-by: Denis Efremov <efremov@linux.com>
Link: https://lore.kernel.org/r/20200824125921.488311-1-efremov@linux.com
[kees: Reworded commit log, add comment to populate_seccomp_data()]
Signed-off-by: Kees Cook <keescook@chromium.org>
Asynchronous termination of a thread outside of the userspace thread
library's knowledge is an unsafe operation that leaves the process in
an inconsistent, corrupt, and possibly unrecoverable state. In order
to make new actions that may be added in the future safe on kernels
not aware of them, change the default action from
SECCOMP_RET_KILL_THREAD to SECCOMP_RET_KILL_PROCESS.
Signed-off-by: Rich Felker <dalias@libc.org>
Link: https://lore.kernel.org/r/20200829015609.GA32566@brightrain.aerifal.cx
[kees: Fixed up coredump selection logic to match]
Signed-off-by: Kees Cook <keescook@chromium.org>
Christian and Kees both pointed out that this is a bit sloppy to open-code
both places, and Christian points out that we leave a dangling pointer to
->notif if file allocation fails. Since we check ->notif for null in order
to determine if it's ok to install a filter, this means people won't be
able to install a filter if the file allocation fails for some reason, even
if they subsequently should be able to.
To fix this, let's hoist this free+null into its own little helper and use
it.
Reported-by: Kees Cook <keescook@chromium.org>
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Tycho Andersen <tycho@tycho.pizza>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20200902140953.1201956-1-tycho@tycho.pizza
Signed-off-by: Kees Cook <keescook@chromium.org>
In seccomp_set_mode_filter() with TSYNC | NEW_LISTENER, we first initialize
the listener fd, then check to see if we can actually use it later in
seccomp_may_assign_mode(), which can fail if anyone else in our thread
group has installed a filter and caused some divergence. If we can't, we
partially clean up the newly allocated file: we put the fd, put the file,
but don't actually clean up the *memory* that was allocated at
filter->notif. Let's clean that up too.
To accomplish this, let's hoist the actual "detach a notifier from a
filter" code to its own helper out of seccomp_notify_release(), so that in
case anyone adds stuff to init_listener(), they only have to add the
cleanup code in one spot. This does a bit of extra locking and such on the
failure path when the filter is not attached, but it's a slow failure path
anyway.
Fixes: 51891498f2 ("seccomp: allow TSYNC and USER_NOTIF together")
Reported-by: syzbot+3ad9614a12f80994c32e@syzkaller.appspotmail.com
Signed-off-by: Tycho Andersen <tycho@tycho.pizza>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20200902014017.934315-1-tycho@tycho.pizza
Signed-off-by: Kees Cook <keescook@chromium.org>
This kills using the do_each_thread/while_each_thread combo to
iterate all threads and uses for_each_process_thread() instead,
maintaining semantics. while_each_thread() is ultimately racy
and deprecated; although in this particular case there is no
concurrency so it doesn't matter. Still lets trivially get rid
of two more users.
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20200907203206.21293-1-dave@stgolabs.net
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
On my system the kernel processes the "kgdb_earlycon" parameter before
the "kgdbcon" parameter. When we setup "kgdb_earlycon" we'll end up
in kgdb_register_callbacks() and "kgdb_use_con" won't have been set
yet so we'll never get around to starting "kgdbcon". Let's remedy
this by detecting that the IO module was already registered when
setting "kgdb_use_con" and registering the console then.
As part of this, to avoid pre-declaring things, move the handling of
the "kgdbcon" further down in the file.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200630151422.1.I4aa062751ff5e281f5116655c976dff545c09a46@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
`kdb_msg_write` operates on a global `struct kgdb_io *` called
`dbg_io_ops`.
It's initialized in `debug_core.c` and checked throughout the debug
flow.
There's a null check in `kdb_msg_write` which triggers static analyzers
and gives the (almost entirely wrong) impression that it can be null.
Coverity scanner caught this as CID 1465042.
I have removed the unnecessary null check and eliminated false-positive
forward null dereference warning.
Signed-off-by: Cengiz Can <cengiz@kernel.wtf>
Link: https://lore.kernel.org/r/20200630082922.28672-1-cengiz@kernel.wtf
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Free kretprobe_instance with RCU callback instead of directly
freeing the object in the kretprobe handler context.
This will make kretprobe run safer in NMI context.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/159870616685.1229682.11978742048709542226.stgit@devnote2
The in_nmi() check in pre_handler_kretprobe() is meant to avoid
recursion, and blindly assumes that anything NMI is recursive.
However, since commit:
9b38cc704e ("kretprobe: Prevent triggering kretprobe from within kprobe_flush_task")
there is a better way to detect and avoid actual recursion.
By setting a dummy kprobe, any actual exceptions will terminate early
(by trying to handle the dummy kprobe), and recursion will not happen.
Employ this to avoid the kretprobe_table_lock() recursion, replacing
the over-eager in_nmi() check.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/159870615628.1229682.6087311596892125907.stgit@devnote2
Add a generic kretprobe trampoline handler for unifying
the all cloned /arch/* kretprobe trampoline handlers.
The generic kretprobe trampoline handler is based on the
x86 implementation, because it is the latest implementation.
It has frame pointer checking, kprobe_busy_begin/end and
return address fixup for user handlers.
[ mingo: Minor edits. ]
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/159870600138.1229682.3424065380448088833.stgit@devnote2
With commit 896fbe20b4 ("printk: use the lockless ringbuffer"),
printk() started silently dropping messages without text because such
records are not supported by the new printk ringbuffer.
Add support for such records.
Currently dataless records are denoted by INVALID_LPOS in order
to recognize failed prb_reserve() calls. Change the ringbuffer
to instead use two different identifiers (FAILED_LPOS and
NO_LPOS) to distinguish between failed prb_reserve() records and
successful dataless records, respectively.
Fixes: 896fbe20b4 ("printk: use the lockless ringbuffer")
Fixes: https://lkml.kernel.org/r/20200718121053.GA691245@elver.google.com
Reported-by: Marco Elver <elver@google.com>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200721132528.9661-1-john.ogness@linutronix.de
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Merge tag 'v5.9-rc4' into drm-next
Backmerge 5.9-rc4 as there is a nasty qxl conflict
that needs to be resolved.
Signed-off-by: Dave Airlie <airlied@redhat.com>
The sparse tool complains as follows:
kernel/trace/blktrace.c:796:5: warning:
symbol 'blk_trace_bio_get_cgid' was not declared. Should it be static?
This function is not used outside of blktrace.c, so this commit
marks it static.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
On resending an interrupt, we only check the outermost irqchip for
a irq_retrigger callback. However, this callback could be implemented
at an inner level. Use irq_chip_retrigger_hierarchy() in this case.
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Merge misc fixes from Andrew Morton:
"19 patches.
Subsystems affected by this patch series: MAINTAINERS, ipc, fork,
checkpatch, lib, and mm (memcg, slub, pagemap, madvise, migration,
hugetlb)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
include/linux/log2.h: add missing () around n in roundup_pow_of_two()
mm/khugepaged.c: fix khugepaged's request size in collapse_file
mm/hugetlb: fix a race between hugetlb sysctl handlers
mm/hugetlb: try preferred node first when alloc gigantic page from cma
mm/migrate: preserve soft dirty in remove_migration_pte()
mm/migrate: remove unnecessary is_zone_device_page() check
mm/rmap: fixup copying of soft dirty and uffd ptes
mm/migrate: fixup setting UFFD_WP flag
mm: madvise: fix vma user-after-free
checkpatch: fix the usage of capture group ( ... )
fork: adjust sysctl_max_threads definition to match prototype
ipc: adjust proc_ipc_sem_dointvec definition to match prototype
mm: track page table modifications in __apply_to_page_range()
MAINTAINERS: IA64: mark Status as Odd Fixes only
MAINTAINERS: add LLVM maintainers
MAINTAINERS: update Cavium/Marvell entries
mm: slub: fix conversion of freelist_corrupted()
mm: memcg: fix memcg reclaim soft lockup
memcg: fix use-after-free in uncharge_batch
Commit 32927393dc ("sysctl: pass kernel pointers to ->proc_handler")
changed ctl_table.proc_handler to take a kernel pointer. Adjust the
definition of sysctl_max_threads to match its prototype in
linux/sysctl.h which fixes the following sparse error/warning:
kernel/fork.c:3050:47: warning: incorrect type in argument 3 (different address spaces)
kernel/fork.c:3050:47: expected void *
kernel/fork.c:3050:47: got void [noderef] __user *buffer
kernel/fork.c:3036:5: error: symbol 'sysctl_max_threads' redeclared with different type (incompatible argument 3 (different address spaces)):
kernel/fork.c:3036:5: int extern [addressable] [signed] [toplevel] sysctl_max_threads( ... )
kernel/fork.c: note: in included file (through include/linux/key.h, include/linux/cred.h, include/linux/sched/signal.h, include/linux/sched/cputime.h):
include/linux/sysctl.h:242:5: note: previously declared as:
include/linux/sysctl.h:242:5: int extern [addressable] [signed] [toplevel] sysctl_max_threads( ... )
Fixes: 32927393dc ("sysctl: pass kernel pointers to ->proc_handler")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lkml.kernel.org/r/20200825093647.24263-1-tklauser@distanz.ch
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We got slightly different patches removing a double word
in a comment in net/ipv4/raw.c - picked the version from net.
Simple conflict in drivers/net/ethernet/ibm/ibmvnic.c. Use cached
values instead of VNIC login response buffer (following what
commit 507ebe6444 ("ibmvnic: Fix use-after-free of VNIC login
response buffer") did).
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The sparse tool complains as follows:
kernel/smp.c:107:10: warning:
symbol 'csd_bug_count' was not declared. Should it be static?
Because variable is not used outside of smp.c, this commit marks it
static.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
This commit causes csd_lock_wait() to emit diagnostics when a CPU
fails to respond quickly enough to one of the smp_call_function()
family of function calls. These diagnostics are enabled by a new
CSD_LOCK_WAIT_DEBUG Kconfig option that depends on DEBUG_KERNEL.
This commit was inspired by an earlier patch by Josef Bacik.
[ paulmck: Fix for syzbot+0f719294463916a3fc0e@syzkaller.appspotmail.com ]
[ paulmck: Fix KASAN use-after-free issue reported by Qian Cai. ]
[ paulmck: Fix botched nr_cpu_ids comparison per Dan Carpenter. ]
[ paulmck: Apply Peter Zijlstra feedback. ]
Link: https://lore.kernel.org/lkml/00000000000042f21905a991ecea@google.com
Link: https://lore.kernel.org/lkml/0000000000002ef21705a9933cf3@google.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds a destination CPU to __call_single_data, and is inspired
by an earlier commit by Peter Zijlstra. This version adds #ifdef to
permit use by 32-bit systems and supplying the destination CPU for all
smp_call_function*() requests, not just smp_call_function_single().
If need be, 32-bit systems could be accommodated by shrinking the flags
field to 16 bits (the atomic_t variant is currently unused) and by
providing only eight bits for CPU on such systems.
It is not clear that the addition of the fields to __call_single_node
are really needed.
[ paulmck: Apply Boqun Feng feedback on 32-bit builds. ]
Link: https://lore.kernel.org/lkml/20200615164048.GC2531@hirez.programming.kicks-ass.net/
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Andy reported that the syscall treacing for 32bit fast syscall fails:
# ./tools/testing/selftests/x86/ptrace_syscall_32
...
[RUN] SYSEMU
[FAIL] Initial args are wrong (nr=224, args=10 11 12 13 14 4289172732)
...
[RUN] SYSCALL
[FAIL] Initial args are wrong (nr=29, args=0 0 0 0 0 4289172732)
The eason is that the conversion to generic entry code moved the retrieval
of the sixth argument (EBP) after the point where the syscall entry work
runs, i.e. ptrace, seccomp, audit...
Unbreak it by providing a split up version of syscall_enter_from_user_mode().
- syscall_enter_from_user_mode_prepare() establishes state and enables
interrupts
- syscall_enter_from_user_mode_work() runs the entry work
Replace the call to syscall_enter_from_user_mode() in the 32bit fast
syscall C-entry with the split functions and stick the EBP retrieval
between them.
Fixes: 27d6b4d14f ("x86/entry: Use generic syscall entry function")
Reported-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/87k0xdjbtt.fsf@nanos.tec.linutronix.de
Introduce PIDFD_NONBLOCK to support non-blocking pidfd file descriptors.
Ever since the introduction of pidfds and more advanced async io various
programming languages such as Rust have grown support for async event
libraries. These libraries are created to help build epoll-based event loops
around file descriptors. A common pattern is to automatically make all file
descriptors they manage to O_NONBLOCK.
For such libraries the EAGAIN error code is treated specially. When a function
is called that returns EAGAIN the function isn't called again until the event
loop indicates the the file descriptor is ready. Supporting EAGAIN when
waiting on pidfds makes such libraries just work with little effort. In the
following patch we will extend waitid() internally to support non-blocking
pidfds.
This introduces a new flag PIDFD_NONBLOCK that is equivalent to O_NONBLOCK.
This follows the same patterns we have for other (anon inode) file descriptors
such as EFD_NONBLOCK, IN_NONBLOCK, SFD_NONBLOCK, TFD_NONBLOCK and the same for
close-on-exec flags.
Suggested-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/lkml/20200811181236.GA18763@localhost/
Link: https://github.com/joshtriplett/async-pidfd
Link: https://lore.kernel.org/r/20200902102130.147672-2-christian.brauner@ubuntu.com
Passing a non-blocking pidfd to waitid() currently has no effect, i.e. is not
supported. There are users which would like to use waitid() on pidfds that are
O_NONBLOCK and mix it with pidfds that are blocking and both pass them to
waitid().
The expected behavior is to have waitid() return -EAGAIN for non-blocking
pidfds and to block for blocking pidfds without needing to perform any
additional checks for flags set on the pidfd before passing it to waitid().
Non-blocking pidfds will return EAGAIN from waitid() when no child process is
ready yet. Returning -EAGAIN for non-blocking pidfds makes it easier for event
loops that handle EAGAIN specially.
It also makes the API more consistent and uniform. In essence, waitid() is
treated like a read on a non-blocking pidfd or a recvmsg() on a non-blocking
socket.
With the addition of support for non-blocking pidfds we support the same
functionality that sockets do. For sockets() recvmsg() supports MSG_DONTWAIT
for pidfds waitid() supports WNOHANG. Both flags are per-call options. In
contrast non-blocking pidfds and non-blocking sockets are a setting on an open
file description affecting all threads in the calling process as well as other
processes that hold file descriptors referring to the same open file
description. Both behaviors, per call and per open file description, have
genuine use-cases.
The implementation should be straightforward:
- If a non-blocking pidfd is passed and WNOHANG is not raised we simply raise
the WNOHANG flag internally. When do_wait() returns indicating that there are
eligible child processes but none have exited yet we set EAGAIN. If no child
process exists we continue returning ECHILD.
- If a non-blocking pidfd is passed and WNOHANG is raised waitid() will
continue returning 0, i.e. it will not set EAGAIN. This ensure backwards
compatibility with applications passing WNOHANG explicitly with pidfds.
A concrete use-case that was brought on-list was Josh's async pidfd library.
Ever since the introduction of pidfds and more advanced async io various
programming languages such as Rust have grown support for async event
libraries. These libraries are created to help build epoll-based event loops
around file descriptors. A common pattern is to automatically make all file
descriptors they manage to O_NONBLOCK.
For such libraries the EAGAIN error code is treated specially. When a function
is called that returns EAGAIN the function isn't called again until the event
loop indicates the the file descriptor is ready. Supporting EAGAIN when
waiting on pidfds makes such libraries just work with little effort.
Suggested-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Jann Horn <jannh@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Link: https://lore.kernel.org/lkml/20200811181236.GA18763@localhost/
Link: https://github.com/joshtriplett/async-pidfd
Link: https://lore.kernel.org/r/20200902102130.147672-3-christian.brauner@ubuntu.com
syzbot reports,
WARNING: inconsistent lock state
5.9.0-rc2-syzkaller #0 Not tainted
--------------------------------
inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
syz-executor.0/26715 takes:
(padata_works_lock){+.?.}-{2:2}, at: padata_do_parallel kernel/padata.c:220
{IN-SOFTIRQ-W} state was registered at:
spin_lock include/linux/spinlock.h:354 [inline]
padata_do_parallel kernel/padata.c:220
...
__do_softirq kernel/softirq.c:298
...
sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1091
asm_sysvec_apic_timer_interrupt arch/x86/include/asm/idtentry.h:581
Possible unsafe locking scenario:
CPU0
----
lock(padata_works_lock);
<Interrupt>
lock(padata_works_lock);
padata_do_parallel() takes padata_works_lock with softirqs enabled, so a
deadlock is possible if, on the same CPU, the lock is acquired in
process context and then softirq handling done in an interrupt leads to
the same path.
Fix by leaving softirqs disabled while do_parallel holds
padata_works_lock.
Reported-by: syzbot+f4b9f49e38e25eb4ef52@syzkaller.appspotmail.com
Fixes: 4611ce2246 ("padata: allocate work structures for parallel jobs from a pool")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull networking fixes from David Miller:
1) Use netif_rx_ni() when necessary in batman-adv stack, from Jussi
Kivilinna.
2) Fix loss of RTT samples in rxrpc, from David Howells.
3) Memory leak in hns_nic_dev_probe(), from Dignhao Liu.
4) ravb module cannot be unloaded, fix from Yuusuke Ashizuka.
5) We disable BH for too lokng in sctp_get_port_local(), add a
cond_resched() here as well, from Xin Long.
6) Fix memory leak in st95hf_in_send_cmd, from Dinghao Liu.
7) Out of bound access in bpf_raw_tp_link_fill_link_info(), from
Yonghong Song.
8) Missing of_node_put() in mt7530 DSA driver, from Sumera
Priyadarsini.
9) Fix crash in bnxt_fw_reset_task(), from Michael Chan.
10) Fix geneve tunnel checksumming bug in hns3, from Yi Li.
11) Memory leak in rxkad_verify_response, from Dinghao Liu.
12) In tipc, don't use smp_processor_id() in preemptible context. From
Tuong Lien.
13) Fix signedness issue in mlx4 memory allocation, from Shung-Hsi Yu.
14) Missing clk_disable_prepare() in gemini driver, from Dan Carpenter.
15) Fix ABI mismatch between driver and firmware in nfp, from Louis
Peens.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (110 commits)
net/smc: fix sock refcounting in case of termination
net/smc: reset sndbuf_desc if freed
net/smc: set rx_off for SMCR explicitly
net/smc: fix toleration of fake add_link messages
tg3: Fix soft lockup when tg3_reset_task() fails.
doc: net: dsa: Fix typo in config code sample
net: dp83867: Fix WoL SecureOn password
nfp: flower: fix ABI mismatch between driver and firmware
tipc: fix shutdown() of connectionless socket
ipv6: Fix sysctl max for fib_multipath_hash_policy
drivers/net/wan/hdlc: Change the default of hard_header_len to 0
net: gemini: Fix another missing clk_disable_unprepare() in probe
net: bcmgenet: fix mask check in bcmgenet_validate_flow()
amd-xgbe: Add support for new port mode
net: usb: dm9601: Add USB ID of Keenetic Plus DSL
vhost: fix typo in error message
net: ethernet: mlx4: Fix memory allocation in mlx4_buddy_init()
pktgen: fix error message with wrong function name
net: ethernet: ti: am65-cpsw: fix rmii 100Mbit link mode
cxgb4: fix thermal zone device registration
...
Currently, for hashmap, the bpf iterator will grab a bucket lock, a
spinlock, before traversing the elements in the bucket. This can ensure
all bpf visted elements are valid. But this mechanism may cause
deadlock if update/deletion happens to the same bucket of the
visited map in the program. For example, if we added bpf_map_update_elem()
call to the same visited element in selftests bpf_iter_bpf_hash_map.c,
we will have the following deadlock:
============================================
WARNING: possible recursive locking detected
5.9.0-rc1+ #841 Not tainted
--------------------------------------------
test_progs/1750 is trying to acquire lock:
ffff9a5bb73c5e70 (&htab->buckets[i].raw_lock){....}-{2:2}, at: htab_map_update_elem+0x1cf/0x410
but task is already holding lock:
ffff9a5bb73c5e20 (&htab->buckets[i].raw_lock){....}-{2:2}, at: bpf_hash_map_seq_find_next+0x94/0x120
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&htab->buckets[i].raw_lock);
lock(&htab->buckets[i].raw_lock);
*** DEADLOCK ***
...
Call Trace:
dump_stack+0x78/0xa0
__lock_acquire.cold.74+0x209/0x2e3
lock_acquire+0xba/0x380
? htab_map_update_elem+0x1cf/0x410
? __lock_acquire+0x639/0x20c0
_raw_spin_lock_irqsave+0x3b/0x80
? htab_map_update_elem+0x1cf/0x410
htab_map_update_elem+0x1cf/0x410
? lock_acquire+0xba/0x380
bpf_prog_ad6dab10433b135d_dump_bpf_hash_map+0x88/0xa9c
? find_held_lock+0x34/0xa0
bpf_iter_run_prog+0x81/0x16e
__bpf_hash_map_seq_show+0x145/0x180
bpf_seq_read+0xff/0x3d0
vfs_read+0xad/0x1c0
ksys_read+0x5f/0xe0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
...
The bucket_lock first grabbed in seq_ops->next() called by bpf_seq_read(),
and then grabbed again in htab_map_update_elem() in the bpf program, causing
deadlocks.
Actually, we do not need bucket_lock here, we can just use rcu_read_lock()
similar to netlink iterator where the rcu_read_{lock,unlock} likes below:
seq_ops->start():
rcu_read_lock();
seq_ops->next():
rcu_read_unlock();
/* next element */
rcu_read_lock();
seq_ops->stop();
rcu_read_unlock();
Compared to old bucket_lock mechanism, if concurrent updata/delete happens,
we may visit stale elements, miss some elements, or repeat some elements.
I think this is a reasonable compromise. For users wanting to avoid
stale, missing/repeated accesses, bpf_map batch access syscall interface
can be used.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200902235340.2001375-1-yhs@fb.com
CPUs can go offline shortly after kfree_call_rcu() has been invoked,
which can leave memory stranded until those CPUs come back online.
This commit therefore drains the kcrp of each CPU, not just the
ones that happen to be online.
Acked-by: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Zqiang <qiang.zhang@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The rcu_segcblist_accelerate() function returns true iff it is necessary
to request another grace period. A tracing session showed that this
function unnecessarily requests grace periods.
For example, consider the following sequence of events:
1. Callbacks are queued only on the NEXT segment of CPU A's callback list.
2. CPU A runs RCU_SOFTIRQ, accelerating these callbacks from NEXT to WAIT.
3. Thus rcu_segcblist_accelerate() returns true, requesting grace period N.
4. RCU's grace-period kthread wakes up on CPU B and starts grace period N.
4. CPU A notices the new grace period and invokes RCU_SOFTIRQ.
5. CPU A's RCU_SOFTIRQ again invokes rcu_segcblist_accelerate(), but
there are no new callbacks. However, rcu_segcblist_accelerate()
nevertheless (uselessly) requests a new grace period N+1.
This extra grace period results in additional lock contention and also
additional wakeups, all for no good reason.
This commit therefore adds a check to rcu_segcblist_accelerate() that
prevents the return of true when there are no new callbacks.
This change reduces the number of grace periods (GPs) and wakeups in each
of eleven five-second rcutorture runs as follows:
+----+-------------------+-------------------+
| # | Number of GPs | Number of Wakeups |
+====+=========+=========+=========+=========+
| 1 | With | Without | With | Without |
+----+---------+---------+---------+---------+
| 2 | 75 | 89 | 113 | 119 |
+----+---------+---------+---------+---------+
| 3 | 62 | 91 | 105 | 123 |
+----+---------+---------+---------+---------+
| 4 | 60 | 79 | 98 | 110 |
+----+---------+---------+---------+---------+
| 5 | 63 | 79 | 99 | 112 |
+----+---------+---------+---------+---------+
| 6 | 57 | 89 | 96 | 123 |
+----+---------+---------+---------+---------+
| 7 | 64 | 85 | 97 | 118 |
+----+---------+---------+---------+---------+
| 8 | 58 | 83 | 98 | 113 |
+----+---------+---------+---------+---------+
| 9 | 57 | 77 | 89 | 104 |
+----+---------+---------+---------+---------+
| 10 | 66 | 82 | 98 | 119 |
+----+---------+---------+---------+---------+
| 11 | 52 | 82 | 83 | 117 |
+----+---------+---------+---------+---------+
The reduction in the number of wakeups ranges from 5% to 40%.
Cc: urezki@gmail.com
[ paulmck: Rework commit log and comment. ]
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
During the LPC RCU BoF Paul asked how come the "USED" <- "IN-NMI"
detector doesn't trip over rcu_read_lock()'s lockdep annotation.
Looking into this I found a very embarrasing typo in
verify_lock_unused():
- if (!(class->usage_mask & LOCK_USED))
+ if (!(class->usage_mask & LOCKF_USED))
fixing that will indeed cause rcu_read_lock() to insta-splat :/
The above typo means that instead of testing for: 0x100 (1 <<
LOCK_USED), we test for 8 (LOCK_USED), which corresponds to (1 <<
LOCK_ENABLED_HARDIRQ).
So instead of testing for _any_ used lock, it will only match any lock
used with interrupts enabled.
The rcu_read_lock() annotation uses .check=0, which means it will not
set any of the interrupt bits and will thus never match.
In order to properly fix the situation and allow rcu_read_lock() to
correctly work, split LOCK_USED into LOCK_USED and LOCK_USED_READ and by
having .read users set USED_READ and test USED, pure read-recursive
locks are permitted.
Fixes: f6f48e1804 ("lockdep: Teach lockdep about "USED" <- "IN-NMI" inversions")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20200902160323.GK1362448@hirez.programming.kicks-ass.net
Currently, task_file iterator iterates all files from all tasks.
This may potentially visit a lot of duplicated files if there are
many tasks sharing the same files, e.g., typical pthreads
where these pthreads and the main thread are sharing the same files.
This patch changed task_file iterator to skip a particular task
if that task shares the same files as its group_leader (the task
having the same tgid and also task->tgid == task->pid).
This will preserve the same result, visiting all files from all
tasks, and will reduce runtime cost significantl, e.g., if there are
a lot of pthreads and the process has a lot of open files.
Suggested-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/bpf/20200902023112.1672792-1-yhs@fb.com
When kernel module loading failed, user space only get one of the
following error messages:
- ENOEXEC
This is the most confusing one. From corrupted ELF header to bad
WRITE|EXEC flags check introduced by in module_enforce_rwx_sections()
all returns this error number.
- EPERM
This is for blacklisted modules. But mod doesn't do extra explain
on this error either.
- ENOMEM
The only error which needs no explain.
This means, if a user got "Exec format error" from modprobe, it provides
no meaningful way for the user to debug, and will take extra time
communicating to get extra info.
So this patch will add extra error messages for -ENOEXEC and -EPERM
errors, allowing user to do better debugging and reporting.
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Daniel Borkmann says:
====================
pull-request: bpf-next 2020-09-01
The following pull-request contains BPF updates for your *net-next* tree.
There are two small conflicts when pulling, resolve as follows:
1) Merge conflict in tools/lib/bpf/libbpf.c between 88a8212028 ("libbpf: Factor
out common ELF operations and improve logging") in bpf-next and 1e891e513e
("libbpf: Fix map index used in error message") in net-next. Resolve by taking
the hunk in bpf-next:
[...]
scn = elf_sec_by_idx(obj, obj->efile.btf_maps_shndx);
data = elf_sec_data(obj, scn);
if (!scn || !data) {
pr_warn("elf: failed to get %s map definitions for %s\n",
MAPS_ELF_SEC, obj->path);
return -EINVAL;
}
[...]
2) Merge conflict in drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c between
9647c57b11 ("xsk: i40e: ice: ixgbe: mlx5: Test for dma_need_sync earlier for
better performance") in bpf-next and e20f0dbf20 ("net/mlx5e: RX, Add a prefetch
command for small L1_CACHE_BYTES") in net-next. Resolve the two locations by retaining
net_prefetch() and taking xsk_buff_dma_sync_for_cpu() from bpf-next. Should look like:
[...]
xdp_set_data_meta_invalid(xdp);
xsk_buff_dma_sync_for_cpu(xdp, rq->xsk_pool);
net_prefetch(xdp->data);
[...]
We've added 133 non-merge commits during the last 14 day(s) which contain
a total of 246 files changed, 13832 insertions(+), 3105 deletions(-).
The main changes are:
1) Initial support for sleepable BPF programs along with bpf_copy_from_user() helper
for tracing to reliably access user memory, from Alexei Starovoitov.
2) Add BPF infra for writing and parsing TCP header options, from Martin KaFai Lau.
3) bpf_d_path() helper for returning full path for given 'struct path', from Jiri Olsa.
4) AF_XDP support for shared umems between devices and queues, from Magnus Karlsson.
5) Initial prep work for full BPF-to-BPF call support in libbpf, from Andrii Nakryiko.
6) Generalize bpf_sk_storage map & add local storage for inodes, from KP Singh.
7) Implement sockmap/hash updates from BPF context, from Lorenz Bauer.
8) BPF xor verification for scalar types & add BPF link iterator, from Yonghong Song.
9) Use target's prog type for BPF_PROG_TYPE_EXT prog verification, from Udip Pant.
10) Rework BPF tracing samples to use libbpf loader, from Daniel T. Lee.
11) Fix xdpsock sample to really cycle through all buffers, from Weqaar Janjua.
12) Improve type safety for tun/veth XDP frame handling, from Maciej Żenczykowski.
13) Various smaller cleanups and improvements all over the place.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
The functions bq_enqueue(), bq_flush_to_queue(), and bq_xmit_all() in
{cpu,dev}map.c always return zero. Changing the return type from int
to void makes the code easier to follow.
Suggested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200901083928.6199-1-bjorn.topel@gmail.com
Currently the tracepoint site will iterate a vector and issue indirect
calls to however many handlers are registered (ie. the vector is
long).
Using static_call() it is possible to optimize this for the common
case of only having a single handler registered. In this case the
static_call() can directly call this handler. Otherwise, if the vector
is longer than 1, call a function that iterates the whole vector like
the current code.
[peterz: updated to new interface]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20200818135805.279421092@infradead.org
In order to use static_call() to wire up x86_pmu, we need to
initialize earlier, specifically before memory allocation works; copy
some of the tricks from jump_label to enable this.
Primarily we overload key->next to store a sites pointer when there
are no modules, this avoids having to use kmalloc() to initialize the
sites and allows us to run much earlier.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20200818135805.220737930@infradead.org
GCC can turn our static_call(name)(args...) into a tail call, in which
case we get a JMP.d32 into the trampoline (which then does a further
tail-call).
Teach objtool to recognise and mark these in .static_call_sites and
adjust the code patching to deal with this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20200818135805.101186767@infradead.org
Similar to how we disallow kprobes on any other dynamic text
(ftrace/jump_label) also disallow kprobes on inline static_call()s.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200818135804.744920586@infradead.org
Add infrastructure for an arch-specific CONFIG_HAVE_STATIC_CALL_INLINE
option, which is a faster version of CONFIG_HAVE_STATIC_CALL. At
runtime, the static call sites are patched directly, rather than using
the out-of-line trampolines.
Compared to out-of-line static calls, the performance benefits are more
modest, but still measurable. Steven Rostedt did some tracepoint
measurements:
https://lkml.kernel.org/r/20181126155405.72b4f718@gandalf.local.home
This code is heavily inspired by the jump label code (aka "static
jumps"), as some of the concepts are very similar.
For more details, see the comments in include/linux/static_call.h.
[peterz: simplified interface; merged trampolines]
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20200818135804.684334440@infradead.org
Nothing ensures the module exists while we're iterating
mod->jump_entries in __jump_label_mod_text_reserved(), take a module
reference to ensure the module sticks around.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20200818135804.504501338@infradead.org
Now that notifiers got unbroken; use the proper interface to handle
notifier errors and propagate them.
There were already MODULE_STATE_COMING notifiers that failed; notably:
- jump_label_module_notifier()
- tracepoint_module_notify()
- bpf_event_notify()
By propagating this error, we fix those users.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20200818135804.444372853@infradead.org
While auditing all module notifiers I noticed a whole bunch of fail
wrt the return value. Notifiers have a 'special' return semantics.
As is; NOTIFY_DONE vs NOTIFY_OK is a bit vague; but
notifier_from_errno(0) results in NOTIFY_OK and NOTIFY_DONE has a
comment that says "Don't care".
From this I've used NOTIFY_DONE when the function completely ignores
the callback and notifier_to_error() isn't used.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Robert Richter <rric@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20200818135804.385360407@infradead.org
The current notifiers have the following error handling pattern all
over the place:
int err, nr;
err = __foo_notifier_call_chain(&chain, val_up, v, -1, &nr);
if (err & NOTIFIER_STOP_MASK)
__foo_notifier_call_chain(&chain, val_down, v, nr-1, NULL)
And aside from the endless repetition thereof, it is broken. Consider
blocking notifiers; both calls take and drop the rwsem, this means
that the notifier list can change in between the two calls, making @nr
meaningless.
Fix this by replacing all the __foo_notifier_call_chain() functions
with foo_notifier_call_chain_robust() that embeds the above pattern,
but ensures it is inside a single lock region.
Note: I switched atomic_notifier_call_chain_robust() to use
the spinlock, since RCU cannot provide the guarantee
required for the recovery.
Note: software_resume() error handling was broken afaict.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20200818135804.325626653@infradead.org
CMA_MAX_NAME should be visible to CMA's users as they might need it to set
the name of CMA areas and avoid hardcoding the size locally.
So this patch moves CMA_MAX_NAME from local header file to include/linux
header file and removes the hardcode in both hugetlb.c and contiguous.c.
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Right now, drivers like ARM SMMU are using dma_alloc_coherent() to get
coherent DMA buffers to save their command queues and page tables. As
there is only one default CMA in the whole system, SMMUs on nodes other
than node0 will get remote memory. This leads to significant latency.
This patch provides per-numa CMA so that drivers like SMMU can get local
memory. Tests show localizing CMA can decrease dma_unmap latency much.
For instance, before this patch, SMMU on node2 has to wait for more than
560ns for the completion of CMD_SYNC in an empty command queue; with this
patch, it needs 240ns only.
A positive side effect of this patch would be improving performance even
further for those users who are worried about performance more than DMA
security and use iommu.passthrough=1 to skip IOMMU. With local CMA, all
drivers can get local coherent DMA buffers.
Also, this patch changes the default CONFIG_CMA_AREAS to 19 in NUMA. As
1+CONFIG_CMA_AREAS should be quite enough for most servers on the market
even they enable both hugetlb_cma and pernuma_cma.
2 numa nodes: 2(hugetlb) + 2(pernuma) + 1(default global cma) = 5
4 numa nodes: 4(hugetlb) + 4(pernuma) + 1(default global cma) = 9
8 numa nodes: 8(hugetlb) + 8(pernuma) + 1(default global cma) = 17
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Technically the bpf programs can sleep while attached to bpf_lsm_file_mprotect,
but such programs need to access user memory. So they're in might_fault()
category. Which means they cannot be called from file_mprotect lsm hook that
takes write lock on mm->mmap_lock.
Adjust the test accordingly.
Also add might_fault() to __bpf_prog_enter_sleepable() to catch such deadlocks early.
Fixes: 1e6c62a882 ("bpf: Introduce sleepable BPF programs")
Fixes: e68a144547 ("selftests/bpf: Add sleepable tests")
Reported-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200831201651.82447-1-alexei.starovoitov@gmail.com
In the core runtime, we must minimize any calls to external library
functions to avoid any kind of recursion. This can happen even though
instrumentation is disabled for called functions, but tracing is
enabled.
Most recently, prandom_u32() added a tracepoint, which can cause
problems for KCSAN even if the rcuidle variant is used. For example:
kcsan -> prandom_u32() -> trace_prandom_u32_rcuidle ->
srcu_read_lock_notrace -> __srcu_read_lock -> kcsan ...
While we could disable KCSAN in kcsan_setup_watchpoint(), this does not
solve other unexpected behaviour we may get due recursing into functions
that may not be tolerant to such recursion:
__srcu_read_lock -> kcsan -> ... -> __srcu_read_lock
Therefore, switch to using prandom_u32_state(), which is uninstrumented,
and does not have a tracepoint.
Link: https://lkml.kernel.org/r/20200821063043.1949509-1-elver@google.com
Link: https://lkml.kernel.org/r/20200820172046.GA177701@elver.google.com
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
- Move disabling of the local APIC after invoking fixup_irqs() to ensure
that interrupts which are incoming are noted in the IRR and not ignored.
- Unbreak affinity setting. The rework of the entry code reused the
regular exception entry code for device interrupts. The vector number is
pushed into the errorcode slot on the stack which is then lifted into an
argument and set to -1 because that's regs->orig_ax which is used in
quite some places to check whether the entry came from a syscall. But it
was overlooked that orig_ax is used in the affinity cleanup code to
validate whether the interrupt has arrived on the new target. It turned
out that this vector check is pointless because interrupts are never
moved from one vector to another on the same CPU. That check is a
historical leftover from the time where x86 supported multi-CPU
affinities, but not longer needed with the now strict single CPU
affinity. Famous last words ...
- Add a missing check for an empty cpumask into the matrix allocator. The
affinity change added a warning to catch the case where an interrupt is
moved on the same CPU to a different vector. This triggers because a
condition with an empty cpumask returns an assignment from the allocator
as the allocator uses for_each_cpu() without checking the cpumask for
being empty. The historical inconsistent for_each_cpu() behaviour of
ignoring the cpumask and unconditionally claiming that CPU0 is in the
mask striked again. Sigh.
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Merge tag 'x86-urgent-2020-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner:
"Three interrupt related fixes for X86:
- Move disabling of the local APIC after invoking fixup_irqs() to
ensure that interrupts which are incoming are noted in the IRR and
not ignored.
- Unbreak affinity setting.
The rework of the entry code reused the regular exception entry
code for device interrupts. The vector number is pushed into the
errorcode slot on the stack which is then lifted into an argument
and set to -1 because that's regs->orig_ax which is used in quite
some places to check whether the entry came from a syscall.
But it was overlooked that orig_ax is used in the affinity cleanup
code to validate whether the interrupt has arrived on the new
target. It turned out that this vector check is pointless because
interrupts are never moved from one vector to another on the same
CPU. That check is a historical leftover from the time where x86
supported multi-CPU affinities, but not longer needed with the now
strict single CPU affinity. Famous last words ...
- Add a missing check for an empty cpumask into the matrix allocator.
The affinity change added a warning to catch the case where an
interrupt is moved on the same CPU to a different vector. This
triggers because a condition with an empty cpumask returns an
assignment from the allocator as the allocator uses for_each_cpu()
without checking the cpumask for being empty. The historical
inconsistent for_each_cpu() behaviour of ignoring the cpumask and
unconditionally claiming that CPU0 is in the mask struck again.
Sigh.
plus a new entry into the MAINTAINER file for the HPE/UV platform"
* tag 'x86-urgent-2020-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq/matrix: Deal with the sillyness of for_each_cpu() on UP
x86/irq: Unbreak interrupt affinity setting
x86/hotplug: Silence APIC only after all interrupts are migrated
MAINTAINERS: Add entry for HPE Superdome Flex (UV) maintainers
- Prevent recursion by using raw_cpu_* operations
- Fixup the interrupt state in the cpu idle code to be consistent
- Push rcu_idle_enter/exit() invocations deeper into the idle path so
that the lock operations are inside the RCU watching sections
- Move trace_cpu_idle() into generic code so it's called before RCU goes
idle.
- Handle raw_local_irq* vs. local_irq* operations correctly
- Move the tracepoints out from under the lockdep recursion handling
which turned out to be fragile and inconsistent.
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Merge tag 'locking-urgent-2020-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Thomas Gleixner:
"A set of fixes for lockdep, tracing and RCU:
- Prevent recursion by using raw_cpu_* operations
- Fixup the interrupt state in the cpu idle code to be consistent
- Push rcu_idle_enter/exit() invocations deeper into the idle path so
that the lock operations are inside the RCU watching sections
- Move trace_cpu_idle() into generic code so it's called before RCU
goes idle.
- Handle raw_local_irq* vs. local_irq* operations correctly
- Move the tracepoints out from under the lockdep recursion handling
which turned out to be fragile and inconsistent"
* tag 'locking-urgent-2020-08-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
lockdep,trace: Expose tracepoints
lockdep: Only trace IRQ edges
mips: Implement arch_irqs_disabled()
arm64: Implement arch_irqs_disabled()
nds32: Implement arch_irqs_disabled()
locking/lockdep: Cleanup
x86/entry: Remove unused THUNKs
cpuidle: Move trace_cpu_idle() into generic code
cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic
sched,idle,rcu: Push rcu_idle deeper into the idle path
cpuidle: Fixup IRQ state
lockdep: Use raw_cpu_*() for per-cpu variables
Most of the CPU mask operations behave the same way, but for_each_cpu() and
it's variants ignore the cpumask argument and claim that CPU0 is always in
the mask. This is historical, inconsistent and annoying behaviour.
The matrix allocator uses for_each_cpu() and can be called on UP with an
empty cpumask. The calling code does not expect that this succeeds but
until commit e027fffff7 ("x86/irq: Unbreak interrupt affinity setting")
this went unnoticed. That commit added a WARN_ON() to catch cases which
move an interrupt from one vector to another on the same CPU. The warning
triggers on UP.
Add a check for the cpumask being empty to prevent this.
Fixes: 2f75d9e1c9 ("genirq: Implement bitmap matrix allocator")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Sleepable BPF programs can now use copy_from_user() to access user memory.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: KP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/bpf/20200827220114.69225-4-alexei.starovoitov@gmail.com
Introduce sleepable BPF programs that can request such property for themselves
via BPF_F_SLEEPABLE flag at program load time. In such case they will be able
to use helpers like bpf_copy_from_user() that might sleep. At present only
fentry/fexit/fmod_ret and lsm programs can request to be sleepable and only
when they are attached to kernel functions that are known to allow sleeping.
The non-sleepable programs are relying on implicit rcu_read_lock() and
migrate_disable() to protect life time of programs, maps that they use and
per-cpu kernel structures used to pass info between bpf programs and the
kernel. The sleepable programs cannot be enclosed into rcu_read_lock().
migrate_disable() maps to preempt_disable() in non-RT kernels, so the progs
should not be enclosed in migrate_disable() as well. Therefore
rcu_read_lock_trace is used to protect the life time of sleepable progs.
There are many networking and tracing program types. In many cases the
'struct bpf_prog *' pointer itself is rcu protected within some other kernel
data structure and the kernel code is using rcu_dereference() to load that
program pointer and call BPF_PROG_RUN() on it. All these cases are not touched.
Instead sleepable bpf programs are allowed with bpf trampoline only. The
program pointers are hard-coded into generated assembly of bpf trampoline and
synchronize_rcu_tasks_trace() is used to protect the life time of the program.
The same trampoline can hold both sleepable and non-sleepable progs.
When rcu_read_lock_trace is held it means that some sleepable bpf program is
running from bpf trampoline. Those programs can use bpf arrays and preallocated
hash/lru maps. These map types are waiting on programs to complete via
synchronize_rcu_tasks_trace();
Updates to trampoline now has to do synchronize_rcu_tasks_trace() and
synchronize_rcu_tasks() to wait for sleepable progs to finish and for
trampoline assembly to finish.
This is the first step of introducing sleepable progs. Eventually dynamically
allocated hash maps can be allowed and networking program types can become
sleepable too.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: KP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/bpf/20200827220114.69225-3-alexei.starovoitov@gmail.com
Most of the maps do not use max_entries during verification time.
Thus, those map_meta_equal() do not need to enforce max_entries
when it is inserted as an inner map during runtime. The max_entries
check is removed from the default implementation bpf_map_meta_equal().
The prog_array_map and xsk_map are exception. Its map_gen_lookup
uses max_entries to generate inline lookup code. Thus, they will
implement its own map_meta_equal() to enforce max_entries.
Since there are only two cases now, the max_entries check
is not refactored and stays in its own .c file.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200828011813.1970516-1-kafai@fb.com
Some properties of the inner map is used in the verification time.
When an inner map is inserted to an outer map at runtime,
bpf_map_meta_equal() is currently used to ensure those properties
of the inserting inner map stays the same as the verification
time.
In particular, the current bpf_map_meta_equal() checks max_entries which
turns out to be too restrictive for most of the maps which do not use
max_entries during the verification time. It limits the use case that
wants to replace a smaller inner map with a larger inner map. There are
some maps do use max_entries during verification though. For example,
the map_gen_lookup in array_map_ops uses the max_entries to generate
the inline lookup code.
To accommodate differences between maps, the map_meta_equal is added
to bpf_map_ops. Each map-type can decide what to check when its
map is used as an inner map during runtime.
Also, some map types cannot be used as an inner map and they are
currently black listed in bpf_map_meta_alloc() in map_in_map.c.
It is not unusual that the new map types may not aware that such
blacklist exists. This patch enforces an explicit opt-in
and only allows a map to be used as an inner map if it has
implemented the map_meta_equal ops. It is based on the
discussion in [1].
All maps that support inner map has its map_meta_equal points
to bpf_map_meta_equal in this patch. A later patch will
relax the max_entries check for most maps. bpf_types.h
counts 28 map types. This patch adds 23 ".map_meta_equal"
by using coccinelle. -5 for
BPF_MAP_TYPE_PROG_ARRAY
BPF_MAP_TYPE_(PERCPU)_CGROUP_STORAGE
BPF_MAP_TYPE_STRUCT_OPS
BPF_MAP_TYPE_ARRAY_OF_MAPS
BPF_MAP_TYPE_HASH_OF_MAPS
The "if (inner_map->inner_map_meta)" check in bpf_map_meta_alloc()
is moved such that the same error is returned.
[1]: https://lore.kernel.org/bpf/20200522022342.899756-1-kafai@fb.com/
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200828011806.1970400-1-kafai@fb.com
UAPI Changes:
Cross-subsystem Changes:
Core Changes:
- ttm: various cleanups and reworks of the API
Driver Changes:
- ast: various cleanups
- gma500: A few fixes, conversion to GPIOd API
- hisilicon: Change of maintainer, various reworks
- ingenic: Clock handling and formats support improvements
- mcde: improvements to the DSI support
- mgag200: Support G200 desktop cards
- mxsfb: Support the i.MX7 and i.MX8M and the alpha plane
- panfrost: support devfreq
- ps8640: Retrieve the EDID from eDP control, misc improvements
- tidss: Add a workaround for AM65xx YUV formats handling
- virtio: a few cleanups, support for virtio-gpu exported resources
- bridges: Support the chained bridges on more drivers,
new bridges: Toshiba TC358762, Toshiba TC358775, Lontium LT9611
- panels: Convert to dev_ based logging, read orientation from the DT,
various fixes, new panels: Mantix MLAF057WE51-X, Chefree CH101OLHLWH-002,
Powertip PH800480T013, KingDisplay KD116N21-30NV-A010
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Merge tag 'drm-misc-next-2020-08-27' of git://anongit.freedesktop.org/drm/drm-misc into drm-next
drm-misc-next for 5.10:
UAPI Changes:
Cross-subsystem Changes:
Core Changes:
- ttm: various cleanups and reworks of the API
Driver Changes:
- ast: various cleanups
- gma500: A few fixes, conversion to GPIOd API
- hisilicon: Change of maintainer, various reworks
- ingenic: Clock handling and formats support improvements
- mcde: improvements to the DSI support
- mgag200: Support G200 desktop cards
- mxsfb: Support the i.MX7 and i.MX8M and the alpha plane
- panfrost: support devfreq
- ps8640: Retrieve the EDID from eDP control, misc improvements
- tidss: Add a workaround for AM65xx YUV formats handling
- virtio: a few cleanups, support for virtio-gpu exported resources
- bridges: Support the chained bridges on more drivers,
new bridges: Toshiba TC358762, Toshiba TC358775, Lontium LT9611
- panels: Convert to dev_ based logging, read orientation from the DT,
various fixes, new panels: Mantix MLAF057WE51-X, Chefree CH101OLHLWH-002,
Powertip PH800480T013, KingDisplay KD116N21-30NV-A010
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20200827155517.do6emeacetpturli@gilmour.lan
The "page" pointer can be used with out being initialized.
Fixes: d7e673ec2c ("dma-pool: Only allocate from CMA when in same memory zone")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
bpf selftest test_progs/test_sk_assign failed with llvm 11 and llvm 12.
Compared to llvm 10, llvm 11 and 12 generates xor instruction which
is not handled properly in verifier. The following illustrates the
problem:
16: (b4) w5 = 0
17: ... R5_w=inv0 ...
...
132: (a4) w5 ^= 1
133: ... R5_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ...
...
37: (bc) w8 = w5
38: ... R5=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff))
R8_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ...
...
41: (bc) w3 = w8
42: ... R3_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) ...
45: (56) if w3 != 0x0 goto pc+1
... R3_w=inv0 ...
46: (b7) r1 = 34
47: R1_w=inv34 R7=pkt(id=0,off=26,r=38,imm=0)
47: (0f) r7 += r1
48: R1_w=invP34 R3_w=inv0 R7_w=pkt(id=0,off=60,r=38,imm=0)
48: (b4) w9 = 0
49: R1_w=invP34 R3_w=inv0 R7_w=pkt(id=0,off=60,r=38,imm=0)
49: (69) r1 = *(u16 *)(r7 +0)
invalid access to packet, off=60 size=2, R7(id=0,off=60,r=38)
R7 offset is outside of the packet
At above insn 132, w5 = 0, but after w5 ^= 1, we give a really conservative
value of w5. At insn 45, in reality the condition should be always false.
But due to conservative value for w3, the verifier evaluates it could be
true and this later leads to verifier failure complaining potential
packet out-of-bound access.
This patch implemented proper XOR support in verifier.
In the above example, we have:
132: R5=invP0
132: (a4) w5 ^= 1
133: R5_w=invP1
...
37: (bc) w8 = w5
...
41: (bc) w3 = w8
42: R3_w=invP1
...
45: (56) if w3 != 0x0 goto pc+1
47: R3_w=invP1
...
processed 353 insns ...
and the verifier can verify the program successfully.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200825064608.2017937-1-yhs@fb.com
This patch adds changes in verifier to make decisions such as granting
of read / write access or enforcement of return code status based on
the program type of the target program while using dynamic program
extension (of type BPF_PROG_TYPE_EXT).
The BPF_PROG_TYPE_EXT type can be used to extend types such as XDP, SKB
and others. Since the BPF_PROG_TYPE_EXT program type on itself is just a
placeholder for those, we need this extended check for those extended
programs to actually work with proper access, while using this option.
Specifically, it introduces following changes:
- may_access_direct_pkt_data:
allow access to packet data based on the target prog
- check_return_code:
enforce return code based on the target prog
(currently, this check is skipped for EXT program)
- check_ld_abs:
check for 'may_access_skb' based on the target prog
- check_map_prog_compatibility:
enforce the map compatibility check based on the target prog
- may_update_sockmap:
allow sockmap update based on the target prog
Some other occurrences of prog->type is left as it without replacing
with the 'resolved' type:
- do_check_common() and check_attach_btf_id():
already have specific logic to handle the EXT prog type
- jit_subprogs() and bpf_check():
Not changed for jit compilation or while inferring env->ops
Next few patches in this series include selftests for some of these cases.
Signed-off-by: Udip Pant <udippant@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200825232003.2877030-2-udippant@fb.com
Because kfree_skb already checked NULL skb parameter,
so the additional check is unnecessary, just remove it.
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Currently, the chainkey of a lock chain is a hash sum of the class_idx
of all the held locks, the read/write status are not taken in to
consideration while generating the chainkey. This could result into a
problem, if we have:
P1()
{
read_lock(B);
lock(A);
}
P2()
{
lock(A);
read_lock(B);
}
P3()
{
lock(A);
write_lock(B);
}
, and P1(), P2(), P3() run one by one. And when running P2(), lockdep
detects such a lock chain A -> B is not a deadlock, then it's added in
the chain cache, and then when running P3(), even if it's a deadlock, we
could miss it because of the hit of chain cache. This could be confirmed
by self testcase "chain cached mixed R-L/L-W ".
To resolve this, we use concept "hlock_id" to generate the chainkey, the
hlock_id is a tuple (hlock->class_idx, hlock->read), which fits in a u16
type. With this, the chainkeys are different is the lock sequences have
the same locks but different read/write status.
Besides, since we use "hlock_id" to generate chainkeys, the chain_hlocks
array now store the "hlock_id"s rather than lock_class indexes.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-15-boqun.feng@gmail.com
Since we have all the fundamental to handle recursive read locks, we now
add them into the dependency graph.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-13-boqun.feng@gmail.com
Currently, in safe->unsafe detection, lockdep misses the fact that a
LOCK_ENABLED_IRQ_*_READ usage and a LOCK_USED_IN_IRQ_*_READ usage may
cause deadlock too, for example:
P1 P2
<irq disabled>
write_lock(l1); <irq enabled>
read_lock(l2);
write_lock(l2);
<in irq>
read_lock(l1);
Actually, all of the following cases may cause deadlocks:
LOCK_USED_IN_IRQ_* -> LOCK_ENABLED_IRQ_*
LOCK_USED_IN_IRQ_*_READ -> LOCK_ENABLED_IRQ_*
LOCK_USED_IN_IRQ_* -> LOCK_ENABLED_IRQ_*_READ
LOCK_USED_IN_IRQ_*_READ -> LOCK_ENABLED_IRQ_*_READ
To fix this, we need to 1) change the calculation of exclusive_mask() so
that READ bits are not dropped and 2) always call usage() in
mark_lock_irq() to check usage deadlocks, even when the new usage of the
lock is READ.
Besides, adjust usage_match() and usage_acculumate() to recursive read
lock changes.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-12-boqun.feng@gmail.com
check_redundant() will report redundancy if it finds a path could
replace the about-to-add dependency in the BFS search. With recursive
read lock changes, we certainly need to change the match function for
the check_redundant(), because the path needs to match not only the lock
class but also the dependency kinds. For example, if the about-to-add
dependency @prev -> @next is A -(SN)-> B, and we find a path A -(S*)->
.. -(*R)->B in the dependency graph with __bfs() (for simplicity, we can
also say we find an -(SR)-> path from A to B), we can not replace the
dependency with that path in the BFS search. Because the -(SN)->
dependency can make a strong path with a following -(S*)-> dependency,
however an -(SR)-> path cannot.
Further, we can replace an -(SN)-> dependency with a -(EN)-> path, that
means if we find a path which is stronger than or equal to the
about-to-add dependency, we can report the redundancy. By "stronger", it
means both the start and the end of the path are not weaker than the
start and the end of the dependency (E is "stronger" than S and N is
"stronger" than R), so that we can replace the dependency with that
path.
To make sure we find a path whose start point is not weaker than the
about-to-add dependency, we use a trick: the ->only_xr of the root
(start point) of __bfs() is initialized as @prev-> == 0, therefore if
@prev is E, __bfs() will pick only -(E*)-> for the first dependency,
otherwise, __bfs() can pick -(E*)-> or -(S*)-> for the first dependency.
To make sure we find a path whose end point is not weaker than the
about-to-add dependency, we replace the match function for __bfs()
check_redundant(), we check for the case that either @next is R
(anything is not weaker than it) or the end point of the path is N
(which is not weaker than anything).
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-11-boqun.feng@gmail.com
Currently, lockdep only has limit support for deadlock detection for
recursive read locks.
This patch support deadlock detection for recursive read locks. The
basic idea is:
We are about to add dependency B -> A in to the dependency graph, we use
check_noncircular() to find whether we have a strong dependency path
A -> .. -> B so that we have a strong dependency circle (a closed strong
dependency path):
A -> .. -> B -> A
, which doesn't have two adjacent dependencies as -(*R)-> L -(S*)->.
Since A -> .. -> B is already a strong dependency path, so if either
B -> A is -(E*)-> or A -> .. -> B is -(*N)->, the circle A -> .. -> B ->
A is strong, otherwise not. So we introduce a new match function
hlock_conflict() to replace the class_equal() for the deadlock check in
check_noncircular().
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-10-boqun.feng@gmail.com
The "match" parameter of __bfs() is used for checking whether we hit a
match in the search, therefore it should return a boolean value rather
than an integer for better readability.
This patch then changes the return type of the function parameter and the
match functions to bool.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-9-boqun.feng@gmail.com
Now we have four types of dependencies in the dependency graph, and not
all the pathes carry real dependencies (the dependencies that may cause
a deadlock), for example:
Given lock A and B, if we have:
CPU1 CPU2
============= ==============
write_lock(A); read_lock(B);
read_lock(B); write_lock(A);
(assuming read_lock(B) is a recursive reader)
then we have dependencies A -(ER)-> B, and B -(SN)-> A, and a
dependency path A -(ER)-> B -(SN)-> A.
In lockdep w/o recursive locks, a dependency path from A to A
means a deadlock. However, the above case is obviously not a
deadlock, because no one holds B exclusively, therefore no one
waits for the other to release B, so who get A first in CPU1 and
CPU2 will run non-blockingly.
As a result, dependency path A -(ER)-> B -(SN)-> A is not a
real/strong dependency that could cause a deadlock.
From the observation above, we know that for a dependency path to be
real/strong, no two adjacent dependencies can be as -(*R)-> -(S*)->.
Now our mission is to make __bfs() traverse only the strong dependency
paths, which is simple: we record whether we only have -(*R)-> for the
previous lock_list of the path in lock_list::only_xr, and when we pick a
dependency in the traverse, we 1) filter out -(S*)-> dependency if the
previous lock_list only has -(*R)-> dependency (i.e. ->only_xr is true)
and 2) set the next lock_list::only_xr to true if we only have -(*R)->
left after we filter out dependencies based on 1), otherwise, set it to
false.
With this extension for __bfs(), we now need to initialize the root of
__bfs() properly (with a correct ->only_xr), to do so, we introduce some
helper functions, which also cleans up a little bit for the __bfs() root
initialization code.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-8-boqun.feng@gmail.com
To add recursive read locks into the dependency graph, we need to store
the types of dependencies for the BFS later. There are four types of
dependencies:
* Exclusive -> Non-recursive dependencies: EN
e.g. write_lock(prev) held and try to acquire write_lock(next)
or non-recursive read_lock(next), which can be represented as
"prev -(EN)-> next"
* Shared -> Non-recursive dependencies: SN
e.g. read_lock(prev) held and try to acquire write_lock(next) or
non-recursive read_lock(next), which can be represented as
"prev -(SN)-> next"
* Exclusive -> Recursive dependencies: ER
e.g. write_lock(prev) held and try to acquire recursive
read_lock(next), which can be represented as "prev -(ER)-> next"
* Shared -> Recursive dependencies: SR
e.g. read_lock(prev) held and try to acquire recursive
read_lock(next), which can be represented as "prev -(SR)-> next"
So we use 4 bits for the presence of each type in lock_list::dep. Helper
functions and macros are also introduced to convert a pair of locks into
lock_list::dep bit and maintain the addition of different types of
dependencies.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-7-boqun.feng@gmail.com
lock_list::distance is always not greater than MAX_LOCK_DEPTH (which
is 48 right now), so a u16 will fit. This patch reduces the size of
lock_list::distance to save space, so that we can introduce other fields
to help detect recursive read lock deadlocks without increasing the size
of lock_list structure.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-6-boqun.feng@gmail.com
Currently, __bfs() will do a breadth-first search in the dependency
graph and visit each lock class in the graph exactly once, so for
example, in the following graph:
A ---------> B
| ^
| |
+----------> C
a __bfs() call starts at A, will visit B through dependency A -> B and
visit C through dependency A -> C and that's it, IOW, __bfs() will not
visit dependency C -> B.
This is OK for now, as we only have strong dependencies in the
dependency graph, so whenever there is a traverse path from A to B in
__bfs(), it means A has strong dependencies to B (IOW, B depends on A
strongly). So no need to visit all dependencies in the graph.
However, as we are going to add recursive-read lock into the dependency
graph, as a result, not all the paths mean strong dependencies, in the
same example above, dependency A -> B may be a weak dependency and
traverse A -> C -> B may be a strong dependency path. And with the old
way of __bfs() (i.e. visiting every lock class exactly once), we will
miss the strong dependency path, which will result into failing to find
a deadlock. To cure this for the future, we need to find a way for
__bfs() to visit each dependency, rather than each class, exactly once
in the search until we find a match.
The solution is simple:
We used to mark lock_class::lockdep_dependency_gen_id to indicate a
class has been visited in __bfs(), now we change the semantics a little
bit: we now mark lock_class::lockdep_dependency_gen_id to indicate _all
the dependencies_ in its lock_{after,before} have been visited in the
__bfs() (note we only take one direction in a __bfs() search). In this
way, every dependency is guaranteed to be visited until we find a match.
Note: the checks in mark_lock_accessed() and lock_accessed() are
removed, because after this modification, we may call these two
functions on @source_entry of __bfs(), which may not be the entry in
"list_entries"
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-5-boqun.feng@gmail.com
__bfs() could return four magic numbers:
1: search succeeds, but none match.
0: search succeeds, find one match.
-1: search fails because of the cq is full.
-2: search fails because a invalid node is found.
This patch cleans things up by using a enum type for the return value
of __bfs() and its friends, this improves the code readability of the
code, and further, could help if we want to extend the BFS.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-4-boqun.feng@gmail.com
On the archs using QUEUED_RWLOCKS, read_lock() is not always a recursive
read lock, actually it's only recursive if in_interrupt() is true. So
change the annotation accordingly to catch more deadlocks.
Note we used to treat read_lock() as pure recursive read locks in
lib/locking-seftest.c, and this is useful, especially for the lockdep
development selftest, so we keep this via a variable to force switching
lock annotation for read_lock().
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-2-boqun.feng@gmail.com
SD_DEGENERATE_GROUPS_MASK is only useful for sched/topology.c, but still
gets defined for anyone who imports topology.h, leading to a flurry of
unused variable warnings.
Move it out of the header and place it next to the SD degeneration
functions in sched/topology.c.
Fixes: 4ee4ea443a ("sched/topology: Introduce SD metaflag for flags needing > 1 groups")
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200825133216.9163-2-valentin.schneider@arm.com
Defining an array in a header imported all over the place clearly is a daft
idea, that still didn't stop me from doing it.
Leave a declaration of sd_flag_debug in topology.h and move its definition
to sched/debug.c.
Fixes: b6e862f386 ("sched/topology: Define and assign sched_domain flag metadata")
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200825133216.9163-1-valentin.schneider@arm.com
sched_submit_work() is considered to be a hot path. The preempt_disable()
instruction is a compiler barrier and forces the compiler to load
task_struct::flags for the second comparison.
By using a local variable, the compiler can load the value once and keep it in
a register for the second comparison.
Verified on x86-64 with gcc-10.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200819200025.lqvmyefqnbok5i4f@linutronix.de
The code in reweight_entity() can be simplified.
For a sched entity on the rq, the entity accounting can be replaced by
cfs_rq instantaneous load updates currently called from within the
entity accounting.
Even though an entity on the rq can't represent a task in
reweight_entity() (a task is always dequeued before calling this
function) and so the numa task accounting and the rq->cfs_tasks list
management of the entity accounting are never called, the redundant
cfs_rq->nr_running decrement/increment will be avoided.
Signed-off-by: Jiang Biao <benbjiang@tencent.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200811113209.34057-1-benbjiang@tencent.com
In find_energy_efficient_cpu() 'cpu_cap' could be less that 'util'.
It might be because of RT, DL (so higher sched class than CFS), irq or
thermal pressure signal, which reduce the capacity value.
In such situation the result of 'cpu_cap - util' might be negative but
stored in the unsigned long. Then it might be compared with other unsigned
long when uclamp_rq_util_with() reduced the 'util' such that is passes the
fits_capacity() check.
Prevent this situation and make the arithmetic more safe.
Fixes: 1d42509e47 ("sched/fair: Make EAS wakeup placement consider uclamp restrictions")
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20200810083004.26420-1-lukasz.luba@arm.com
SMT siblings share caches, so cache hotness should be irrelevant for
cross-sibling migration.
Signed-off-by: Josh Don <joshdon@google.com>
Proposed-by: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200804193413.510651-1-joshdon@google.com
The lockdep tracepoints are under the lockdep recursion counter, this
has a bunch of nasty side effects:
- TRACE_IRQFLAGS doesn't work across the entire tracepoint
- RCU-lockdep doesn't see the tracepoints either, hiding numerous
"suspicious RCU usage" warnings.
Pull the trace_lock_*() tracepoints completely out from under the
lockdep recursion handling and completely rely on the trace level
recusion handling -- also, tracing *SHOULD* not be taking locks in any
case.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.782688941@infradead.org
Remove trace_cpu_idle() from the arch_cpu_idle() implementations and
put it in the generic code, right before disabling RCU. Gets rid of
more trace_*_rcuidle() users.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.428433395@infradead.org
Lots of things take locks, due to a wee bug, rcu_lockdep didn't notice
that the locking tracepoints were using RCU.
Push rcu_idle_{enter,exit}() as deep as possible into the idle paths,
this also resolves a lot of _rcuidle()/RCU_NONIDLE() usage.
Specifically, sched_clock_idle_wakeup_event() will use ktime which
will use seqlocks which will tickle lockdep, and
stop_critical_timings() uses lock.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200821085348.310943801@infradead.org
Sven reported that commit a21ee6055c ("lockdep: Change
hardirq{s_enabled,_context} to per-cpu variables") caused trouble on
s390 because their this_cpu_*() primitives disable preemption which
then lands back tracing.
On the one hand, per-cpu ops should use preempt_*able_notrace() and
raw_local_irq_*(), on the other hand, we can trivialy use raw_cpu_*()
ops for this.
Fixes: a21ee6055c ("lockdep: Change hardirq{s_enabled,_context} to per-cpu variables")
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200821085348.192346882@infradead.org
Adding d_path helper function that returns full path for
given 'struct path' object, which needs to be the kernel
BTF 'path' object. The path is returned in buffer provided
'buf' of size 'sz' and is zero terminated.
bpf_d_path(&file->f_path, buf, size);
The helper calls directly d_path function, so there's only
limited set of function it can be called from. Adding just
very modest set for the start.
Updating also bpf.h tools uapi header and adding 'path' to
bpf_helpers_doc.py script.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: KP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-11-jolsa@kernel.org
Adding support to define sorted set of BTF ID values.
Following defines sorted set of BTF ID values:
BTF_SET_START(btf_allowlist_d_path)
BTF_ID(func, vfs_truncate)
BTF_ID(func, vfs_fallocate)
BTF_ID(func, dentry_open)
BTF_ID(func, vfs_getattr)
BTF_ID(func, filp_close)
BTF_SET_END(btf_allowlist_d_path)
It defines following 'struct btf_id_set' variable to access
values and count:
struct btf_id_set btf_allowlist_d_path;
Adding 'allowed' callback to struct bpf_func_proto, to allow
verifier the check on allowed callers.
Adding btf_id_set_contains function, which will be used by
allowed callbacks to verify the caller's BTF ID value is
within allowed set.
Also removing extra '\' in __BTF_ID_LIST macro.
Added BTF_SET_START_GLOBAL macro for global sets.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-10-jolsa@kernel.org
Adding btf_struct_ids_match function to check if given address provided
by BTF object + offset is also address of another nested BTF object.
This allows to pass an argument to helper, which is defined via parent
BTF object + offset, like for bpf_d_path (added in following changes):
SEC("fentry/filp_close")
int BPF_PROG(prog_close, struct file *file, void *id)
{
...
ret = bpf_d_path(&file->f_path, ...
The first bpf_d_path argument is hold by verifier as BTF file object
plus offset of f_path member.
The btf_struct_ids_match function will walk the struct file object and
check if there's nested struct path object on the given offset.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-9-jolsa@kernel.org
Adding btf_struct_walk function that walks through the
struct type + given offset and returns following values:
enum bpf_struct_walk_result {
/* < 0 error */
WALK_SCALAR = 0,
WALK_PTR,
WALK_STRUCT,
};
WALK_SCALAR - when SCALAR_VALUE is found
WALK_PTR - when pointer value is found, its ID is stored
in 'next_btf_id' output param
WALK_STRUCT - when nested struct object is found, its ID is stored
in 'next_btf_id' output param
It will be used in following patches to get all nested
struct objects for given type and offset.
The btf_struct_access now calls btf_struct_walk function,
as long as it gets nested structs as return value.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-8-jolsa@kernel.org
Andrii suggested we can simply jump to again label
instead of making recursion call.
Suggested-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-7-jolsa@kernel.org
Adding type_id pointer as argument to __btf_resolve_size
to return also BTF ID of the resolved type. It will be
used in following changes.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-6-jolsa@kernel.org
If the resolved type is array, make btf_resolve_size return also
ID of the elem type. It will be needed in following changes.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-5-jolsa@kernel.org
Moving btf_resolve_size into __btf_resolve_size and
keeping btf_resolve_size public with just first 3
arguments, because the rest of the arguments are not
used by outside callers.
Following changes are adding more arguments, which
are not useful to outside callers. They will be added
to the __btf_resolve_size function.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-4-jolsa@kernel.org
The CC_CAN_LINK checks that the host compiler can link, but bpf_preload
relies on libbpf which in turn needs libelf to be present during linking.
allmodconfig runs in odd setups with cross compilers and missing host
libraries like libelf. Instead of extending kconfig with every possible
library that bpf_preload might need disallow building BPF_PRELOAD in
such build-only configurations.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Adds support for both bpf_{sk, inode}_storage_{get, delete} to be used
in LSM programs. These helpers are not used for tracing programs
(currently) as their usage is tied to the life-cycle of the object and
should only be used where the owning object won't be freed (when the
owning object is passed as an argument to the LSM hook). Thus, they
are safer to use in LSM hooks than tracing. Usage of local storage in
tracing programs will probably follow a per function based whitelist
approach.
Since the UAPI helper signature for bpf_sk_storage expect a bpf_sock,
it, leads to a compilation warning for LSM programs, it's also updated
to accept a void * pointer instead.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-7-kpsingh@chromium.org
Similar to bpf_local_storage for sockets, add local storage for inodes.
The life-cycle of storage is managed with the life-cycle of the inode.
i.e. the storage is destroyed along with the owning inode.
The BPF LSM allocates an __rcu pointer to the bpf_local_storage in the
security blob which are now stackable and can co-exist with other LSMs.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200825182919.1118197-6-kpsingh@chromium.org
Replace a comma between expression statements by a semicolon.
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lore.kernel.org/r/20200818062651.21680-1-vulab@iscas.ac.cn
Commit f2e10bff16 ("bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link")
added link query for raw_tp. One of fields in link_info is to
fill a user buffer with tp_name. The Scurrent checking only
declares "ulen && !ubuf" as invalid. So "!ulen && ubuf" will be
valid. Later on, we do "copy_to_user(ubuf, tp_name, ulen - 1)" which
may overwrite user memory incorrectly.
This patch fixed the problem by disallowing "!ulen && ubuf" case as well.
Fixes: f2e10bff16 ("bpf: Add support for BPF_OBJ_GET_INFO_BY_FD for bpf_link")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200821191054.714731-1-yhs@fb.com
This commit adds an rcutorture.leakpointer module parameter that
intentionally leaks an RCU-protected pointer out of the RCU read-side
critical section and checks to see if the corresponding grace period
has elapsed, emitting a WARN_ON_ONCE() if so. This module parameter can
be used to test facilities like CONFIG_RCU_STRICT_GRACE_PERIOD that end
grace periods quickly.
While in the area, also document rcutorture.irqreader, which was
previously left out.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, registering and unregistering the OOM notifier is done
right before and after the test, respectively. This will not work
well for multi-threaded tests, so this commit hoists this registering
and unregistering up into the rcu_torture_fwd_prog_init() and
rcu_torture_fwd_prog_cleanup() functions.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently in the unlikely event that buf fails to be allocated it
is dereferenced a few times. Use the errexit flag to determine if
buf should be written to to avoid the null pointer dereferences.
Addresses-Coverity: ("Dereference after null check")
Fixes: f518f154ec ("refperf: Dynamically allocate experiment-summary output buffer")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The current rcutorture forward-progress code assumes that it is the
only cause of out-of-memory (OOM) events. For script-based rcutorture
testing, this assumption is in fact correct. However, testing based
on modprobe/rmmod might well encounter external OOM events, which could
happen at any time.
This commit therefore properly synchronizes the interaction between
rcutorture's forward-progress testing and its OOM notifier by adding a
global mutex.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The conversion of rcu_fwds to dynamic allocation failed to actually
allocate the required structure. This commit therefore allocates it,
frees it, and updates rcu_fwds accordingly. While in the area, it
abstracts the cleanup actions into rcu_torture_fwd_prog_cleanup().
Fixes: 5155be9994 ("rcutorture: Dynamically allocate rcu_fwds structure")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The sparse tool complains as follows:
kernel/locking/locktorture.c:569:6: warning:
symbol 'torture_percpu_rwsem_init' was not declared. Should it be static?
And this function is not used outside of locktorture.c,
so this commit marks it static.
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds code to print the grace-period number at the start
of the test along with both the grace-period number and the number of
elapsed grace periods at the end of the test. Note that variants of
RCU)without the notion of a grace-period number (for example, Tiny RCU)
just print zeroes.
[ paulmck: Adjust commit log. ]
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
KCSAN is now in mainline, so this commit removes the stubs for the
data_race(), ASSERT_EXCLUSIVE_WRITER(), and ASSERT_EXCLUSIVE_ACCESS()
macros.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The "cpu" parameter to rcu_report_qs_rdp() is not used, with rdp->cpu
being used instead. Furtheremore, every call to rcu_report_qs_rdp()
invokes it on rdp->cpu. This commit therefore removes this unused "cpu"
parameter and converts a check of rdp->cpu against smp_processor_id()
to a WARN_ON_ONCE().
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The CONFIG_PREEMPT=n instance of rcu_read_unlock is even more
aggressively than that of CONFIG_PREEMPT=y in deferring reporting
quiescent states to the RCU core. This is just what is wanted in normal
use because it reduces overhead, but the resulting delay is not what
is wanted for kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y.
This commit therefore adds an rcu_read_unlock_strict() function that
checks for exceptional conditions, and reports the newly started
quiescent state if it is safe to do so, also doing a spin-delay if
requested via rcutree.rcu_unlock_delay. This commit also adds a call
to rcu_read_unlock_strict() from the CONFIG_PREEMPT=n instance of
__rcu_read_unlock().
[ paulmck: Fixed bug located by kernel test robot <lkp@intel.com> ]
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
A kernel built with CONFIG_RCU_STRICT_GRACE_PERIOD=y needs a quiescent
state to appear very shortly after a CPU has noticed a new grace period.
Placing an RCU reader immediately after this point is ineffective because
this normally happens in softirq context, which acts as a big RCU reader.
This commit therefore introduces a new per-CPU work_struct, which is
used at the end of rcu_core() processing to schedule an RCU read-side
critical section from within a clean environment.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The goal of this series is to increase the probability of tools like
KASAN detecting that an RCU-protected pointer was used outside of its
RCU read-side critical section. Thus far, the approach has been to make
grace periods and callback processing happen faster. Another approach
is to delay the pointer leaker. This commit therefore allows a delay
to be applied to exit from RCU read-side critical sections.
This slowdown is specified by a new rcutree.rcu_unlock_delay kernel boot
parameter that specifies this delay in microseconds, defaulting to zero.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, each CPU discovers the end of a given grace period on its
own time, which is again good for efficiency but bad for fast grace
periods, given that it is things like kfree() within the RCU callbacks
that will cause trouble for pointers leaked from RCU read-side critical
sections. This commit therefore uses on_each_cpu() to IPI each CPU
after grace-period cleanup in order to inform each CPU of the end of
the old grace period in a timely manner, but only in kernels build with
CONFIG_RCU_STRICT_GRACE_PERIOD=y.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, each CPU discovers the beginning of a given grace period
on its own time, which is again good for efficiency but bad for fast
grace periods. This commit therefore uses on_each_cpu() to IPI each
CPU after grace-period initialization in order to inform each CPU of
the new grace period in a timely manner, but only in kernels build with
CONFIG_RCU_STRICT_GRACE_PERIOD=y.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
A given CPU normally notes a new grace period during one RCU_SOFTIRQ,
but avoids reporting the corresponding quiescent state until some later
RCU_SOFTIRQ. This leisurly approach improves efficiency by increasing
the number of update requests served by each grace period, but is not
what is needed for kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y.
This commit therefore adds a new rcu_strict_gp_check_qs() function
which, in CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels, simply enters and
immediately exist an RCU read-side critical section. If the CPU is
in a quiescent state, the rcu_read_unlock() will attempt to report an
immediate quiescent state. This rcu_strict_gp_check_qs() function is
invoked from note_gp_changes(), so that a CPU just noticing a new grace
period might immediately report a quiescent state for that grace period.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The rcu_preempt_deferred_qs_irqrestore() function is invoked at
the end of an RCU read-side critical section (for example, directly
from rcu_read_unlock()) and, if .need_qs is set, invokes rcu_qs() to
report the new quiescent state. This works, except that rcu_qs() only
updates per-CPU state, leaving reporting of the actual quiescent state
to a later call to rcu_report_qs_rdp(), for example from within a later
RCU_SOFTIRQ instance. Although this approach is exactly what you want if
you are more concerned about efficiency than about short grace periods,
in CONFIG_RCU_STRICT_GRACE_PERIOD=y kernels, short grace periods are
the name of the game.
This commit therefore makes rcu_preempt_deferred_qs_irqrestore() directly
invoke rcu_report_qs_rdp() in CONFIG_RCU_STRICT_GRACE_PERIOD=y, thus
shortening grace periods.
Historical note: To the best of my knowledge, causing rcu_read_unlock()
to directly report a quiescent state first appeared in Jim Houston's
and Joe Korty's JRCU. This is the second instance of a Linux-kernel RCU
feature being inspired by JRCU, the first being RCU callback offloading
(as in the RCU_NOCB_CPU Kconfig option).
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The ->rcu_read_unlock_special.b.need_qs field in the task_struct
structure indicates that the RCU core needs a quiscent state from the
corresponding task. The __rcu_read_unlock() function checks this (via
an eventual call to rcu_preempt_deferred_qs_irqrestore()), and if set
reports a quiscent state immediately upon exit from the outermost RCU
read-side critical section.
Currently, this flag is only set when the scheduling-clock interrupt
decides that the current RCU grace period is too old, as in about
one full second too old. But if the kernel has been built with
CONFIG_RCU_STRICT_GRACE_PERIOD=y, we clearly do not want to wait that
long. This commit therefore sets the .need_qs field immediately at the
start of the RCU read-side critical section from within __rcu_read_lock()
in order to unconditionally enlist help from __rcu_read_unlock().
But note the additional check for rcu_state.gp_kthread, which prevents
attempts to awaken RCU's grace-period kthread during early boot before
there is a scheduler. Leaving off this check results in early boot hangs.
So early that there is no console output. Thus, this additional check
fails until such time as RCU's grace-period kthread has been created,
avoiding these empty-console hangs.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The value of DEFAULT_RCU_BLIMIT is normally set to 10, the idea being to
avoid needless response-time degradation due to RCU callback invocation.
However, when CONFIG_RCU_STRICT_GRACE_PERIOD=y it is better to avoid
throttling callback execution in order to better detect pointer
leaks from RCU read-side critical sections. This commit therefore
sets the value of DEFAULT_RCU_BLIMIT to 1000 in kernels built with
CONFIG_RCU_STRICT_GRACE_PERIOD=y.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
If there are idle CPUs, RCU's grace-period kthread will wait several
jiffies before even thinking about polling them. This promotes
efficiency, which is normally a good thing, but when the kernel
has been built with CONFIG_RCU_STRICT_GRACE_PERIOD=y, we care more
about short grace periods. This commit therefore restricts the
default jiffies_till_first_fqs value to zero in kernels built with
CONFIG_RCU_STRICT_GRACE_PERIOD=y, which causes RCU's grace-period kthread
to poll for idle CPUs immediately after starting a grace period.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Because strict RCU grace periods will complete more quickly, they will
experience greater lock contention on each leaf rcu_node structure's
->lock. This commit therefore reduces the leaf fanout in order to reduce
this lock contention.
Note that this also has the effect of reducing the number of CPUs
supported to 16 in the case of CONFIG_RCU_FANOUT_LEAF=2 or 81 in the
case of CONFIG_RCU_FANOUT_LEAF=3. However, greater numbers of CPUs are
probably a bad idea when using CONFIG_RCU_STRICT_GRACE_PERIOD=y. Those
wishing to live dangerously are free to edit their kernel/rcu/Kconfig
files accordingly.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
People running automated tests have asked for a way to make RCU minimize
grace-period duration in order to increase the probability of KASAN
detecting a pointer being improperly leaked from an RCU read-side critical
section, for example, like this:
rcu_read_lock();
p = rcu_dereference(gp);
do_something_with(p); // OK
rcu_read_unlock();
do_something_else_with(p); // BUG!!!
The rcupdate.rcu_expedited boot parameter is a start in this direction,
given that it makes calls to synchronize_rcu() instead invoke the faster
(and more wasteful) synchronize_rcu_expedited(). However, this does
nothing to shorten RCU grace periods that are instead initiated by
call_rcu(), and RCU pointer-leak bugs can involve call_rcu() just as
surely as they can synchronize_rcu().
This commit therefore adds a RCU_STRICT_GRACE_PERIOD Kconfig option
that will be used to shorten normal (non-expedited) RCU grace periods.
This commit also dumps out a message when this option is in effect.
Later commits will actually shorten grace periods.
Reported-by Jann Horn <jannh@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit further avoids conflation of rcuperf with the kernel's perf
feature by renaming kernel/rcu/rcuperf.c to kernel/rcu/rcuscale.c, and
also by similarly renaming the functions and variables inside this file.
This has the side effect of changing the names of the kernel boot
parameters, so kernel-parameters.txt and ver_functions.sh are also
updated. The rcutorture --torture type was also updated from rcuperf
to rcuscale.
[ paulmck: Fix bugs located by Stephen Rothwell. ]
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Although the test loop does randomly delay, which would provide quiescent
states and so forth, it is possible for there to be a series of long
smp_call_function*() handler runtimes with no delays, which results in
softlockup and RCU CPU stall warning messages. This commit therefore
inserts a cond_resched() into the main test loop.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
On uniprocessor systems, smp_call_function() does nothing. This commit
therefore avoids complaining about the lack of handler accesses in the
single-CPU case where there is no handler.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, CPU-hotplug operations might result in all but two
of (say) 100 CPUs being offline, which in turn might result in
false-positive diagnostics due to overload. This commit therefore
causes scftorture_invoker() kthreads for offline CPUs to loop blocking
for 200 milliseconds at a time, thus continuously adjusting the number
of threads to match the number of online CPUs.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds a "default" case to the switch statement in
scftorture_invoke_one() which contains a WARN_ON_ONCE() and an assignment
to ->scfc_out to suppress knock-on warnings. These knock-on warnings
could otherwise cause the user to think that there was a memory-ordering
problem in smp_call_function() instead of a bug in scftorture.c itself.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The sparse tool complains as follows
kernel/scftorture.c:124:1: warning:
symbol '__pcpu_scope_scf_torture_rand' was not declared. Should it be static?
And this per-CPU variable is not used outside of scftorture.c,
so this commit marks it static.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Detecting smp_call_function() memory misordering requires close timing,
so it is necessary to have the checks immediately before and after
the call to the smp_call_function*() function under test. This commit
therefore inserts barrier() calls to prevent the compiler from optimizing
memory-misordering detection down into the zone of extreme improbability.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit prints error counts on the statistics line and also adds a
"!!!" if any of the counters are non-zero. Allocation failures are
(somewhat) forgiven, but all other errors result in a "FAILURE" print
at the end of the test.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit hoists much of the initialization of the scf_check
structure out of the switch statement, thus saving a few lines of code.
The initialization of the ->scfc_in field remains in each leg of the
switch statement in order to more heavily stress memory ordering.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit moves checking of the ->scfc_out field and the freeing of
the scf_check structure down below the end of switch statement, thus
saving a few lines of code.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds checks for memory misordering across calls to and
returns from smp_call_function() in the case where the caller waits.
Misordering results in a splat.
Note that in contrast to smp_call_function_single(), this code does not
test memory ordering into the handler in the no-wait case because none
of the handlers would be able to free the scf_check structure without
introducing heavy synchronization to work out which was last.
[ paulmck: s/GFP_KERNEL/GFP_ATOMIC/ per kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds checks for memory misordering across calls to and
returns from smp_call_function_many() in the case where the caller waits.
Misordering results in a splat.
Note that in contrast to smp_call_function_single(), this code does not
test memory ordering into the handler in the no-wait case because none
of the handlers would be able to free the scf_check structure without
introducing heavy synchronization to work out which was last.
[ paulmck: s/GFP_KERNEL/GFP_ATOMIC/ per kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds checks for memory misordering across calls to
smp_call_function_single() and also across returns in the case where
the caller waits. Misordering results in a splat.
[ paulmck: s/GFP_KERNEL/GFP_ATOMIC/ per kernel test robot feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit summarizes the per-thread statistics, providing counts of
the number of single, many, and all calls, both no-wait and wait, and,
for the single case, the number where the target CPU was offline.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, can_stop_idle_tick() prints "NOHZ: local_softirq_pending HH"
(where "HH" is the hexadecimal softirq vector number) when one or more
non-RCU softirq handlers are still enabled when checking to stop the
scheduler-tick interrupt. This message is not as enlightening as one
might hope, so this commit changes it to "NOHZ tick-stop error: Non-RCU
local softirq work is pending, handler #HH".
Reported-by: Andy Lutomirski <luto@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit uses the scftorture.weight* kernel parameters to randomly
chooses between smp_call_function_single(), smp_call_function_many(),
and smp_call_function(). For each variant, it also randomly chooses
whether to invoke it synchronously (wait=1) or asynchronously (wait=0).
The percentage weighting for each option are dumped to the console log
(search for "scf_sel_dump").
This accumulates statistics, which a later commit will dump out at the
end of the run.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds an smp_call_function() torture test that repeatedly
invokes this function and complains if things go badly awry.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The x86/entry work removed all uses of __rcu_is_watching(), therefore
this commit removes it entirely.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <x86@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The RCU grace-period kthread's force-quiescent state (FQS) loop should
never see an offline CPU that has not yet reported a quiescent state.
After all, the offline CPU should have reported a quiescent state
during the CPU-offline process, or, failing that, by rcu_gp_init()
if it ran concurrently with either the CPU going offline or the last
task on a leaf rcu_node structure exiting its RCU read-side critical
section while all CPUs corresponding to that structure are offline.
The FQS loop should therefore complain if it does see an offline CPU
that has not yet reported a quiescent state.
And it does, but only once the grace period has been in force for a
full second. This commit therefore makes this warning more aggressive,
so that it will trigger as soon as the condition makes its appearance.
Light testing with TREE03 and hotplug shows no warnings. This commit
also converts the warning to WARN_ON_ONCE() in order to stave off possible
log spam.
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Since at least v4.19, the FQS loop no longer reports quiescent states
for offline CPUs except in emergency situations.
This commit therefore fixes the comment in rcu_gp_init() to match the
current code.
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit increases RCU's ability to defend itself by emitting a warning
if one of the nocb CB kthreads invokes the GP kthread's wait function.
This warning augments a similar check that is carried out at the end
of rcutorture testing and when RCU CPU stall warnings are emitted.
The problem with those checks is that the miscreants have long since
departed and disposed of any and all evidence.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
When the rcu_cpu_started per-CPU variable was added by commit
f64c6013a2 ("rcu/x86: Provide early rcu_cpu_starting() callback"),
there were multiple sets of per-CPU rcu_data structures. Therefore, the
rcu_cpu_started flag was added as a separate per-CPU variable. But now
there is only one set of per-CPU rcu_data structures, so this commit
moves rcu_cpu_started to a new ->cpu_started field in that structure.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Given that sysfs can change the value of rcu_cpu_stall_ftrace_dump at any
time, this commit adds a READ_ONCE() to the accesses to that variable.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Given that sysfs can change the value of rcu_kick_kthreads at any time,
this commit adds a READ_ONCE() to the sole access to that variable.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Given that sysfs can change the value of rcu_resched_ns at any time,
this commit adds a READ_ONCE() to the sole access to that variable.
While in the area, this commit also adds bounds checking, clamping the
value to at least a millisecond, but no longer than a second.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Given that sysfs can change the value of rcu_divisor at any time, this
commit adds a READ_ONCE to the sole access to that variable. While in
the area, this commit also adds bounds checking, clamping the value to
a shift that makes sense for a signed long.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The rcu_data structure's ->nocb_timer field is used to defer wakeups of
the corresponding no-CBs CPU's grace-period kthread ("rcuog*"), and that
structure's ->nocb_defer_wakeup field is used to track such deferral.
This means that the show_rcu_nocb_state() printing an error when those
fields are set for a CPU not corresponding to a no-CBs grace-period
kthread is erroneous.
This commit therefore switches the check from ->nocb_timer to
->nocb_bypass_timer and removes the check of ->nocb_defer_wakeup.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Originally, the call to rcu_preempt_blocked_readers_cgp() from
force_qs_rnp() had to be conditioned on CONFIG_PREEMPT_RCU=y, as in
commit a77da14ce9 ("rcu: Yet another fix for preemption and CPU
hotplug"). However, there is now a CONFIG_PREEMPT_RCU=n definition of
rcu_preempt_blocked_readers_cgp() that unconditionally returns zero, so
invoking it is now safe. In addition, the CONFIG_PREEMPT_RCU=n definition
of rcu_initiate_boost() simply releases the rcu_node structure's ->lock,
which is what happens when the "if" condition evaluates to false.
This commit therefore drops the IS_ENABLED(CONFIG_PREEMPT_RCU) check,
so that rcu_initiate_boost() is called only in CONFIG_PREEMPT_RCU=y
kernels when there are readers blocking the current grace period.
This does not change the behavior, but reduces code-reader confusion by
eliminating non-CONFIG_PREEMPT_RCU=y calls to rcu_initiate_boost().
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
On callback overload, it is necessary to quickly detect idle CPUs,
and rcu_gp_fqs_check_wake() checks for this condition. Unfortunately,
the code following the call to this function does not repeat this check,
which means that in reality no actual quiescent-state forcing, instead
only a couple of quick and pointless wakeups at the beginning of the
grace period.
This commit therefore adds a check for the RCU_GP_FLAG_OVLD flag in
the post-wakeup "if" statement in rcu_gp_fqs_loop().
Fixes: 1fca4d12f4 ("rcu: Expedite first two FQS scans under callback-overload conditions")
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
A message of the form "rcu: !!! lDTs ." can be tracked down, but
doing so is not trivial. This commit therefore eases this process by
adding text so that this error message now reads as follows:
"rcu: nocb GP activity on CB-only CPU!!! lDTs ."
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
During acceleration of CB, the rsp's gp_seq is rcu_seq_snap'd. This is
the value used for acceleration - it is the value of gp_seq at which it
is safe the execute all callbacks in the callback list.
The rdp's gp_seq is not very useful for this scenario. Make
rcu_grace_period report the gp_seq_req instead as it allows one to
reason about how the acceleration works.
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit moves the initialization of the CONFIG_PREEMPT=n version of
the rcu_exp_handler() function's rdp and rnp local variables into their
respective declarations to save a couple lines of code.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
KCSAN is now in mainline, so this commit removes the stubs for the
data_race(), ASSERT_EXCLUSIVE_WRITER(), and ASSERT_EXCLUSIVE_ACCESS()
macros.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
KCSAN is now in mainline, so this commit removes the stubs for the
data_race(), ASSERT_EXCLUSIVE_WRITER(), and ASSERT_EXCLUSIVE_ACCESS()
macros.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
KCSAN is now in mainline, so this commit removes the stubs for the
data_race(), ASSERT_EXCLUSIVE_WRITER(), and ASSERT_EXCLUSIVE_ACCESS()
macros.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Remove kcsan_counter_inc/dec() functions, as they perform no other
logic, and are no longer needed.
This avoids several calls in kcsan_setup_watchpoint() and
kcsan_found_watchpoint(), as well as lets the compiler warn us about
potential out-of-bounds accesses as the array's size is known at all
usage sites at compile-time.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Use the same pr_fmt throughout for consistency. [ The only exception is
report.c, where the format must be kept precisely as-is. ]
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Show a message in the kernel log if KCSAN was enabled early.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Remove the debugfs test command, as it is no longer needed now that we
have the KUnit+Torture based kcsan-test module. This is to avoid
confusion around how KCSAN should be tested, as only the kcsan-test
module is maintained.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Simplify checking prefixes and length calculation of constant strings.
For the former, the kernel provides str_has_prefix(), and the latter we
should just use strlen("..") because GCC and Clang have optimizations
that optimize these into constants.
No functional change intended.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Simplify counter ID to name mapping by using an array with designated
inits. This way, we can turn a run-time BUG() into a compile-time static
assertion failure if a counter name is missing.
No functional change intended.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Changes kcsan-test module to support checking reports that include
compound instrumentation. Since we should not fail the test if this
support is unavailable, we have to add a config variable that the test
can use to decide what to check for.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Add missing CONFIG_KCSAN_IGNORE_ATOMICS checks for the builtin atomics
instrumentation.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
For compound instrumentation and assert accesses, skew the watchpoint
delay to be longer if randomized. This is useful to improve race
detection for such accesses.
For compound accesses we should increase the delay as we've aggregated
both read and write instrumentation. By giving up 1 call into the
runtime, we're less likely to set up a watchpoint and thus less likely
to detect a race. We can balance this by increasing the watchpoint
delay.
For assert accesses, we know these are of increased interest, and we
wish to increase our chances of detecting races for such checks.
Note that, kcsan_udelay_{task,interrupt} define the upper bound delays.
When randomized, delays are uniformly distributed between [0, delay].
Skewing the delay does not break this promise as long as the defined
upper bounds are still adhered to. The current skew results in delays
uniformly distributed between [delay/2, delay].
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Add support for compounded read-write instrumentation if supported by
the compiler. Adds the necessary instrumentation functions, and a new
type which is used to generate a more descriptive report.
Furthermore, such compounded memory access instrumentation is excluded
from the "assume aligned writes up to word size are atomic" rule,
because we cannot assume that the compiler emits code that is atomic for
compound ops.
LLVM/Clang added support for the feature in:
785d41a261
The new instrumentation is emitted for sets of memory accesses in the
same basic block to the same address with at least one read appearing
before a write. These typically result from compound operations such as
++, --, +=, -=, |=, &=, etc. but also equivalent forms such as "var =
var + 1". Where the compiler determines that it is equivalent to emit a
call to a single __tsan_read_write instead of separate __tsan_read and
__tsan_write, we can then benefit from improved performance and better
reporting for such access patterns.
The new reports now show that the ops are both reads and writes, for
example:
read-write to 0xffffffff90548a38 of 8 bytes by task 143 on cpu 3:
test_kernel_rmw_array+0x45/0xa0
access_thread+0x71/0xb0
kthread+0x21e/0x240
ret_from_fork+0x22/0x30
read-write to 0xffffffff90548a38 of 8 bytes by task 144 on cpu 2:
test_kernel_rmw_array+0x45/0xa0
access_thread+0x71/0xb0
kthread+0x21e/0x240
ret_from_fork+0x22/0x30
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Adds test case to kcsan-test module, to test atomic builtin
instrumentation works.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Some architectures (currently e.g. s390 partially) implement atomics
using the compiler's atomic builtins (__atomic_*, __sync_*). To support
enabling KCSAN on such architectures in future, or support experimental
use of these builtins, implement support for them.
We should also avoid breaking KCSAN kernels due to use (accidental or
otherwise) of atomic builtins in drivers, as has happened in the past:
https://lkml.kernel.org/r/5231d2c0-41d9-6721-e15f-a7eedf3ce69e@infradead.org
The instrumentation is subtly different from regular reads/writes: TSAN
instrumentation replaces the use of atomic builtins with a call into the
runtime, and the runtime's job is to also execute the desired atomic
operation. We rely on the __atomic_* compiler builtins, available with
all KCSAN-supported compilers, to implement each TSAN atomic
instrumentation function.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
version messed up the reload of the syscall number from pt_regs after
ptrace and seccomp which breaks syscall number rewriting.
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Merge tag 'core-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull entry fix from Thomas Gleixner:
"A single bug fix for the common entry code.
The transcription of the x86 version messed up the reload of the
syscall number from pt_regs after ptrace and seccomp which breaks
syscall number rewriting"
* tag 'core-urgent-2020-08-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
core/entry: Respect syscall number rewrites
Pull networking fixes from David Miller:
"Nothing earth shattering here, lots of small fixes (f.e. missing RCU
protection, bad ref counting, missing memset(), etc.) all over the
place:
1) Use get_file_rcu() in task_file iterator, from Yonghong Song.
2) There are two ways to set remote source MAC addresses in macvlan
driver, but only one of which validates things properly. Fix this.
From Alvin Šipraga.
3) Missing of_node_put() in gianfar probing, from Sumera
Priyadarsini.
4) Preserve device wanted feature bits across multiple netlink
ethtool requests, from Maxim Mikityanskiy.
5) Fix rcu_sched stall in task and task_file bpf iterators, from
Yonghong Song.
6) Avoid reset after device destroy in ena driver, from Shay
Agroskin.
7) Missing memset() in netlink policy export reallocation path, from
Johannes Berg.
8) Fix info leak in __smc_diag_dump(), from Peilin Ye.
9) Decapsulate ECN properly for ipv6 in ipv4 tunnels, from Mark
Tomlinson.
10) Fix number of data stream negotiation in SCTP, from David Laight.
11) Fix double free in connection tracker action module, from Alaa
Hleihel.
12) Don't allow empty NHA_GROUP attributes, from Nikolay Aleksandrov"
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (46 commits)
net: nexthop: don't allow empty NHA_GROUP
bpf: Fix two typos in uapi/linux/bpf.h
net: dsa: b53: check for timeout
tipc: call rcu_read_lock() in tipc_aead_encrypt_done()
net/sched: act_ct: Fix skb double-free in tcf_ct_handle_fragments() error flow
net: sctp: Fix negotiation of the number of data streams.
dt-bindings: net: renesas, ether: Improve schema validation
gre6: Fix reception with IP6_TNL_F_RCV_DSCP_COPY
hv_netvsc: Fix the queue_mapping in netvsc_vf_xmit()
hv_netvsc: Remove "unlikely" from netvsc_select_queue
bpf: selftests: global_funcs: Check err_str before strstr
bpf: xdp: Fix XDP mode when no mode flags specified
selftests/bpf: Remove test_align leftovers
tools/resolve_btfids: Fix sections with wrong alignment
net/smc: Prevent kernel-infoleak in __smc_diag_dump()
sfc: fix build warnings on 32-bit
net: phy: mscc: Fix a couple of spelling mistakes "spcified" -> "specified"
libbpf: Fix map index used in error message
net: gemini: Fix missing free_netdev() in error path of gemini_ethernet_port_probe()
net: atlantic: Use readx_poll_timeout() for large timeout
...
printk wants to store various timestamps (MONOTONIC, REALTIME, BOOTTIME) to
make correlation of dmesg from several systems easier.
Provide an interface to retrieve all three timestamps in one go.
There are some caveats:
1) Boot time and late sleep time injection
Boot time is a racy access on 32bit systems if the sleep time injection
happens late during resume and not in timekeeping_resume(). That could be
avoided by expanding struct tk_read_base with boot offset for 32bit and
adding more overhead to the update. As this is a hard to observe once per
resume event which can be filtered with reasonable effort using the
accurate mono/real timestamps, it's probably not worth the trouble.
Aside of that it might be possible on 32 and 64 bit to observe the
following when the sleep time injection happens late:
CPU 0 CPU 1
timekeeping_resume()
ktime_get_fast_timestamps()
mono, real = __ktime_get_real_fast()
inject_sleep_time()
update boot offset
boot = mono + bootoffset;
That means that boot time already has the sleep time adjustment, but
real time does not. On the next readout both are in sync again.
Preventing this for 64bit is not really feasible without destroying the
careful cache layout of the timekeeper because the sequence count and
struct tk_read_base would then need two cache lines instead of one.
2) Suspend/resume timestamps
Access to the time keeper clock source is disabled accross the innermost
steps of suspend/resume. The accessors still work, but the timestamps
are frozen until time keeping is resumed which happens very early.
For regular suspend/resume there is no observable difference vs. sched
clock, but it might affect some of the nasty low level debug printks.
OTOH, access to sched clock is not guaranteed accross suspend/resume on
all systems either so it depends on the hardware in use.
If that turns out to be a real problem then this could be mitigated by
using sched clock in a similar way as during early boot. But it's not as
trivial as on early boot because it needs some careful protection
against the clock monotonic timestamp jumping backwards on resume.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200814115512.159981360@linutronix.de
During early boot the NMI safe timekeeper returns 0 until the first
clocksource becomes available.
This prevents it from being used for printk or other facilities which today
use sched clock. sched clock can be available way before timekeeping is
initialized.
The obvious workaround for this is to utilize the early sched clock in the
default dummy clock read function until a clocksource becomes available.
After switching to the clocksource clock MONOTONIC and BOOTTIME will not
jump because the timekeeping_init() bases clock MONOTONIC on sched clock
and the offset between clock MONOTONIC and BOOTTIME is zero during boot.
Clock REALTIME cannot provide useful timestamps during early boot up to
the point where a persistent clock becomes available, which is either in
timekeeping_init() or later when the RTC driver which might depend on I2C
or other subsystems is initialized.
There is a minor difference to sched_clock() vs. suspend/resume. As the
timekeeper clock source might not be accessible during suspend, after
timekeeping_suspend() timestamps freeze up to the point where
timekeeping_resume() is invoked. OTOH this is true for some sched clock
implementations as well.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200814115512.041422402@linutronix.de
Allow calling bpf_map_update_elem on sockmap and sockhash from a BPF
context. The synchronization required for this is a bit fiddly: we
need to prevent the socket from changing its state while we add it
to the sockmap, since we rely on getting a callback via
sk_prot->unhash. However, we can't just lock_sock like in
sock_map_sk_acquire because that might sleep. So instead we disable
softirq processing and use bh_lock_sock to prevent further
modification.
Yet, this is still not enough. BPF can be called in contexts where
the current CPU might have locked a socket. If the BPF can get
a hold of such a socket, inserting it into a sockmap would lead to
a deadlock. One straight forward example are sock_ops programs that
have ctx->sk, but the same problem exists for kprobes, etc.
We deal with this by allowing sockmap updates only from known safe
contexts. Improper usage is rejected by the verifier.
I've audited the enabled contexts to make sure they can't run in
a locked context. It's possible that CGROUP_SKB and others are
safe as well, but the auditing here is much more difficult. In
any case, we can extend the safe contexts when the need arises.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-6-lmb@cloudflare.com
The verifier assumes that map values are simple blobs of memory, and
therefore treats ARG_PTR_TO_MAP_VALUE, etc. as such. However, there are
map types where this isn't true. For example, sockmap and sockhash store
sockets. In general this isn't a big problem: we can just
write helpers that explicitly requests PTR_TO_SOCKET instead of
ARG_PTR_TO_MAP_VALUE.
The one exception are the standard map helpers like map_update_elem,
map_lookup_elem, etc. Here it would be nice we could overload the
function prototype for different kinds of maps. Unfortunately, this
isn't entirely straight forward:
We only know the type of the map once we have resolved meta->map_ptr
in check_func_arg. This means we can't swap out the prototype
in check_helper_call until we're half way through the function.
Instead, modify check_func_arg to treat ARG_PTR_TO_MAP_VALUE to
mean "the native type for the map" instead of "pointer to memory"
for sockmap and sockhash. This means we don't have to modify the
function prototype at all
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-5-lmb@cloudflare.com
Don't go via map->ops to call sock_map_update_elem, since we know
what function to call in bpf_map_update_value. Since we currently
don't allow calling map_update_elem from BPF context, we can remove
ops->map_update_elem and rename the function to sock_map_update_elem_sys.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-4-lmb@cloudflare.com
For bpf_map_elem and bpf_sk_local_storage bpf iterators,
additional map_id should be shown for fdinfo and
userspace query. For example, the following is for
a bpf_map_elem iterator.
$ cat /proc/1753/fdinfo/9
pos: 0
flags: 02000000
mnt_id: 14
link_type: iter
link_id: 34
prog_tag: 104be6d3fe45e6aa
prog_id: 173
target_name: bpf_map_elem
map_id: 127
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200821184419.574240-1-yhs@fb.com
This patch implemented bpf_link callback functions
show_fdinfo and fill_link_info to support link_query
interface.
The general interface for show_fdinfo and fill_link_info
will print/fill the target_name. Each targets can
register show_fdinfo and fill_link_info callbacks
to print/fill more target specific information.
For example, the below is a fdinfo result for a bpf
task iterator.
$ cat /proc/1749/fdinfo/7
pos: 0
flags: 02000000
mnt_id: 14
link_type: iter
link_id: 11
prog_tag: 990e1f8152f7e54f
prog_id: 59
target_name: task
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200821184418.574122-1-yhs@fb.com
Alexei Starovoitov says:
====================
pull-request: bpf 2020-08-21
The following pull-request contains BPF updates for your *net* tree.
We've added 11 non-merge commits during the last 5 day(s) which contain
a total of 12 files changed, 78 insertions(+), 24 deletions(-).
The main changes are:
1) three fixes in BPF task iterator logic, from Yonghong.
2) fix for compressed dwarf sections in vmlinux, from Jiri.
3) fix xdp attach regression, from Andrii.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
syzbot crashed on the VM_BUG_ON_PAGE(PageTail) in munlock_vma_page(), when
called from uprobes __replace_page(). Which of many ways to fix it?
Settled on not calling when PageCompound (since Head and Tail are equals
in this context, PageCompound the usual check in uprobes.c, and the prior
use of FOLL_SPLIT_PMD will have cleared PageMlocked already).
Fixes: 5a52c9df62 ("uprobe: use FOLL_SPLIT_PMD instead of FOLL_SPLIT")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org> [5.4+]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2008161338360.20413@eggly.anvils
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The transcript of the x86 entry code to the generic version failed to
reload the syscall number from ptregs after ptrace and seccomp have run,
which both can modify the syscall number in ptregs. It returns the original
syscall number instead which is obviously not the right thing to do.
Reload the syscall number to fix that.
Fixes: 142781e108 ("entry: Provide generic syscall entry functionality")
Reported-by: Kyle Huey <me@kylehuey.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kyle Huey <me@kylehuey.com>
Tested-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/87blj6ifo8.fsf@nanos.tec.linutronix.de
- fix out more fallout from the dma-pool changes
(Nicolas Saenz Julienne, me)
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Merge tag 'dma-mapping-5.9-1' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping fixes from Christoph Hellwig:
"Fix more fallout from the dma-pool changes (Nicolas Saenz Julienne,
me)"
* tag 'dma-mapping-5.9-1' of git://git.infradead.org/users/hch/dma-mapping:
dma-pool: Only allocate from CMA when in same memory zone
dma-pool: fix coherent pool allocations for IOMMU mappings
Add kernel module with user mode driver that populates bpffs with
BPF iterators.
$ mount bpffs /my/bpffs/ -t bpf
$ ls -la /my/bpffs/
total 4
drwxrwxrwt 2 root root 0 Jul 2 00:27 .
drwxr-xr-x 19 root root 4096 Jul 2 00:09 ..
-rw------- 1 root root 0 Jul 2 00:27 maps.debug
-rw------- 1 root root 0 Jul 2 00:27 progs.debug
The user mode driver will load BPF Type Formats, create BPF maps, populate BPF
maps, load two BPF programs, attach them to BPF iterators, and finally send two
bpf_link IDs back to the kernel.
The kernel will pin two bpf_links into newly mounted bpffs instance under
names "progs.debug" and "maps.debug". These two files become human readable.
$ cat /my/bpffs/progs.debug
id name attached
11 dump_bpf_map bpf_iter_bpf_map
12 dump_bpf_prog bpf_iter_bpf_prog
27 test_pkt_access
32 test_main test_pkt_access test_pkt_access
33 test_subprog1 test_pkt_access_subprog1 test_pkt_access
34 test_subprog2 test_pkt_access_subprog2 test_pkt_access
35 test_subprog3 test_pkt_access_subprog3 test_pkt_access
36 new_get_skb_len get_skb_len test_pkt_access
37 new_get_skb_ifindex get_skb_ifindex test_pkt_access
38 new_get_constant get_constant test_pkt_access
The BPF program dump_bpf_prog() in iterators.bpf.c is printing this data about
all BPF programs currently loaded in the system. This information is unstable
and will change from kernel to kernel as ".debug" suffix conveys.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200819042759.51280-4-alexei.starovoitov@gmail.com
The program and map iterators work similar to seq_file-s.
Once the program is pinned in bpffs it can be read with "cat" tool
to print human readable output. In this case about BPF programs and maps.
For example:
$ cat /sys/fs/bpf/progs.debug
id name attached
5 dump_bpf_map bpf_iter_bpf_map
6 dump_bpf_prog bpf_iter_bpf_prog
$ cat /sys/fs/bpf/maps.debug
id name max_entries
3 iterator.rodata 1
To avoid kernel build dependency on clang 10 separate bpf skeleton generation
into manual "make" step and instead check-in generated .skel.h into git.
Unlike 'bpftool prog show' in-kernel BTF name is used (when available)
to print full name of BPF program instead of 16-byte truncated name.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200819042759.51280-3-alexei.starovoitov@gmail.com
Refactor the code a bit to extract bpf_link_by_id() helper.
It's similar to existing bpf_prog_by_id().
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200819042759.51280-2-alexei.starovoitov@gmail.com
The old _do_fork() helper doesn't follow naming conventions of in-kernel
helpers for syscalls. The process creation cleanup in [1] didn't change the
name to something more reasonable mainly because _do_fork() was used in quite a
few places. So sending this as a separate series seemed the better strategy.
This commit does two things:
1. renames _do_fork() to kernel_clone() but keeps _do_fork() as a simple static
inline wrapper around kernel_clone().
2. Changes the return type from long to pid_t. This aligns kernel_thread() and
kernel_clone(). Also, the return value from kernel_clone that is surfaced in
fork(), vfork(), clone(), and clone3() is taken from pid_vrn() which returns
a pid_t too.
Follow-up patches will switch each caller of _do_fork() and each place where it
is referenced over to kernel_clone(). After all these changes are done, we can
remove _do_fork() completely and will only be left with kernel_clone().
[1]: 9ba27414f2 ("Merge tag 'fork-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux")
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Link: https://lore.kernel.org/r/20200819104655.436656-2-christian.brauner@ubuntu.com
SD_PREFER_SIBLING is currently considered in sd_parent_degenerate() but not
in sd_degenerate(). It too hinges on load balancing, and thus won't have
any effect when set on a domain with a single group. Add it to
SD_DEGENERATE_GROUPS_MASK.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-12-valentin.schneider@arm.com
We currently set this flag *only* on domains whose topology level exactly
match the level where we detect asymmetry (as returned by
asym_cpu_capacity_level()). This is rather problematic.
Say there are two clusters in the system, one with a lone big CPU and the
other with a mix of big and LITTLE CPUs (as is allowed by DynamIQ):
DIE [ ]
MC [ ][ ]
0 1 2 3 4
L L B B B
asym_cpu_capacity_level() will figure out that the MC level is the one
where all CPUs can see a CPU of max capacity, and we will thus set
SD_ASYM_CPUCAPACITY at MC level for all CPUs.
That lone big CPU will degenerate its MC domain, since it would be alone in
there, and will end up with just a DIE domain. Since the flag was only set
at MC, this CPU ends up not seeing any SD with the flag set, which is
broken.
Rather than clearing dflags at every topology level, clear it before
entering the topology level loop. This will properly propagate upwards
flags that are set starting from a certain level.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-11-valentin.schneider@arm.com
If there is only a single NUMA node in the system, the only NUMA topology
level that will be generated will be NODE (identity distance), which
doesn't have SD_SERIALIZE.
This means we don't need this special case in sd_parent_degenerate(), as
having the NODE level "naturally" covers it. Thus, remove it.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-10-valentin.schneider@arm.com
Decoding the output of /proc/sys/kernel/sched_domain/cpu*/domain*/flags has
always been somewhat annoying, as one needs to go fetch the bit -> name
mapping from the source code itself. This encoding can be saved in a script
somewhere, but that isn't safe from flags being added, removed or even
shuffled around.
What matters for debugging purposes is to get *which* flags are set in a
given domain, their associated value is pretty much meaningless.
Make the sd flags debug file output flag names.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-7-valentin.schneider@arm.com
Now that we have some description of what we expect the flags layout to
be, we can use that to assert at runtime that the actual layout is sane.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-6-valentin.schneider@arm.com
This flag was introduced in 2014 by commit:
d77b3ed5c9 ("sched: Add a new SD_SHARE_POWERDOMAIN for sched_domain")
but AFAIA it was never leveraged by the scheduler. The closest thing I can
think of is EAS caring about frequency domains, and it does that by
leveraging performance domains.
Remove the flag. No change in functionality is expected.
Suggested-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-2-valentin.schneider@arm.com
Currently when traversing all tasks, the next tid
is always increased by one. This may result in
visiting the same task multiple times in a
pid namespace.
This patch fixed the issue by seting the next
tid as pid_nr_ns(pid, ns) + 1, similar to
funciton next_tgid().
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Link: https://lore.kernel.org/bpf/20200818222310.2181500-1-yhs@fb.com
In our production system, we observed rcu stalls when
'bpftool prog` is running.
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: \x097-....: (20999 ticks this GP) idle=302/1/0x4000000000000000 softirq=1508852/1508852 fqs=4913
\x09(t=21031 jiffies g=2534773 q=179750)
NMI backtrace for cpu 7
CPU: 7 PID: 184195 Comm: bpftool Kdump: loaded Tainted: G W 5.8.0-00004-g68bfc7f8c1b4 #6
Hardware name: Quanta Twin Lakes MP/Twin Lakes Passive MP, BIOS F09_3A17 05/03/2019
Call Trace:
<IRQ>
dump_stack+0x57/0x70
nmi_cpu_backtrace.cold+0x14/0x53
? lapic_can_unplug_cpu.cold+0x39/0x39
nmi_trigger_cpumask_backtrace+0xb7/0xc7
rcu_dump_cpu_stacks+0xa2/0xd0
rcu_sched_clock_irq.cold+0x1ff/0x3d9
? tick_nohz_handler+0x100/0x100
update_process_times+0x5b/0x90
tick_sched_timer+0x5e/0xf0
__hrtimer_run_queues+0x12a/0x2a0
hrtimer_interrupt+0x10e/0x280
__sysvec_apic_timer_interrupt+0x51/0xe0
asm_call_on_stack+0xf/0x20
</IRQ>
sysvec_apic_timer_interrupt+0x6f/0x80
asm_sysvec_apic_timer_interrupt+0x12/0x20
RIP: 0010:task_file_seq_get_next+0x71/0x220
Code: 00 00 8b 53 1c 49 8b 7d 00 89 d6 48 8b 47 20 44 8b 18 41 39 d3 76 75 48 8b 4f 20 8b 01 39 d0 76 61 41 89 d1 49 39 c1 48 19 c0 <48> 8b 49 08 21 d0 48 8d 04 c1 4c 8b 08 4d 85 c9 74 46 49 8b 41 38
RSP: 0018:ffffc90006223e10 EFLAGS: 00000297
RAX: ffffffffffffffff RBX: ffff888f0d172388 RCX: ffff888c8c07c1c0
RDX: 00000000000f017b RSI: 00000000000f017b RDI: ffff888c254702c0
RBP: ffffc90006223e68 R08: ffff888be2a1c140 R09: 00000000000f017b
R10: 0000000000000002 R11: 0000000000100000 R12: ffff888f23c24118
R13: ffffc90006223e60 R14: ffffffff828509a0 R15: 00000000ffffffff
task_file_seq_next+0x52/0xa0
bpf_seq_read+0xb9/0x320
vfs_read+0x9d/0x180
ksys_read+0x5f/0xe0
do_syscall_64+0x38/0x60
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f8815f4f76e
Code: c0 e9 f6 fe ff ff 55 48 8d 3d 76 70 0a 00 48 89 e5 e8 36 06 02 00 66 0f 1f 44 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 52 c3 66 0f 1f 84 00 00 00 00 00 55 48 89 e5
RSP: 002b:00007fff8f9df578 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000000000170b9c0 RCX: 00007f8815f4f76e
RDX: 0000000000001000 RSI: 00007fff8f9df5b0 RDI: 0000000000000007
RBP: 00007fff8f9e05f0 R08: 0000000000000049 R09: 0000000000000010
R10: 00007f881601fa40 R11: 0000000000000246 R12: 00007fff8f9e05a8
R13: 00007fff8f9e05a8 R14: 0000000001917f90 R15: 000000000000e22e
Note that `bpftool prog` actually calls a task_file bpf iterator
program to establish an association between prog/map/link/btf anon
files and processes.
In the case where the above rcu stall occured, we had a process
having 1587 tasks and each task having roughly 81305 files.
This implied 129 million bpf prog invocations. Unfortunwtely none of
these files are prog/map/link/btf files so bpf iterator/prog needs
to traverse all these files and not able to return to user space
since there are no seq_file buffer overflow.
This patch fixed the issue in bpf_seq_read() to limit the number
of visited objects. If the maximum number of visited objects is
reached, no more objects will be visited in the current syscall.
If there is nothing written in the seq_file buffer, -EAGAIN will
return to the user so user can try again.
The maximum number of visited objects is set at 1 million.
In our Intel Xeon D-2191 2.3GHZ 18-core server, bpf_seq_read()
visiting 1 million files takes around 0.18 seconds.
We did not use cond_resched() since for some iterators, e.g.,
netlink iterator, where rcu read_lock critical section spans between
consecutive seq_ops->next(), which makes impossible to do cond_resched()
in the key while loop of function bpf_seq_read().
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/bpf/20200818222309.2181348-1-yhs@fb.com
Current perf assumes that events in a group are independent. Close an
event doesn't impact the value of the other events in the same group.
If the closed event is a member, after the event closure, other events
are still running like a group. If the closed event is a leader, other
events are running as singleton events.
Add PERF_EV_CAP_SIBLING to allow events to indicate they require being
part of a group, and when the leader dies they cannot exist
independently.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-8-kan.liang@linux.intel.com
Checkpatch tool reports
"ERROR: do not initialise globals/statics to 0"
To fix this, audit_sig_sid is uninitialized
As this is stored in the .bss section,
the compiler can initialize the variable automatically.
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Variables sig_pid, audit_sig_uid and audit_sig_sid
are only used in the audit.c file across the kernel
Hence it appears no reason for declaring them as globals
This patch removes their global declarations from the .h file
and change them into static in the .c file.
Signed-off-by: Jules Irenge <jbi.octave@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull networking fixes from David Miller:
"Another batch of fixes:
1) Remove nft_compat counter flush optimization, it generates warnings
from the refcount infrastructure. From Florian Westphal.
2) Fix BPF to search for build id more robustly, from Jiri Olsa.
3) Handle bogus getopt lengths in ebtables, from Florian Westphal.
4) Infoleak and other fixes to j1939 CAN driver, from Eric Dumazet and
Oleksij Rempel.
5) Reset iter properly on mptcp sendmsg() error, from Florian
Westphal.
6) Show a saner speed in bonding broadcast mode, from Jarod Wilson.
7) Various kerneldoc fixes in bonding and elsewhere, from Lee Jones.
8) Fix double unregister in bonding during namespace tear down, from
Cong Wang.
9) Disable RP filter during icmp_redirect selftest, from David Ahern"
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (75 commits)
otx2_common: Use devm_kcalloc() in otx2_config_npa()
net: qrtr: fix usage of idr in port assignment to socket
selftests: disable rp_filter for icmp_redirect.sh
Revert "net: xdp: pull ethernet header off packet after computing skb->protocol"
phylink: <linux/phylink.h>: fix function prototype kernel-doc warning
mptcp: sendmsg: reset iter on error redux
net: devlink: Remove overzealous WARN_ON with snapshots
tipc: not enable tipc when ipv6 works as a module
tipc: fix uninit skb->data in tipc_nl_compat_dumpit()
net: Fix potential wrong skb->protocol in skb_vlan_untag()
net: xdp: pull ethernet header off packet after computing skb->protocol
ipvlan: fix device features
bonding: fix a potential double-unregister
can: j1939: add rxtimer for multipacket broadcast session
can: j1939: abort multipacket broadcast session when timeout occurs
can: j1939: cancel rxtimer on multipacket broadcast session complete
can: j1939: fix support for multipacket broadcast message
net: fddi: skfp: cfm: Remove seemingly unused variable 'ID_sccs'
net: fddi: skfp: cfm: Remove set but unused variable 'oldstate'
net: fddi: skfp: smt: Remove seemingly unused variable 'ID_sccs'
...
With latest `bpftool prog` command, we observed the following kernel
panic.
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD dfe894067 P4D dfe894067 PUD deb663067 PMD 0
Oops: 0010 [#1] SMP
CPU: 9 PID: 6023 ...
RIP: 0010:0x0
Code: Bad RIP value.
RSP: 0000:ffffc900002b8f18 EFLAGS: 00010286
RAX: ffff8883a405f400 RBX: ffff888e46a6bf00 RCX: 000000008020000c
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8883a405f400
RBP: ffff888e46a6bf50 R08: 0000000000000000 R09: ffffffff81129600
R10: ffff8883a405f300 R11: 0000160000000000 R12: 0000000000002710
R13: 000000e9494b690c R14: 0000000000000202 R15: 0000000000000009
FS: 00007fd9187fe700(0000) GS:ffff888e46a40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000de5d33002 CR4: 0000000000360ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
rcu_core+0x1a4/0x440
__do_softirq+0xd3/0x2c8
irq_exit+0x9d/0xa0
smp_apic_timer_interrupt+0x68/0x120
apic_timer_interrupt+0xf/0x20
</IRQ>
RIP: 0033:0x47ce80
Code: Bad RIP value.
RSP: 002b:00007fd9187fba40 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000002 RBX: 00007fd931789160 RCX: 000000000000010c
RDX: 00007fd9308cdfb4 RSI: 00007fd9308cdfb4 RDI: 00007ffedd1ea0a8
RBP: 00007fd9187fbab0 R08: 000000000000000e R09: 000000000000002a
R10: 0000000000480210 R11: 00007fd9187fc570 R12: 00007fd9316cc400
R13: 0000000000000118 R14: 00007fd9308cdfb4 R15: 00007fd9317a9380
After further analysis, the bug is triggered by
Commit eaaacd2391 ("bpf: Add task and task/file iterator targets")
which introduced task_file bpf iterator, which traverses all open file
descriptors for all tasks in the current namespace.
The latest `bpftool prog` calls a task_file bpf program to traverse
all files in the system in order to associate processes with progs/maps, etc.
When traversing files for a given task, rcu read_lock is taken to
access all files in a file_struct. But it used get_file() to grab
a file, which is not right. It is possible file->f_count is 0 and
get_file() will unconditionally increase it.
Later put_file() may cause all kind of issues with the above
as one of sympotoms.
The failure can be reproduced with the following steps in a few seconds:
$ cat t.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#define N 10000
int fd[N];
int main() {
int i;
for (i = 0; i < N; i++) {
fd[i] = open("./note.txt", 'r');
if (fd[i] < 0) {
fprintf(stderr, "failed\n");
return -1;
}
}
for (i = 0; i < N; i++)
close(fd[i]);
return 0;
}
$ gcc -O2 t.c
$ cat run.sh
#/bin/bash
for i in {1..100}
do
while true; do ./a.out; done &
done
$ ./run.sh
$ while true; do bpftool prog >& /dev/null; done
This patch used get_file_rcu() which only grabs a file if the
file->f_count is not zero. This is to ensure the file pointer
is always valid. The above reproducer did not fail for more
than 30 minutes.
Fixes: eaaacd2391 ("bpf: Add task and task/file iterator targets")
Suggested-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/bpf/20200817174214.252601-1-yhs@fb.com
Impose a limit on the number of watches that a user can hold so that
they can't use this mechanism to fill up all the available memory.
This is done by putting a counter in user_struct that's incremented when
a watch is allocated and decreased when it is released. If the number
exceeds the RLIMIT_NOFILE limit, the watch is rejected with EAGAIN.
This can be tested by the following means:
(1) Create a watch queue and attach it to fd 5 in the program given - in
this case, bash:
keyctl watch_session /tmp/nlog /tmp/gclog 5 bash
(2) In the shell, set the maximum number of files to, say, 99:
ulimit -n 99
(3) Add 200 keyrings:
for ((i=0; i<200; i++)); do keyctl newring a$i @s || break; done
(4) Try to watch all of the keyrings:
for ((i=0; i<200; i++)); do echo $i; keyctl watch_add 5 %:a$i || break; done
This should fail when the number of watches belonging to the user hits
99.
(5) Remove all the keyrings and all of those watches should go away:
for ((i=0; i<200; i++)); do keyctl unlink %:a$i; done
(6) Kill off the watch queue by exiting the shell spawned by
watch_session.
Fixes: c73be61ced ("pipe: Add general notification queue support")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'io_uring-5.9-2020-08-15' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
"A few differerent things in here.
Seems like syzbot got some more io_uring bits wired up, and we got a
handful of reports and the associated fixes are in here.
General fixes too, and a lot of them marked for stable.
Lastly, a bit of fallout from the async buffered reads, where we now
more easily trigger short reads. Some applications don't really like
that, so the io_read() code now handles short reads internally, and
got a cleanup along the way so that it's now easier to read (and
documented). We're now passing tests that failed before"
* tag 'io_uring-5.9-2020-08-15' of git://git.kernel.dk/linux-block:
io_uring: short circuit -EAGAIN for blocking read attempt
io_uring: sanitize double poll handling
io_uring: internally retry short reads
io_uring: retain iov_iter state over io_read/io_write calls
task_work: only grab task signal lock when needed
io_uring: enable lookup of links holding inflight files
io_uring: fail poll arm on queue proc failure
io_uring: hold 'ctx' reference around task_work queue + execute
fs: RWF_NOWAIT should imply IOCB_NOIO
io_uring: defer file table grabbing request cleanup for locked requests
io_uring: add missing REQ_F_COMP_LOCKED for nested requests
io_uring: fix recursive completion locking on oveflow flush
io_uring: use TWA_SIGNAL for task_work uncondtionally
io_uring: account locked memory before potential error case
io_uring: set ctx sq/cq entry count earlier
io_uring: Fix NULL pointer dereference in loop_rw_iter()
io_uring: add comments on how the async buffered read retry works
io_uring: io_async_buf_func() need not test page bit
changes to arch/sh.
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Merge tag 'sh-for-5.9' of git://git.libc.org/linux-sh
Pull arch/sh updates from Rich Felker:
"Cleanup, SECCOMP_FILTER support, message printing fixes, and other
changes to arch/sh"
* tag 'sh-for-5.9' of git://git.libc.org/linux-sh: (34 commits)
sh: landisk: Add missing initialization of sh_io_port_base
sh: bring syscall_set_return_value in line with other architectures
sh: Add SECCOMP_FILTER
sh: Rearrange blocks in entry-common.S
sh: switch to copy_thread_tls()
sh: use the generic dma coherent remap allocator
sh: don't allow non-coherent DMA for NOMMU
dma-mapping: consolidate the NO_DMA definition in kernel/dma/Kconfig
sh: unexport register_trapped_io and match_trapped_io_handler
sh: don't include <asm/io_trapped.h> in <asm/io.h>
sh: move the ioremap implementation out of line
sh: move ioremap_fixed details out of <asm/io.h>
sh: remove __KERNEL__ ifdefs from non-UAPI headers
sh: sort the selects for SUPERH alphabetically
sh: remove -Werror from Makefiles
sh: Replace HTTP links with HTTPS ones
arch/sh/configs: remove obsolete CONFIG_SOC_CAMERA*
sh: stacktrace: Remove stacktrace_ops.stack()
sh: machvec: Modernize printing of kernel messages
sh: pci: Modernize printing of kernel messages
...
- Fix mitigation state sysfs output
- Fix an FPU xstate/sxave code assumption bug triggered by Architectural LBR support
- Fix Lightning Mountain SoC TSC frequency enumeration bug
- Fix kexec debug output
- Fix kexec memory range assumption bug
- Fix a boundary condition in the crash kernel code
- Optimize porgatory.ro generation a bit
- Enable ACRN guests to use X2APIC mode
- Reduce a __text_poke() IRQs-off critical section for the benefit of PREEMPT_RT
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
"Misc fixes and small updates all around the place:
- Fix mitigation state sysfs output
- Fix an FPU xstate/sxave code assumption bug triggered by
Architectural LBR support
- Fix Lightning Mountain SoC TSC frequency enumeration bug
- Fix kexec debug output
- Fix kexec memory range assumption bug
- Fix a boundary condition in the crash kernel code
- Optimize porgatory.ro generation a bit
- Enable ACRN guests to use X2APIC mode
- Reduce a __text_poke() IRQs-off critical section for the benefit of
PREEMPT_RT"
* tag 'x86-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/alternatives: Acquire pte lock with interrupts enabled
x86/bugs/multihit: Fix mitigation reporting when VMX is not in use
x86/fpu/xstate: Fix an xstate size check warning with architectural LBRs
x86/purgatory: Don't generate debug info for purgatory.ro
x86/tsr: Fix tsc frequency enumeration bug on Lightning Mountain SoC
kexec_file: Correctly output debugging information for the PT_LOAD ELF header
kexec: Improve & fix crash_exclude_mem_range() to handle overlapping ranges
x86/crash: Correct the address boundary of function parameters
x86/acrn: Remove redundant chars from ACRN signature
x86/acrn: Allow ACRN guest to use X2APIC mode
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"Two fixes: fix a new tracepoint's output value, and fix the formatting
of show-state syslog printouts"
* tag 'sched-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/debug: Fix the alignment of the show-state debug output
sched: Fix use of count for nr_running tracepoint
plus a RAPL HW-enablement for Intel SPR platforms.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"Misc fixes, an expansion of perf syscall access to CAP_PERFMON
privileged tools, plus a RAPL HW-enablement for Intel SPR platforms"
* tag 'perf-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/rapl: Add support for Intel SPR platform
perf/x86/rapl: Support multiple RAPL unit quirks
perf/x86/rapl: Fix missing psys sysfs attributes
hw_breakpoint: Remove unused __register_perf_hw_breakpoint() declaration
kprobes: Remove show_registers() function prototype
perf/core: Take over CAP_SYS_PTRACE creds to CAP_PERFMON capability
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'locking-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixlets from Ingo Molnar:
"A documentation fix and a 'fallthrough' macro update"
* tag 'locking-urgent-2020-08-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Convert to use the preferred 'fallthrough' macro
Documentation/locking/locktypes: Fix a typo
Merge more updates from Andrew Morton:
"Subsystems affected by this patch series: mm/hotfixes, lz4, exec,
mailmap, mm/thp, autofs, sysctl, mm/kmemleak, mm/misc and lib"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (35 commits)
virtio: pci: constify ioreadX() iomem argument (as in generic implementation)
ntb: intel: constify ioreadX() iomem argument (as in generic implementation)
rtl818x: constify ioreadX() iomem argument (as in generic implementation)
iomap: constify ioreadX() iomem argument (as in generic implementation)
sh: use generic strncpy()
sh: clkfwk: remove r8/r16/r32
include/asm-generic/vmlinux.lds.h: align ro_after_init
mm: annotate a data race in page_zonenum()
mm/swap.c: annotate data races for lru_rotate_pvecs
mm/rmap: annotate a data race at tlb_flush_batched
mm/mempool: fix a data race in mempool_free()
mm/list_lru: fix a data race in list_lru_count_one
mm/memcontrol: fix a data race in scan count
mm/page_counter: fix various data races at memsw
mm/swapfile: fix and annotate various data races
mm/filemap.c: fix a data race in filemap_fault()
mm/swap_state: mark various intentional data races
mm/page_io: mark various intentional data races
mm/frontswap: mark various intentional data races
mm/kmemleak: silence KCSAN splats in checksum
...
Since commit 61a47c1ad3 ("sysctl: Remove the sysctl system call"),
sys_sysctl is actually unavailable: any input can only return an error.
We have been warning about people using the sysctl system call for years
and believe there are no more users. Even if there are users of this
interface if they have not complained or fixed their code by now they
probably are not going to, so there is no point in warning them any
longer.
So completely remove sys_sysctl on all architectures.
[nixiaoming@huawei.com: s390: fix build error for sys_call_table_emu]
Link: http://lkml.kernel.org/r/20200618141426.16884-1-nixiaoming@huawei.com
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Will Deacon <will@kernel.org> [arm/arm64]
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bin Meng <bin.meng@windriver.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: chenzefeng <chenzefeng2@huawei.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Diego Elio Pettenò <flameeyes@flameeyes.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kars de Jong <jongk@linux-m68k.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Paul Burton <paulburton@kernel.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Sven Schnelle <svens@stackframe.org>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Zhou Yanjie <zhouyanjie@wanyeetech.com>
Link: http://lkml.kernel.org/r/20200616030734.87257-1-nixiaoming@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Daniel Borkmann says:
====================
pull-request: bpf 2020-08-15
The following pull-request contains BPF updates for your *net* tree.
We've added 23 non-merge commits during the last 4 day(s) which contain
a total of 32 files changed, 421 insertions(+), 141 deletions(-).
The main changes are:
1) Fix sock_ops ctx access splat due to register override, from John Fastabend.
2) Batch of various fixes to libbpf, bpftool, and selftests when testing build
in 32-bit mode, from Andrii Nakryiko.
3) Fix vmlinux.h generation on ARM by mapping GCC built-in types (__Poly*_t)
to equivalent ones clang can work with, from Jean-Philippe Brucker.
4) Fix build_id lookup in bpf_get_stackid() helper by walking all NOTE ELF
sections instead of just first, from Jiri Olsa.
5) Avoid use of __builtin_offsetof() in libbpf for CO-RE, from Yonghong Song.
6) Fix segfault in test_mmap due to inconsistent length params, from Jianlin Lv.
7) Don't override errno in libbpf when logging errors, from Toke Høiland-Jørgensen.
8) Fix v4_to_v6 sockaddr conversion in sk_lookup test, from Stanislav Fomichev.
9) Add link to bpf-helpers(7) man page to BPF doc, from Joe Stringer.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This remoes the code from the COW path to call debug_dma_assert_idle(),
which was added many years ago.
Google shows that it hasn't caught anything in the 6+ years we've had it
apart from a false positive, and Hugh just noticed how it had a very
unfortunate spinlock serialization in the COW path.
He fixed that issue the previous commit (a85ffd59bd: "dma-debug: fix
debug_dma_assert_idle(), use rcu_read_lock()"), but let's see if anybody
even notices when we remove this function entirely.
NOTE! We keep the dma tracking infrastructure that was added by the
commit that introduced it. Partly to make it easier to resurrect this
debug code if we ever deside to, and partly because that tracking by pfn
and offset looks quite reasonable.
The problem with this debug code was simply that it was expensive and
didn't seem worth it, not that it was wrong per se.
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 2a9127fcf2 ("mm: rewrite wait_on_page_bit_common()
logic") improved unlock_page(), it has become more noticeable how
cow_user_page() in a kernel with CONFIG_DMA_API_DEBUG=y can create and
suffer from heavy contention on DMA debug's radix_lock in
debug_dma_assert_idle().
It is only doing a lookup: use rcu_read_lock() and rcu_read_unlock()
instead; though that does require the static ents[] to be moved
onstack...
...but, hold on, isn't that radix_tree_gang_lookup() and loop doing
quite the wrong thing: searching CACHELINES_PER_PAGE entries for an
exact match with the first cacheline of the page in question?
radix_tree_gang_lookup() is the right tool for the job, but we need
nothing more than to check the first entry it can find, reporting if
that falls anywhere within the page.
(Is RCU safe here? As safe as using the spinlock was. The entries are
never freed, so don't need to be freed by RCU. They may be reused, and
there is a faint chance of a race, with an offending entry reused while
printing its error info; but the spinlock did not prevent that either,
and I agree that it's not worth worrying about. ]
[ Side noe: this patch is a clear improvement to the status quo, but the
next patch will be removing this debug function entirely.
But just in case we decide we want to resurrect the debugging code
some day, I'm first applying this improvement patch so that it doesn't
get lost - Linus ]
Fixes: 3b7a6418c7 ("dma debug: account for cachelines and read-only mappings in overlap tracking")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Preparatory work to allow S390 to switch over to the generic VDSO
implementation.
S390 requires that the VDSO data pointer is handed in to the counter
read function when time namespace support is enabled. Adding the pointer
is a NOOP for all other architectures because the compiler is supposed
to optimize that out when it is unused in the architecture specific
inline. The change also solved a similar problem for MIPS which
fortunately has time namespaces not yet enabled.
S390 needs to update clock related VDSO data independent of the
timekeeping updates. This was solved so far with yet another sequence
counter in the S390 implementation. A better solution is to utilize the
already existing VDSO sequence count for this. The core code now exposes
helper functions which allow to serialize against the timekeeper code
and against concurrent readers.
S390 needs extra data for their clock readout function. The initial
common VDSO data structure did not provide a way to add that. It now has
an embedded architecture specific struct embedded which defaults to an
empty struct.
Doing this now avoids tree dependencies and conflicts post rc1 and
allows all other architectures which work on generic VDSO support to
work from a common upstream base.
- A trivial comment fix.
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Merge tag 'timers-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timekeeping updates from Thomas Gleixner:
"A set of timekeeping/VDSO updates:
- Preparatory work to allow S390 to switch over to the generic VDSO
implementation.
S390 requires that the VDSO data pointer is handed in to the
counter read function when time namespace support is enabled.
Adding the pointer is a NOOP for all other architectures because
the compiler is supposed to optimize that out when it is unused in
the architecture specific inline. The change also solved a similar
problem for MIPS which fortunately has time namespaces not yet
enabled.
S390 needs to update clock related VDSO data independent of the
timekeeping updates. This was solved so far with yet another
sequence counter in the S390 implementation. A better solution is
to utilize the already existing VDSO sequence count for this. The
core code now exposes helper functions which allow to serialize
against the timekeeper code and against concurrent readers.
S390 needs extra data for their clock readout function. The initial
common VDSO data structure did not provide a way to add that. It
now has an embedded architecture specific struct embedded which
defaults to an empty struct.
Doing this now avoids tree dependencies and conflicts post rc1 and
allows all other architectures which work on generic VDSO support
to work from a common upstream base.
- A trivial comment fix"
* tag 'timers-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time: Delete repeated words in comments
lib/vdso: Allow to add architecture-specific vdso data
timekeeping/vsyscall: Provide vdso_update_begin/end()
vdso/treewide: Add vdso_data pointer argument to __arch_get_hw_counter()
posix CPU timers into task work context. The tick interrupt is reduced to a
quick check which queues the work which is doing the heavy lifting before
returning to user space or going back to guest mode. Moving this out is
deferring the signal delivery slightly but posix CPU timers are inaccurate
by nature as they depend on the tick so there is no real damage. The
relevant test cases all passed.
This lifts the last offender for RT out of the hard interrupt context tick
handler, but it also has the general benefit that the actual heavy work is
accounted to the task/process and not to the tick interrupt itself.
Further optimizations are possible to break long sighand lock hold and
interrupt disabled (on !RT kernels) times when a massive amount of posix
CPU timers (which are unpriviledged) is armed for a task/process.
This is currently only enabled for x86 because the architecture has to
ensure that task work is handled in KVM before entering a guest, which was
just established for x86 with the new common entry/exit code which got
merged post 5.8 and is not the case for other KVM architectures.
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Merge tag 'timers-core-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull more timer updates from Thomas Gleixner:
"A set of posix CPU timer changes which allows to defer the heavy work
of posix CPU timers into task work context. The tick interrupt is
reduced to a quick check which queues the work which is doing the
heavy lifting before returning to user space or going back to guest
mode. Moving this out is deferring the signal delivery slightly but
posix CPU timers are inaccurate by nature as they depend on the tick
so there is no real damage. The relevant test cases all passed.
This lifts the last offender for RT out of the hard interrupt context
tick handler, but it also has the general benefit that the actual
heavy work is accounted to the task/process and not to the tick
interrupt itself.
Further optimizations are possible to break long sighand lock hold and
interrupt disabled (on !RT kernels) times when a massive amount of
posix CPU timers (which are unpriviledged) is armed for a
task/process.
This is currently only enabled for x86 because the architecture has to
ensure that task work is handled in KVM before entering a guest, which
was just established for x86 with the new common entry/exit code which
got merged post 5.8 and is not the case for other KVM architectures"
* tag 'timers-core-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Select POSIX_CPU_TIMERS_TASK_WORK
posix-cpu-timers: Provide mechanisms to defer timer handling to task_work
posix-cpu-timers: Split run_posix_cpu_timers()
unlock the descriptor lock.
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Merge tag 'irq-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
"Two fixes in the core interrupt code which ensure that all error exits
unlock the descriptor lock"
* tag 'irq-urgent-2020-08-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
genirq: Unlock irq descriptor after errors
genirq/PM: Always unlock IRQ descriptor in rearm_wake_irq()
Summary of modules changes for the 5.9 merge window:
- Have modules that use symbols from proprietary modules inherit the
TAINT_PROPRIETARY_MODULE taint, in an effort to prevent GPL shim modules that
are used to circumvent _GPL exports. These are modules that claim to be GPL
licensed while also using symbols from proprietary modules. Such modules will
be rejected while non-GPL modules will inherit the proprietary taint.
- Module export space cleanup. Unexport symbols that are unused outside of
module.c or otherwise used in only built-in code.
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull module updates from Jessica Yu:
"The most important change would be Christoph Hellwig's patch
implementing proprietary taint inheritance, in an effort to discourage
the creation of GPL "shim" modules that interface between GPL symbols
and proprietary symbols.
Summary:
- Have modules that use symbols from proprietary modules inherit the
TAINT_PROPRIETARY_MODULE taint, in an effort to prevent GPL shim
modules that are used to circumvent _GPL exports. These are modules
that claim to be GPL licensed while also using symbols from
proprietary modules. Such modules will be rejected while non-GPL
modules will inherit the proprietary taint.
- Module export space cleanup. Unexport symbols that are unused
outside of module.c or otherwise used in only built-in code"
* tag 'modules-for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
modules: inherit TAINT_PROPRIETARY_MODULE
modules: return licensing information from find_symbol
modules: rename the licence field in struct symsearch to license
modules: unexport __module_address
modules: unexport __module_text_address
modules: mark each_symbol_section static
modules: mark find_symbol static
modules: mark ref_module static
modules: linux/moduleparam.h: drop duplicated word in a comment
There is no guarantee to CMA's placement, so allocating a zone specific
atomic pool from CMA might return memory from a completely different
memory zone. To get around this double check CMA's placement before
allocating from it.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
When allocating coherent pool memory for an IOMMU mapping we don't care
about the DMA mask. Move the guess for the initial GFP mask into the
dma_direct_alloc_pages and pass dma_coherent_ok as a function pointer
argument so that it doesn't get applied to the IOMMU case.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Amit Pundir <amit.pundir@linaro.org>
Current sysrq(t) output task fields name are not aligned with
actual task fields value, e.g.:
kernel: sysrq: Show State
kernel: task PC stack pid father
kernel: systemd S12456 1 0 0x00000000
kernel: Call Trace:
kernel: ? __schedule+0x240/0x740
To make it more readable, print fields name together with task fields
value in the same line, with fixed width:
kernel: sysrq: Show State
kernel: task:systemd state:S stack:12920 pid: 1 ppid: 0 flags:0x00000000
kernel: Call Trace:
kernel: __schedule+0x282/0x620
Signed-off-by: Libing Zhou <libing.zhou@nokia-sbell.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200814030236.37835-1-libing.zhou@nokia-sbell.com
Pull networking fixes from David Miller:
"Some merge window fallout, some longer term fixes:
1) Handle headroom properly in lapbether and x25_asy drivers, from
Xie He.
2) Fetch MAC address from correct r8152 device node, from Thierry
Reding.
3) In the sw kTLS path we should allow MSG_CMSG_COMPAT in sendmsg,
from Rouven Czerwinski.
4) Correct fdputs in socket layer, from Miaohe Lin.
5) Revert troublesome sockptr_t optimization, from Christoph Hellwig.
6) Fix TCP TFO key reading on big endian, from Jason Baron.
7) Missing CAP_NET_RAW check in nfc, from Qingyu Li.
8) Fix inet fastreuse optimization with tproxy sockets, from Tim
Froidcoeur.
9) Fix 64-bit divide in new SFC driver, from Edward Cree.
10) Add a tracepoint for prandom_u32 so that we can more easily
perform usage analysis. From Eric Dumazet.
11) Fix rwlock imbalance in AF_PACKET, from John Ogness"
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (49 commits)
net: openvswitch: introduce common code for flushing flows
af_packet: TPACKET_V3: fix fill status rwlock imbalance
random32: add a tracepoint for prandom_u32()
Revert "ipv4: tunnel: fix compilation on ARCH=um"
net: accept an empty mask in /sys/class/net/*/queues/rx-*/rps_cpus
net: ethernet: stmmac: Disable hardware multicast filter
net: stmmac: dwmac1000: provide multicast filter fallback
ipv4: tunnel: fix compilation on ARCH=um
vsock: fix potential null pointer dereference in vsock_poll()
sfc: fix ef100 design-param checking
net: initialize fastreuse on inet_inherit_port
net: refactor bind_bucket fastreuse into helper
net: phy: marvell10g: fix null pointer dereference
net: Fix potential memory leak in proto_register()
net: qcom/emac: add missed clk_disable_unprepare in error path of emac_clks_phase1_init
ionic_lif: Use devm_kcalloc() in ionic_qcq_alloc()
net/nfc/rawsock.c: add CAP_NET_RAW check.
hinic: fix strncpy output truncated compile warnings
drivers/net/wan/x25_asy: Added needed_headroom and a skb->len check
net/tls: Fix kmap usage
...
If JOBCTL_TASK_WORK is already set on the targeted task, then we need
not go through {lock,unlock}_task_sighand() to set it again and queue
a signal wakeup. This is safe as we're checking it _after_ adding the
new task_work with cmpxchg().
The ordering is as follows:
task_work_add() get_signal()
--------------------------------------------------------------
STORE(task->task_works, new_work); STORE(task->jobctl);
mb(); mb();
LOAD(task->jobctl); LOAD(task->task_works);
This speeds up TWA_SIGNAL handling quite a bit, which is important now
that io_uring is relying on it for all task_work deliveries.
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jann Horn <jannh@google.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
In irq_set_irqchip_state(), the irq descriptor is not unlocked after an
error is encountered. While that should never happen in practice, a buggy
driver may trigger it. This would result in a lockup, so fix it.
Fixes: 1d0326f352 ("genirq: Check irq_data_get_irq_chip() return value before use")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200811180012.80269-1-linux@roeck-us.net
Currently when we look for build id within bpf_get_stackid helper
call, we check the first NOTE section and we fail if build id is
not there.
However on some system (Fedora) there can be multiple NOTE sections
in binaries and build id data is not always the first one, like:
$ readelf -a /usr/bin/ls
...
[ 2] .note.gnu.propert NOTE 0000000000000338 00000338
0000000000000020 0000000000000000 A 0 0 8358
[ 3] .note.gnu.build-i NOTE 0000000000000358 00000358
0000000000000024 0000000000000000 A 0 0 437c
[ 4] .note.ABI-tag NOTE 000000000000037c 0000037c
...
So the stack_map_get_build_id function will fail on build id retrieval
and fallback to BPF_STACK_BUILD_ID_IP.
This patch is changing the stack_map_get_build_id code to iterate
through all the NOTE sections and try to get build id data from
each of them.
When tracing on sched_switch tracepoint that does bpf_get_stackid
helper call kernel build, I can see about 60% increase of successful
build id retrieval. The rest seems fails on -EFAULT.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20200812123102.20032-1-jolsa@kernel.org
Backmerging drm-next into drm-misc-next for nouveau and panel updates.
Resolves a conflict between ttm and nouveau, where struct ttm_mem_res got
renamed to struct ttm_resource.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
