Create struct msi_device_data and add a pointer of that type to struct
dev_msi_info, which is part of struct device. Provide an allocator function
which can be invoked from the MSI interrupt allocation code pathes.
Add a properties field to the data structure as a first member so the
allocation size is not zero bytes. The field will be uses later on.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211210221813.676660809@linutronix.de
Make the bounds propagation in __reg_assign_32_into_64() slightly more
robust and readable by aligning it similarly as we did back in the
__reg_combine_64_into_32() counterpart. Meaning, only propagate or
pessimize them as a smin/smax pair.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
For the case where both s32_{min,max}_value bounds are positive, the
__reg_assign_32_into_64() directly propagates them to their 64 bit
counterparts, otherwise it pessimises them into [0,u32_max] universe and
tries to refine them later on by learning through the tnum as per comment
in mentioned function. However, that does not always happen, for example,
in mov32 operation we call zext_32_to_64(dst_reg) which invokes the
__reg_assign_32_into_64() as is without subsequent bounds update as
elsewhere thus no refinement based on tnum takes place.
Thus, not calling into the __update_reg_bounds() / __reg_deduce_bounds() /
__reg_bound_offset() triplet as we do, for example, in case of ALU ops via
adjust_scalar_min_max_vals(), will lead to more pessimistic bounds when
dumping the full register state:
Before fix:
0: (b4) w0 = -1
1: R0_w=invP4294967295
(id=0,imm=ffffffff,
smin_value=4294967295,smax_value=4294967295,
umin_value=4294967295,umax_value=4294967295,
var_off=(0xffffffff; 0x0),
s32_min_value=-1,s32_max_value=-1,
u32_min_value=-1,u32_max_value=-1)
1: (bc) w0 = w0
2: R0_w=invP4294967295
(id=0,imm=ffffffff,
smin_value=0,smax_value=4294967295,
umin_value=4294967295,umax_value=4294967295,
var_off=(0xffffffff; 0x0),
s32_min_value=-1,s32_max_value=-1,
u32_min_value=-1,u32_max_value=-1)
Technically, the smin_value=0 and smax_value=4294967295 bounds are not
incorrect, but given the register is still a constant, they break assumptions
about const scalars that smin_value == smax_value and umin_value == umax_value.
After fix:
0: (b4) w0 = -1
1: R0_w=invP4294967295
(id=0,imm=ffffffff,
smin_value=4294967295,smax_value=4294967295,
umin_value=4294967295,umax_value=4294967295,
var_off=(0xffffffff; 0x0),
s32_min_value=-1,s32_max_value=-1,
u32_min_value=-1,u32_max_value=-1)
1: (bc) w0 = w0
2: R0_w=invP4294967295
(id=0,imm=ffffffff,
smin_value=4294967295,smax_value=4294967295,
umin_value=4294967295,umax_value=4294967295,
var_off=(0xffffffff; 0x0),
s32_min_value=-1,s32_max_value=-1,
u32_min_value=-1,u32_max_value=-1)
Without the smin_value == smax_value and umin_value == umax_value invariant
being intact for const scalars, it is possible to leak out kernel pointers
from unprivileged user space if the latter is enabled. For example, when such
registers are involved in pointer arithmtics, then adjust_ptr_min_max_vals()
will taint the destination register into an unknown scalar, and the latter
can be exported and stored e.g. into a BPF map value.
Fixes: 3f50f132d8 ("bpf: Verifier, do explicit ALU32 bounds tracking")
Reported-by: Kuee K1r0a <liulin063@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
If the audit daemon were ever to get stuck in a stopped state the
kernel's kauditd_thread() could get blocked attempting to send audit
records to the userspace audit daemon. With the kernel thread
blocked it is possible that the audit queue could grow unbounded as
certain audit record generating events must be exempt from the queue
limits else the system enter a deadlock state.
This patch resolves this problem by lowering the kernel thread's
socket sending timeout from MAX_SCHEDULE_TIMEOUT to HZ/10 and tweaks
the kauditd_send_queue() function to better manage the various audit
queues when connection problems occur between the kernel and the
audit daemon. With this patch, the backlog may temporarily grow
beyond the defined limits when the audit daemon is stopped and the
system is under heavy audit pressure, but kauditd_thread() will
continue to make progress and drain the queues as it would for other
connection problems. For example, with the audit daemon put into a
stopped state and the system configured to audit every syscall it
was still possible to shutdown the system without a kernel panic,
deadlock, etc.; granted, the system was slow to shutdown but that is
to be expected given the extreme pressure of recording every syscall.
The timeout value of HZ/10 was chosen primarily through
experimentation and this developer's "gut feeling". There is likely
no one perfect value, but as this scenario is limited in scope (root
privileges would be needed to send SIGSTOP to the audit daemon), it
is likely not worth exposing this as a tunable at present. This can
always be done at a later date if it proves necessary.
Cc: stable@vger.kernel.org
Fixes: 5b52330bbf ("audit: fix auditd/kernel connection state tracking")
Reported-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Tested-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Due to the audit control mutex necessary for serializing audit
userspace messages we haven't been able to block/penalize userspace
processes that attempt to send audit records while the system is
under audit pressure. The result is that privileged userspace
applications have a priority boost with respect to audit as they are
not bound by the same audit queue throttling as the other tasks on
the system.
This patch attempts to restore some balance to the system when under
audit pressure by blocking these privileged userspace tasks after
they have finished their audit processing, and dropped the audit
control mutex, but before they return to userspace.
Reported-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Tested-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The implementation of BPF_CMPXCHG on a high level has the following parameters:
.-[old-val] .-[new-val]
BPF_R0 = cmpxchg{32,64}(DST_REG + insn->off, BPF_R0, SRC_REG)
`-[mem-loc] `-[old-val]
Given a BPF insn can only have two registers (dst, src), the R0 is fixed and
used as an auxilliary register for input (old value) as well as output (returning
old value from memory location). While the verifier performs a number of safety
checks, it misses to reject unprivileged programs where R0 contains a pointer as
old value.
Through brute-forcing it takes about ~16sec on my machine to leak a kernel pointer
with BPF_CMPXCHG. The PoC is basically probing for kernel addresses by storing the
guessed address into the map slot as a scalar, and using the map value pointer as
R0 while SRC_REG has a canary value to detect a matching address.
Fix it by checking R0 for pointers, and reject if that's the case for unprivileged
programs.
Fixes: 5ffa25502b ("bpf: Add instructions for atomic_[cmp]xchg")
Reported-by: Ryota Shiga (Flatt Security)
Acked-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The change in commit 37086bfdc7 ("bpf: Propagate stack bounds to registers
in atomics w/ BPF_FETCH") around check_mem_access() handling is buggy since
this would allow for unprivileged users to leak kernel pointers. For example,
an atomic fetch/and with -1 on a stack destination which holds a spilled
pointer will migrate the spilled register type into a scalar, which can then
be exported out of the program (since scalar != pointer) by dumping it into
a map value.
The original implementation of XADD was preventing this situation by using
a double call to check_mem_access() one with BPF_READ and a subsequent one
with BPF_WRITE, in both cases passing -1 as a placeholder value instead of
register as per XADD semantics since it didn't contain a value fetch. The
BPF_READ also included a check in check_stack_read_fixed_off() which rejects
the program if the stack slot is of __is_pointer_value() if dst_regno < 0.
The latter is to distinguish whether we're dealing with a regular stack spill/
fill or some arithmetical operation which is disallowed on non-scalars, see
also 6e7e63cbb0 ("bpf: Forbid XADD on spilled pointers for unprivileged
users") for more context on check_mem_access() and its handling of placeholder
value -1.
One minimally intrusive option to fix the leak is for the BPF_FETCH case to
initially check the BPF_READ case via check_mem_access() with -1 as register,
followed by the actual load case with non-negative load_reg to propagate
stack bounds to registers.
Fixes: 37086bfdc7 ("bpf: Propagate stack bounds to registers in atomics w/ BPF_FETCH")
Reported-by: <n4ke4mry@gmail.com>
Acked-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
== Background ==
Support for large, "dynamic" fpstates was recently merged. This
included code to ensure that sigaltstacks are sufficiently sized for
these large states. A new lock was added to remove races between
enabling large features and setting up sigaltstacks.
== Problem ==
The new lock (sigaltstack_lock()) is acquired in the sigreturn path
before restoring the old sigaltstack. Unfortunately, contention on the
new lock causes a measurable signal handling performance regression [1].
However, the common case is that no *changes* are made to the
sigaltstack state at sigreturn.
== Solution ==
do_sigaltstack() acquires sigaltstack_lock() and is used for both
sys_sigaltstack() and restoring the sigaltstack in sys_sigreturn().
Check for changes to the sigaltstack before taking the lock. If no
changes were made, return before acquiring the lock.
This removes lock contention from the common-case sigreturn path.
[1] https://lore.kernel.org/lkml/20211207012128.GA16074@xsang-OptiPlex-9020/
Fixes: 3aac3ebea0 ("x86/signal: Implement sigaltstack size validation")
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20211210225503.12734-1-chang.seok.bae@intel.com
If a cset is already on preloaded list, this means we have already setup
this cset properly for migration.
This patch just relocates the root cgrp lookup which isn't used anyway
when the cset is already on the preloaded list.
[tj@kernel.org: rephrase the commit log]
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch enables KCSAN for arm64, with updates to build rules
to not use KCSAN for several incompatible compilation units.
Recent GCC version(at least GCC10) made outline-atomics as the
default option(unlike Clang), which will cause linker errors
for kernel/kcsan/core.o. Disables the out-of-line atomics by
no-outline-atomics to fix the linker errors.
Meanwhile, as Mark said[1], some latent issues are needed to be
fixed which isn't just a KCSAN problem, we make the KCSAN depends
on EXPERT for now.
Tested selftest and kcsan_test(built with GCC11 and Clang 13),
and all passed.
[1] https://lkml.kernel.org/r/YadiUPpJ0gADbiHQ@FVFF77S0Q05N
Acked-by: Marco Elver <elver@google.com> # kernel/kcsan
Tested-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Link: https://lore.kernel.org/r/20211211131734.126874-1-wangkefeng.wang@huawei.com
[catalin.marinas@arm.com: added comment to justify EXPERT]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
On arm64, user space counter access will be controlled differently
compared to x86. On x86, access in the strictest mode is enabled for all
tasks in an MM when any event is mmap'ed. For arm64, access is
explicitly requested for an event and only enabled when the event's
context is active. This avoids hooks into the arch context switch code
and gives better control of when access is enabled.
In order to configure user space access when the PMU is enabled, it is
necessary to know if any event (currently active or not) in the current
context has user space accessed enabled. Add a counter similar to other
counters in the context to avoid walking the event list every time.
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211208201124.310740-3-robh@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
In non trivial scenarios, the action id alone is not sufficient to
identify the program causing the warning. Before the previous patch,
the generated stack-trace pointed out at least the involved device
driver.
Let's additionally include the program name and id, and the relevant
device name.
If the user needs additional infos, he can fetch them via a kernel
probe, leveraging the arguments added here.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/ddb96bb975cbfddb1546cf5da60e77d5100b533c.1638189075.git.pabeni@redhat.com
In validate_change(), there is a check since v2.6.12 to make sure that
each of the child cpusets must be a subset of a parent cpuset. IOW, it
allows child cpusets to restrict what changes can be made to a parent's
"cpuset.cpus". This actually violates one of the core principles of the
default hierarchy where a cgroup higher up in the hierarchy should be
able to change configuration however it sees fit as deligation breaks
down otherwise.
To address this issue, the check is now removed for the default hierarchy
to free parent cpusets from being restricted by child cpusets. The
check will still apply for legacy hierarchy.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The exit code of kernel threads has different semantics than the
exit_code of userspace tasks. To avoid confusion and allow
the userspace implementation to change as needed move
the kernel thread exit code into struct kthread.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Today the rules are a bit iffy and arbitrary about which kernel
threads have struct kthread present. Both idle threads and thread
started with create_kthread want struct kthread present so that is
effectively all kernel threads. Make the rule that if PF_KTHREAD
and the task is running then struct kthread is present.
This will allow the kernel thread code to using tsk->exit_code
with different semantics from ordinary processes.
To make ensure that struct kthread is present for all
kernel threads move it's allocation into copy_process.
Add a deallocation of struct kthread in exec for processes
that were kernel threads.
Move the allocation of struct kthread for the initial thread
earlier so that it is not repeated for each additional idle
thread.
Move the initialization of struct kthread into set_kthread_struct
so that the structure is always and reliably initailized.
Clear set_child_tid in free_kthread_struct to ensure the kthread
struct is reliably freed during exec. The function
free_kthread_struct does not need to clear vfork_done during exec as
exec_mm_release called from exec_mmap has already cleared vfork_done.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Update complete_and_exit to call kthread_exit instead of do_exit.
Change the name to reflect this change in functionality. All of the
users of complete_and_exit are causing the current kthread to exit so
this change makes it clear what is happening.
Move the implementation of kthread_complete_and_exit from
kernel/exit.c to to kernel/kthread.c. As this function is kthread
specific it makes most sense to live with the kthread functions.
There are no functional change.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Update module_put_and_exit to call kthread_exit instead of do_exit.
Change the name to reflect this change in functionality. All of the
users of module_put_and_exit are causing the current kthread to exit
so this change makes it clear what is happening. There is no
functional change.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The way the per task_struct exit_code is used by kernel threads is not
quite compatible how it is used by userspace applications. The low
byte of the userspace exit_code value encodes the exit signal. While
kthreads just use the value as an int holding ordinary kernel function
exit status like -EPERM.
Add kthread_exit to clearly separate the two kinds of uses.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Now that there are no more modular uses of do_exit remove the EXPORT_SYMBOL.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
When the kernel detects it is oops or otherwise force killing a task
while it exits the code poorly attempts to permanently stop the task
from scheduling.
I say poorly because it is possible for a task in TASK_UINTERRUPTIBLE
to be woken up.
As it makes no sense for the task to continue call do_task_dead
instead which actually does the work and permanently removes the task
from the scheduler. Guaranteeing the task will never be woken
up again.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The beginning of do_exit has become cluttered and difficult to read as
it is filled with checks to handle things that can only happen when
the kernel is operating improperly.
Now that we have a dedicated function for cleaning up a task when the
kernel is operating improperly move the checks there.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
There are two big uses of do_exit. The first is it's design use to be
the guts of the exit(2) system call. The second use is to terminate
a task after something catastrophic has happened like a NULL pointer
in kernel code.
Add a function make_task_dead that is initialy exactly the same as
do_exit to cover the cases where do_exit is called to handle
catastrophic failure. In time this can probably be reduced to just a
light wrapper around do_task_dead. For now keep it exactly the same so
that there will be no behavioral differences introducing this new
concept.
Replace all of the uses of do_exit that use it for catastraphic
task cleanup with make_task_dead to make it clear what the code
is doing.
As part of this rename rewind_stack_do_exit
rewind_stack_and_make_dead.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Adding following helpers for tracing programs:
Get n-th argument of the traced function:
long bpf_get_func_arg(void *ctx, u32 n, u64 *value)
Get return value of the traced function:
long bpf_get_func_ret(void *ctx, u64 *value)
Get arguments count of the traced function:
long bpf_get_func_arg_cnt(void *ctx)
The trampoline now stores number of arguments on ctx-8
address, so it's easy to verify argument index and find
return value argument's position.
Moving function ip address on the trampoline stack behind
the number of functions arguments, so it's now stored on
ctx-16 address if it's needed.
All helpers above are inlined by verifier.
Also bit unrelated small change - using newly added function
bpf_prog_has_trampoline in check_get_func_ip.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211208193245.172141-5-jolsa@kernel.org
Adding support to access arguments with int pointer arguments
in tracing programs.
Currently we allow tracing programs to access only pointers to
string (char pointer), void pointers and pointers to structs.
If we try to access argument which is pointer to int, verifier
will fail to load the program with;
R1 type=ctx expected=fp
; int BPF_PROG(fmod_ret_test, int _a, __u64 _b, int _ret)
0: (bf) r6 = r1
; int BPF_PROG(fmod_ret_test, int _a, __u64 _b, int _ret)
1: (79) r9 = *(u64 *)(r6 +8)
func 'bpf_modify_return_test' arg1 type INT is not a struct
There is no harm for the program to access int pointer argument.
We are already doing that for string pointer, which is pointer
to int with 1 byte size.
Changing the is_string_ptr to generic integer check and renaming
it to btf_type_is_int.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211208193245.172141-2-jolsa@kernel.org
Coverity issued the following warning:
6685 cands = bpf_core_add_cands(cands, main_btf, 1);
6686 if (IS_ERR(cands))
>>> CID 1510300: (RETURN_LOCAL)
>>> Returning pointer "cands" which points to local variable "local_cand".
6687 return cands;
It's a false positive.
Add ERR_CAST() to silence it.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Merge misc fixes from Andrew Morton:
"21 patches.
Subsystems affected by this patch series: MAINTAINERS, mailmap, and mm
(mlock, pagecache, damon, slub, memcg, hugetlb, and pagecache)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (21 commits)
mm: bdi: initialize bdi_min_ratio when bdi is unregistered
hugetlbfs: fix issue of preallocation of gigantic pages can't work
mm/memcg: relocate mod_objcg_mlstate(), get_obj_stock() and put_obj_stock()
mm/slub: fix endianness bug for alloc/free_traces attributes
selftests/damon: split test cases
selftests/damon: test debugfs file reads/writes with huge count
selftests/damon: test wrong DAMOS condition ranges input
selftests/damon: test DAMON enabling with empty target_ids case
selftests/damon: skip test if DAMON is running
mm/damon/vaddr-test: remove unnecessary variables
mm/damon/vaddr-test: split a test function having >1024 bytes frame size
mm/damon/vaddr: remove an unnecessary warning message
mm/damon/core: remove unnecessary error messages
mm/damon/dbgfs: remove an unnecessary error message
mm/damon/core: use better timer mechanisms selection threshold
mm/damon/core: fix fake load reports due to uninterruptible sleeps
timers: implement usleep_idle_range()
filemap: remove PageHWPoison check from next_uptodate_page()
mailmap: update email address for Guo Ren
MAINTAINERS: update kdump maintainers
...
cpu_util_cfs() was created by commit d4edd662ac ("sched/cpufreq: Use
the DEADLINE utilization signal") to enable the access to CPU
utilization from the Schedutil CPUfreq governor.
Commit a07630b8b2 ("sched/cpufreq/schedutil: Use util_est for OPP
selection") added util_est support later.
The only thing cpu_util() is doing on top of what cpu_util_cfs() already
does is to clamp the return value to the [0..capacity_orig] capacity
range of the CPU. Integrating this into cpu_util_cfs() is not harming
the existing users (Schedutil and CPUfreq cooling (latter via
sched_cpu_util() wrapper)).
For straightforwardness, prefer to keep using `int cpu` as the function
parameter over using `struct rq *rq` which might avoid some calls to
cpu_rq(cpu) -> per_cpu(runqueues, cpu) -> RELOC_HIDE().
Update cfs_util()'s documentation and reuse it for cpu_util_cfs().
Remove cpu_util().
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20211118164240.623551-1-dietmar.eggemann@arm.com
Patch series "mm/damon: Fix fake /proc/loadavg reports", v3.
This patchset fixes DAMON's fake load report issue. The first patch
makes yet another variant of usleep_range() for this fix, and the second
patch fixes the issue of DAMON by making it using the newly introduced
function.
This patch (of 2):
Some kernel threads such as DAMON could need to repeatedly sleep in
micro seconds level. Because usleep_range() sleeps in uninterruptible
state, however, such threads would make /proc/loadavg reports fake load.
To help such cases, this commit implements a variant of usleep_range()
called usleep_idle_range(). It is same to usleep_range() but sets the
state of the current task as TASK_IDLE while sleeping.
Link: https://lkml.kernel.org/r/20211126145015.15862-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20211126145015.15862-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: John Stultz <john.stultz@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrii Nakryiko says:
====================
bpf-next 2021-12-10 v2
We've added 115 non-merge commits during the last 26 day(s) which contain
a total of 182 files changed, 5747 insertions(+), 2564 deletions(-).
The main changes are:
1) Various samples fixes, from Alexander Lobakin.
2) BPF CO-RE support in kernel and light skeleton, from Alexei Starovoitov.
3) A batch of new unified APIs for libbpf, logging improvements, version
querying, etc. Also a batch of old deprecations for old APIs and various
bug fixes, in preparation for libbpf 1.0, from Andrii Nakryiko.
4) BPF documentation reorganization and improvements, from Christoph Hellwig
and Dave Tucker.
5) Support for declarative initialization of BPF_MAP_TYPE_PROG_ARRAY in
libbpf, from Hengqi Chen.
6) Verifier log fixes, from Hou Tao.
7) Runtime-bounded loops support with bpf_loop() helper, from Joanne Koong.
8) Extend branch record capturing to all platforms that support it,
from Kajol Jain.
9) Light skeleton codegen improvements, from Kumar Kartikeya Dwivedi.
10) bpftool doc-generating script improvements, from Quentin Monnet.
11) Two libbpf v0.6 bug fixes, from Shuyi Cheng and Vincent Minet.
12) Deprecation warning fix for perf/bpf_counter, from Song Liu.
13) MAX_TAIL_CALL_CNT unification and MIPS build fix for libbpf,
from Tiezhu Yang.
14) BTF_KING_TYPE_TAG follow-up fixes, from Yonghong Song.
15) Selftests fixes and improvements, from Ilya Leoshkevich, Jean-Philippe
Brucker, Jiri Olsa, Maxim Mikityanskiy, Tirthendu Sarkar, Yucong Sun,
and others.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (115 commits)
libbpf: Add "bool skipped" to struct bpf_map
libbpf: Fix typo in btf__dedup@LIBBPF_0.0.2 definition
bpftool: Switch bpf_object__load_xattr() to bpf_object__load()
selftests/bpf: Remove the only use of deprecated bpf_object__load_xattr()
selftests/bpf: Add test for libbpf's custom log_buf behavior
selftests/bpf: Replace all uses of bpf_load_btf() with bpf_btf_load()
libbpf: Deprecate bpf_object__load_xattr()
libbpf: Add per-program log buffer setter and getter
libbpf: Preserve kernel error code and remove kprobe prog type guessing
libbpf: Improve logging around BPF program loading
libbpf: Allow passing user log setting through bpf_object_open_opts
libbpf: Allow passing preallocated log_buf when loading BTF into kernel
libbpf: Add OPTS-based bpf_btf_load() API
libbpf: Fix bpf_prog_load() log_buf logic for log_level 0
samples/bpf: Remove unneeded variable
bpf: Remove redundant assignment to pointer t
selftests/bpf: Fix a compilation warning
perf/bpf_counter: Use bpf_map_create instead of bpf_create_map
samples: bpf: Fix 'unknown warning group' build warning on Clang
samples: bpf: Fix xdp_sample_user.o linking with Clang
...
====================
Link: https://lore.kernel.org/r/20211210234746.2100561-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull tracing fixes from Steven Rostedt:
"Tracing, ftrace and tracefs fixes:
- Have tracefs honor the gid mount option
- Have new files in tracefs inherit the parent ownership
- Have direct_ops unregister when it has no more functions
- Properly clean up the ops when unregistering multi direct ops
- Add a sample module to test the multiple direct ops
- Fix memory leak in error path of __create_synth_event()"
* tag 'trace-v5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix possible memory leak in __create_synth_event() error path
ftrace/samples: Add module to test multi direct modify interface
ftrace: Add cleanup to unregister_ftrace_direct_multi
ftrace: Use direct_ops hash in unregister_ftrace_direct
tracefs: Set all files to the same group ownership as the mount option
tracefs: Have new files inherit the ownership of their parent
Pull aio poll fixes from Eric Biggers:
"Fix three bugs in aio poll, and one issue with POLLFREE more broadly:
- aio poll didn't handle POLLFREE, causing a use-after-free.
- aio poll could block while the file is ready.
- aio poll called eventfd_signal() when it isn't allowed.
- POLLFREE didn't handle multiple exclusive waiters correctly.
This has been tested with the libaio test suite, as well as with test
programs I wrote that reproduce the first two bugs. I am sending this
pull request myself as no one seems to be maintaining this code"
* tag 'aio-poll-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux:
aio: Fix incorrect usage of eventfd_signal_allowed()
aio: fix use-after-free due to missing POLLFREE handling
aio: keep poll requests on waitqueue until completed
signalfd: use wake_up_pollfree()
binder: use wake_up_pollfree()
wait: add wake_up_pollfree()
The discussion about removing the side effect of irq_set_affinity_hint() of
actually applying the cpumask (if not NULL) as affinity to the interrupt,
unearthed a few unpleasantries:
1) The modular perf drivers rely on the current behaviour for the very
wrong reasons.
2) While none of the other drivers prevents user space from changing
the affinity, a cursorily inspection shows that there are at least
expectations in some drivers.
#1 needs to be cleaned up anyway, so that's not a problem
#2 might result in subtle regressions especially when irqbalanced (which
nowadays ignores the affinity hint) is disabled.
Provide new interfaces:
irq_update_affinity_hint() - Only sets the affinity hint pointer
irq_set_affinity_and_hint() - Set the pointer and apply the affinity to
the interrupt
Make irq_set_affinity_hint() a wrapper around irq_apply_affinity_hint() and
document it to be phased out.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210501021832.743094-1-jesse.brandeburg@intel.com
Link: https://lore.kernel.org/r/20210903152430.244937-2-nitesh@redhat.com
Commit 354e8f1970 ("bpf: Support <8-byte scalar spill and refill")
introduced support in the verifier to track <8B spill/fills of scalars.
The backtracking logic for the precision bit was however skipping
spill/fills of less than 8B. That could cause state pruning to consider
two states equivalent when they shouldn't be.
As an example, consider the following bytecode snippet:
0: r7 = r1
1: call bpf_get_prandom_u32
2: r6 = 2
3: if r0 == 0 goto pc+1
4: r6 = 3
...
8: [state pruning point]
...
/* u32 spill/fill */
10: *(u32 *)(r10 - 8) = r6
11: r8 = *(u32 *)(r10 - 8)
12: r0 = 0
13: if r8 == 3 goto pc+1
14: r0 = 1
15: exit
The verifier first walks the path with R6=3. Given the support for <8B
spill/fills, at instruction 13, it knows the condition is true and skips
instruction 14. At that point, the backtracking logic kicks in but stops
at the fill instruction since it only propagates the precision bit for
8B spill/fill. When the verifier then walks the path with R6=2, it will
consider it safe at instruction 8 because R6 is not marked as needing
precision. Instruction 14 is thus never walked and is then incorrectly
removed as 'dead code'.
It's also possible to lead the verifier to accept e.g. an out-of-bound
memory access instead of causing an incorrect dead code elimination.
This regression was found via Cilium's bpf-next CI where it was causing
a conntrack map update to be silently skipped because the code had been
removed by the verifier.
This commit fixes it by enabling support for <8B spill/fills in the
bactracking logic. In case of a <8B spill/fill, the full 8B stack slot
will be marked as needing precision. Then, in __mark_chain_precision,
any tracked register spilled in a marked slot will itself be marked as
needing precision, regardless of the spill size. This logic makes two
assumptions: (1) only 8B-aligned spill/fill are tracked and (2) spilled
registers are only tracked if the spill and fill sizes are equal. Commit
ef979017b8 ("bpf: selftest: Add verifier tests for <8-byte scalar
spill and refill") covers the first assumption and the next commit in
this patchset covers the second.
Fixes: 354e8f1970 ("bpf: Support <8-byte scalar spill and refill")
Signed-off-by: Paul Chaignon <paul@isovalent.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Nested contexts, such as nested interrupts or scheduler code, share the
same kcsan_ctx. When such a nested context reads an inconsistent
reorder_access due to an interrupt during set_reorder_access(), we can
observe the following warning:
| ------------[ cut here ]------------
| Cannot find frame for torture_random kernel/torture.c:456 in stack trace
| WARNING: CPU: 13 PID: 147 at kernel/kcsan/report.c:343 replace_stack_entry kernel/kcsan/report.c:343
| ...
| Call Trace:
| <TASK>
| sanitize_stack_entries kernel/kcsan/report.c:351 [inline]
| print_report kernel/kcsan/report.c:409
| kcsan_report_known_origin kernel/kcsan/report.c:693
| kcsan_setup_watchpoint kernel/kcsan/core.c:658
| rcutorture_one_extend kernel/rcu/rcutorture.c:1475
| rcutorture_loop_extend kernel/rcu/rcutorture.c:1558 [inline]
| ...
| </TASK>
| ---[ end trace ee5299cb933115f5 ]---
| ==================================================================
| BUG: KCSAN: data-race in _raw_spin_lock_irqsave / rcutorture_one_extend
|
| write (reordered) to 0xffffffff8c93b300 of 8 bytes by task 154 on cpu 12:
| queued_spin_lock include/asm-generic/qspinlock.h:80 [inline]
| do_raw_spin_lock include/linux/spinlock.h:185 [inline]
| __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
| _raw_spin_lock_irqsave kernel/locking/spinlock.c:162
| try_to_wake_up kernel/sched/core.c:4003
| sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097
| asm_sysvec_apic_timer_interrupt arch/x86/include/asm/idtentry.h:638
| set_reorder_access kernel/kcsan/core.c:416 [inline] <-- inconsistent reorder_access
| kcsan_setup_watchpoint kernel/kcsan/core.c:693
| rcutorture_one_extend kernel/rcu/rcutorture.c:1475
| rcutorture_loop_extend kernel/rcu/rcutorture.c:1558 [inline]
| rcu_torture_one_read kernel/rcu/rcutorture.c:1600
| rcu_torture_reader kernel/rcu/rcutorture.c:1692
| kthread kernel/kthread.c:327
| ret_from_fork arch/x86/entry/entry_64.S:295
|
| read to 0xffffffff8c93b300 of 8 bytes by task 147 on cpu 13:
| rcutorture_one_extend kernel/rcu/rcutorture.c:1475
| rcutorture_loop_extend kernel/rcu/rcutorture.c:1558 [inline]
| ...
The warning is telling us that there was a data race which KCSAN wants
to report, but the function where the original access (that is now
reordered) happened cannot be found in the stack trace, which prevents
KCSAN from generating the right stack trace. The stack trace of "write
(reordered)" now only shows where the access was reordered to, but
should instead show the stack trace of the original write, with a final
line saying "reordered to".
At the point where set_reorder_access() is interrupted, it just set
reorder_access->ptr and size, at which point size is non-zero. This is
sufficient (if ctx->disable_scoped is zero) for further accesses from
nested contexts to perform checking of this reorder_access.
That then happened in _raw_spin_lock_irqsave(), which is called by
scheduler code. However, since reorder_access->ip is still stale (ptr
and size belong to a different ip not yet set) this finally leads to
replace_stack_entry() not finding the frame in reorder_access->ip and
generating the above warning.
Fix it by ensuring that a nested context cannot access reorder_access
while we update it in set_reorder_access(): set ctx->disable_scoped for
the duration that reorder_access is updated, which effectively locks
reorder_access and prevents concurrent use by nested contexts. Note,
set_reorder_access() can do the update only if disabled_scoped is zero
on entry, and must therefore set disable_scoped back to non-zero after
the initial check in set_reorder_access().
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The barrier tests in selftest and the kcsan_test module only need the
spinlock and mutex to test correct barrier instrumentation. Therefore,
these were initially placed on the stack.
However, lockdep asserts that locks are in static storage, and will
generate this warning:
| INFO: trying to register non-static key.
| The code is fine but needs lockdep annotation, or maybe
| you didn't initialize this object before use?
| turning off the locking correctness validator.
| CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.16.0-rc1+ #3208
| Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014
| Call Trace:
| <TASK>
| dump_stack_lvl+0x88/0xd8
| dump_stack+0x15/0x1b
| register_lock_class+0x6b3/0x840
| ...
| test_barrier+0x490/0x14c7
| kcsan_selftest+0x47/0xa0
| ...
To fix, move the test locks into static storage.
Fixing the above also revealed that lock operations are strengthened on
first use with lockdep enabled, due to lockdep calling out into
non-instrumented files (recall that kernel/locking/lockdep.c is not
instrumented with KCSAN).
Only kcsan_test checks for over-instrumentation of *_lock() operations,
where we can simply "warm up" the test locks to avoid the test case
failing with lockdep.
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
There's no fundamental reason to disable KCSAN for scheduler code,
except for excessive noise and performance concerns (instrumenting
scheduler code is usually a good way to stress test KCSAN itself).
However, several core sched functions imply memory barriers that are
invisible to KCSAN without instrumentation, but are required to avoid
false positives. Therefore, unconditionally enable instrumentation of
memory barriers in scheduler code. Also update the comment to reflect
this and be a bit more brief.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
