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924de3b8c9
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Eric W. Biederman 924de3b8c9 fork: Have new threads join on-going signal group stops 
There are only two signals that are delivered to every member of a
signal group: SIGSTOP and SIGKILL.  Signal delivery requires every
signal appear to be delivered either before or after a clone syscall.
SIGKILL terminates the clone so does not need to be considered.  Which
leaves only SIGSTOP that needs to be considered when creating new
threads.

Today in the event of a group stop TIF_SIGPENDING will get set and the
fork will restart ensuring the fork syscall participates in the group
stop.

A fork (especially of a process with a lot of memory) is one of the
most expensive system so we really only want to restart a fork when
necessary.

It is easy so check to see if a SIGSTOP is ongoing and have the new
thread join it immediate after the clone completes.  Making it appear
the clone completed happened just before the SIGSTOP.

The calculate_sigpending function will see the bits set in jobctl and
set TIF_SIGPENDING to ensure the new task takes the slow path to userspace.

V2: The call to task_join_group_stop was moved before the new task is
    added to the thread group list.  This should not matter as
    sighand->siglock is held over both the addition of the threads,
    the call to task_join_group_stop and do_signal_stop.  But the change
    is trivial and it is one less thing to worry about when reading
    the code.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-08-03 20:20:14 -05:00
..
bpf Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-06-16 07:39:34 +09:00
cgroup docs: Fix some broken references 2018-06-15 18:10:01 -03:00
configs kconfig: tinyconfig: remove stale stack protector fixups 2018-06-15 07:15:28 +09:00
debug treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
events pid: Implement PIDTYPE_TGID 2018-07-21 10:43:12 -05:00
gcov gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT 2018-06-08 18:56:02 +09:00
irq Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-10 09:44:53 -07:00
livepatch livepatch: Allow to call a custom callback when freeing shadow variables 2018-04-17 13:42:48 +02:00
locking treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
power fix a series of Documentation/ broken file name references 2018-06-15 18:10:01 -03:00
printk Printk changes for 4.18 2018-06-06 16:04:55 -07:00
rcu treewide: Use array_size() in vmalloc() 2018-06-12 16:19:22 -07:00
sched signal: Add calculate_sigpending() 2018-08-03 20:10:31 -05:00
time signal: Pass pid and pid type into send_sigqueue 2018-07-21 10:43:12 -05:00
trace docs: Fix some broken references 2018-06-15 18:10:01 -03:00
.gitignore
acct.c
async.c
audit_fsnotify.c fsnotify: add fsnotify_add_inode_mark() wrappers 2018-05-18 14:58:22 +02:00
audit_tree.c fsnotify: add fsnotify_add_inode_mark() wrappers 2018-05-18 14:58:22 +02:00
audit_watch.c \n 2018-06-17 05:06:18 +09:00
audit.c audit: use inline function to get audit context 2018-05-14 17:24:18 -04:00
audit.h audit: track the owner of the command mutex ourselves 2018-02-23 11:22:22 -05:00
auditfilter.c audit: use existing session info function 2018-05-18 15:47:54 -04:00
auditsc.c audit: Fix wrong task in comparison of session ID 2018-05-21 14:27:43 -04:00
backtracetest.c
bounds.c
capability.c
compat.c Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 20:27:54 -07:00
configs.c
context_tracking.c
cpu_pm.c
cpu.c cpu/hotplug: Fix unused function warning 2018-03-15 20:34:40 +01:00
crash_core.c mm: split page_type out from _mapcount 2018-06-07 17:34:37 -07:00
crash_dump.c
cred.c
delayacct.c delayacct: Use raw_spinlocks 2018-04-27 14:34:51 +02:00
dma.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
elfcore.c
exec_domain.c proc: introduce proc_create_single{,_data} 2018-05-16 07:23:35 +02:00
exit.c signal: Pass pid type into group_send_sig_info 2018-07-21 12:57:35 -05:00
extable.c
fail_function.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
fork.c fork: Have new threads join on-going signal group stops 2018-08-03 20:20:14 -05:00
freezer.c
futex_compat.c
futex.c
groups.c
hung_task.c kernel/hung_task.c: show all hung tasks before panic 2018-06-07 17:34:39 -07:00
iomem.c memremap: split devm_memremap_pages() and memremap() infrastructure 2018-05-15 23:08:33 -07:00
irq_work.c
jump_label.c jump_label: Disable jump labels in __exit code 2018-03-20 08:57:17 +01:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c sched/core / kcov: avoid kcov_area during task switch 2018-06-15 07:55:24 +09:00
kexec_core.c kexec: yield to scheduler when loading kimage segments 2018-06-15 07:55:24 +09:00
kexec_file.c treewide: Use array_size() in vzalloc() 2018-06-12 16:19:22 -07:00
kexec_internal.h
kexec.c kexec: call do_kexec_load() in compat syscall directly 2018-04-02 20:15:01 +02:00
kmod.c
kprobes.c kprobes: Fix random address output of blacklist file 2018-04-25 10:27:56 -04:00
ksysfs.c
kthread.c kthread: Allow kthread_park() on a parked kthread 2018-05-25 08:03:51 +02:00
latencytop.c
Makefile Merge branch 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-10 10:17:09 -07:00
memremap.c mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS 2018-05-22 06:59:39 -07:00
module_signing.c
module-internal.h
module.c Modules updates for v4.18 2018-06-16 07:36:39 +09:00
notifier.c
nsproxy.c
padata.c
panic.c Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables 2018-06-14 12:21:18 +09:00
params.c kernel/params.c: downgrade warning for unsafe parameters 2018-04-11 10:28:37 -07:00
pid_namespace.c Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-03 19:15:32 -07:00
pid.c pid: Implement PIDTYPE_TGID 2018-07-21 10:43:12 -05:00
profile.c
ptrace.c
range.c
reboot.c
relay.c kernel/relay.c: change return type to vm_fault_t 2018-06-15 07:55:24 +09:00
resource.c libnvdimm for 4.18 2018-06-08 17:21:52 -07:00
rseq.c rseq: Introduce restartable sequences system call 2018-06-06 11:58:31 +02:00
seccomp.c audit/stable-4.18 PR 20180605 2018-06-06 16:34:00 -07:00
signal.c fork: Have new threads join on-going signal group stops 2018-08-03 20:20:14 -05:00
smp.c
smpboot.c
smpboot.h
softirq.c Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-04 19:59:22 -07:00
stacktrace.c
stop_machine.c Linux 4.17-rc5 2018-05-15 08:10:50 +02:00
sys_ni.c Merge branch 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-06-10 10:17:09 -07:00
sys.c mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct 2018-06-07 17:34:34 -07:00
sysctl_binary.c staging: irda: remove remaining remants of irda code removal 2018-04-16 11:26:49 +02:00
sysctl.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
task_work.c
taskstats.c
test_kprobes.c
torture.c rcu: Rename cond_resched_rcu_qs() to cond_resched_tasks_rcu_qs() 2018-05-15 10:27:29 -07:00
tracepoint.c tracepoints: Fix the descriptions of tracepoint_probe_register{_prio} 2018-05-28 12:49:51 -04:00
tsacct.c
ucount.c headers: untangle kmemleak.h from mm.h 2018-04-05 21:36:27 -07:00
uid16.c fs: add do_fchownat(), ksys_fchown() helpers and ksys_{,l}chown() wrappers 2018-04-02 20:15:59 +02:00
uid16.h kernel: provide ksys_*() wrappers for syscalls called by kernel/uid16.c 2018-04-02 20:15:30 +02:00
umh.c umh: fix race condition 2018-06-07 16:56:28 -04:00
up.c
user_namespace.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c uts: create "struct uts_namespace" from kmem_cache 2018-04-11 10:28:35 -07:00
watchdog_hld.c
watchdog.c
workqueue_internal.h workqueue: Set worker->desc to workqueue name by default 2018-05-18 08:47:13 -07:00
workqueue.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00