Oleg Nesterov 3245d6acab exit: fix race between wait_consider_task() and wait_task_zombie() ... wait_consider_task() checks EXIT_ZOMBIE after EXIT_DEAD/EXIT_TRACE and both checks can fail if we race with EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE change in between, gcc needs to reload p->exit_state after security_task_wait(). In this case ->notask_error will be wrongly cleared and do_wait() can hang forever if it was the last eligible child. Many thanks to Arne who carefully investigated the problem. Note: this bug is very old but it was pure theoretical until commit b3ab03160d ("wait: completely ignore the EXIT_DEAD tasks"). Before this commit "-O2" was probably enough to guarantee that compiler won't read ->exit_state twice. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Arne Goedeke <el@laramies.com> Tested-by: Arne Goedeke <el@laramies.com> Cc: <stable@vger.kernel.org> [3.15+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2015-01-08 15:10:51 -08:00
..
bpf	bpf: verifier: add checks for BPF_ABS | BPF_IND instructions	2014-12-05 21:47:32 -08:00
configs
debug	kdb: replace strnicmp with strncasecmp	2014-10-14 02:18:25 +02:00
events	Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-19 13:15:24 -08:00
gcov	gcov: enable GCOV_PROFILE_ALL from ARCH Kconfigs	2014-12-13 12:42:51 -08:00
irq	genirq: Prevent proc race against freeing of irq descriptors	2014-12-13 13:33:07 +01:00
locking	locking/mutex: Don't assume TASK_RUNNING	2014-10-28 10:55:08 +01:00
power	PM: Eliminate CONFIG_PM_RUNTIME	2014-12-19 22:55:06 +01:00
printk	This code is a fork from the trace-3.19 pull as it needed the trace_seq	2014-12-13 14:04:41 -08:00
rcu	Merge branches 'torture.2014.11.03a', 'cpu.2014.11.03a', 'doc.2014.11.13a', 'fixes.2014.11.13a', 'signal.2014.10.29a' and 'rt.2014.10.29a' into HEAD	2014-11-13 10:39:04 -08:00
sched	sched_show_task: fix unsafe usage of ->real_parent	2014-12-10 17:41:09 -08:00
time	Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-19 13:29:20 -08:00
trace	More ACPI and power management updates for 3.19-rc1	2014-12-18 20:28:33 -08:00
.gitignore
acct.c	acct: eliminate compile warning	2014-10-09 22:26:04 -04:00
async.c	kernel/async.c: switch to pr_foo()	2014-10-09 22:26:04 -04:00
audit_tree.c	fsnotify: unify inode and mount marks handling	2014-12-13 12:42:53 -08:00
audit_watch.c
audit.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2014-12-30 10:45:47 -08:00
audit.h
auditfilter.c	Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit	2014-12-23 18:13:16 -08:00
auditsc.c	Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit	2014-12-31 14:52:18 -08:00
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c
cgroup.c	cgroup: implement cgroup_get_e_css()	2014-11-18 02:49:52 -05:00
compat.c
configs.c
context_tracking.c	sched: stop the unbound recursion in preempt_schedule_context()	2014-10-28 10:46:05 +01:00
cpu_pm.c
cpu.c	cpu: Avoid puts_pending overflow	2014-11-03 19:21:01 -08:00
cpuset.c	Merge branch 'for-3.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2014-12-11 18:57:19 -08:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	exit: fix race between wait_consider_task() and wait_task_zombie()	2015-01-08 15:10:51 -08:00
extable.c	ftrace/x86/extable: Add is_ftrace_trampoline() function	2014-11-19 15:25:26 -05:00
fork.c	mm: use new helper functions around the i_mmap_mutex	2014-12-13 12:42:45 -08:00
freezer.c	freezer: remove obsolete comments in __thaw_task()	2014-10-21 23:44:20 +02:00
futex_compat.c
futex.c	futex: Fix a race condition between REQUEUE_PI and task death	2014-10-26 16:16:18 +01:00
groups.c	userns: Don't allow setgroups until a gid mapping has been setablished	2014-12-09 16:58:40 -06:00
hung_task.c
irq_work.c	percpu: Convert remaining __get_cpu_var uses in 3.18-rcX	2014-10-29 11:18:18 -04:00
jump_label.c
kallsyms.c	kernel/kallsyms.c: use __seq_open_private()	2014-10-14 02:18:16 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c	kexec: remove unnecessary KERN_ERR from kexec.c	2014-12-13 12:42:51 -08:00
kmod.c	usermodehelper: kill the kmod_thread_locker logic	2014-12-10 17:41:17 -08:00
kprobes.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux	2014-12-11 17:30:55 -08:00
ksysfs.c
kthread.c	kernel/kthread.c: partial revert of 81c98869fa ("kthread: ensure locality of task_struct allocations")	2014-10-09 22:25:51 -04:00
latencytop.c
Makefile	kernel: res_counter: remove the unused API	2014-12-10 17:41:04 -08:00
module_signing.c
module-internal.h
module.c	The exciting thing here is the getting rid of stop_machine on module	2014-12-18 20:55:41 -08:00
notifier.c
nsproxy.c	bury struct proc_ns in fs/proc	2014-12-04 14:34:54 -05:00
padata.c
panic.c	kernel: add panic_on_warn	2014-12-10 17:41:10 -08:00
params.c	param: do not set store func without write perm	2014-12-18 12:38:51 +10:30
pid_namespace.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-12-16 15:53:03 -08:00
pid.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2014-12-16 15:53:03 -08:00
profile.c
ptrace.c	exit: ptrace: shift "reap dead" code from exit_ptrace() to forget_original_parent()	2014-12-10 17:41:10 -08:00
range.c
reboot.c
relay.c
resource.c	x86: optimize resource lookups for ioremap	2014-10-14 02:18:22 +02:00
seccomp.c	Merge branch 'x86-seccomp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-10-14 02:27:06 +02:00
signal.c	Merge branch 'x86-mpx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2014-12-10 09:34:43 -08:00
smp.c	Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2014-10-15 07:48:18 +02:00
smpboot.c	sched, smp: Correctly deal with nested sleeps	2014-10-28 10:56:24 +01:00
smpboot.h
softirq.c	rcu: Remove "cpu" argument to rcu_note_context_switch()	2014-11-03 19:20:34 -08:00
stacktrace.c	stacktrace: introduce snprint_stack_trace for buffer output	2014-12-13 12:42:48 -08:00
stop_machine.c
sys_ni.c	syscalls: implement execveat() system call	2014-12-13 12:42:51 -08:00
sys.c	x86, mpx: On-demand kernel allocation of bounds tables	2014-11-18 00:58:53 +01:00
sysctl_binary.c	kernel: add panic_on_warn	2014-12-10 17:41:10 -08:00
sysctl.c	As the merge window is still open, and this code was not as complex	2014-12-16 12:53:59 -08:00
system_certificates.S
system_keyring.c
task_work.c
taskstats.c	kill f_dentry uses	2014-11-19 13:01:25 -05:00
test_kprobes.c
torture.c
tracepoint.c
tsacct.c
uid16.c	groups: Consolidate the setgroups permission checks	2014-12-05 17:19:27 -06:00
up.c
user_namespace.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2014-12-17 12:31:40 -08:00
user-return-notifier.c
user.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2014-12-17 12:31:40 -08:00
utsname_sysctl.c
utsname.c	copy address of proc_ns_ops into ns_common	2014-12-04 14:34:47 -05:00
watchdog.c	Merge branch 'for-3.18-consistent-ops' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2014-10-15 07:48:18 +02:00
workqueue_internal.h
workqueue.c	workqueue: allow rescuer thread to do more work.	2014-12-08 12:39:16 -05:00