Oleg Nesterov d66d207818 wait: fix reparent_leader() vs EXIT_DEAD->EXIT_ZOMBIE race ... commit dfccbb5e49 upstream. wait_task_zombie() first does EXIT_ZOMBIE->EXIT_DEAD transition and drops tasklist_lock. If this task is not the natural child and it is traced, we change its state back to EXIT_ZOMBIE for ->real_parent. The last transition is racy, this is even documented in 50b8d25748 "ptrace: partially fix the do_wait(WEXITED) vs EXIT_DEAD->EXIT_ZOMBIE race". wait_consider_task() tries to detect this transition and clear ->notask_error but we can't rely on ptrace_reparented(), debugger can exit and do ptrace_unlink() before its sub-thread sets EXIT_ZOMBIE. And there is another problem which were missed before: this transition can also race with reparent_leader() which doesn't reset >exit_signal if EXIT_DEAD, assuming that this task must be reaped by someone else. So the tracee can be re-parented with ->exit_signal != SIGCHLD, and if /sbin/init doesn't use __WALL it becomes unreapable. Change reparent_leader() to update ->exit_signal even if EXIT_DEAD. Note: this is the simple temporary hack for -stable, it doesn't try to solve all problems, it will be reverted by the next changes. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Jan Kratochvil <jan.kratochvil@redhat.com> Reported-by: Michal Schmidt <mschmidt@redhat.com> Tested-by: Michal Schmidt <mschmidt@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Lennart Poettering <lpoetter@redhat.com> Cc: Roland McGrath <roland@hack.frob.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2014-04-26 17:13:20 -07:00
..
debug
events	perf: Fix hotplug splat	2014-03-11 16:10:02 -07:00
gcov
irq	genirq: Remove racy waitqueue_active check	2014-03-23 21:37:05 -07:00
power	PM / Hibernate: Hibernate/thaw fixes/improvements	2014-02-20 10:45:33 -08:00
sched	sched: Fix double normalization of vruntime	2014-03-23 21:37:03 -07:00
time	time: Fix overflow when HZ is smaller than 60	2014-02-22 10:32:46 -08:00
trace	tracing: Do not add event files for modules that fail tracepoints	2014-03-23 21:37:06 -07:00
.gitignore
acct.c
async.c
audit.c	audit: wait_for_auditd() should use TASK_UNINTERRUPTIBLE	2014-04-14 06:44:15 -07:00
audit.h
audit_tree.c	kernel/audit_tree.c: tree will leak memory when failure occurs in audit_trim_trees()	2013-05-11 13:48:14 -07:00
audit_watch.c
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cgroup.c	cgroup: cgroup_subsys->fork() should be called after the task is added to css_set	2014-03-11 16:10:03 -07:00
cgroup_freezer.c	cgroup: cgroup_subsys->fork() should be called after the task is added to css_set	2014-03-11 16:10:03 -07:00
compat.c
configs.c
cpu.c	CPU hotplug: provide a generic helper to disable/enable CPU hotplug	2013-06-20 11:58:44 -07:00
cpu_pm.c
cpuset.c	cpuset: fix a race condition in __cpuset_node_allowed_softwall()	2014-03-23 21:37:05 -07:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	wait: fix reparent_leader() vs EXIT_DEAD->EXIT_ZOMBIE race	2014-04-26 17:13:20 -07:00
extable.c
fork.c	cgroup: cgroup_subsys->fork() should be called after the task is added to css_set	2014-03-11 16:10:03 -07:00
freezer.c
futex.c	futex: fix handling of read-only-mapped hugepages	2013-12-20 07:34:19 -08:00
futex_compat.c
groups.c
hrtimer.c	hrtimers: Move SMP function call to thread context	2013-07-28 16:26:47 -07:00
hung_task.c
irq_work.c
itimer.c
jump_label.c
kallsyms.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c
kfifo.c
kmod.c	usermodehelper: check subprocess_info->path != NULL	2013-05-19 10:54:50 -07:00
kprobes.c
ksysfs.c
kthread.c
latencytop.c
lockdep.c
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
Makefile
module.c
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
notifier.c
nsproxy.c
padata.c
panic.c
params.c
pid.c
pid_namespace.c
posix-cpu-timers.c
posix-timers.c
printk.c	printk: Fix rq->lock vs logbuf_lock unlock lock inversion	2014-04-14 06:44:16 -07:00
profile.c
ptrace.c	exec/ptrace: fix get_dumpable() incorrect tests	2013-11-29 10:50:34 -08:00
range.c
rcu.h
rcupdate.c
rcutiny.c
rcutiny_plugin.h
rcutorture.c
rcutree.c
rcutree.h
rcutree_plugin.h
rcutree_trace.c
relay.c
res_counter.c
resource.c
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rtmutex_common.h
rwsem.c
seccomp.c
semaphore.c
signal.c	kernel/signal.c: stop info leak via the tkill and the tgkill syscalls	2013-04-25 21:19:54 -07:00
smp.c
softirq.c
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys.c	reboot: rigrate shutdown/reboot to boot cpu	2013-06-20 11:58:45 -07:00
sys_ni.c
sysctl.c
sysctl_binary.c
taskstats.c
test_kprobes.c
time.c
timeconst.pl
timer.c	timer: Fix jiffies wrap behavior of round_jiffies_common()	2013-07-21 18:19:01 -07:00
tracepoint.c	tracing: Do not add event files for modules that fail tracepoints	2014-03-23 21:37:06 -07:00
tsacct.c
uid16.c
up.c
user-return-notifier.c
user.c
user_namespace.c
utsname.c
utsname_sysctl.c
wait.c
watchdog.c
workqueue.c	workqueue: cond_resched() after processing each work item	2014-04-14 06:44:16 -07:00
workqueue_sched.h