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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-05-23 13:04:41 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-05-24 09:56:10 -0700 |
| commit | da7978b0348d497688541e2d2f5739aa2a2c334f (patch) | |
| tree | f4f55bf4293ff203f598e7a57959da1c5a7ad295 /kernel/signal.c | |
| parent | dfc7064500061677720fa26352963c772d3ebe6b (diff) | |
| download | linux-da7978b0348d497688541e2d2f5739aa2a2c334f.tar.gz linux-da7978b0348d497688541e2d2f5739aa2a2c334f.tar.bz2 linux-da7978b0348d497688541e2d2f5739aa2a2c334f.zip | |
signals: fix sigqueue_free() vs __exit_signal() race
__exit_signal() does flush_sigqueue(tsk->pending) outside of ->siglock.
This can race with another thread doing sigqueue_free(), we can free the
same SIGQUEUE_PREALLOC sigqueue twice or corrupt the pending->list.
Note that even sys_exit_group() can trigger this race, not only
sys_timer_delete().
Move the callsite of flush_sigqueue(tsk->pending) under ->siglock.
This patch doesn't touch flush_sigqueue(->shared_pending) below, it is
called when there are no other threads which can play with signals, and
sigqueue_free() can't be used outside of our thread group.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 72bb4f51f963..12ffea7c201d 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1242,7 +1242,8 @@ void sigqueue_free(struct sigqueue *q) /* * If the signal is still pending remove it from the * pending queue. We must hold ->siglock while testing - * q->list to serialize with collect_signal(). + * q->list to serialize with collect_signal() or with + * __exit_signal()->flush_sigqueue(). */ spin_lock_irqsave(lock, flags); if (!list_empty(&q->list)) |