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[PATCH] fix de_thread vs it_real_fn() deadlock

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de_thread() calls del_timer_sync(->real_timer) under ->sighand->siglock.
This is deadlockable, it_real_fn sends a signal and needs this lock too.

Also, delete unneeded ->real_timer.data assignment.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Oleg Nesterov 2005-10-30 15:02:17 -08:00 committed by Linus Torvalds
parent 2f51201662
commit 932aeafbe8
1 changed files with 2 additions and 1 deletions
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3
fs/exec.c
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@ -641,8 +641,10 @@ static inline int de_thread(struct task_struct *tsk)
* before we can safely let the old group leader die.
*/
sig->real_timer.data = (unsigned long)current;
spin_unlock_irq(lock);
if (del_timer_sync(&sig->real_timer))
add_timer(&sig->real_timer);
spin_lock_irq(lock);
}
while (atomic_read(&sig->count) > count) {
sig->group_exit_task = current;
@ -654,7 +656,6 @@ static inline int de_thread(struct task_struct *tsk)
}
sig->group_exit_task = NULL;
sig->notify_count = 0;
sig->real_timer.data = (unsigned long)current;
spin_unlock_irq(lock);
/*