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authorOleg Nesterov <oleg@tv-sign.ru>2005-10-30 15:02:17 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-30 17:37:19 -0800
commit932aeafbe8521a9a9d790152d66020e0fef2029b (patch)
tree09b95edbd9c160962027a9b3dcbf3cb7fc7a2b90
parent2f51201662b28dbf8c15fb7eb972bc51c6cc3fa5 (diff)
[PATCH] fix de_thread vs it_real_fn() deadlock
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>
-rw-r--r--fs/exec.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 1de69cdc0e6..fc02dadc604 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -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);
/*