Currently sigqueue_free() removes sigqueue from list, but doesn't cancel the
pending signal. This is not consistent, the task should either receive the
"full" signal along with siginfo_t, or it shouldn't see the signal at all.
Change sigqueue_free() to clear SIGQUEUE_PREALLOC but leave sigqueue on list
if it is queued.
Note: I am not sure we shouldn't do the opposite, free sigqueue + cancel the
pending signal, but this needs some ugly changes. Perhaps we should reconsider
this change later. See also http://bugzilla.kernel.org/show_bug.cgi?id=10460
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- 25/kernel/signal.c~2_SF_DONT_REMOVE 2008-05-03 18:27:03.000000000 +0400
+++ 25/kernel/signal.c 2008-05-03 19:12:36.000000000 +0400
@@ -1240,18 +1240,22 @@ void sigqueue_free(struct sigqueue *q)
BUG_ON(!(q->flags & SIGQUEUE_PREALLOC));
/*
- * 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() or with
+ * We must hold ->siglock while testing q->list
+ * to serialize with collect_signal() or with
* __exit_signal()->flush_sigqueue().
*/
spin_lock_irqsave(lock, flags);
+ /*
+ * If it is queued it will be freed when dequeued,
+ * like the "regular" sigqueue.
+ */
+ q->flags &= ~SIGQUEUE_PREALLOC;
if (!list_empty(&q->list))
- list_del_init(&q->list);
+ q = NULL;
spin_unlock_irqrestore(lock, flags);
- q->flags &= ~SIGQUEUE_PREALLOC;
- __sigqueue_free(q);
+ if (q)
+ __sigqueue_free(q);
}
int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
--
