Commit c8e85b4f authored May 26, 2008 by Oleg Nesterov Committed by Linus Torvalds May 26, 2008

posix timers: sigqueue_free: don't free sigqueue if it is queued



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 receive the signal at all.

Change sigqueue_free() to clear SIGQUEUE_PREALLOC but leave sigqueue on list
if it is queued.

This is a user-visible change. If the signal is blocked, it stays queued
after sys_timer_delete() until unblocked with the "stale" si_code/si_value,
and of course it is still counted wrt RLIMIT_SIGPENDING which also limits
the number of posix timers.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Austin Clements <amdragon+kernelbugzilla@mit.edu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 84a88165

kernel/signal.c

+10 −6

Original line number	Diff line number	Diff line
		@@ -1240,17 +1240,21 @@ 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);
		q->flags &= ~SIGQUEUE_PREALLOC;
		/*
		* If it is queued it will be freed when dequeued,
		* like the "regular" sigqueue.
		*/
		if (!list_empty(&q->list))
		list_del_init(&q->list);
		q = NULL;
		spin_unlock_irqrestore(lock, flags);

		q->flags &= ~SIGQUEUE_PREALLOC;
		if (q)
		__sigqueue_free(q);
		}

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