From c8e85b4f4b9ee23bf0e79bdeb3da274a0f9c663f Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Mon, 26 May 2008 20:55:42 +0400 Subject: [PATCH] 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 Cc: Austin Clements Cc: Roland McGrath Signed-off-by: Linus Torvalds --- kernel/signal.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/kernel/signal.c b/kernel/signal.c index 12ffea7c201d..2955f6c4f36e 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -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); + 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; - __sigqueue_free(q); + if (q) + __sigqueue_free(q); } int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) -- 2.20.1