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authorOleg Nesterov <oleg@tv-sign.ru>2008-09-22 14:42:46 -0700
committerThomas Gleixner <tglx@linutronix.de>2008-09-24 15:45:47 +0200
commit4aa7361179bed905fd0f35b236a5c65db683b9e0 (patch)
tree115b16f51fafc38f8a76c9fd7e71ce44884aa8e7
parentbb34d92f643086d546b49cef680f6f305ed84414 (diff)
posix-timers: don't switch to ->group_leader if ->it_process dies
posix_timer_event() drops SIGEV_THREAD_ID and switches to ->group_leader if send_sigqueue() fails. This is not very useful and doesn't work reliably. send_sigqueue() can only fail if ->it_process is dead. But it can die before it dequeues the SI_TIMER signal, in that case the timer stops anyway. Remove this code. I guess it was needed a long ago to ensure that the timer is not destroyed when when its creator thread dies. Q: perhaps it makes sense to change sys_timer_settime() to return an error if ->it_process is dead? Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: mingo@elte.hu Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--kernel/posix-timers.c19
1 files changed, 5 insertions, 14 deletions
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index e36d5798cbf..3dfd15aecc6 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -298,6 +298,7 @@ void do_schedule_next_timer(struct siginfo *info)
int posix_timer_event(struct k_itimer *timr, int si_private)
{
+ int shared, ret;
/*
* FIXME: if ->sigq is queued we can race with
* dequeue_signal()->do_schedule_next_timer().
@@ -316,20 +317,10 @@ int posix_timer_event(struct k_itimer *timr, int si_private)
timr->sigq->info.si_tid = timr->it_id;
timr->sigq->info.si_value = timr->it_sigev_value;
- if (timr->it_sigev_notify & SIGEV_THREAD_ID) {
- struct task_struct *leader;
- int ret = send_sigqueue(timr->sigq, timr->it_process, 0);
-
- if (likely(ret >= 0))
- return ret;
-
- timr->it_sigev_notify = SIGEV_SIGNAL;
- leader = timr->it_process->group_leader;
- put_task_struct(timr->it_process);
- timr->it_process = leader;
- }
-
- return send_sigqueue(timr->sigq, timr->it_process, 1);
+ shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID);
+ ret = send_sigqueue(timr->sigq, timr->it_process, shared);
+ /* If we failed to send the signal the timer stops. */
+ return ret > 0;
}
EXPORT_SYMBOL_GPL(posix_timer_event);