Commit 0b0577f6 authored Nov 02, 2011 by Manfred Spraul Committed by Linus Torvalds Nov 02, 2011

ipc/sem.c: handle spurious wakeups



semtimedop() does not handle spurious wakeups, it returns -EINTR to user
space.  Most other schedule() users would just loop and not return to user
space.  The patch adds such a loop to semtimedop()

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 3c24783b

ipc/sem.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -1426,6 +1426,8 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,

		queue.status = -EINTR;
		queue.sleeper = current;

		sleep_again:
		current->state = TASK_INTERRUPTIBLE;
		sem_unlock(sma);

		@@ -1478,6 +1480,13 @@ SYSCALL_DEFINE4(semtimedop, int, semid, struct sembuf __user *, tsops,
		*/
		if (timeout && jiffies_left == 0)
		error = -EAGAIN;

		/*
		* If the wakeup was spurious, just retry
		*/
		if (error == -EINTR && !signal_pending(current))
		goto sleep_again;

		unlink_queue(sma, &queue);

		out_unlock_free: