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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>
This commit is contained in:
Manfred Spraul 2011-11-02 13:38:52 -07:00 committed by Linus Torvalds
parent 3c24783bb2
commit 0b0577f608
1 changed files with 9 additions and 0 deletions
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9
ipc/sem.c
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@ -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: