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| author | Manfred Spraul <manfred@colorfullife.com> | 2011-11-02 13:38:52 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-11-02 16:07:01 -0700 |
| commit | 0b0577f6080c0645b079dcc03fdbaf40d928beb8 (patch) | |
| tree | 0dcedf3f2e6c3aa9c363a4c6272225ebfa1c61c5 | |
| parent | 3c24783bb2deafaa106b7e69a97540071afc590c (diff) | |
| download | lwn-0b0577f6080c0645b079dcc03fdbaf40d928beb8.tar.gz lwn-0b0577f6080c0645b079dcc03fdbaf40d928beb8.zip | |
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>
| -rw-r--r-- | ipc/sem.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/ipc/sem.c b/ipc/sem.c index fb13be17945b..227948f28ce6 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -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: |