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authorManfred Spraul <manfred@colorfullife.com>2011-11-02 20:38:52 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2011-11-02 23:07:01 (GMT)
commit0b0577f6080c0645b079dcc03fdbaf40d928beb8 (patch)
tree0dcedf3f2e6c3aa9c363a4c6272225ebfa1c61c5 /ipc
parent3c24783bb2deafaa106b7e69a97540071afc590c (diff)
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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>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/sem.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/ipc/sem.c b/ipc/sem.c
index fb13be1..227948f 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: