The patch titled
Subject: ipc/sem.c: handle spurious wakeups
has been added to the -mm tree. Its filename is
ipc-semc-handle-spurious-wakeups.patch
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------------------------------------------------------
From: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxx>
Reported-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxx>
---
ipc/sem.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff -puN ipc/sem.c~ipc-semc-handle-spurious-wakeups ipc/sem.c
--- a/ipc/sem.c~ipc-semc-handle-spurious-wakeups
+++ a/ipc/sem.c
@@ -1426,6 +1426,8 @@ SYSCALL_DEFINE4(semtimedop, int, semid,
queue.status = -EINTR;
queue.sleeper = current;
+
+sleep_again:
current->state = TASK_INTERRUPTIBLE;
sem_unlock(sma);
@@ -1478,6 +1480,13 @@ SYSCALL_DEFINE4(semtimedop, int, semid,
*/
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:
_
Subject: Subject: ipc/sem.c: handle spurious wakeups
Patches currently in -mm which might be from manfred@xxxxxxxxxxxxxxxx are
ipc-mqueue-cleanup-definition-names-and-locations.patch
ipc-mqueue-switch-back-to-using-non-max-values-on-create.patch
ipc-mqueue-enforce-hard-limits.patch
ipc-mqueue-update-maximums-for-the-mqueue-subsystem.patch
ipc-semc-fix-return-code-race-with-semop-vs-semop-semctlipc_rmid.patch
ipc-semc-handle-spurious-wakeups.patch
ipc-semc-replace-busy-loop-with-completion.patch
slab-leaks3-default-y.patch
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