[PATCH] ipc/sem.c: scan complex wait-for-zero after undefined updates

[Manfred Spraul]

After an update of a semaphore array that does not use struct sembuf,
complex wait-for-zero operations were not checked if they are able to
proceed.

Andrew: Could you add it to -mm?
I've introduced the bug with
   ipc-sem-separate-wait-for-zero-and-alter-tasks-into-seperate-queues.patch

Signed-off-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
---
 ipc/sem.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/ipc/sem.c b/ipc/sem.c
index f9d1c06..ad9daca 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -785,8 +785,10 @@ static int do_smart_wakeup_zero(struct sem_array *sma, struct sembuf *sops,
 		 * Assume all were changed.
 		 */
 		for (i = 0; i < sma->sem_nsems; i++) {
-			if (sma->sem_base[i].semval == 0)
+			if (sma->sem_base[i].semval == 0) {
+				got_zero = 1;
 				semop_completed |= wake_const_ops(sma, i, pt);
+			}
 		}
 	}
 	/*
-- 
1.8.1.4

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