From de2657f94acd4f0df44626db7c4d2b71babc8cd3 Mon Sep 17 00:00:00 2001
From: Rik van Riel <riel@redhat.com>
Date: Thu, 9 May 2013 16:59:59 -0400
Subject: ipc,sem: fix semctl(..., GETNCNT)

The semctl GETNCNT returns the number of semops waiting for the
specified semaphore to become nonzero.  After commit 9f1bc2c9022c
("ipc,sem: have only one list in struct sem_queue"), the semops waiting
on just one semaphore are waiting on that semaphore's list.

In order to return the correct count, we have to walk that list too, in
addition to the sem_array's list for complex operations.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/ipc/sem.c b/ipc/sem.c
index 04b264d..a7e40ed 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -796,6 +796,13 @@ static int count_semncnt (struct sem_array * sma, ushort semnum)
 	struct sem_queue * q;
 
 	semncnt = 0;
+	list_for_each_entry(q, &sma->sem_base[semnum].sem_pending, list) {
+		struct sembuf * sops = q->sops;
+		BUG_ON(sops->sem_num != semnum);
+		if ((sops->sem_op < 0) && !(sops->sem_flg & IPC_NOWAIT))
+			semncnt++;
+	}
+
 	list_for_each_entry(q, &sma->sem_pending, list) {
 		struct sembuf * sops = q->sops;
 		int nsops = q->nsops;
-- 
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