From 9fe28f703d44ff1ddecdca945bfb5fc87de5e8ad Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Mon, 7 Mar 2011 18:09:24 -0500
Subject: [PATCH] fix off-by-one error in sem_(timed)wait (using old sem value
 instead of new)

---
 src/thread/sem_timedwait.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/thread/sem_timedwait.c b/src/thread/sem_timedwait.c
index e6604364..e6c2495a 100644
--- a/src/thread/sem_timedwait.c
+++ b/src/thread/sem_timedwait.c
@@ -7,7 +7,7 @@ int sem_timedwait(sem_t *sem, const struct timespec *at)
 
 	for (;;) {
 		if (a_fetch_add(sem->__val, -1) > 0) return 0;
-		val = a_fetch_add(sem->__val, 1);
+		val = a_fetch_add(sem->__val, 1)+1;
 		CANCELPT_BEGIN;
 		if (val <= 0 && __timedwait(sem->__val, val, CLOCK_REALTIME, at, 0) == ETIMEDOUT) {
 			errno = ETIMEDOUT;
-- 
GitLab