fix off-by-one error in sem_(timed)wait (using old sem value instead of new)

[musl] / src / thread / sem_timedwait.c

diff --git a/src/thread/sem_timedwait.c b/src/thread/sem_timedwait.c
index e660436..e6c2495 100644 (file)
--- 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;