X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Fthread%2Fsem_post.c;h=148ab780e8f94d04ac2a0e222ff1f8631096708a;hp=8f4700c3058a4735516a5ae94330fb59df004234;hb=88c4e720317845a8e01aee03f142ba82674cd23d;hpb=88798393cab009ce78fe498051072db71ba9d035

diff --git a/src/thread/sem_post.c b/src/thread/sem_post.c
index 8f4700c3..148ab780 100644
--- a/src/thread/sem_post.c
+++ b/src/thread/sem_post.c
@@ -3,8 +3,11 @@
 
 int sem_post(sem_t *sem)
 {
-	a_inc(sem->__val);
-	if (sem->__val[1])
-		__wake(sem->__val, 1, 0);
+	int val, waiters;
+	do {
+		val = sem->__val[0];
+		waiters = sem->__val[1];
+	} while (a_cas(sem->__val, val, val+1+(val<0)) != val);
+	if (val<0 || waiters) __wake(sem->__val, 1, 0);
 	return 0;
 }