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-rw-r--r--src/thread/pthread_cond_broadcast.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/src/thread/pthread_cond_broadcast.c b/src/thread/pthread_cond_broadcast.c
index 4fab9994..7e5ea91c 100644
--- a/src/thread/pthread_cond_broadcast.c
+++ b/src/thread/pthread_cond_broadcast.c
@@ -30,8 +30,12 @@ int pthread_cond_broadcast(pthread_cond_t *c)
 	}
 
 	/* Move waiter count to the mutex */
-	w = a_swap(&c->_c_waiters, 0);
-	a_fetch_add(&m->_m_waiters, w);
+	for (;;) {
+		w = c->_c_waiters;
+		a_fetch_add(&m->_m_waiters, w);
+		if (a_cas(&c->_c_waiters, w, 0) == w) break;
+		a_fetch_add(&m->_m_waiters, -w);
+	}
 
 	/* Perform the futex requeue, waking one waiter unless we know
 	 * that the calling thread holds the mutex. */