another cond var fix: requeue count race condition

[musl] / src / thread / pthread_cond_broadcast.c

diff --git a/src/thread/pthread_cond_broadcast.c b/src/thread/pthread_cond_broadcast.c
index 9c6a462..848e288 100644 (file)
--- a/src/thread/pthread_cond_broadcast.c
+++ b/src/thread/pthread_cond_broadcast.c
@@ -22,12 +22,8 @@ int pthread_cond_broadcast(pthread_cond_t *c)
        m = c->_c_mutex;
 
        /* Move waiter count to the mutex */
-       for (;;) {
-               int w = c->_c_waiters2;
-               a_fetch_add(&m->_m_waiters, w);
-               if (a_cas(&c->_c_waiters2, w, 0) == w) break;
-               a_fetch_add(&m->_m_waiters, -w);
-       }
+       a_fetch_add(&m->_m_waiters, c->_c_waiters2);
+       c->_c_waiters2 = 0;
 
        /* Perform the futex requeue, waking one waiter unless we know
         * that the calling thread holds the mutex. */