From 53cd8c5a29b57ef3776ce152e00544752f3ce790 Mon Sep 17 00:00:00 2001 From: Bobby Bingham Date: Sun, 4 Oct 2015 14:55:29 -0500 Subject: [PATCH] add missing memory barrier to pthread_join POSIX requires pthread_join to synchronize memory on success. The futex wait inside __timedwait_cp cannot handle this because it's not called in all cases. Also, in the case of a spurious wake, tid can become zero between the wake and when the joining thread checks it. --- src/thread/pthread_join.c | 1 + 1 file changed, 1 insertion(+) diff --git a/src/thread/pthread_join.c b/src/thread/pthread_join.c index 966b4ab0..694d377a 100644 --- a/src/thread/pthread_join.c +++ b/src/thread/pthread_join.c @@ -13,6 +13,7 @@ int __pthread_join(pthread_t t, void **res) if (cs == PTHREAD_CANCEL_ENABLE) __pthread_setcancelstate(cs, 0); while ((tmp = t->tid)) __timedwait_cp(&t->tid, tmp, 0, 0, 0); __pthread_setcancelstate(cs, 0); + a_barrier(); if (res) *res = t->result; if (t->map_base) __munmap(t->map_base, t->map_size); return 0;