Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date: Sun,  4 Oct 2015 14:55:29 -0500
From: Bobby Bingham <>
Subject: [PATCH v2 1/2] pthread: add missing memory barrier

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 966b4ab..694d377 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;

Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.