From: Bobby Bingham <koorogi@koorogi.info>
To: musl@lists.openwall.com
Subject: [PATCH v2 1/2] pthread: add missing memory barrier
Date: Sun, 4 Oct 2015 14:55:29 -0500 [thread overview]
Message-ID: <1443988530-23978-1-git-send-email-koorogi@koorogi.info> (raw)
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;
--
2.6.0
next reply other threads:[~2015-10-04 19:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-04 19:55 Bobby Bingham [this message]
2015-10-04 19:55 ` [PATCH v2 2/2] pthread: implement try/timed join variants Bobby Bingham
2015-10-12 2:30 ` Rich Felker
2015-10-16 3:15 ` Rich Felker
2016-05-07 18:48 ` [PATCH v3] " Bobby Bingham
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