From: Bobby Bingham <koorogi@koorogi.info>
To: musl@lists.openwall.com
Subject: [PATCH 1/2] pthread: add missing memory barrier
Date: Mon, 28 Sep 2015 16:58:44 -0500 [thread overview]
Message-ID: <1443477525-24743-1-git-send-email-koorogi@koorogi.info> (raw)
posix requires pthread_join to synchronize memory on success. in the
case that we call __timedwait_cp, we can rely on its futex_wake call
to synchronize memory, but we need a memory barrier for the case where
we don't call it.
---
src/thread/pthread_join.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/src/thread/pthread_join.c b/src/thread/pthread_join.c
index 966b4ab..eb78e2f 100644
--- a/src/thread/pthread_join.c
+++ b/src/thread/pthread_join.c
@@ -11,7 +11,9 @@ int __pthread_join(pthread_t t, void **res)
__pthread_testcancel();
__pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
if (cs == PTHREAD_CANCEL_ENABLE) __pthread_setcancelstate(cs, 0);
- while ((tmp = t->tid)) __timedwait_cp(&t->tid, tmp, 0, 0, 0);
+ if (!(tmp = t->tid)) a_barrier();
+ else do __timedwait_cp(&t->tid, tmp, 0, 0, 0);
+ while ((tmp = t->tid));
__pthread_setcancelstate(cs, 0);
if (res) *res = t->result;
if (t->map_base) __munmap(t->map_base, t->map_size);
--
2.5.3
next reply other threads:[~2015-09-28 21:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-28 21:58 Bobby Bingham [this message]
2015-09-28 21:58 ` [PATCH 2/2] pthread: implement try/timed join variants Bobby Bingham
2015-09-28 22:21 ` [PATCH 1/2] pthread: add missing memory barrier Rich Felker
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1443477525-24743-1-git-send-email-koorogi@koorogi.info \
--to=koorogi@koorogi.info \
--cc=musl@lists.openwall.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/musl/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).