From 8b1d81f4eed25b1f883d68871a9e5d4c655e888b Mon Sep 17 00:00:00 2001 From: russell Date: Mon, 28 Jan 2008 17:15:41 +0000 Subject: Make some deadlock related fixes. These bugs were discovered and reported internally at Digium by Steve Pitts. - Fix up chan_local to ensure that the channel lock is held before the local pvt lock. - Don't hold the channel lock when executing the timing function, as it can cause a deadlock when using chan_local. This actually changes the code back to be how it was before the change for issue #10765. But, I added some other locking that I think will prevent the problem reported there, as well. git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@100581 f38db490-d61c-443f-a65b-d21fe96a405b --- channels/chan_local.c | 37 ++++++++++++++++++------------------- 1 file changed, 18 insertions(+), 19 deletions(-) (limited to 'channels') diff --git a/channels/chan_local.c b/channels/chan_local.c index cbf7f7f48..3795be9c6 100644 --- a/channels/chan_local.c +++ b/channels/chan_local.c @@ -154,8 +154,6 @@ static int local_queue_frame(struct local_pvt *p, int isoutbound, struct ast_fra { struct ast_channel *other = NULL; -retrylock: - /* Recalculate outbound channel */ other = isoutbound ? p->owner : p->chan; @@ -173,27 +171,28 @@ retrylock: ast_clear_flag(p, LOCAL_GLARE_DETECT); return 0; } - if (ast_mutex_trylock(&other->lock)) { - /* Failed to lock. Release main lock and try again */ - ast_mutex_unlock(&p->lock); - if (us) { - if (ast_mutex_unlock(&us->lock)) { - ast_log(LOG_WARNING, "%s wasn't locked while sending %d/%d\n", - us->name, f->frametype, f->subclass); - us = NULL; - } + + ast_mutex_unlock(&p->lock); + + /* Ensure that we have both channels locked */ + if (us) { + while (ast_channel_trylock(other)) { + ast_channel_unlock(us); + usleep(1); + ast_channel_lock(us); } - /* Wait just a bit */ - usleep(1); - /* Only we can destroy ourselves, so we can't disappear here */ - if (us) - ast_mutex_lock(&us->lock); - ast_mutex_lock(&p->lock); - goto retrylock; + } else { + ast_channel_lock(other); } + ast_queue_frame(other, f); - ast_mutex_unlock(&other->lock); + + ast_channel_unlock(other); + + ast_mutex_lock(&p->lock); + ast_clear_flag(p, LOCAL_GLARE_DETECT); + return 0; } -- cgit v1.2.3