Deadlock prevention in chan_local.

(closes issue #13676)
Reported by: tacvbo
Patches:
      13676.patch uploaded by putnopvut (license 60)
Tested by: tacvbo



git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@148912 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_local.c

@@ -554,8 +554,12 @@ static int local_hangup(struct ast_channel *ast)
 	} else {
 		p->owner = NULL;
 		ast_module_user_remove(p->u_owner);
+		while (p->chan && ast_channel_trylock(p->chan)) {
+			DEADLOCK_AVOIDANCE(&p->lock);
+		}
 		if (p->chan) {
 			ast_queue_hangup(p->chan);
+			ast_channel_unlock(p->chan);
 		}
 	}