From: Corey Farrell <git@cfware.com>
Date: Fri, 7 Mar 2014 22:50:40 +0000 (+0000)
Subject: chan_sip: Fix deadlock of monlock between unload_module and do_monitor
X-Git-Tag: 1.8.27.0-rc1~17
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=dbfbcbb1c72d58ffcae457085b0dc31b17f8f62d;p=thirdparty%2Fasterisk.git

chan_sip: Fix deadlock of monlock between unload_module and do_monitor

Release monlock before calling pthread_join.  This ensures do_monitor
cannot freeze by locking monlock during module unload.

(closes issue ASTERISK-21406)
Reported by: Corey Farrell
Review: https://reviewboard.asterisk.org/r/3284/


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@410224 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 97acd4cce7..367130c19b 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -32061,12 +32061,16 @@ static int unload_module(void)
 
 	ast_mutex_lock(&monlock);
 	if (monitor_thread && (monitor_thread != AST_PTHREADT_STOP) && (monitor_thread != AST_PTHREADT_NULL)) {
-		pthread_cancel(monitor_thread);
-		pthread_kill(monitor_thread, SIGURG);
-		pthread_join(monitor_thread, NULL);
+		pthread_t th = monitor_thread;
+		monitor_thread = AST_PTHREADT_STOP;
+		pthread_cancel(th);
+		pthread_kill(th, SIGURG);
+		ast_mutex_unlock(&monlock);
+		pthread_join(th, NULL);
+	} else {
+		monitor_thread = AST_PTHREADT_STOP;
+		ast_mutex_unlock(&monlock);
 	}
-	monitor_thread = AST_PTHREADT_STOP;
-	ast_mutex_unlock(&monlock);
 
 	/* Destroy all the dialogs and free their memory */
 	i = ao2_iterator_init(dialogs, 0);