From bb4e0c7f7cdff4d6c3d44f1fab9bcffc7c8db0b1 Mon Sep 17 00:00:00 2001
From: David Vossel <dvossel@digium.com>
Date: Tue, 28 Jun 2011 20:32:22 +0000
Subject: [PATCH] Merged revisions 325339 via svnmerge from
https://origsvn.digium.com/svn/asterisk/branches/1.8
........
r325339 | dvossel | 2011-06-28 15:31:00 -0500 (Tue, 28 Jun 2011) | 4 lines
Fixes locking inversion caused by holding sip pvt lock during async_goto.
(closes ASTERISK-17352)
........
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@325345 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
channels/chan_sip.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index f3a9693165..a4adb6f365 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -23441,13 +23441,21 @@ static int handle_request_refer(struct sip_pvt *p, struct sip_request *req, int
}
ast_set_flag(&p->flags[0], SIP_DEFER_BYE_ON_TRANSFER); /* Delay hangup */
-
- /* For blind transfers, move the call to the new extensions. For attended transfers on multiple
- servers - generate an INVITE with Replaces. Either way, let the dial plan decided */
- /* indicate before masquerade so the indication actually makes it to the real channel
- when using local channels with MOH passthru */
- ast_indicate(current.chan2, AST_CONTROL_UNHOLD);
- res = ast_async_goto(current.chan2, p->refer->refer_to_context, p->refer->refer_to, 1);
+ {
+ char *refer_to_context = ast_strdupa(p->refer->refer_to_context);
+ char *refer_to = ast_strdupa(p->refer->refer_to);
+
+ /* Do not hold the pvt lock during the indicate and async_goto. Those functions
+ * lock channels which will invalidate locking order if the pvt lock is held.*/
+ ao2_unlock(p);
+ /* For blind transfers, move the call to the new extensions. For attended transfers on multiple
+ * servers - generate an INVITE with Replaces. Either way, let the dial plan decided */
+ /* indicate before masquerade so the indication actually makes it to the real channel
+ *when using local channels with MOH passthru */
+ ast_indicate(current.chan2, AST_CONTROL_UNHOLD);
+ res = ast_async_goto(current.chan2, refer_to_context, refer_to, 1);
+ ao2_lock(p);
+ }
if (!res) {
ast_manager_event_multichan(EVENT_FLAG_CALL, "Transfer", 2, chans,
--
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