[Asterisk-code-review] res/res rtp asterisk: Fix assignment after ao2 decrement (asterisk[13.6])

[Matt Jordan]

Matt Jordan has submitted this change and it was merged.

Change subject: res/res_rtp_asterisk: Fix assignment after ao2 decrement
......................................................................


res/res_rtp_asterisk: Fix assignment after ao2 decrement

When we decide we will no longer schedule an RTCP write, we remove the
reference to the RTP instance, then assign -1 to the stored scheduler ID
in case something else comes along and wants to see if anything is scheduled.

That scheduler ID is on the RTP instance. After 60a9172d7ef2 was merged to
fix the regression introduced by 3cf0f29310, this improper assignment on a
potentially destroyed object started getting tripped on the build agents.

Frankly, this should have been crashing a lot more often earlier. I can only
assume that the timing was changed just enough by both changes to start
actually hitting this problem.

As it is, simply moving the assignment prior to the ao2 deference is sufficient
to keep the RTP instance from being referenced when it is very, truly,
aboslutely dead.

(Note that it is still good practice to assign -1 to the scheduler ID when we
know we won't be scheduling it again, as the ao2 deref *may* not always destroy
the ao2 object.)

ASTERISK-25449

Change-Id: Ie6d3cb4adc7b1a6c078b1c38c19fc84cf787cda7
---
M res/res_rtp_asterisk.c
1 file changed, 1 insertion(+), 1 deletion(-)

Approvals:
  Anonymous Coward #1000019: Verified
  Matt Jordan: Looks good to me, approved
  Corey Farrell: Looks good to me, but someone else must approve



diff --git a/res/res_rtp_asterisk.c b/res/res_rtp_asterisk.c
index fb6a5be..390fd08 100644
--- a/res/res_rtp_asterisk.c
+++ b/res/res_rtp_asterisk.c
@@ -3199,8 +3199,8 @@
 		/*
 		 * Not being rescheduled.
 		 */
-		ao2_ref(instance, -1);
 		rtp->rtcp->schedid = -1;
+		ao2_ref(instance, -1);
 	}
 
 	return res;

-- 
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Gerrit-MessageType: merged
Gerrit-Change-Id: Ie6d3cb4adc7b1a6c078b1c38c19fc84cf787cda7
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 13.6
Gerrit-Owner: Matt Jordan <mjordan at digium.com>
Gerrit-Reviewer: Anonymous Coward #1000019
Gerrit-Reviewer: Corey Farrell <git at cfware.com>
Gerrit-Reviewer: Matt Jordan <mjordan at digium.com>