[asterisk-bugs] [Asterisk 0016175]: Revision 202007 Introduces Deadlock

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
====================================================================== 
https://issues.asterisk.org/view.php?id=16175 
====================================================================== 
Reported By:                paul-tg
Assigned To:                
====================================================================== 
Project:                    Asterisk
Issue ID:                   16175
Category:                   Channels/chan_sip/CodecHandling
Reproducibility:            random
Severity:                   major
Priority:                   normal
Status:                     feedback
Asterisk Version:           1.6.2.0-rc3 
JIRA:                       SWP-335 
Regression:                 Yes 
Reviewboard Link:           https://reviewboard.asterisk.org/r/287/ 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!): 202007 
Request Review:              
====================================================================== 
Date Submitted:             2009-11-03 19:23 CST
Last Modified:              2009-11-10 09:22 CST
====================================================================== 
Summary:                    Revision 202007 Introduces Deadlock
Description: 
After upgrading from 1.6.0-beta9 to 1.6.2-rc2, we are experiencing
deadlocks in try_suggested_sip_codec().  "core show locks" points to code
introduced in revision 202007, which ironically was intended to protect
against deadlocks.  The Asterisk build is completely stock except for a
modified SIP response code in chan_sip.c:handle_request_invite().

We have had two deadlocks so far in as many weeks, both times during
periods of lower than average call load.
====================================================================== 

---------------------------------------------------------------------- 
 (0113549) mnicholson (administrator) - 2009-11-10 09:22
 https://issues.asterisk.org/view.php?id=16175#c113549 
---------------------------------------------------------------------- 
The deadlock is caused because my modifications to try_suggested_sip_codec
expect the sip_pvt to be locked.  In some cases it is not locked when
try_suggested_sip_codec is called.  In these cases, during the deadlock
protection code the pvt is locked and never unlocked causing your deadlock.
 I am going to revert this change as I do not think it is necessary in this
branch. 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2009-11-10 09:22 mnicholson     Note Added: 0113549                          
======================================================================