[asterisk-bugs] [Asterisk 0010895]: deadlock between ast_softhangup and zt_bridge (using mixmonitor on bridged channels)

[noreply at bugs.digium.com]

The following issue has been ASSIGNED. 
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http://bugs.digium.com/view.php?id=10895 
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Reported By:                peterh
Assigned To:                russell
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Project:                    Asterisk
Issue ID:                   10895
Category:                   Channels/chan_zap
Reproducibility:            random
Severity:                   major
Priority:                   normal
Status:                     assigned
Asterisk Version:           1.4.11  
SVN Branch (only for SVN checkouts, not tarball releases): N/A  
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             10-05-2007 05:44 CDT
Last Modified:              10-05-2007 11:23 CDT
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Summary:                    deadlock between ast_softhangup and zt_bridge (using
mixmonitor on bridged channels)
Description: 
mixmonitor claims channel->lock (c1) and makes ast_softhangup for
the bridged peer(c0) but chan_zap holds the lock for c0 -> deadlock


--- chan_zap.c.orig     2007-08-14 11:09:09.000000000 +0200
+++ chan_zap.c  2007-10-04 16:31:01.000000000 +0200
@@ -3338,7 +3338,10 @@
                /* Here's our main loop...  Start by locking things,
looking for private parts,
                   and then balking if anything is wrong */
                ast_mutex_lock(&c0->lock);
-               ast_mutex_lock(&c1->lock);
+               if (ast_mutex_trylock(&c1->lock)) {
+                   ast_mutex_unlock(&c0->lock);
+                   continue;
+               }
                p0 = c0->tech_pvt;
                p1 = c1->tech_pvt;
====================================================================== 

---------------------------------------------------------------------- 
 svnbot - 10-05-07 11:23  
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Repository: asterisk
Revision: 84783

U   branches/1.4/channels/chan_zap.c

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r84783 | russell | 2007-10-05 11:23:56 -0500 (Fri, 05 Oct 2007) | 4 lines

Do deadlock avoidance in a couple more places.  You can't lock two
channels
at the same time without doing extra work to make sure it succeeds.
(closes issue http://bugs.digium.com/view.php?id=10895, patch by me)

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Issue History 
Date Modified   Username       Field                    Change               
====================================================================== 
10-05-07 11:23  svnbot         Checkin                                      
10-05-07 11:23  svnbot         Note Added: 0071535                          
10-05-07 11:23  svnbot         Status                   new => assigned     
10-05-07 11:23  svnbot         Assigned To               => russell         
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