[asterisk-bugs] [Asterisk 0015349]: Deadlock in do_monitor() of chan_sip

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=15349 
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Reported By:                samy
Assigned To:                
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Project:                    Asterisk
Issue ID:                   15349
Category:                   Channels/chan_sip/General
Reproducibility:            have not tried
Severity:                   major
Priority:                   normal
Status:                     new
Asterisk Version:           1.6.0.10 
Regression:                 No 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2009-06-17 22:08 CDT
Last Modified:              2009-06-22 09:34 CDT
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Summary:                    Deadlock in do_monitor() of chan_sip
Description: 
Unfortunately I have no steps to reproduce this. Had about 30 calls going
through, all calls are SIP, and randomly ran into a SIP deadlock (`sip show
channels` would cause console to hang, no new SIP calls would begin).

It sort of looks like `dialoglist` is an infinite loop (every member
points to at least one other member, there is never a ->next that points to
null), but I don't see how that could happen in the code so I'm not sure.

I did get `core show locks` output a few times, and I have a modified
version that provides the time of the last time each lock was
locked/unlocked. This is interesting because we can see lock
https://issues.asterisk.org/view.php?id=0 never
changes and is held for multiple minutes before I restart, but lock
https://issues.asterisk.org/view.php?id=1
changes constantly.

The fact that lock https://issues.asterisk.org/view.php?id=1 (lock on
dialog->sip_pvt) is constantly changing in
do_monitor makes me think `dialoglist` is an infinite loop.
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---------------------------------------------------------------------- 
 (0106790) svnbot (reporter) - 2009-06-22 09:34
 https://issues.asterisk.org/view.php?id=15349#c106790 
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Repository: asterisk
Revision: 202336

U   branches/1.4/channels/chan_sip.c

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r202336 | mmichelson | 2009-06-22 09:34:05 -0500 (Mon, 22 Jun 2009) | 25
lines

Fix a possible infinite loop in SDP parsing during glare situation.

There was a while loop in get_ip_and_port_from_sdp which was controlled
by a call to get_sdp_iterate. The loop would exit either if what we were
searching for was found or if the return was NULL. The problem is that
get_sdp_iterate never returns NULL. This means that if what we were
searching
for was not present, the loop would run infinitely. This modification of
the
loop fixes the problem.

(closes issue https://issues.asterisk.org/view.php?id=15213)
Reported by: schmidts

(closes issue https://issues.asterisk.org/view.php?id=15349)
Reported by: samy

(closes issue https://issues.asterisk.org/view.php?id=14464)
Reported by: pj

(closes issue https://issues.asterisk.org/view.php?id=15345)
Reported by: aragon
Patches:
      sip_inf_loop.patch uploaded by mmichelson (license 60)
Tested by: aragon


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http://svn.digium.com/view/asterisk?view=rev&revision=202336 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2009-06-22 09:34 svnbot         Checkin                                      
2009-06-22 09:34 svnbot         Note Added: 0106790                          
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