[asterisk-bugs] [Asterisk 0018441]: Deadlock in chan_sip

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=18441 
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Reported By:                Alric
Assigned To:                
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Project:                    Asterisk
Issue ID:                   18441
Category:                   Core/General
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     acknowledged
Asterisk Version:           SVN 
JIRA:                       SWP-2737 
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): 1.8 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2010-12-08 17:10 CST
Last Modified:              2011-01-27 09:02 CST
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Summary:                    Deadlock in chan_sip
Description: 
I've been testing T.38 with my SIP provider using a Linksys ATA and a fax
machine behind it.

I initiate the fax with my fax machine and it connects with the other end.
 Shortly after the fax machine thinks the call disconnects.  If I type a
'core show channels' at this point, I don't see any active channels.  At
this point the PBX does not accept any more calls.  Commands also seem to
not go through on the CLI until I 'exit' and 'asterisk -vvvvvr' again.

Asterisk is compiled with DONT_OPTIMIZE and DEBUG_THREADS.  I have run
this scenario 3 to 5 times now with the same result so I am faithful I can
reproduce it as needed.

Attached is the output from 'core show locks' after the presumed deadlock.
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 (0131113) Alric (reporter) - 2011-01-27 09:02
 https://issues.asterisk.org/view.php?id=18441#c131113 
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I traced this back to faxdetect = yes.

I had that parameter set to yes, but I had no fax extension defined.  I
got the inspiration to check on that from the fax detection things that
were added between 1.6.1.11 and 1.6.1.12.  I see some additional locks and
unlocks were added.  I don't have the C knowledge to say if those locks are
related though.

It does look like that section of code (near line 6610 on 1.6.1.12, line
6980 on 1.8.2.2) has remained relatively unchanged through all those
versions. 

Issue History 
Date Modified    Username       Field                    Change               
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2011-01-27 09:02 Alric          Note Added: 0131113                          
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