[asterisk-bugs] [Asterisk 0018310]: [patch] hint state changes deadlock/race

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=18310 
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Reported By:                one47
Assigned To:                
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Project:                    Asterisk
Issue ID:                   18310
Category:                   Core/PBX
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     ready for testing
Asterisk Version:           1.6.2.14 
JIRA:                       SWP-2541 
Regression:                 No 
Reviewboard Link:            
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2010-11-15 12:19 CST
Last Modified:              2010-12-11 01:19 CST
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Summary:                    [patch] hint state changes deadlock/race
Description: 
VERY similar to https://issues.asterisk.org/view.php?id=18165, but this is a
different deadlock path, so I have
raised a separate report.

Thread 1: taskprocessor  -> handle_statechange
    Lock order = conlock, hints, hint, pvt
Thread 2: chan_sip.c:  handle_request_do -> handle_response_notify
    Lock order = pvt, conlock

Thread2 only gets into the conlock if STATECHANGEQUEUE is true, ie. there
are rapid state changes happening on a subscribed hint.
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Relationships       ID      Summary
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related to          0018165 [patch] hint state changes deadlock pro...
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 (0129547) schmidts (manager) - 2010-12-11 01:19
 https://issues.asterisk.org/view.php?id=18310#c129547 
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i am gonna try this patch against 1.8 to see the performance impact on
this. As you know handle_statechange has a great impact on call handling
performance so waiting there could maybe cause a regression.

IMHO the best way of really solving this would be moving the callbacks
itself to ao2 objects so we dont need the context lock anymore. 

Issue History 
Date Modified    Username       Field                    Change               
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2010-12-11 01:19 schmidts       Note Added: 0129547                          
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