[asterisk-bugs] [Asterisk 0018165]: [patch] hint state changes deadlock problem

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=18165 
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Reported By:                antonio
Assigned To:                jpeeler
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Project:                    Asterisk
Issue ID:                   18165
Category:                   Core/PBX
Reproducibility:            have not tried
Severity:                   major
Priority:                   normal
Status:                     assigned
Asterisk Version:           1.6.2.13 
JIRA:                       SWP-2495 
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:             2010-10-19 13:45 CDT
Last Modified:              2010-11-08 11:32 CST
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Summary:                    [patch] hint state changes deadlock problem
Description: 
What happens is there are two threads that lock resources in a different
order causing a deadlock.

The threads are:

1. from taskprocessor handle_statechange() is called. This one locks
ast_rdlock_contexts, and then eventually call cb_extensionstate() which
immediately does a sip_pvt_lock()

2. do_monitor calls sipsock_read() which calls handle_request_do() which
calls find_call(), which does a sip_pvt_lock() too. The incoming request is
a subscription, so it calls ast_get_hint(), which calls
ast_hint_extension() which calls ast_rdlock_contexts(). Deadlock.

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Relationships       ID      Summary
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has duplicate       0018205 PBX hangup
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 (0128698) one47 (reporter) - 2010-11-08 11:32
 https://issues.asterisk.org/view.php?id=18165#c128698 
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I am working on a 1.6.2.13 version of this patch. In the meantime, the
original patch appears to be missing a call to
      ao2_ref(hint, -1);
in the
      if(hint) { ... }
test near the start of ast_add_hint.

I do not have 1.4 downloaded, so could not easily generate an updated
patch. 

Issue History 
Date Modified    Username       Field                    Change               
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2010-11-08 11:32 one47          Note Added: 0128698                          
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