[asterisk-bugs] [Asterisk 0019403]: [patch] Call pickup deadlock in ast_do_masquerade

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=19403 
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Reported By:                one47
Assigned To:                
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Project:                    Asterisk
Issue ID:                   19403
Category:                   Core/Channels
Reproducibility:            always
Severity:                   block
Priority:                   normal
Status:                     new
Asterisk Version:           1.6.2.18 
JIRA:                        
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:             2011-06-03 04:03 CDT
Last Modified:              2011-06-03 04:55 CDT
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Summary:                    [patch] Call pickup deadlock in ast_do_masquerade
Description: 
Using *8 call pickup can readily cause a deadlock where ast_do_masquerade()
has a channel locked, when calling ast_channel_free() - ast_channel_free
requests the channels (channel list) lock, which breaks locking order
requirements and caused a deadlock.
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 (0135667) alecdavis (manager) - 2011-06-03 04:55
 https://issues.asterisk.org/view.php?id=19403#c135667 
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Using SVN-branch-1.6.2-r321210M

deadlock CoreShowLocks-1.6.2-r321210.txt

Setup, 2 internal calls to SIP C, don't answer SIP C:
SIP A  ---> SIP C
SIP B  ---> SIP C

Pickup at exactly the same time.
SIP D *8 pickup
SIP E *8 pickup
 
I'm able to get a deadlock by 2 callers (SIP A and B) ringing same
extension (SIP C), and another 2 (SIP D and E) attempt to pick up (SIP C)
the ringing extension.

This is not that repeatable. Wish it was. 

Issue History 
Date Modified    Username       Field                    Change               
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2011-06-03 04:55 alecdavis      Note Added: 0135667                          
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