[asterisk-bugs] [Asterisk 0016678]: [patch] segfault on chanspy due to race in main/channel.c

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=16678 
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Reported By:                tim_ringenbach
Assigned To:                dvossel
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Project:                    Asterisk
Issue ID:                   16678
Category:                   Applications/app_chanspy
Reproducibility:            random
Severity:                   minor
Priority:                   normal
Status:                     confirmed
Target Version:             1.4.31
Asterisk Version:           1.4.29 
JIRA:                       SWP-783 
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:             2010-01-22 17:52 CST
Last Modified:              2010-02-12 17:30 CST
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Summary:                    [patch] segfault on chanspy due to race in
main/channel.c
Description: 
When channel.c destroys the datastore on the channel, it doesn't hold the
channel lock while calling the destroy callback. It really ought to,
because otherwise it's accessing the datastore list without locking. I've
gotten a segfault trying to lock the mutex in the ds destroy function in
app_chanspy because of this race.

Holding the channel lock during the destroy should be safe because it is
also held during the fixup callback, and app_chanspy has already been
patched to avoid the possible deadlock from that locking order issue.
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 (0118054) svnbot (reporter) - 2010-02-12 17:30
 https://issues.asterisk.org/view.php?id=16678#c118054 
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Repository: asterisk
Revision: 246545

U   branches/1.4/main/channel.c

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r246545 | dvossel | 2010-02-12 17:30:18 -0600 (Fri, 12 Feb 2010) | 16
lines

lock channel during datastore removal

On channel destruction the channel's datastores are removed and
destroyed.  Since there are public API calls to find and remove
datastores on a channel, a lock should be held whenever datastores are
removed and destroyed.  This resolves a crash caused by a race
condition in app_chanspy.c.

(closes issue https://issues.asterisk.org/view.php?id=16678)
Reported by: tim_ringenbach
Patches:
      datastore_destroy_race.diff uploaded by tim ringenbach (license 540)
Tested by: dvossel



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http://svn.digium.com/view/asterisk?view=rev&revision=246545 

Issue History 
Date Modified    Username       Field                    Change               
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2010-02-12 17:30 svnbot         Checkin                                      
2010-02-12 17:30 svnbot         Note Added: 0118054                          
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