[asterisk-bugs] [Zaptel 0009379]: [patch] zt_specchan_open race because ZT_FLAG_OPEN testing and setting is not atomic

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A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=9379 
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Reported By:                Matti
Assigned To:                mattf
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Project:                    Zaptel
Issue ID:                   9379
Category:                   zaptel (the module)
Reproducibility:            have not tried
Severity:                   minor
Priority:                   normal
Status:                     assigned
Zaptel Version:             1.4.7.1  
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        No 
Request Review:              
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Date Submitted:             03-26-2007 07:55 CDT
Last Modified:              04-05-2008 18:04 CDT
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Summary:                    [patch] zt_specchan_open race because ZT_FLAG_OPEN
testing and setting is not atomic
Description: 
Function zt_specchan_open in file zaptel.c can have a race condition
because ZT_FLAG_OPEN testing and setting is not atomic. The function should
check and set the flag holding the spin lock continuously in and between
the following lines:
if (chans[unit]->flags & ZT_FLAG_OPEN)
chans[unit]->flags |= ZT_FLAG_OPEN;
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Relationships       ID      Summary
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related to          0010806 Channel opening and unregistering race
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---------------------------------------------------------------------- 
 mattf - 04-05-08 18:04  
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I think I agree with Mark.  Many of these issues would be much simpler if
we used the atomic test_and_set and test_and_clear_bit routines.  I'm
currently auditing a few of these code paths and will add some patches
which use these routines to fix this issue.  I'm starting with the
open/release routines.  An initial version of my patch for these routines
is about to be attached, Matti, if you would like to see how I am doing it
and critique. 

Issue History 
Date Modified   Username       Field                    Change               
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04-05-08 18:04  mattf          Note Added: 0085046                          
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