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

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=9379 
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Reported By:                Matti
Assigned To:                sruffell
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Project:                    DAHDI-linux
Issue ID:                   9379
Category:                   zaptel (the module)
Reproducibility:            have not tried
Severity:                   minor
Priority:                   normal
Status:                     assigned
JIRA:                        
Reviewboard Link:            
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Date Submitted:             2007-03-26 07:55 CDT
Last Modified:              2010-10-20 07:23 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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 (0128229) svnbot (reporter) - 2010-10-20 07:23
 https://issues.asterisk.org/view.php?id=9379#c128229 
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Repository: dahdi
Revision: 9444

U   linux/trunk/drivers/dahdi/dahdi-base.c
U   linux/trunk/drivers/dahdi/tor2.c
U   linux/trunk/drivers/dahdi/wct1xxp.c
U   linux/trunk/drivers/dahdi/wct4xxp/base.c
U   linux/trunk/drivers/dahdi/wcte11xp.c
U   linux/trunk/drivers/dahdi/wcte12xp/base.c
U   linux/trunk/include/dahdi/kernel.h

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r9444 | sruffell | 2010-10-20 07:23:18 -0500 (Wed, 20 Oct 2010) | 12 lines

dahdi: Atomically set/test if channel has associated network device.

Push all tests for the DAHDI_FLAGBIT_NETDEV flag behind a
'dahdi_have_netdev' function so if CONFIG_DAHDI_NET is not defined the
compiler can just remove all the flag tests.  Also, makes sure that the
bit is checked / set atomically.

(closes issue https://issues.asterisk.org/view.php?id=9379)

Signed-off-by: Shaun Ruffell <sruffell at digium.com>
Acked-by: Kinsey Moore <kmoore at digium.com>
Acked-by: Russ Meyerriecks <rmeyerriecks at digium.com>
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http://svn.digium.com/view/dahdi?view=rev&revision=9444 

Issue History 
Date Modified    Username       Field                    Change               
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2010-10-20 07:23 svnbot         Checkin                                      
2010-10-20 07:23 svnbot         Note Added: 0128229                          
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