[asterisk-bugs] [Zaptel 0011661]: ztcfg default behavior + races in zaptel drivers + unsuspecting admins cause kernel crashes

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=11661 
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Reported By:                sim
Assigned To:                
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Project:                    Zaptel
Issue ID:                   11661
Category:                   Core-General
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Zaptel Version:             1.4.7.1 
SVN Branch (only for SVN checkouts, not tarball releases): N/A  
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             12-31-2007 18:29 CST
Last Modified:              01-02-2008 14:16 CST
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Summary:                    ztcfg default behavior  + races in zaptel drivers +
unsuspecting admins cause kernel crashes
Description: 
I have witnessed more than 5 different people accidentally run "ztcfg" on
production systems in an attempt to try to poke at zaptel to find the
source of an issue.  One runs through "zttool", "ztdiag", "zttest", etc.,
and usually "ztcfg" if they do not know better, expecting it to behave
similar to "ifconfig".  This _should_ just reset the PRIs (in a perfect
world), but instead it tends to cause a kernel Oops in zt_init_tone_state
due to races in zaptel when channels are active.

I bet this has been causing people to kill their Asterisk servers around
the globe for many years now, and I think this is serious enough to warrant
an interface change.  I propose we either change "ztcfg" to require an
argument before applying any changes, or we make it do something similar to
checking for Asterisk running first, and not apply configuration if so
unless an override argument is specified.

If agreed, I can easily write and submit a patch -- just let me know.
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---------------------------------------------------------------------- 
 Corydon76 - 01-02-08 14:16  
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Well, I still don't think ztcfg needs to be where the fix needs to take
place.  To avoid bouncing your PRIs, you should ideally check within the
kernel driver whether the config is already in place, and, if so, don't do
anything.  There are tools other than ztcfg which are able to set
configuration, so the fix should properly be in the kernel driver, not in
ztcfg. 

Issue History 
Date Modified   Username       Field                    Change               
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01-02-08 14:16  Corydon76      Note Added: 0076226                          
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