[mythtv-users] help diagnosing mythbackend service crashing

[Larry]

On 3/1/10 2:58 AM, mythtv-users-request at mythtv.org wrote:
> Message: 16
> Date: Sun, 28 Feb 2010 22:04:37 -0500
> From: "Michael T. Dean"<mtdean at thirdcontact.com>
> Subject: Re: [mythtv-users] help diagnosing mythbackend service
> 	crashing
> To: Discussion about mythtv<mythtv-users at mythtv.org>
> Message-ID:<4B8B2EC5.60600 at thirdcontact.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 02/28/2010 09:53 PM, Larry wrote:
>    
>> >  Hello all,
>> >
>> >  I'm trying to figure out why in the last 3 week or so my once
>> >  extremely stable backend system has suddenly started having an issue
>> >  with the mythbackend service causing it do die.
>> >
>> >  System is running CENTOS 5.4 w kernel 2.6.18-164.11.1.el5
>> >
>> >  mythbackend version mythtv-backend-0.22-227.el5
>> >
>> >  The mythbackend logs show nothing so I'm guessing I need to turn on
>> >  some additional logging so I can capture what is happening.  Thats the
>> >  part that I need help with.
>> >
>> >  I start the mythbackend service with the standard /etc/rc.d/init.d
>> >  scripts and would like to modify that if possible to get the
>> >  additional logging. I say this because I have monit currently watching
>> >  over the system and restarting it when it crashes now. Monit was added
>> >  in after the crashes started to make the system more wife/kid friendly.
>> >
>> >  I'm sure I will be back with additional questions once I get some of
>> >  the log information unless google throws me a bone on the error but
>> >  right now I need to figure out how to get more debugs out of the system.
>> >
>> >  Thanks for your assistance!
>>      
> The best information you could provide to help us diagnose the crashing
> is a gdb thread backtrace, as described athttp://mythtv.org/wiki/Debugging
>
> Logs will almost definitely have no useful information for diagnosing
> the crash.
>
> Mike
>
>
>
>    

Just so I'm doing this right here is what I have done.

First I installed the atrpms-debug packages

yum --enablerepo=atrpms-debuginfo install mythtv-debuginfo


Then I added the following to my /etc/rc.d/init.d/mythbackend script 
inside the start section

ulimit -c unlimited
echo 1>  /proc/sys/kernel/core_uses_pid
echo "/tmp/core.%t.%u.%p.%e">  /proc/sys/kernel/core_pattern


once the system dies is horrible death and gets restarted I should run 
the following:

$ sudo gdb mythbackend -c /tmp/core.[rest_of_the_file_name] 2>&1 | tee mythtv_backtrace.txt
set pagination off
thread apply all bt
quit

and all the goodness should be available in the mythtv_backtrace.txt file?

Anything else that I should do ?  I just want to make sure I'm capturing 
everything that is needed.



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