[mythtv-users] Myth backend lockup

[R. G. Newbury]

On 08/04/2015 03:17 PM, Tom Bishop wrote:
>
>
> On Tue, Aug 4, 2015 at 2:07 PM, Hika van den Hoven <hikavdh at gmail.com
> <mailto:hikavdh at gmail.com>> wrote:
>
>     Hoi Gary,
>
>     Tuesday, August 4, 2015, 8:58:18 PM, you wrote:
>
>     > On Tue, Aug 4, 2015 at 6:43 PM, Tom Bishop <bishoptf at gmail.com <mailto:bishoptf at gmail.com>> wrote:
>     >> Trying to find some ideas of where to start
>
>     > I do not recall any repeatably reports of lockups on 0.27, but
>     > timing can be everything, and timing in a vm is often different,
>     > which may expose some underlying problem.
>
>     > I would try to attach to the backend process with gdb and
>     > "thread apply all bt" to see what is going on.
>     > _______________________________________________
>
>     Is it a lockup or a crash? I know that in the past my mythbackend
>     service sometimes disappeared. Since then I have a cron job checking
>     every minute and restarting if needed. It hasn't happened in a long
>     time, but I keep it there.
>
>
> I still see the process running but you cannot connect to the database,
> if you try to bring up the mythweb etc, they timeout.  The logging just
> stops when it has the issue, like I said the linux VM is up and running
> and I can ssh to it etc.

I have had lockups occurring with master since about January. Symptom is 
a complete lockup. SSH etc do not work. These happen irregularly and I 
was unable to find any logged information. In case it was a memory 
problem I swapped the memory with the office file server. Nope.

The lockups occur at any time. The frontend locks up too, but the last 
operating time is shown on the front page of the frontend. I have had 
lockups occur at 2:30 in the morning, when there were no recordings 
being made. The only possible source that I can think of is some race 
condition against mythcommflag, since that would be the only *extra* 
thing running at the time of day.

And I saw nothing from the gdb trace I tried.. although there is astrong 
possibility that I did that wrong. First time and working blind. Tab A 
in slot C? B in C and A in D????? What????

Geoff

-- 
              R. Geoffrey Newbury