[mythtv] [mythtv-commits] Ticket #1805: Backend not responding, with backtrace and log

Jim Westfall jwestfall at surrealistic.net
Sat May 13 03:47:25 UTC 2006

MythTV <mythtv at cvs.mythtv.org> wrote [05.13.06]:
> #1805: Backend not responding, with backtrace and log
> -------------------------------------+--------------------------------------
>  Reporter:  tom at redpepperracing.com  |       Owner:  ijr
>      Type:  defect                   |      Status:  new
>  Priority:  minor                    |   Milestone:     
> Component:  mythtv                   |     Version:     
>  Severity:  medium                   |  
> -------------------------------------+--------------------------------------
>  The symptom that I have been experiencing is that the backend will all of
>  a sudden stop  responding to connection requests. The process is still
>  running, and it's not eating CPU, but neither a frontend nor mythweb can
>  connect to the backend. I finally managed to get a backtrace and backend
>  log when it happened.
>  Version:
>  root at mythtv:/var/log# mythbackend --version
>  Library API version: 0.19.20060331-1
>  Source code version: 9918
>  Options compiled in:
>   linux debug using_lmsensors using_v4l using_oss using_alsa using_ivtv
>  using_lirc using_x11 using_xv using_xrandr using_frontend using_backend
>  Machine is an AMD Sempron 2200, 512MB RAM, 2xPVR-250.
>  See attached backtrace and backend log from around where it happened. I
>  was experimenting with de-interlace and XvMC settings, so I was going in
>  and out of live tv a number of times just before it happened. Not sure if
>  that is related. It also seems to happen around the turn of the hour when
>  a couple of recordings start. Also of note is that the recordings continue
>  to actually record until I stop and restart the backend process, and
>  resume when it comes up.

I assume you have a slave backend too?  

Looking at the backtrace (your master backend?) it appears to have a lock 
on the socket that is waiting for a slave backend to respond about 
generating a pixmap.  At the same time the main app thread is trying to 
process a customEvent, which is blocked trying to get the lock on the 
same socket.  The main app thread being blocked like this is likely 
causing all qt event processing to stop.


More information about the mythtv-dev mailing list