Backend not responding, with backtrace and log

[tom@…]

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@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.

[tom@…]

Backtrace of running mythbackend process

[tom@…]

Backend logfile from before the problem to restart of the process

[justifiably@…]

Remark: I started a thread on the dev list about this fault (or at least, a fault with very similar symptoms): "Recording/scheduling thread dying?" I haven't been able to repeat the crash at will but it usually happens within a day of uptime. I've tried various patches/suggestions mentioned on the dev list (MythSocket?, qt with mysqlclient_r, disabling slave backend) but none of these have fixed the issue.

[tom@…]

Just happened again, I believe the comment on the -dev list about it having to do with a slave backend generating a thumbnail is correct. This time when it happened I had all tuner in the master being used, and the first tuner in the slave jsut started a recording, and when I went to the frontend to look at the recordings list, the front end hung; the slave recording was the first in the list, and there was no thumbnail. I managed to get a backtrace from the master, the slave gave me an error when I tried to generate the bt, and I have logs from both backends. See attached.

Tom

[tom@…]

Master backend backtrace

[tom@…]

Master backend log

[tom@…]

Slave backend log

[tom@…]

Forgot version information

Master backend 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

Slave backend Library API version: 0.19.20060331-1 Source code version: 9918M 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

[tom@…]

Happened again, this time I got backtrace and logs from both backends and log from the frontend. It does appear that there is something going on with the slave writing the thumbnail, but it only seems to appear under certain circumstances. I think I figured out what triggers it, but it's not reproducible, in that it doesn't do it every time, but when it does do it, the steps are the same:

• go into live tv (mine is setup so live tv defaults to using the last card on the slave)
• convert the live tv program to be saved as a recording
• exit to main menu
• enter Watch Recordings section
• boom, backend stops responding, no thumbnail is shown

Attached are all logs and bt, version info:

Library API version: 0.19.20060522-1 Source code version: 10064 Options compiled in:

linux debug using_lmsensors using_v4l using_oss using_alsa using_ivtv using_ip_rec using_lirc using_x11 using_xv using_xrandr using_frontend using_backend

[Isaac Richards]

Should have been fixed by MythSocket? changes - if not, reopen.