[mythtv-users] Backend crashes all the time

[tim at electronghost.co.uk]

> During the last week, I've had several
> crashes on my backend.

I get these too, though I've added a bit of code to make them happen
earlier while looking for the cause. My investigations suggest some kind
of memory scribble. I've posted a bit of information to Ticket #4820
(which may yet turn out to be the wrong ticket for it, but never mind :-)

I can provoke it quite quickly by channel hopping, as it tends to happen
on a channel change in LiveTV, and specifically on a corrupted SIGNAL
message. Is that where you get it?

> $ /usr/local/bin/mythbackend --version
> Please include all output in bug reports.
> MythTV Version   : 16332
> MythTV Branch    : trunk
> Library API      : 0.21.20080224-1
> Network Protocol : 40
> Options compiled in:
>   linux release using_oss using_backend using_dbox2 using_dvb
> using_frontend using_hdhomerun using_iptv using_ivtv using_joystick_menu
> using_v4l using_x11 using_xrandr using_xv using_bindings_perl
> using_bindings_python using_opengl using_ffmpeg_threads using_live
>
> Sometimes when the backend crashes I just get a line
> like:
>
> # fgrep segfault /var/log/messages
> Mar  3 09:22:22 mogens1 kernel: mythbackend[16969]: segfault at ce631207
> eip 0063bf94 esp abffcf1c error 5
> Mar  3 09:23:27 mogens1 kernel: mythbackend[17088]: segfault at 1830c0b9
> eip 0063bf9a esp bff9a71c error 4
>
> Sometimes I get a more detailed error message in
> /var/log/mythtv/mythbackend.log:
>
> *** glibc detected *** /usr/local/bin/mythbackend: malloc(): memory
> corruption (fast): 0x0828c467 ***
> ======= Backtrace: =========
> /lib/libc.so.6[0x63e631]
> /lib/libc.so.6(__libc_malloc+0x7e)[0x63f2ee]
> /usr/lib/libstdc++.so.6(_Znwj+0x27)[0xae0b27]
> /usr/lib/qt-3.3/lib/libqt-mt.so.3(_ZN7QString9setLengthEj+0x93)[0x4d2da463]
> /usr/lib/qt-3.3/lib/libqt-mt.so.3[0x4d2dd354]
> /usr/lib/qt-3.3/lib/libqt-mt.so.3(_ZNK7QString3argExii+0x112)[0x4d2df9c2]
> /usr/local/lib/libmythtv-0.21.so.0(_ZNK18SignalMonitorValue9GetStatusEv+0x1ff)[0xb77f1daf]
> [0x8418148]
> ======= Memory map: ========
>