[mythtv] Segfault when entering program guide

Anders Bruun Olsen anders at bruun-olsen.net
Mon Nov 29 22:27:24 UTC 2004


On Sat, Nov 27, 2004 at 07:20:15PM -0500, Isaac Richards wrote:
> > I am not a C/C++ programmer, but through the help of Google I have found
> > out how to do what I hope is a useful gdb dump, located here:
> > http://drzero.skumleren.net/mythtv-segfault-2004-11-23.txt
> > It was done running mythtv 0.16 and qt 3.3.3 with debug useflag.
> Using gentoo?  It looks to be an issue in Qt, and there's not much I can do 
> about it in Myth.  Try current cvs, though, and see if that's any better.

Okay, the problem has been solved now. It was not an issue in Qt.
The above gdb debug dump was caused by the database not containing any
schedule data, and it seems that in libs/libmythtv/infostructs.cpp in
ChannelInfo::Text chanstr, callsign and channame is being used without
checkning that they actually contain anything, which seems to be what
caused that segfault.
Next after that it kept segfaulting, but I couldn't recreate a similar
output. This time I had completely wiped mythtv and it's database from
my machine and reinstalled it, this time adding only 1 channel (no point
in setting up a whole bunch of channels if it doesn't work right?) and
after many days of trying this and that and finally getting some help
from a nice guy in a local LUG it dawned upon me that maybe mythtv
expects the data extracted from mysql to contain more that one channel,
and thus an iteration fails because only one channel is defined. And
that proved to be correct, after adding one more channel, it works.
So, it might be an idea for an experienced dev to run over the code that
draws the program-guide and make sure that it can handle if only one
channel is defined.

-- 
Anders
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