Segmentation fault with FD_SET

[banogabor@…]

I've found a annoying bug in Mythfrontend UI. My Myth system is run on separated frontend and backend. The backend works correctly, records series, etc... When I try to play back any program and would like to navigate any series subtitles, at series group select I've allways got segmentation fault and the machine exits from mythfrontend. If I stay on default group or any built-in group, then I can browse recorded programs one-by-one.

I'm localized the bug (with --verbose all), but I cannot to fix it. The mythfrontend answers with segmentation fault, when the backend server sends an 'Empty FD_SET'.

[Dibblah]

Backtrace, please.

[anonymous]

Backtrace? How do you mean? (sorry, I don't understand everything in english)

[Dibblah]

http://www.mythtv.org/wiki/Debugging

[banogabor@…]

Okay, but this take some more time...

[banogabor@…]

producted segfault

[banogabor@…]

Ok, I'm reproduced this fault and attached the result to this ticket

[sphery]

Any chance you could install the debug symbols, as described in the above-linked wiki page, to make the backtrace a lot easier to read. And please see http://www.mythtv.org/docs/mythtv-HOWTO-22.html#ss22.2 (linked from the page above) for the actual gdb commands to run (including thread apply all bt full ).

[banogabor@…]

backtrace about error

[banogabor@…]

I made it as your suggested desciption, on a fully new system.

[danielk]

(In [22872]) Refs #7617. This commit may or may not fix the segfault, but it does fix actual bugs.

[robertm]

Is this bug still present in .23-fixes?

[anonymous]

I'm tried this new version of mythtv. It works better, so no longer stops with segfault, but still doesn't handles accentuated letters correcly. When a select a view filter, what contains any accentuated letters, I'm got "there are no recording in your current view" message and doesn't appear any recorded programs on the right side.

[anonymous]

I'm mistaken, still be segfault, but not in all of themes. No segfault on Terra and Mythcenter theme. The former of my write refers these two themes

[sphery]

banogabor, can you test with the attached patch on either 0.23-fixes or trunk and let us know if it helps? Thanks.

[anonymous]

Sorry. I'm tried it with latest trunk version, but same all everything. Unfortunatelly didn't help this patch.

[sphery]

Can you get us a new backtrace with debug symbols for trunk (without the patch), as the code where you got the segfault in the attached backtrace doesn't exist anymore (got moved and changed a bit). Thanks.

[anonymous]

OK,I'll do it. But I'm detected another interest thing: I was an feel: maybe when I've got the 'no recordings' message, the frontend doesn't send any queries to the database. And yes! I run frontend with '-v database' option, and watched it what does. It does really not send any queries to database. Whether why?

[banogabor@…]

Segfault in mythUI

[anonymous]

I think, may I found the source of error: The 2297 row in playbackbox.cpp file in programs folder. I think need to put dual colon beetween double quotes instead of single. I'm tried it and works: no segfault already, but the show filtering still not works well. Please fix it, if had verification.

[cpinkham]

Can you try changing that line to the following instead of changing the double quotes to single quotes?

Change this:

QString grpHost = sgroup + ":" + host;

To this:

QString grpHost = QString("%1:%2").arg(sgroup).arg(host);

See if that still segfaults.

[anonymous]

Sorry, this change isn't fix this problem.

[anonymous]

The error be an other function. Because the host object doesn't always contain valid data and the object first usage here, therefore the segfault is be here too. I was go back to the before 'findArtworkFile' function call. I'm inserted a 'VERBOSE' line for watching 'artworkHost' object contain. The score: the segfault moved here. Because the 'All program' and 'Watch list' doesn't produce segfault and writes the object value correctly, therefore I think this error is about 'artworkHost' object filling, when reach to 635 row (artworkHost = (*(m_progLists[groupname].begin()))->hostname;).

[cpinkham]

(In [24176]) Don't try to find artwork if there are no items in the current group.

References #7617. Ticket can be closed after it's a confirmed fix.

[cpinkham]

(In [24177]) Carry over [24176] from trunk.

Don't try to find artwork if there are no items in the current group.

References #7617. Ticket will be closed after it's a confirmed fix.

[anonymous]

Ok, now good. Thank you!

[cpinkham]

Closing, confirmed fixed.