Deleting programs from within PBB causes segfault about 1/4 of the time

[jppoet@…]

Using the D key to delete programs in PBB results in a segfault about 1/4 of the time.

What may be interesting, is I can predict when the segfault is going to happen, because the pop-up dialog asking for confirmation (allow re-record, etc), does not instantly appear -- Instead it kind of stutters into existence. Whenever it stutters into view, as soon as I select what mode of deletion I want, mythfrontend segfaults.

Trunk Revision: 19866 metallurgy-ui theme

BT attached

[jppoet@…]

BT of PBB delete segfault

[anonymous]

When the segfault happens, chanid is invalid in:

QString ProgramInfo::MakeUniqueKey(void) const
{
    return chanid + "_" + recstartts.toString(Qt::ISODate);
}

(gdb) p chanid
$2 = {static null = {<No data fields>}, static shared_null = {ref = {_q_value = 27622}, alloc = 0, size = 0, data = 0x7d099a, clean = 0, simpletext = 0, righttoleft = 0, asciiCache = 0, capacity = 0, reserved = 0, array = {0}}, static shared_empty = {ref = {_q_value = 11598}, alloc = 0, size = 0, data = 0x39fdc27dba, clean = 0, simpletext = 0, righttoleft = 0, asciiCache = 0, capacity = 0, reserved = 0, array = {0}}, d = 0xd420fa0, static codecForCStrings = 0x0}

[jppoet@…]

Alternate BT

[jppoet@…]

Adding another BT. This one is different then the first, but caused by the same scenario, except I did not see the pop-up dialog "stutter" into existence.

[R. Geoffrey Newbury <newbury@…>]

My experience is that it seg-faults 100% of the time when deleting from the PBB. Does NOT do so when deleting while playing the recording. Mythfrontend -v playback,extra is:

<date-time> Warning: container 'pbbmainmenupopup' is missing child 'title' Segmentation fault

[stuartm]

Reasonably certain that this is a race condition with the RECORDING_LIST_CHANGE event invalidating the ProgramInfo pointer for the item to be deleted. Are you deleting these recordings immediately after watching? What happens if you wait 30 seconds first?

On a side note, RECORDING_LIST_CHANGE events are inefficient, causing a complete rebuild of the ProgInfo cache and UI list even though the change is usually minimal - addition or removal of one or two recordings. I'd be much happier if they included a list of recordings added and removed, that would allow much smoother and faster updates of the UI as well as avoiding problems like that above.

[jppoet@…]

I get the crashes most often when deleting a batch of shows, one at a time. Most of the time, I have not watched the episode in question at all.

I am debugging a recording issue, and I am starting/stopping/starting/stopping/... mythbackend which results in a long list of short recordings. I get the crash when I go and clean up all of those short snippets.

[stuartm]

(In [20171]) Fix for segfault when deleting recordings immediately after playback. Tested this as best I can with the myriad different paths to the deletion of recording, but there are a great number of variables involved so let me know if you see strange behaviour with deletion. Closes #6191