[mythtv-users] Segfault on starting playback

[Stephen Robertson]

On Thu, Aug 30, 2012 at 5:41 PM, Jim Stichnoth <stichnot at gmail.com> wrote:
> On Sun, Aug 26, 2012 at 1:12 PM, Stephen Robertson
> <stephengrobertson at gmail.com> wrote:
>> On Sunday, August 26, 2012, Douglas Mackay wrote:
>>>
>>> On 26 August 2012 10:53, Douglas Mackay <douglas.mackay at gmail.com> wrote:
>>> > On 26 August 2012 10:01, Douglas Mackay <douglas.mackay at gmail.com>
>>> > wrote:
>>> >> Not sure if this helps but I'm also experiencing a similar issue.
>>> >>
>>> >> I've got two crash reports on Launchpad (one from a remote frontend
>>> >> and the other from the backend)
>>> >>
>>> >> https://bugs.launchpad.net/mythbuntu/+bug/1041788
>>> >> https://bugs.launchpad.net/mythbuntu/+bug/1041797
>>> >
>>> > If I manually run mythpreviewgen on the recording then is crashes
>>> > about 50% of the time. This recording was from Freeview (UK).
>>>
>>> I've done further testing and from what I can see it just affects BBC
>>> channels (SD, HD on both UK Freeview and UK Freesat). These channels
>>> have digital teletext services.
>>>
>>> Sample (6MB) - http://www.filedropper.com/100120120826105500
>>> ______________________________________________
>>
>>
>> I hadn't noticed this as the vast majority of my recordings are BBC but this
>> seems to be the case for me too.
>
> This is a request for help from the people who are experiencing these
> crashes.  I am trying to investigate this problem (there are at least
> 3 tickets that seem to be reporting this same thing), but it is
> challenging because I can't reproduce the crash on my system.
> However, there are indications from valgrind that uninitialized memory
> may be involved.  Specifically, if I use valgrind in this way:
>
> valgrind --leak-check=full --error-limit=no --show-reachable=yes
> /usr/mythtrunk/bin/mythavtest -v general,playback,libav --loglevel
> debug myth://Videos@192.168.0.205:6543/broken.mpg
>
> Part of the valgrind output looks like this:
>
> ...
> 2012-08-29 13:17:33.668634 D  mpegts_add_stream: stream #11, has id
> 0x1c25 and codec DSMCC_B, type Data at 0x134ef380
> ==15679== Conditional jump or move depends on uninitialised value(s)
> ==15679==    at 0x411497E: mpegts_push_section (mpegts-mythtv.c:674)
> ==15679==    by 0x4114B6E: write_section_data (mpegts-mythtv.c:401)
> ==15679==    by 0x41173CD: handle_packet (mpegts-mythtv.c:2527)
> ==15679==    by 0x7021BC63: ???
> ==15679==
> ==15679== Conditional jump or move depends on uninitialised value(s)
> ==15679==    at 0x4114985: mpegts_push_section (mpegts-mythtv.c:684)
> ==15679==    by 0x4114B6E: write_section_data (mpegts-mythtv.c:401)
> ==15679==    by 0x41173CD: handle_packet (mpegts-mythtv.c:2527)
> ==15679==    by 0x7021BC63: ???
> ==15679==
> ==15679== Conditional jump or move depends on uninitialised value(s)
> ==15679==    at 0x411497E: mpegts_push_section (mpegts-mythtv.c:674)
> ==15679==    by 0x4114B6E: write_section_data (mpegts-mythtv.c:401)
> ==15679==    by 0x41173CD: handle_packet (mpegts-mythtv.c:2527)
> ==15679==    by 0x8792: ???
> ==15679==
> ==15679== Conditional jump or move depends on uninitialised value(s)
> ==15679==    at 0x4114985: mpegts_push_section (mpegts-mythtv.c:684)
> ==15679==    by 0x4114B6E: write_section_data (mpegts-mythtv.c:401)
> ==15679==    by 0x41173CD: handle_packet (mpegts-mythtv.c:2527)
> ==15679==    by 0x8792: ???
> ==15679==
> ==15679== Conditional jump or move depends on uninitialised value(s)
> ==15679==    at 0x411497E: mpegts_push_section (mpegts-mythtv.c:674)
> ==15679==    by 0x4114B6E: write_section_data (mpegts-mythtv.c:401)
> ==15679==    by 0x41173CD: handle_packet (mpegts-mythtv.c:2527)
> ==15679==    by 0x6FDC685: ??? (in /usr/lib/libQtGui.so.4.6.2)
> ==15679==
> ==15679== Conditional jump or move depends on uninitialised value(s)
> ==15679==    at 0x4114985: mpegts_push_section (mpegts-mythtv.c:684)
> ==15679==    by 0x4114B6E: write_section_data (mpegts-mythtv.c:401)
> ==15679==    by 0x41173CD: handle_packet (mpegts-mythtv.c:2527)
> ==15679==    by 0x6FDC685: ??? (in /usr/lib/libQtGui.so.4.6.2)
> ==15679==
> ==15679== Conditional jump or move depends on uninitialised value(s)
> ==15679==    at 0x411497E: mpegts_push_section (mpegts-mythtv.c:674)
> ==15679==    by 0x4114B6E: write_section_data (mpegts-mythtv.c:401)
> ==15679==    by 0x41173CD: handle_packet (mpegts-mythtv.c:2527)
> ==15679==    by 0x1F03EB59: ???
> ==15679==
> ==15679== Conditional jump or move depends on uninitialised value(s)
> ==15679==    at 0x4114985: mpegts_push_section (mpegts-mythtv.c:684)
> ==15679==    by 0x4114B6E: write_section_data (mpegts-mythtv.c:401)
> ==15679==    by 0x41173CD: handle_packet (mpegts-mythtv.c:2527)
> ==15679==    by 0x1F03EB59: ???
> ==15679==
> 2012-08-29 13:17:35.174329 I  AFD: Stream #0, has id 0x12d codec id
> MPEG2VIDEO, type Video, bitrate 15000000 at 0x12c8d720
> ...
>
> This valgrind output related to mpegts-mythtv.c lines 674 and 684
> seems to correlate to the stack traces in the crash reports, and
> appears just after the last bit of log output before the crashes.
>
> So I'd like to ask anyone who can reproduce this crash, if they can
> run valgrind in the same way, and see where the crash happens with
> respect to the valgrind output.
>
> Jim
> _______________________________________________

Not at all familiar with valgrind so don't know what to pull out so
the whole thing (>8MB) is at
https://www.dropbox.com/s/lf9m1vm94b5ndlu/valgrind.txt?m

Anything else I can help with just let me know.

Stephen