Opened 16 years ago
Closed 15 years ago
#5356 closed defect (invalid)
Internal DVD playback segfaults using multiple cores.
Reported by: | john | Owned by: | skamithi |
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Priority: | minor | Milestone: | 0.22 |
Component: | DVD Playback | Version: | 0.21-fixes |
Severity: | medium | Keywords: | dual core dvd iso segfault |
Cc: | Ticket locked: | no |
Description
A large number of my dvd.iso files cause mythfrontend to segfault. I traced it down to being associated with using a playback profile that enabled load sharing across both cores (cpu =2 in the playback profile)
I attach a backtrace, from a segfault. Same iso plays when cpu = 1 in playback profile.
Also discussed : http://www.gossamer-threads.com/lists/mythtv/dev/333939#333939
John
Attachments (5)
Change History (22)
comment:1 Changed 16 years ago by
Component: | mythvideo → mythtv |
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Resolution: | → worksforme |
Status: | new → closed |
comment:2 Changed 16 years ago by
Resolution: | worksforme |
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Status: | closed → new |
I highly doubt this is the wrong CPU type this user is using.
CFLAGS="-g -O2 -fPIC -DPIC" ./configure --prefix=/usr --enable-lirc --enable-audio-alsa \
--enable-audio-oss --enable-audio-jack --enable-audio-arts --enable-dvb \ --enable-ivtv --enable-firewire --enable-joystick-menu \ --enable-opengl-vsync --with-bindings=perl --enable-opengl-video \ --enable-ffmpeg-pthreads\ --compile-type=profile --cpu=i686 --enable-mmx --enable-xvmc --enable-xvmc-vld --enable-xvmc-pro --enable-glx-procaddrarb --enable-libfaad --enable-libfaac --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-libfftw3
That's what he is compiled for.
comment:3 Changed 16 years ago by
I have confirmed this using both the vanilla Ubuntu 8.04 build as well as manual build using options in previous comment (ie cpu=i686).
One of my test machines is a P4 with hyperthreading. Switching hyperthreading on (in BIOS, resulting in the system seeing 2 CPUs) causes segfault during DVD playback. When this is switched off in BIOS however (With no other changes to the system, including kernel), then previously problematic DVDs will play without any issue.
comment:4 Changed 16 years ago by
I have the same issue when i use my (happauge) remote control. When i use a vnc client to contol MythTV, there are no problems playing the DVD.
comment:5 Changed 16 years ago by
the above comment was not the right conclusion, but just coinsidence. Sorry
comment:6 Changed 16 years ago by
I have the sort of the same problem. DVD playback on image files sometimes makes the internal player to segfault. I noticed this happens more often when beforehand playing anything with mplayer and then playing something with the internal player.
Logs just state: Segmentation fault without any more information.
comment:7 Changed 16 years ago by
Component: | mythtv → DVD Playback |
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comment:8 Changed 15 years ago by
Status: | new → assigned |
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comment:9 Changed 15 years ago by
Owner: | changed from Anduin Withers to skamithi |
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comment:10 Changed 15 years ago by
Can we have some more backtraces from other people that are affected and with different DVDs? There are a couple of oddities in the original backtrace but they may be unrelated and I'd like to see if we can make any correlation.
Please give details of mythtv versions, distribution versions along with the DVD title and video profiles being used.
comment:11 Changed 15 years ago by
Status: | assigned → infoneeded |
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comment:12 Changed 15 years ago by
I have reproduced this bug on my Intel dual core running Fedora 10 with the MythTV release-0-21-fixes svn revision 20038.
It does only segfault with "Decoder: standard" and with "MaxCPUs: 2". It does not segfault with only one CPU. It also does not segfault with "Decoder: libmpeg2" (1 or 2 CPU's).
It only crashes on a few iso images, but it is 100% reproducible on those iso images.
Attachment iso-segfault-traceback-2.txt will be included.
Changed 15 years ago by
Attachment: | iso-segfault-traceback-2.txt added |
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segfault traceback for iso image playback with standard decoder and 2 CPUs
Changed 15 years ago by
Attachment: | gdb-log-songfestival.txt added |
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gdb log for DVD "Songfestival" (fedora 8, mythtv svn 20069)
Changed 15 years ago by
Attachment: | gdb-log-safini.txt added |
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gdb log for DVD "A Safini" (fedora 8, mythtv svn 20069)
Changed 15 years ago by
Attachment: | gdb-log-nederpop2.txt added |
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gdb log for DVD "Nederpop2" (fedora 8, mythtv svn 20069)
comment:13 Changed 15 years ago by
Added three attachments with gdb logs, now produced with the gdb settings as described in the MythTV documentation pages. This time the logs are made on an older machine with an E4600 CPU running Fedora 8. MythTV release-0-21-fixes svn 20069, compiled today.
If you run it without gdb then you get the following line in /var/log/messages:
Feb 28 10:56:33 zolder kernel: mythfrontend[15257]: segfault at 7fe7e41880d8 ip 7fe7eb2d282e sp 450d49d8 error 7 in libmythavcodec-0.21.so.0.21.0[7fe7eb099000+32b000]
Running from the commandline (without gdb) there are a lot of [mpeg2video] messages which suggest that the DVD image is not error-free. Here are the last lines:
2009-02-28 11:17:05.448 [mpeg2video @ 0x7f571b39f380]ac-tex damaged at 0 15 2009-02-28 11:17:05.448 [mpeg2video @ 0x7f571b39f380]00 motion_type at 10 16 2009-02-28 11:17:05.448 [mpeg2video @ 0x7f571b39f380]ac-tex damaged at 0 17 2009-02-28 11:17:05.473 [mpeg2video @ 0x7f571b39f380]Warning MVs not available Segmentation fault
Also, the gdb tracebacks do always contain functions from file error_resilience.c which suggests that the buggy code might be trying to correct the [mpeg2video] errors.
Hope this helps! If there is a patch for this I can of course test it.
Klaas.
comment:14 Changed 15 years ago by
Status: | infoneeded → assigned |
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comment:16 Changed 15 years ago by
Status: | assigned → infoneeded |
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comment:17 Changed 15 years ago by
Resolution: | → invalid |
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Status: | infoneeded → closed |
No feedback from ticket submitter in 30 days
traceback appears to be on mmx functions. I think this is a system problem. perhaps your kernel is not configured correctly or mythtv is not compiled with the correct options. i have a dual-core frontend and dual core dev laptop. both of which have no issues when i select cpu = 2, and this is my default setting.
unless someone else reports the same issue, i'm going to mark this as a worksforme. I had problems once on my dual core frontend when I compiled mythtv with the pentiumpro option by mistake instead of pentium4 (32bit kernel). opengl vsync stopped working properly causing all sorts of hangs and lockups. when i compiled it with the correct cpu type, everything works like a champ.