[mythtv-commits] Ticket #6736: strange mythtv segfaults

MythTV mythtv at cvs.mythtv.org
Sat Jul 18 12:49:10 UTC 2009


#6736: strange mythtv segfaults
-----------------------------------------+----------------------------------
 Reporter:  markus.doits at googlemail.com  |       Owner:  ijr    
     Type:  defect                       |      Status:  new    
 Priority:  major                        |   Milestone:  unknown
Component:  MythTV - Mythtranscode       |     Version:  head   
 Severity:  medium                       |     Mlocked:  0      
-----------------------------------------+----------------------------------
 using svn rev 20947.

 so first running simply ./configure:

 {{{
 # Basic Settings
 Compile type              release
 Compiler cache            symlink gcc
 DistCC                    no
 qmake                     /usr/bin/qmake-qt4
 install prefix            /usr/local
 runtime prefix            /usr/local
 CPU                       x86 x86_64 (model name        : Intel(R)
 Core(TM)2 Quad  CPU   Q9300  @ 2.50GHz)
 big-endian                no
 runtime cpu detection     no
 yasm                      yes
 MMX enabled               yes
 MMX2 enabled              yes
 3DNow! enabled            yes
 3DNow! extended enabled   yes
 SSE enabled               yes
 SSSE3 enabled             yes
 CMOV enabled              yes
 CMOV is fast              yes

 # Input Support
 Joystick menu             yes
 lirc support              yes
 Video4Linux sup.          yes
 ivtv support              yes
 HR-PVR support            yes
 FireWire support          yes
 DVB support               yes [/usr/include]
 HDHomeRun support         yes
 IPTV support              yes

 # Sound Output Support
 PulseAudio support        yes
 OSS support               yes
 ALSA support              yes
 aRts support              yes
 JACK support              yes
 libfftw3 support          no

 # Video Output Support
 x11 support               yes
 xrandr support            yes
 xv support                yes
 XvMC support              yes
 XvMC VLD support          yes
 XvMC pro support          no
 XvMC libs                 -lXvMCW
 VDPAU support             yes
 OpenGL video              yes
 OpenGL vsync              yes
 DirectFB                  yes
 Fribidi formatting        no
 MHEG support              yes

 # Misc Features
 multi threaded libavcodec yes
 Frontend                  yes
 Backend                   yes

 # Bindings
 bindings_perl             yes
 bindings_python           yes
 }}}

 it builds fine. but here, using mythtranscode gives the following (i
 removed various "no debugging symbols found"-lines):
 {{{
 (gdb) run -i 1014_20090718134400.mpg -o /tmp/bla -p autodetect
 --showprogress
 (no debugging symbols found)
 Starting program: /usr/local/bin/mythtranscode -i 1014_20090718134400.mpg
 -o /tmp/bla -p autodetect --showprogress
 (no debugging symbols found)
 ...
 009-07-18 14:19:05.855 Using runtime prefix = /usr/local
 2009-07-18 14:19:05.855 Empty LocalHostName.
 [New Thread 0x7febfa056950 (LWP 9340)]
 [Thread 0x7febfa056950 (LWP 9340) exited]
 2009-07-18 14:19:05.881 New DB connection, total: 1
 2009-07-18 14:19:05.884 Closing DB connection named 'DBManager0'
 2009-07-18 14:19:05.884 Enabled verbose msgs: important
 2009-07-18 14:19:05.886 New DB connection, total: 2
 2009-07-18 14:19:05.891 New DB connection, total: 3
 2009-07-18 14:19:06.531 Using protocol version 45
 [New Thread 0x7febfa056950 (LWP 9341)]
 [New Thread 0x7febf7824950 (LWP 9342)]
 [New Thread 0x7febf7023950 (LWP 9343)]
 [New Thread 0x7febf6822950 (LWP 9344)]
 [New Thread 0x7febf6019950 (LWP 9345)]
 2009-07-18 14:19:06.704 Transcode: Looking for autodetect profile:
 Autodetect from 576i
 2009-07-18 14:19:06.719 Transcode: Using autodetect profile: MPEG2
 [New Thread 0x7febf5607950 (LWP 9346)]
 [New Thread 0x7febf4dfe950 (LWP 9347)]
 strange error flushing buffer ...
 2009-07-18 14:19:06.780 mythtranscode: 0% Completed @ 0 fps.
 2009-07-18 14:19:10.902 Processed: 219 of 1925 frames(8 seconds)
 2009-07-18 14:19:15.904 Processed: 513 of 1925 frames(20 seconds)
 2009-07-18 14:19:20.914 Processed: 832 of 1925 frames(33 seconds)
 2009-07-18 14:19:25.915 Processed: 1143 of 1925 frames(45 seconds)
 2009-07-18 14:19:26.789 mythtranscode: 62% Completed @ 60.004 fps.
 2009-07-18 14:19:30.916 Processed: 1461 of 1925 frames(58 seconds)
 2009-07-18 14:19:35.933 Processed: 1793 of 1925 frames(71 seconds)

 Program received signal SIGSEGV, Segmentation fault.
 [Switching to Thread 0x7fec0afd77a0 (LWP 9339)]
 0x00007fec08ef6b90 in sws_freeContext () from
 /usr/local/lib/libmythswscale-0.22.so.0
 (gdb) bt
 #0  0x00007fec08ef6b90 in sws_freeContext () from
 /usr/local/lib/libmythswscale-0.22.so.0
 #1  0x00000000004204cd in ?? ()
 #2  0x0000000000414e61 in ?? ()
 #3  0x00007fec027425a6 in __libc_start_main () from /lib/libc.so.6
 #4  0x0000000000409949 in ?? ()
 #5  0x00007fff65dda098 in ?? ()
 #6  0x000000000000001c in ?? ()
 #7  0x0000000000000008 in ?? ()
 #8  0x00007fff65ddb073 in ?? ()
 #9  0x00007fff65ddb090 in ?? ()
 #10 0x00007fff65ddb093 in ?? ()
 #11 0x00007fff65ddb0ab in ?? ()
 #12 0x00007fff65ddb0ae in ?? ()
 #13 0x00007fff65ddb0b7 in ?? ()
 #14 0x00007fff65ddb0ba in ?? ()
 #15 0x00007fff65ddb0c5 in ?? ()
 #16 0x0000000000000000 in ?? ()
 }}}

 okey, so now i want to debug it, therefore: ./configure --compile-
 type=debug

 builds fine, but now see mythtranscode (nothing removed from output):

 {{{
 (gdb) run -i 1014_20090718134400.mpg -o /tmp/bla -p autodetect
 --showprogress
 The program being debugged has been started already.
 Start it from the beginning? (y or n) y
 `/usr/local/bin/mythtranscode' has changed; re-reading symbols.
 Starting program: /usr/local/bin/mythtranscode -i 1014_20090718134400.mpg
 -o /tmp/bla -p autodetect --showprogress
 [Thread debugging using libthread_db enabled]
 [New Thread 0x7f936cbed7a0 (LWP 18012)]
 2009-07-18 14:27:49.013 Using runtime prefix = /usr/local
 2009-07-18 14:27:49.013 Empty LocalHostName.
 [New Thread 0x7f935b969950 (LWP 18013)]
 [Thread 0x7f935b969950 (LWP 18013) exited]
 2009-07-18 14:27:49.041 New DB connection, total: 1
 2009-07-18 14:27:49.044 Closing DB connection named 'DBManager0'
 2009-07-18 14:27:49.044 Enabled verbose msgs: important
 2009-07-18 14:27:49.046 New DB connection, total: 2
 2009-07-18 14:27:49.047 New DB connection, total: 3
 2009-07-18 14:27:49.136 Using protocol version 45
 [New Thread 0x7f935b969950 (LWP 18014)]
 [New Thread 0x7f9359137950 (LWP 18015)]
 [New Thread 0x7f9358936950 (LWP 18016)]
 [New Thread 0x7f9358135950 (LWP 18017)]
 [New Thread 0x7f935792c950 (LWP 18018)]
 2009-07-18 14:27:49.349 Transcode: Looking for autodetect profile:
 Autodetect from 576i
 2009-07-18 14:27:49.376 Transcode: Using autodetect profile: MPEG2
 [New Thread 0x7f9356f1a950 (LWP 18019)]
 [New Thread 0x7f9356711950 (LWP 18020)]
 strange error flushing buffer ...
 2009-07-18 14:27:49.449 mythtranscode: 0% Completed @ 0 fps.
 2009-07-18 14:27:54.065 Processed: 247 of 1925 frames(9 seconds)
 2009-07-18 14:27:59.071 Processed: 548 of 1925 frames(21 seconds)
 2009-07-18 14:28:04.075 Processed: 873 of 1925 frames(34 seconds)
 2009-07-18 14:28:09.081 Processed: 1185 of 1925 frames(47 seconds)
 2009-07-18 14:28:09.462 mythtranscode: 62% Completed @ 60.2794 fps.
 2009-07-18 14:28:14.090 Processed: 1491 of 1925 frames(59 seconds)
 2009-07-18 14:28:19.106 Processed: 1814 of 1925 frames(72 seconds)
 [Thread 0x7f935792c950 (LWP 18018) exited]
 [Thread 0x7f9358135950 (LWP 18017) exited]
 [Thread 0x7f9359137950 (LWP 18015) exited]
 [Thread 0x7f9358936950 (LWP 18016) exited]
 [Thread 0x7f935b969950 (LWP 18014) exited]

 Program exited normally.
 }}}

 looks fine. so enabling debug mode seems to fix mythtranscode segfault.

 but the problem remains running mythtranscode from within mythtv, e.g.
 mythweb. i click on "transcode" at the recording and logs say:
 {{{
 0       15126   transcode       5       0       2009-07-18 14:30:41
 eltarun         Transcode Errored       Sportschau live "DTM Qualifying /
 Formel 3 Euroserie": Autodetect (exit status 0, job status was "Running")
 1       15125   transcode       5       0       2009-07-18 14:30:09
 eltarun         Transcode Starting      Sportschau live "DTM Qualifying /
 Formel 3 Euroserie": Autodetect (47.6 MB)
 }}}

 and "dmesg" shows:
 {{{
 [ 6729.185090] mythtranscode[18311] general protection ip:7f967becdc05
 sp:7fff028ea340 error:0 in libc-2.9.so[7f967be5a000+149000]
 }}}

 switching back now to compile-type=release and trying to transcode from
 within mythttv gives dmesg-output:

 {{{
 [ 7064.605586] mythtranscode[26766]: segfault at 883 ip 00007f1fb1672b90
 sp 00007fff2544b750 error 4 in
 libmythswscale-0.22.so.0.22.0[7f1fb1650000+3b000]
 }}}
 but this doesn't come up when using gdb.

 after clicking around trying to transcode various other recordings i now
 also got (compile-type=release)
 {{{
 [ 7524.682222] mythtranscode[3725] general protection ip:7ff7cdb3f344
 sp:7fff6e1b9d50 error:0 in libmythavutil-0.22.so.0.22.0[7ff7cdb38000+c000]
 }}}

 what's going on? is my system (debian squeeze/sid) broken or mythtv? how
 can i debug this further?

 thanks for your help

-- 
Ticket URL: <http://svn.mythtv.org/trac/ticket/6736>
MythTV <http://www.mythtv.org/>
MythTV


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