[mythtv-commits] Ticket #9026: Backend lockup

MythTV mythtv at cvs.mythtv.org
Tue Sep 28 09:53:32 UTC 2010

#9026: Backend lockup
     Reporter:  Richard <mythtv@…>            |       Owner:  danielk   
         Type:  defect                        |      Status:  new       
     Priority:  minor                         |   Milestone:  unknown   
    Component:  MythTV - Recording            |     Version:  Trunk Head
     Severity:  medium                        |    Keywords:            
Ticket locked:  0                             |  
 Whilst trying to watch a video while the backend was recording, the
 frontend reported socket timeouts.

 The backend process appeared to be consuming excessive CPU, so I attached
 the debugger and obtained the following backtrace:
 #0  0x00007f825ab38049 in pthread_cond_wait@@GLIBC_2.3.2 () from
 #1  0x00007f825b691cd3 in QMutexPrivate::wait (this=0x827480, timeout=-1)
 at thread/qmutex_unix.cpp:80
 #2  0x00007f825b68d895 in QMutex::lock (this=0x820840) at
 #3  0x00000000004b0dbd in relock (this=<value optimized out>) at
 #4  QMutexLocker (this=<value optimized out>) at
 #5  Scheduler::GetRecStatus (this=<value optimized out>) at
 #6  0x000000000049df7b in MainServer::customEvent (this=<value optimized
 out>, e=<value optimized out>) at mainserver.cpp:1019
 #7  0x00007f825b787335 in QObject::event (this=0x82dea0, e=0x7f82400ea0f0)
 at kernel/qobject.cpp:1142
 #8  0x00007f825b777ddc in QCoreApplication::notifyInternal
 (this=0x7ffff61c0930, receiver=0x82dea0, event=0x7f82400ea0f0) at
 #9  0x00007f825b7789ea in sendEvent (event=<value optimized out>,
 receiver=<value optimized out>) at kernel/qcoreapplication.h:213
 #10 QCoreApplicationPrivate::sendPostedEvents (event=<value optimized
 out>, receiver=<value optimized out>) at kernel/qcoreapplication.cpp:1247
 #11 0x00007f825b7a0803 in sendPostedEvents () at
 #12 postEventSourceDispatch () at kernel/qeventdispatcher_glib.cpp:276
 #13 0x00007f825ad84dee in g_main_context_dispatch () from
 #14 0x00007f825ad887b8 in ?? () from /usr/lib64/libglib-2.0.so.0
 #15 0x00007f825ad888e0 in g_main_context_iteration () from
 #16 0x00007f825b7a03a3 in QEventDispatcherGlib::processEvents
 (this=0x7b1250, flags=<value optimized out>) at
 #17 0x00007f825b776712 in QEventLoop::processEvents (this=<value optimized
 out>, flags=DWARF-2 expression error: DW_OP_reg operations must be used
 either alone or in conjuction with DW_OP_piece.
 ) at kernel/qeventloop.cpp:149
 #18 0x00007f825b776ae4 in QEventLoop::exec (this=0x7ffff61c0490,
 flags=DWARF-2 expression error: DW_OP_reg operations must be used either
 alone or in conjuction with DW_OP_piece.
 ) at kernel/qeventloop.cpp:201
 #19 0x00007f825b778c99 in QCoreApplication::exec () at
 #20 0x00000000005445da in run_backend (cmdline=<value optimized out>) at
 #21 0x000000000044b3f4 in main (argc=4, argv=<value optimized out>) at

 Version details:
 MythTV Version   : 26319M
 MythTV Branch    : trunk
 Network Protocol : 62
 Library API      : 0.23.20100913-1
 QT Version       : 4.5.3
 Options compiled in:
  linux profile using_alsa using_oss using_backend using_bindings_perl
 using_bindings_python using_dvb using_frontend using_hdhomerun using_hdpvr
 using_iptv using_ivtv using_joystick_menu using_lirc using_mheg
 using_opengl_video using_opengl_vsync using_qtdbus using_qtwebkit
 using_v4l using_x11 using_xrandr using_xv using_xvmc using_xvmc_vld
 using_xvmcw using_bindings_perl using_bindings_python using_mythtranscode
 using_opengl using_vdpau using_ffmpeg_threads using_live using_mheg


 This problem looks very similar to that mentioned by Tomi Orava in
 http://svn.mythtv.org/trac/ticket/8952.  Not sure if it is really related
 or not.

 Relevent bit of the backend log attached.  Note: It appears to have had
 some sort of device contention around the same time.

 For what it's worth - I dumped a core file at the time of the issue.  Let
 me know if there is more data required.

Ticket URL: <http://svn.mythtv.org/trac/ticket/9026>
MythTV <http://www.mythtv.org/>
MythTV Media Center

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