[mythtv-commits] Ticket #1147: core dump when moving back in menus

[MythTV]

#1147: core dump when moving back in menus
---------------------------------------+------------------------------------
 Reporter:  Cougar <cougar at random.ee>  |        Owner:  danielk
     Type:  defect                     |       Status:  new    
 Priority:  major                      |    Milestone:  0.19   
Component:  mythtv                     |      Version:  head   
 Severity:  medium                     |   Resolution:         
---------------------------------------+------------------------------------
Comment (by Cougar <cougar at random.ee>):

 OK, the same problem when doublepressing ESC when leaving from playback to
 playback menu and trying go back to main menu

 {{{
 #0  0x41525dec in QMutex::lock () from /usr/lib/libqt-mt.so.3
 #1  0x406677ad in PreviewGenerator::disconnectSafe (this=0x8298268)
     at qmutex.h:96
 #2  0x08084bfe in ~PlaybackBox (this=0xbfa75afc) at playbackbox.cpp:320
 #3  0x08062457 in startPlayback () at main.cpp:194
 #4  0x0806c69a in TVMenuCallback (data=0x81d68a0, selection=@0x310020)
     at main.cpp:334
 #5  0x40d5f09c in ThemedMenuPrivate::handleAction (this=0x823e6b0,
     action=@0x822a658) at themedmenu.cpp:2508
 #6  0x40d5ff20 in ThemedMenuPrivate::keyPressHandler (this=0x823e6b0,
     e=0xbfa76880) at themedmenu.cpp:2336
 #7  0x40d601ab in ThemedMenu::keyPressEvent (this=0x82a0a50, e=0xbfa76880)
     at themedmenu.cpp:2714
 #8  0x412be3f9 in QWidget::event () from /usr/lib/libqt-mt.so.3
 #9  0x41224d41 in QApplication::internalNotify () from /usr/lib/libqt-
 mt.so.3
 #10 0x41225bbf in QApplication::notify () from /usr/lib/libqt-mt.so.3
 #11 0x411b90dc in QETWidget::translateKeyEvent () from /usr/lib/libqt-
 mt.so.3
 #12 0x411bea05 in QApplication::x11ProcessEvent () from /usr/lib/libqt-
 mt.so.3
 #13 0x411d2bea in QEventLoop::processEvents () from /usr/lib/libqt-mt.so.3
 #14 0x4123bc53 in QEventLoop::enterLoop () from /usr/lib/libqt-mt.so.3
 #15 0x412246bf in QApplication::enter_loop () from /usr/lib/libqt-mt.so.3
 #16 0x40dd367d in MythDialog::exec (this=0x82a0a50) at
 mythdialogs.cpp:1047
 #17 0x0806401d in RunMenu (themedir=@0xbfa76fb8) at main.cpp:498
 ---Type <return> to continue, or q <return> to quit---
 #18 0x0806a81a in main (argc=1, argv=0xbfa77064) at main.cpp:1062
 }}}

 I don't use priview video but image.

 Here is what happened in backend during this time

 {{{
 2006-01-29 23:06:32.237 MainServer::HandleAnnounce Playback
 2006-01-29 23:06:32.237 adding: t42 as a client (events: 0)
 2006-01-29 23:06:32.253 MainServer::HandleAnnounce FileTransfer
 2006-01-29 23:06:32.253 adding: t42 as a remote file transfer
 2006-01-29 23:06:32.253 Could not open
 /media/mythstorage/1001_20060129224001.mpg.png.  6 retries remaining.
 2006-01-29 23:06:32.757 Could not open
 /media/mythstorage/1001_20060129224001.mpg.png.  5 retries remaining.
 2006-01-29 23:06:33.261 Could not open
 /media/mythstorage/1001_20060129224001.mpg.png.  4 retries remaining.
 2006-01-29 23:06:33.765 Could not open
 /media/mythstorage/1001_20060129224001.mpg.png.  3 retries remaining.
 2006-01-29 23:06:34.269 Could not open
 /media/mythstorage/1001_20060129224001.mpg.png.  2 retries remaining.
 2006-01-29 23:06:34.773 Could not open
 /media/mythstorage/1001_20060129224001.mpg.png.  1 retries remaining.
 2006-01-29 23:06:35.277 Could not open
 /media/mythstorage/1001_20060129224001.mpg.png.  0 retries remaining.
 2006-01-29 23:06:35.793
 RingBuf(/media/mythstorage/1001_20060129224001.mpg.png) Error: Invalid
 file descriptor in 'safe_read()'
 }}}

 I just found why this error happened. This is how backend server sees
 these files:

 {{{
 -rw-r--r--  1 cougar users 1213655968 Jan 29 23:10
 /media/mythstorage/1001_20060129224001.mpg
 -rw-------  1   1000 users      26417 Jan 29 23:06
 /media/mythstorage/1001_20060129224001.mpg.png
 }}}

 but as this storage is mounted over NFS to frontend, in frontend there are
 different UID and these files look:

 {{{
 -rw-r--r--  1    500 users 1289366512 Jan 29 23:12
 /media/mythstorage/1001_20060129224001.mpg
 -rw-------  1 cougar users      26417 Jan 29 23:06
 /media/mythstorage/1001_20060129224001.mpg.png
 }}}

 Looks like frontend created this preview image but with umask that is not
 readable for backend server. Maybe this is the reason of core dump?

-- 
Ticket URL: <http://cvs.mythtv.org/trac/ticket/1147>
MythTV <http://www.mythtv.org/>
MythTV