Mythfrontend segfaults due to libQtGui.so.4 with Qt 5.4

[yiannividalis@…]

Hi, after #12399 was fixed, I compiled mythtv successfully, but the frontend segfaults without showing on screen.

I recompiled with debug symbols and I have the gdb.txt result. It seems that /usr/lib/libQtGui.so.4 is to blame.

I can however run mythtv-setup.

I am attaching gdb.txt and mythfrontend.log with --loglevel debug.

[yiannividalis@…]

log with loglevel debug

[stuartm]

Did you recompile the plugins for QT5? Try manually deleting all the plugin .so files from /usr/[local/]lib/mythtv/plugins/

[yiannividalis@…]

I removed the whole /usr/lib/mythtv folder and recompiled without success. There's no /usr/local/lib/mythtv folder, I install it under /usr/lib.

[stuartm]

It's somehow managed to link the QT4 libs instead of the QT5 libs

[yiannividalis@…]

If it's of any help, here's a list of all the qt4 libs the plugins are linked against. I cleaned up the false positive '4' in the 0x values.

yianni@eagle1:~> ldd /usr/lib/mythtv/plugins/libmytharchive.so | grep -i qt | grep 4
        libQtSql.so.4 => /usr/lib/libQtSql.so.4 (0xb44fc000)
        libQtXml.so.4 => /usr/lib/libQtXml.so.4 (0xb44b7000)
        libQtOpenGL.so.4 => /usr/lib/libQtOpenGL.so.4 (0xb43b8000)
        libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0xb38ed000)
        libQtNetwork.so.4 => /usr/lib/libQtNetwork.so.4 (0xb37ab000)
        libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0xb34bd000)
yianni@eagle1:~> ldd /usr/lib/mythtv/plugins/libmythbrowser.so | grep -i qt | grep 4
        libQtWebKit.so.4 => /usr/lib/libQtWebKit.so.4 (0xb28bc000)
        libQtSql.so.4 => /usr/lib/libQtSql.so.4 (0xb287b000)
        libQtXml.so.4 => /usr/lib/libQtXml.so.4 (0xb2836000)
        libQtOpenGL.so.4 => /usr/lib/libQtOpenGL.so.4 (0xb2737000)
        libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0xb1c6d000)
        libQtNetwork.so.4 => /usr/lib/libQtNetwork.so.4 (0xb1b2a000)
        libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0xb183c000)
yianni@eagle1:~> ldd /usr/lib/mythtv/plugins/libmythgallery.so | grep -i qt | grep 4
        libQtSql.so.4 => /usr/lib/libQtSql.so.4 (0xb5093000)
        libQtXml.so.4 => /usr/lib/libQtXml.so.4 (0xb504e000)
        libQtOpenGL.so.4 => /usr/lib/libQtOpenGL.so.4 (0xb4f4f000)
        libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0xb4485000)
        libQtNetwork.so.4 => /usr/lib/libQtNetwork.so.4 (0xb4343000)
        libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0xb4054000)
yianni@eagle1:~> ldd /usr/lib/mythtv/plugins/libmythgame.so | grep -i qt | grep 4
        libQtSql.so.4 => /usr/lib/libQtSql.so.4 (0xb5097000)
        libQtXml.so.4 => /usr/lib/libQtXml.so.4 (0xb5051000)
        libQtOpenGL.so.4 => /usr/lib/libQtOpenGL.so.4 (0xb4f52000)
        libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0xb4488000)
        libQtNetwork.so.4 => /usr/lib/libQtNetwork.so.4 (0xb4346000)
        libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0xb4058000)
yianni@eagle1:~> ldd /usr/lib/mythtv/plugins/libmythmusic.so | grep -i qt | grep 4
        libQtWebKit.so.4 => /usr/lib/libQtWebKit.so.4 (0xb2f96000)
        libQtSql.so.4 => /usr/lib/libQtSql.so.4 (0xb2f55000)
        libQtXml.so.4 => /usr/lib/libQtXml.so.4 (0xb2f0f000)
        libQtOpenGL.so.4 => /usr/lib/libQtOpenGL.so.4 (0xb2e10000)
        libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0xb2346000)
        libQtNetwork.so.4 => /usr/lib/libQtNetwork.so.4 (0xb2204000)
        libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0xb1f16000)
  yianni@eagle1:~> ldd /usr/lib/mythtv/plugins/libmythnetvision.so | grep -i qt | grep 4
        libQtSql.so.4 => /usr/lib/libQtSql.so.4 (0xb4f77000)
        libQtXml.so.4 => /usr/lib/libQtXml.so.4 (0xb4f32000)
        libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0xb4468000)
        libQtNetwork.so.4 => /usr/lib/libQtNetwork.so.4 (0xb4326000)
        libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0xb4038000)
yianni@eagle1:~> ldd /usr/lib/mythtv/plugins/libmythnews.so | grep -i qt | grep 4
        libQtSql.so.4 => /usr/lib/libQtSql.so.4 (0xb5143000)
        libQtXml.so.4 => /usr/lib/libQtXml.so.4 (0xb50fd000)
        libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0xb4633000)
        libQtNetwork.so.4 => /usr/lib/libQtNetwork.so.4 (0xb44f1000)
        libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0xb4203000)
yianni@eagle1:~> ldd /usr/lib/mythtv/plugins/libmythweather.so | grep -i qt | grep 4
        libQtSql.so.4 => /usr/lib/libQtSql.so.4 (0xb511c000)
        libQtXml.so.4 => /usr/lib/libQtXml.so.4 (0xb50d6000)
        libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0xb460c000)
        libQtNetwork.so.4 => /usr/lib/libQtNetwork.so.4 (0xb44ca000)
        libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0xb41dc000)
yianni@eagle1:~> ldd /usr/lib/mythtv/plugins/libmythzoneminder.so | grep -i qt | grep 4
        libQtSql.so.4 => /usr/lib/libQtSql.so.4 (0xb483a000)
        libQtXml.so.4 => /usr/lib/libQtXml.so.4 (0xb47f4000)
        libQtGui.so.4 => /usr/lib/libQtGui.so.4 (0xb3d2a000)
        libQtNetwork.so.4 => /usr/lib/libQtNetwork.so.4 (0xb3be8000)
        libQtCore.so.4 => /usr/lib/libQtCore.so.4 (0xb38fa000)

Please let me know if I can provide any more debugging info.

[stuartm]

From that it's clear that the plugins are being built against QT4, not QT5 - did you specify --qmake= to the plugins configure?

[yiannividalis@…]

Nothing I declared explicitly:

yianni@eagle1:~/mythtv-git/mythplugins> ./configure --previous
Options:  --prefix=/usr --enable-mythgallery 

Configuration settings: 
 
        qmake          /usr/bin/qmake-qt5
 
        MythArchive    plugin will be built
        MythBrowser    plugin will be built
        MythGallery    plugin will be built
        MythGame       plugin will be built
        MythMusic      plugin will be built
        MythNetvision  plugin will be built
        MythNews       plugin will be built
        MythWeather    plugin will be built
        MythZoneMinder plugin will be built
        OpenGL         support will be included in MythGallery
        EXIF           support will be included in MythGallery
        Dcraw          support will be included in MythGallery
        libcdio        support will be included in MythMusic
        FFTW v.3       support will be included in MythMusic

[yiannividalis@…]

In comment 5, by prunning the results that had 4 in the 0x values, it hid that the plugins are linked against qt5 libs, too. I am attaching a file with the full results to keep the comment short.

[yiannividalis@…]

Ok, after some digging I realised that it's the "qmake mythplugins.pro" command included in the built script I use that was building the plugins against the qt4 libraries. I'm sorry I didn't look earlier but I've been using it for years. Also, the command is in the installation instructions for the mythplugins in github. Maybe it should be changed to avoid similar problems by others?

I can now build the plugins and run mythtv without problem, so please close this ticket as fixed.

[Stuart Auchterlonie]

Thanks for the update. Closing now.