Weird termination errors, 0.18 - Segmentation Fault[Solved]

[alberich]

Sometimes I wish I would leave software well enough alone...

On Ubuntu 16.04, using the last freecad-daily ppa ( ...093?), I was getting a
message at startup saying something to the effect

"gitPython not available, using regular addon loader"

Other than this nagging message, freecad appeared to work normally.

But the annoyance level finally got high enough that I decided to address
this by installing the missing package.

After doing so, the gitPython message disappeared and everything seemed
still to be working ok. However, upon exiting freecad it spewed 28 error
messages at me.

[I know this is not the best error report. Bear with me. I don't have that install anymore. Hard evidence to follow.]

I uninstalled and reinstalled freecad with no change.

I downloaded this 0.19 version

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OS: Ubuntu 16.04.6 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.16207 (Git) AppImage
Build type: Release
Branch: master
Hash: 741533941c67da2f721bf1b7c2d55c987fd22a0c
Python version: 3.6.7
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

and it loads cleanly (it does tell me to look in the log file but
doesn't say where to find that file). 0.19 runs fine and exits cleanly.

I have today installed the new 0.18.1 stable ppa

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OS: Ubuntu 16.04.6 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.1.
Build type: Release
Python version: 2.7.12
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

0.18.1 behaves the same as the 0.18 freecad-daily it replaced. That is, it loads
without incident, seems to run fine but, upon exit, throws this alarming pile...

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Program received signal SIGSEGV, Segmentation fault.
#0  /lib/x86_64-linux-gnu/libc.so.6(+0x354b0) [0x7f0e5ce514b0]
#1  0x7f0e5e1388da in QFontEngineX11FT::freeServerGlyphSet(unsigned long) from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x1a
#2  0x7f0e5e140461 in QFontEngineFT::freeGlyphSets() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x91
#3  0x7f0e5e13887c in QFontEngineX11FT::~QFontEngineX11FT() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x1c
#4  0x7f0e5e1388a9 in QFontEngineX11FT::~QFontEngineX11FT() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x9
#5  /usr/lib/x86_64-linux-gnu/libQtGui.so.4(+0x3fd7d6) [0x7f0e5e06e7d6]
#6  0x7f0e5e13a209 in QFontEngineMultiFT::~QFontEngineMultiFT() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x9
#7  0x7f0e5e09bb26 in QTextEngine::resetFontEngineCache() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x66
#8  0x7f0e5e09d186 in QTextEngine::~QTextEngine() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x96
#9  0x7f0e5e0a8175 in QTextLayout::~QTextLayout() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x15
#10  /usr/lib/x86_64-linux-gnu/libQtGui.so.4(+0x86d4b4) [0x7f0e5e4de4b4]
#11  0x7f0e5d9212b1 in QObjectPrivate::deleteChildren() from /usr/lib/x86_64-linux-gnu/libQtCore.so.4+0x81
#12  0x7f0e5de8c2a2 in QWidget::~QWidget() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x332
#13  /usr/lib/python2.7/dist-packages/PySide/QtGui.so(+0x465641) [0x7f0e257e5641]
#14  0x7f0e5d9212b1 in QObjectPrivate::deleteChildren() from /usr/lib/x86_64-linux-gnu/libQtCore.so.4+0x81
#15  0x7f0e5de8c2a2 in QWidget::~QWidget() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4+0x332
#16  /usr/lib/python2.7/dist-packages/PySide/QtGui.so(+0x793f61) [0x7f0e25b13f61]
#17  /usr/lib/x86_64-linux-gnu/libshiboken-python2.7.so.1.2(+0xf2b5) [0x7f0e582042b5]
#18  /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0(+0xc8eb2) [0x7f0e5ea2deb2]
#19  /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0(+0x15d897) [0x7f0e5eac2897]
#20  /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0(PyDict_SetItem+0x7b) [0x7f0e5eac701b]
#21  /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0(_PyModule_Clear+0x16b) [0x7f0e5eb0376b]
#22  /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0(PyImport_Cleanup+0x28e) [0x7f0e5eac050e]
#23  /usr/lib/x86_64-linux-gnu/libpython2.7.so.1.0(Py_Finalize+0xfe) [0x7f0e5ea89e6e]
#24  0x7f0e5ef9e212 in Base::InterpreterSingleton::finalize() from /usr/lib/freecad-python2/lib/libFreeCADBase.so+0x12
#25  0x7f0e5f4c113f in App::Application::destruct() from /usr/lib/freecad-python2/lib/libFreeCADApp.so+0x19f
#26  freecad(main+0x7b1) [0x556681cce721]
#27  /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0) [0x7f0e5ce3c830]
#28  freecad(_start+0x29) [0x556681ccf949]

Anyone have any clues?

p.s., where does freecad put its log files? I can't find any.

[alberich]

In regards to the 0.19 version, I hadn't noticed that I had report panel closed. With that panel open I see

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During initialization the error No module named 'Gui.Command' occurred in /home/mac_aodh/.FreeCAD/Mod/cadquery-freecad-module/InitGui.py
Please look into the log file for further information
During initialization the error No module named 'proxies' occurred in /home/mac_aodh/.FreeCAD/Mod/drawing_dimensioning/InitGui.py
Please look into the log file for further information
During initialization the error No module named 'core' occurred in /home/mac_aodh/.FreeCAD/Mod/assembly2/InitGui.py
es' occurred in /home/mac_aodh/.FreeCAD/Mod/drawing_dimensioning/InitGui.py

so those errors have nothing to do with the 0.18.1 problem. I don't plan to use the 0.19 version yet anyway so no big deal.

[openBrain]

The only clue I can see right now is that the working release (0.19) is compiled with Qt5 while others are compiled with Qt4...

[alberich]

The only clue I can see right now is that the working release (0.19) is compiled with Qt5 while others are compiled with Qt4...

I honestly didn't expect the 0.19 version to work because of the Qt5/Py3 compile but I'm not going to use it anyway. It was just an experiment.

Since my earlier posts I have learned that FC doesn't routinely make a log file, you have to ask for one. So that solves that mystery.
Now that I can get a log file I see in the 0.18.1 file nothing out of the ordinary until this line

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Log: [31mvoid DBusMenuExporterPrivate::addAction(QAction*, int)[0m: Already tracking action "Toggle visibility" under id 239 

Nothing out of the ordinary after that line, either. The termination errors I posted above do not appear in the log file.

[alberich]

Whatever was wrong is no longer there but I have no idea what the cause was.

I did this:

1. Uninstalled gitpython package - no change in freecad exit seg fault behavior

2. Rebooted - no change in freecad exit seg fault behavior

3. Decided to uninstall 0.18.1. Using Unity Launcher, clicked 'uninstall' button for freecad 0.18.1. Prompts for password, then exits. No apparent uninstall actually happened. Freecad icon still on launcher. Clicked icon and freecad starts. Ok, but that doesn't show the console where seg fault errors are reported. Started freecad from command line. Starts cleanly, with no spurious gitpython messages. And - Lo and behold! - freecad now exits without any seg fault message.

The mysteries remain as to what was causing the seg fault in the first place and why an uninstall that didn't uninstall seems to have fixed everything. But I'm fully operational again so it's all good.