Bug#1004007: freecad: Segfaults on armhf when clicking "Ceate New..." or File -> New

[Tobias Frost]

On Wed, Jan 19, 2022 at 08:17:11AM +0000, Serge Schneider wrote:
> Package: freecad
> Version: 0.19.1+dfsg1-2
> Severity: important
> X-Debbugs-Cc: serge at raspberrypi.com
> 
> Dear Maintainer,
> 
> When running FreeCAD, creating a new file crashes with a segfault:
(...)

> This is the same issue as #931458, which was closed because it was reported
> against Raspbian's packages.  However, the issue is reproducible in Debian
> too (using 20210823_raspi_2_bullseye.img.xz).
> 
> The crash seems to have something to do with how Ccoin3D creates the context
> in Qt.
> 
> Rebuilding FreeCAD against Qt4 rather than Qt5 makes it work. It also works
> on arm64.
> 
> The main difference I can see is that Qt is built with OpenGL support on
> arm64, but only OpenGL ES support on armhf.
> 
> Thegq issue has also been reported upstream at
> https://tracker.freecadweb.org/view.php?id=4083, but there hasn't been any
> progess in a few years.

The discussion on the FreCAD forum (pointer to the thread is in the above
FreeCAD ticket), namely the backtrace at 
https://forum.freecadweb.org/viewtopic.php?p=456568#p456568 hints that this
crash is happening somewhere in libcoin: (IF the backtrace is related to what you see as well)
It is calling out to libx11's XDefaultScreenOfDisplay() and it looks like that this
might be a NULL-Pointer passed to that function...
https://codesearch.debian.net/search?q=XScreenOfDisplay+package%3Alibx11&literal=0

That reminds me of https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=969230...

Unfortunatly I do not have any Pi4 I could use for this to debug at my hands.

However, you might want to see if cherry-picking the mentioned patch in
#969230 (https://github.com/coin3d/coin/pull/404/files) and recompile the
coin3 Debian package locally with that patch.. Maybe this does something for you
and helps pin-pointing the problem.


-- 
tobi

> -- System Information:
> Debian Release: 11.0
>   APT prefers stable-security
>   APT policy: (500, 'stable-security'), (500, 'stable')
> Architecture: armhf (armv7l)
> 
> Kernel: Linux 5.10.0-8-armmp (SMP w/4 CPU threads)
> Kernel taint flags: TAINT_CRAP, TAINT_UNSIGNED_MODULE
> Locale: LANG=C, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE not set
> Shell: /bin/sh linked to /usr/bin/dash
> Init: systemd (via /run/systemd/system)
> LSM: AppArmor: enabled
> 
> Versions of packages freecad depends on:
> ii  freecad-python3  0.19.1+dfsg1-2
> 
> Versions of packages freecad recommends:
> ii  calculix-ccx  2.17-3
> ii  graphviz      2.42.2-5
> 
> Versions of packages freecad suggests:
> pn  povray  <none>
> 
> -- no debconf information