[Development] crash in qt_mac_create_imagemask while printing from KDE application

[René J. V. Bertin]

René J.V. Bertin wrote:

In addition to px->pixels==NULL (which it isn't always when the crash occurs), I also notice that px->bytesPerRow has a 
suspicious value. When I see the line `srow = sptr + (y * (sbpr / 4));`, I think that sbpr (px->bytesPerRow) should be equal 
or a known multiple of the mask width `sw`, correct?

The question is, why would px (pixmap.data.data()) seem to be corrupt if pixmap itself is allocated one level up in the 
backtrace? Is this a case of missing initialisation, perhaps?

R.


> Is there anything that can be done with a backtrace like the one below
> that would make it worthwhile to file a bug report? Some prodding after
> liberal use of `volatile` in qt_mac_create_imagemask suggests that
> px->pixels==NULL
> 
> R.
> 
> (lldb) bt all
> * thread #1: tid = 0x6280a, 0x00007fff8914fe20
> libsystem_kernel.dylib`__wait4 + 8, queue = 'com.apple.main-thread', stop
> reason = signal SIGSTOP
>   * frame #0: 0x00007fff8914fe20 libsystem_kernel.dylib`__wait4 + 8
>     frame #1: 0x000000010dab494e
>     libkdeui.5.dylib`KCrash::startProcess(int, char const**, bool)
>     [inlined] startProcessInternal(argc=<unavailable>,
>     directly=<unavailable>) + 265 at kcrash.cpp:556 frame #2:
>     0x000000010dab4845
>     libkdeui.5.dylib`KCrash::startProcess(argc=<unavailable>,
>     argv=<unavailable>, waitAndExit=<unavailable>) + 21 at kcrash.cpp:538
>     frame #3: 0x000000010dab3a79
>     libkdeui.5.dylib`KCrash::defaultCrashHandler(sig=<unavailable>) + 1209
>     at kcrash.cpp:441 frame #4: 0x00007fff886fd5aa
>     libsystem_platform.dylib`_sigtramp + 26 frame #5: 0x000000010e681c21
>     QtGui`qt_mac_create_imagemask(pixmap=<unavailable>,
>     sr=0x00007fff5360b620) + 1057 at qpixmap_mac.cpp:1090 frame #6:
>     0x000000010e78f9ff QtGui`qt_mac_draw_pattern(info=0x00007fef4c72fa80,
>     c=0x00007fef4c70fab0) + 1167 at qpaintengine_mac.cpp:494 frame #7: