Crash in QRegion::cleanUp

[Robin Green]

This is with latest from SVN. At the time I had just logged in to virtual terminal 2 on the guest, and ran "startkde" with DISPLAY pointed at an X server on the host. I had then switched away from the VirtualBox VM window.

Thread 0 Crashed:
0   QtGui                               0x00b414c0 QRegion::cleanUp(QRegion::QRegionData*) + 32
1   QtGui                               0x00b41540 QRegion::operator=(QRegion const&) + 48
2   QtGui                               0x00a1a4dc QWidgetPrivate::qt_widget_event(OpaqueEventHandlerCallRef*, OpaqueEventRef*, void*) + 4220
3   com.apple.HIToolbox                 0x9431f143 DispatchEventToHandlers(EventTargetRec*, OpaqueEventRef*, HandlerCallRec*) + 1181
4   com.apple.HIToolbox                 0x9431e57d SendEventToEventTargetInternal(OpaqueEventRef*, OpaqueEventTargetRef*, HandlerCallRec*) + 405
5   com.apple.HIToolbox                 0x9431e3e2 SendEventToEventTargetWithOptions + 58
6   com.apple.HIToolbox                 0x94341e01 HIView::SendDraw(short, OpaqueGrafPtr*, __HIShape const*, CGContext*) + 475
7   com.apple.HIToolbox                 0x943418ee HIView::RecursiveDrawComposited(__HIShape const*, unsigned long, HIView*, CGContext*, unsigned char, float) + 734
8   com.apple.HIToolbox                 0x94341a52 HIView::RecursiveDrawComposited(__HIShape const*, unsigned long, HIView*, CGContext*, unsigned char, float) + 1090
9   com.apple.HIToolbox                 0x94341a52 HIView::RecursiveDrawComposited(__HIShape const*, unsigned long, HIView*, CGContext*, unsigned char, float) + 1090
10  com.apple.HIToolbox                 0x94341a52 HIView::RecursiveDrawComposited(__HIShape const*, unsigned long, HIView*, CGContext*, unsigned char, float) + 1090
11  com.apple.HIToolbox                 0x94341a52 HIView::RecursiveDrawComposited(__HIShape const*, unsigned long, HIView*, CGContext*, unsigned char, float) + 1090
12  com.apple.HIToolbox                 0x94341a52 HIView::RecursiveDrawComposited(__HIShape const*, unsigned long, HIView*, CGContext*, unsigned char, float) + 1090
13  com.apple.HIToolbox                 0x94340cec HIView::DrawComposited(short, OpaqueGrafPtr*, __HIShape const*, unsigned long, HIView*, CGContext*) + 668
14  com.apple.HIToolbox                 0x943409ff HIView::Draw(short, OpaqueGrafPtr*, unsigned long) + 83
15  com.apple.HIToolbox                 0x9434094f HIView::Render(unsigned long, CGContext*) + 45
16  com.apple.HIToolbox                 0x94348d8b FlushWindowObject(WindowData*, void**, unsigned char) + 749
17  com.apple.HIToolbox                 0x943487a2 FlushAllBuffers(__CFRunLoopObserver*, unsigned long, void*) + 168
18  com.apple.CoreFoundation            0x921739a2 __CFRunLoopDoObservers + 466
19  com.apple.CoreFoundation            0x92174bd2 CFRunLoopRunSpecific + 546
20  com.apple.CoreFoundation            0x92175cd8 CFRunLoopRunInMode + 88
21  QtGui                               0x00a077f2 QEventDispatcherMac::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 690
22  QtCore                              0x004d0e81 QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 65
23  QtCore                              0x004d0f4d QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 157
24  QtCore                              0x004d4ee1 QCoreApplication::exec() + 161
25  VirtualBoxVM                        0x00002583 TrustedMain + 1763 (main.cpp:410)
26  VirtualBoxVM                        0x00001e06 start + 54

[Robin Green]

I just tried again - the crash happens again at approximately the same time, but in a different part of Qt. Looks to be a memory corruption issue.

I will now try to bisect SVN to find the commit responsible.

[Robin Green]

Results of SVN bisection:

Revision 16571 appears not to exhibit this bug.

Revision 16578 reproducibly exhibits this bug (although, again, not with the same stack trace every time - appears to be a memory corruption bug).

Revisions inbetween the above two revisions could not be tested, mostly because NAT networking was broken in those revisions.

[Sander van Leeuwen]

Thanks for the report, but could you please use the developer's mailinglist for such issues? The SVN tree is not an officially supported platform and things change rather quickly there.