Application: kwin_x11 (5.6.4)

Qt Version: 5.6.0
Frameworks Version: 5.22.0
Operating System: Linux 4.6.1-1.g9cdcddd-default x86_64
Distribution: "openSUSE Leap 42.1 (x86_64)"

-- Information about the crash:
When using VirtualBox 5 and editing a VM, KWin crashes when I click on "Ok". This happens every time I edit a VM.

The crash can be reproduced sometimes.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f45df47f800 (LWP 2486))]

Thread 8 (Thread 0x7f45c5f2b700 (LWP 2501)):
#0  0x00007f45dee08bbd in poll () at /lib64/libc.so.6
#1  0x00007f45dc727422 in  () at /usr/lib64/libxcb.so.1
#2  0x00007f45dc72900f in xcb_wait_for_event () at /usr/lib64/libxcb.so.1
#3  0x00007f45c69e4d69 in  () at /usr/lib64/libQt5XcbQpa.so.5
#4  0x00007f45dc9eb079 in  () at /usr/lib64/libQt5Core.so.5
#5  0x00007f45de41c0a4 in start_thread () at /lib64/libpthread.so.0
#6  0x00007f45dee10fed in clone () at /lib64/libc.so.6

Thread 7 (Thread 0x7f45bfdf3700 (LWP 2503)):
#0  0x00007f45dc9e3ab5 in QMutex::lock() () at /usr/lib64/libQt5Core.so.5
#1  0x00007f45dcbadcba in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib64/libQt5Core.so.5
#2  0x00007f45dcbfa584 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#3  0x00007f45dcbaa04b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#4  0x00007f45dc9e65da in QThread::exec() () at /usr/lib64/libQt5Core.so.5
#5  0x00007f45d59b3095 in  () at /usr/lib64/libQt5DBus.so.5
#6  0x00007f45dc9eb079 in  () at /usr/lib64/libQt5Core.so.5
#7  0x00007f45de41c0a4 in start_thread () at /lib64/libpthread.so.0
#8  0x00007f45dee10fed in clone () at /lib64/libc.so.6

Thread 6 (Thread 0x7f45bd19b700 (LWP 2557)):
#0  0x00007f45dee0a253 in select () at /lib64/libc.so.6
#1  0x00007f45dcbf88e9 in qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) () at /usr/lib64/libQt5Core.so.5
#2  0x00007f45dcbfa1b5 in QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) () at /usr/lib64/libQt5Core.so.5
#3  0x00007f45dcbfa5f7 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#4  0x00007f45dcbaa04b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#5  0x00007f45dc9e65da in QThread::exec() () at /usr/lib64/libQt5Core.so.5
#6  0x00007f45d6a404d8 in  () at /usr/lib64/libQt5Qml.so.5
#7  0x00007f45dc9eb079 in  () at /usr/lib64/libQt5Core.so.5
#8  0x00007f45de41c0a4 in start_thread () at /lib64/libpthread.so.0
#9  0x00007f45dee10fed in clone () at /lib64/libc.so.6

Thread 5 (Thread 0x7f45a8f23700 (LWP 2560)):
#0  0x00007f45de42003f in pthread_cond_wait@@GLIBC_2.3.2 () at /lib64/libpthread.so.0
#1  0x00007f45af9f4aa3 in  () at /usr/lib64/dri/r600_dri.so
#2  0x00007f45af9f4227 in  () at /usr/lib64/dri/r600_dri.so
#3  0x00007f45de41c0a4 in start_thread () at /lib64/libpthread.so.0
#4  0x00007f45dee10fed in clone () at /lib64/libc.so.6

Thread 4 (Thread 0x7f45a7b00700 (LWP 2581)):
#0  0x00007f45de42003f in pthread_cond_wait@@GLIBC_2.3.2 () at /lib64/libpthread.so.0
#1  0x00007f45db94f97b in  () at /usr/lib64/libQt5Script.so.5
#2  0x00007f45db94f9a9 in  () at /usr/lib64/libQt5Script.so.5
#3  0x00007f45de41c0a4 in start_thread () at /lib64/libpthread.so.0
#4  0x00007f45dee10fed in clone () at /lib64/libc.so.6

Thread 3 (Thread 0x7f45be39b700 (LWP 9059)):
#0  0x00007f45dee0a253 in select () at /lib64/libc.so.6
#1  0x00007f45dcbf88e9 in qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) () at /usr/lib64/libQt5Core.so.5
#2  0x00007f45dcbfa1b5 in QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) () at /usr/lib64/libQt5Core.so.5
#3  0x00007f45dcbfa5f7 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#4  0x00007f45dcbaa04b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#5  0x00007f45dc9e65da in QThread::exec() () at /usr/lib64/libQt5Core.so.5
#6  0x00007f45d6a404d8 in  () at /usr/lib64/libQt5Qml.so.5
#7  0x00007f45dc9eb079 in  () at /usr/lib64/libQt5Core.so.5
#8  0x00007f45de41c0a4 in start_thread () at /lib64/libpthread.so.0
#9  0x00007f45dee10fed in clone () at /lib64/libc.so.6

Thread 2 (Thread 0x7f451414b700 (LWP 2409)):
#0  0x00007f45dee0a253 in select () at /lib64/libc.so.6
#1  0x00007f45dcbf88e9 in qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) () at /usr/lib64/libQt5Core.so.5
#2  0x00007f45dcbfa1b5 in QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) () at /usr/lib64/libQt5Core.so.5
#3  0x00007f45dcbfa5f7 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#4  0x00007f45dcbaa04b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#5  0x00007f45dc9e65da in QThread::exec() () at /usr/lib64/libQt5Core.so.5
#6  0x00007f45d6a404d8 in  () at /usr/lib64/libQt5Qml.so.5
#7  0x00007f45dc9eb079 in  () at /usr/lib64/libQt5Core.so.5
#8  0x00007f45de41c0a4 in start_thread () at /lib64/libpthread.so.0
#9  0x00007f45dee10fed in clone () at /lib64/libc.so.6

Thread 1 (Thread 0x7f45df47f800 (LWP 2486)):
[KCrash Handler]
#6  0x0000000000000040 in  ()
#7  0x00007f45dcbda9f0 in QObject::connect(QObject const*, char const*, QObject const*, char const*, Qt::ConnectionType) () at /usr/lib64/libQt5Core.so.5
#8  0x00007f45db99382b in  () at /usr/lib64/libQt5Script.so.5
#9  0x00007f45db993904 in  () at /usr/lib64/libQt5Script.so.5
#10 0x00007f45db993bc2 in QScriptEngine::newQObject(QObject*, QScriptEngine::ValueOwnership, QFlags<QScriptEngine::QObjectWrapOption> const&) () at /usr/lib64/libQt5Script.so.5
#11 0x00007f45dea2932c in  () at /usr/lib64/libkwin.so.5
#12 0x00007f45db993f12 in  () at /usr/lib64/libQt5Script.so.5
#13 0x00007f45db9b6dae in  () at /usr/lib64/libQt5Script.so.5
#14 0x00007f45db9be465 in  () at /usr/lib64/libQt5Script.so.5
#15 0x00007f45dcbd61c9 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib64/libQt5Core.so.5
#16 0x00007f45dc182198 in KWin::EffectsHandler::desktopPresenceChanged(KWin::EffectWindow*, int, int) () at /usr/lib64/libkwineffects.so.8
#17 0x00007f45dc182eb0 in  () at /usr/lib64/libkwineffects.so.8
#18 0x00007f45dcbd71f6 in QObject::event(QEvent*) () at /usr/lib64/libQt5Core.so.5
#19 0x00007f45dd8b860c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib64/libQt5Widgets.so.5
#20 0x00007f45dd8bca22 in QApplication::notify(QObject*, QEvent*) () at /usr/lib64/libQt5Widgets.so.5
#21 0x00007f45dcbac005 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib64/libQt5Core.so.5
#22 0x00007f45dcbaddea in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib64/libQt5Core.so.5
#23 0x00007f45dcbfa584 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#24 0x00007f45c6a467dd in  () at /usr/lib64/libQt5XcbQpa.so.5
#25 0x00007f45dcbaa04b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib64/libQt5Core.so.5
#26 0x00007f45dcbb1f56 in QCoreApplication::exec() () at /usr/lib64/libQt5Core.so.5
#27 0x00007f45df0d9d6a in kdemain () at /usr/lib64/libkdeinit5_kwin_x11.so
#28 0x00007f45ded4db05 in __libc_start_main () at /lib64/libc.so.6
#29 0x00000000004007fe in _start ()

Reported using DrKonqi