Application: kwin_x11 (5.10.1)

Qt Version: 5.9.0
Frameworks Version: 5.34.0
Operating System: Linux 4.11.3-1-ARCH x86_64
Distribution (Platform): Archlinux Packages

-- Information about the crash:
- What I was doing when the application crashed:

I was trying to change window using the ALT+TAB hotkey.

- Unusual behavior I noticed:

KWin crashed and then restarted.

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fcbe6414840 (LWP 734))]

Thread 7 (Thread 0x7fcbc3fff700 (LWP 1297)):
#0  0x00007fcbe5e06396 in ppoll () at /usr/lib/libc.so.6
#1  0x00007fcbe33f4471 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/libQt5Core.so.5
#2  0x00007fcbe33f5b5e in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#3  0x00007fcbe339f21a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007fcbe31c140a in QThread::exec() () at /usr/lib/libQt5Core.so.5
#5  0x00007fcbddc52645 in  () at /usr/lib/libQt5Qml.so.5
#6  0x00007fcbe31c5cbd in  () at /usr/lib/libQt5Core.so.5
#7  0x00007fcbdef42297 in start_thread () at /usr/lib/libpthread.so.0
#8  0x00007fcbe5e1025f in clone () at /usr/lib/libc.so.6

Thread 6 (Thread 0x7fcba978d700 (LWP 851)):
#0  0x00007fcbdef4839d in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007fcbe230bac4 in  () at /usr/lib/libQt5Script.so.5
#2  0x00007fcbe230bb09 in  () at /usr/lib/libQt5Script.so.5
#3  0x00007fcbdef42297 in start_thread () at /usr/lib/libpthread.so.0
#4  0x00007fcbe5e1025f in clone () at /usr/lib/libc.so.6

Thread 5 (Thread 0x7fcbaaa9a700 (LWP 844)):
#0  0x00007fcbdef4839d in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007fcbaf4d971b in  () at /usr/lib/xorg/modules/dri/r600_dri.so
#2  0x00007fcbaf4d9447 in  () at /usr/lib/xorg/modules/dri/r600_dri.so
#3  0x00007fcbdef42297 in start_thread () at /usr/lib/libpthread.so.0
#4  0x00007fcbe5e1025f in clone () at /usr/lib/libc.so.6

Thread 4 (Thread 0x7fcbab3e2700 (LWP 843)):
#0  0x00007fcbdef4839d in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007fcbaf4d971b in  () at /usr/lib/xorg/modules/dri/r600_dri.so
#2  0x00007fcbaf4d9447 in  () at /usr/lib/xorg/modules/dri/r600_dri.so
#3  0x00007fcbdef42297 in start_thread () at /usr/lib/libpthread.so.0
#4  0x00007fcbe5e1025f in clone () at /usr/lib/libc.so.6

Thread 3 (Thread 0x7fcbc35da700 (LWP 841)):
#0  0x00007fcbe33a2e50 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib/libQt5Core.so.5
#1  0x00007fcbe33f5974 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#2  0x00007fcbe339f21a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#3  0x00007fcbe31c140a in QThread::exec() () at /usr/lib/libQt5Core.so.5
#4  0x00007fcbddc52645 in  () at /usr/lib/libQt5Qml.so.5
#5  0x00007fcbe31c5cbd in  () at /usr/lib/libQt5Core.so.5
#6  0x00007fcbdef42297 in start_thread () at /usr/lib/libpthread.so.0
#7  0x00007fcbe5e1025f in clone () at /usr/lib/libc.so.6

Thread 2 (Thread 0x7fcbca382700 (LWP 779)):
#0  0x00007fcbe5e06396 in ppoll () at /usr/lib/libc.so.6
#1  0x00007fcbe33f4471 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/libQt5Core.so.5
#2  0x00007fcbe33f5b5e in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#3  0x00007fcbe339f21a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007fcbe31c140a in QThread::exec() () at /usr/lib/libQt5Core.so.5
#5  0x00007fcbdcde8d45 in  () at /usr/lib/libQt5DBus.so.5
#6  0x00007fcbe31c5cbd in  () at /usr/lib/libQt5Core.so.5
#7  0x00007fcbdef42297 in start_thread () at /usr/lib/libpthread.so.0
#8  0x00007fcbe5e1025f in clone () at /usr/lib/libc.so.6

Thread 1 (Thread 0x7fcbe6414840 (LWP 734)):
[KCrash Handler]
#6  0x00007fcbaf82ab22 in  () at /usr/lib/xorg/modules/dri/r600_dri.so
#7  0x00007fcbaf608f25 in  () at /usr/lib/xorg/modules/dri/r600_dri.so
#8  0x00007fcbaf3e4940 in  () at /usr/lib/xorg/modules/dri/r600_dri.so
#9  0x00007fcbaf3a4b30 in  () at /usr/lib/xorg/modules/dri/r600_dri.so
#10 0x00007fcbaf3a4fb9 in  () at /usr/lib/xorg/modules/dri/r600_dri.so
#11 0x00007fcbde30827f in QSGBatchRenderer::Renderer::renderMergedBatch(QSGBatchRenderer::Batch const*) () at /usr/lib/libQt5Quick.so.5
#12 0x00007fcbde3094c5 in QSGBatchRenderer::Renderer::renderBatches() () at /usr/lib/libQt5Quick.so.5
#13 0x00007fcbde30ec24 in QSGBatchRenderer::Renderer::render() () at /usr/lib/libQt5Quick.so.5
#14 0x00007fcbde2ff5cd in QSGRenderer::renderScene(QSGBindable const&) () at /usr/lib/libQt5Quick.so.5
#15 0x00007fcbde2ffa8b in QSGRenderer::renderScene(unsigned int) () at /usr/lib/libQt5Quick.so.5
#16 0x00007fcbde339d40 in QSGDefaultRenderContext::renderNextFrame(QSGRenderer*, unsigned int) () at /usr/lib/libQt5Quick.so.5
#17 0x00007fcbde396868 in QQuickWindowPrivate::renderSceneGraph(QSize const&) () at /usr/lib/libQt5Quick.so.5
#18 0x00007fcbde32c139 in  () at /usr/lib/libQt5Quick.so.5
#19 0x00007fcbde3a0ad6 in QQuickWindow::event(QEvent*) () at /usr/lib/libQt5Quick.so.5
#20 0x00007fcb1f1d27ab in PlasmaQuick::Dialog::event(QEvent*) () at /usr/lib/libKF5PlasmaQuick.so.5
#21 0x00007fcbe40cf46c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#22 0x00007fcbe40d6cf4 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#23 0x00007fcbe33a0b98 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#24 0x00007fcbe3916751 in QWindowPrivate::deliverUpdateRequest() () at /usr/lib/libQt5Gui.so.5
#25 0x00007fcbe3916c69 in QWindow::event(QEvent*) () at /usr/lib/libQt5Gui.so.5
#26 0x00007fcbde3a0a75 in QQuickWindow::event(QEvent*) () at /usr/lib/libQt5Quick.so.5
#27 0x00007fcb1f1d27ab in PlasmaQuick::Dialog::event(QEvent*) () at /usr/lib/libKF5PlasmaQuick.so.5
#28 0x00007fcbe40cf46c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#29 0x00007fcbe40d6cf4 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#30 0x00007fcbe33a0b98 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#31 0x00007fcbe33f7bae in QTimerInfoList::activateTimers() () at /usr/lib/libQt5Core.so.5
#32 0x00007fcbe33f5dc2 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#33 0x00007fcbcd6675bd in  () at /usr/lib/libQt5XcbQpa.so.5
#34 0x00007fcbe339f21a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#35 0x00007fcbe33a7a74 in QCoreApplication::exec() () at /usr/lib/libQt5Core.so.5
#36 0x00007fcbe60d3fd5 in kdemain () at /usr/lib/libkdeinit5_kwin_x11.so
#37 0x00007fcbe5d4343a in __libc_start_main () at /usr/lib/libc.so.6
#38 0x000000000040069a in _start ()

Reported using DrKonqi