Application: kwin_x11 (5.9.4)

Qt Version: 5.7.1
Frameworks Version: 5.31.0
Operating System: Linux 4.10.0-20-generic x86_64
Distribution: Ubuntu 17.04

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

I was using Alt Tab, I have several windows open and after pressing Alt Tab a couple of times, KWin crashed. 

I am able to reproduce this by Alt Tabbing again.

The crash can be reproduced sometimes.

-- Backtrace:
Application: KWin (kwin_x11), signal: Aborted
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f2050007900 (LWP 3380))]

Thread 5 (Thread 0x7f2021d89700 (LWP 3389)):
#0  0x00007f204913d510 in pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f204c4682c4 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007f204c468309 in  () at /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007f20491376da in start_thread (arg=0x7f2021d89700) at pthread_create.c:456
#4  0x00007f204fa4317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 4 (Thread 0x7f202a9c8700 (LWP 3388)):
#0  0x00007f204fa37251 in __GI_ppoll (fds=0x7f201c000ac8, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007f204d2fe251 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f204d2ffb4a in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f204d2ac88a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f204d0d9fe3 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f2047ea4df5 in  () at /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#6  0x00007f204d0dec98 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f20491376da in start_thread (arg=0x7f202a9c8700) at pthread_create.c:456
#8  0x00007f204fa4317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 3 (Thread 0x7f202bfff700 (LWP 3387)):
#0  0x00007f204913d8b9 in pthread_cond_timedwait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:225
#1  0x00007f204d0dfa86 in QWaitCondition::wait(QMutex*, unsigned long) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f204d0db2b2 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f204d0dec98 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f20491376da in start_thread (arg=0x7f202bfff700) at pthread_create.c:456
#5  0x00007f204fa4317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 2 (Thread 0x7f2039010700 (LWP 3382)):
#0  0x00007f204fa37251 in __GI_ppoll (fds=0x7f203400d5a8, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:39
#1  0x00007f204d2fe251 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f204d2ffb4a in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f204d2ac88a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f204d0d9fe3 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f204707d5c5 in  () at /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#6  0x00007f204d0dec98 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f20491376da in start_thread (arg=0x7f2039010700) at pthread_create.c:456
#8  0x00007f204fa4317f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:105

Thread 1 (Thread 0x7f2050007900 (LWP 3380)):
[KCrash Handler]
#6  0x00007f204f97077f in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:58
#7  0x00007f204f97237a in __GI_abort () at abort.c:89
#8  0x00007f204d0c5451 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f20485660e3 in QSGRenderLoop::handleContextCreationFailure(QQuickWindow*, bool) () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#10 0x00007f204856db12 in  () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#11 0x00007f204856defb in  () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#12 0x00007f204d7fe475 in QWindow::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#13 0x00007f20485a4245 in QQuickWindow::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#14 0x00007f202088940b in PlasmaQuick::Dialog::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libKF5PlasmaQuick.so.5
#15 0x00007f204df8635c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#16 0x00007f204df8db11 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#17 0x00007f204d2ae8a0 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#18 0x00007f204d7f370d in QGuiApplicationPrivate::processExposeEvent(QWindowSystemInterfacePrivate::ExposeEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#19 0x00007f204d7f431d in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#20 0x00007f204d7d223b in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#21 0x00007f20380e4a06 in  () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#22 0x00007f204d2ac88a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#23 0x00007f204d2b4ffc in QCoreApplication::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#24 0x00007f204fd0b112 in kdemain () at /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so
#25 0x00007f204f95b3f1 in __libc_start_main (main=0x55d2fe6a17e0, argc=3, argv=0x7fffaeeb9e68, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffaeeb9e58) at ../csu/libc-start.c:291
#26 0x000055d2fe6a181a in _start ()

Reported using DrKonqi