Application: kwin_x11 (5.11.1)

Qt Version: 5.9.2
Frameworks Version: 5.39.0
Operating System: Linux 4.13.7-1-ARCH x86_64
Distribution (Platform): Archlinux Packages

-- Information about the crash:
- What I was doing when the application crashed:
Loging into Plasma Desktop.

- Custom settings of the application:
Enabled desktop effects:  Zoom, Background contrast, Blur, Desaturate Unresponsive Applications, Fall Apart, Maximise, Morphing popups, Screen Edge, Transulency, Window Aperture, Magic Lamp, Dialogue Box Parent, Slide Back, Slide, Desktop Cube, Desktop Grid, Flip Switch, Present Windows.
Compositor:  Compositor on startup = Enabled ; Animation speed = Middle; Scale method = Accurate ; Rendering backend = OpenGL 2.0 ; Tearing prevention = Automatic ; Keep window thumbnails = Only for Shown Windows ; Allow applications to block compositing = Enabled.

The crash can be reproduced sometimes.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f36a2a5f840 (LWP 548))]

Thread 6 (Thread 0x7f366de32700 (LWP 691)):
#0  0x00007f369b39438d in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f369e933ef7 in  () at /usr/lib/libQt5Script.so.5
#2  0x00007f369e933f39 in  () at /usr/lib/libQt5Script.so.5
#3  0x00007f369b38e08a in start_thread () at /usr/lib/libpthread.so.0
#4  0x00007f36a23e924f in clone () at /usr/lib/libc.so.6

Thread 5 (Thread 0x7f367a9dc700 (LWP 654)):
[KCrash Handler]
#5  0x00007f369f94e511 in  () at /usr/lib/libQt5Core.so.5
#6  0x00007f369f8e405e in QLockFile::tryLock(int) () at /usr/lib/libQt5Core.so.5
#7  0x00007f36a17312ba in  () at /usr/lib/libKF5ConfigCore.so.5
#8  0x00007f36a1714725 in KConfig::sync() () at /usr/lib/libKF5ConfigCore.so.5
#9  0x00007f3681f4cc2b in  () at /usr/lib/qt/plugins/org.kde.kwin.platforms/KWinX11Platform.so
#10 0x00007f369f9eed3f in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#11 0x00007f369f9fbb48 in QTimer::timeout(QTimer::QPrivateSignal) () at /usr/lib/libQt5Core.so.5
#12 0x00007f369f9fbeb9 in QTimer::timerEvent(QTimerEvent*) () at /usr/lib/libQt5Core.so.5
#13 0x00007f369f9ef61b in QObject::event(QEvent*) () at /usr/lib/libQt5Core.so.5
#14 0x00007f36a06dcf2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#15 0x00007f36a06e4a06 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#16 0x00007f369f9bf060 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#17 0x00007f369fa19118 in QTimerInfoList::activateTimers() () at /usr/lib/libQt5Core.so.5
#18 0x00007f369fa17214 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#19 0x00007f369f9bd48b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#20 0x00007f369f7d627e in QThread::exec() () at /usr/lib/libQt5Core.so.5
#21 0x00007f369f7dafcb in  () at /usr/lib/libQt5Core.so.5
#22 0x00007f369b38e08a in start_thread () at /usr/lib/libpthread.so.0
#23 0x00007f36a23e924f in clone () at /usr/lib/libc.so.6

Thread 4 (Thread 0x7f367bddd700 (LWP 649)):
#0  0x00007ffd37938b52 in clock_gettime ()
#1  0x00007f36a23f6af6 in clock_gettime () at /usr/lib/libc.so.6
#2  0x00007f369fa195e2 in  () at /usr/lib/libQt5Core.so.5
#3  0x00007f369fa17d7a in QTimerInfoList::updateCurrentTime() () at /usr/lib/libQt5Core.so.5
#4  0x00007f369fa18356 in QTimerInfoList::timerWait(timespec&) () at /usr/lib/libQt5Core.so.5
#5  0x00007f369fa172c5 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#6  0x00007f369f9bd48b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#7  0x00007f369f7d627e in QThread::exec() () at /usr/lib/libQt5Core.so.5
#8  0x00007f3699e96bc9 in  () at /usr/lib/libQt5Qml.so.5
#9  0x00007f369f7dafcb in  () at /usr/lib/libQt5Core.so.5
#10 0x00007f369b38e08a in start_thread () at /usr/lib/libpthread.so.0
#11 0x00007f36a23e924f in clone () at /usr/lib/libc.so.6

Thread 3 (Thread 0x7f368297b700 (LWP 633)):
#0  0x00007ffd37938b52 in clock_gettime ()
#1  0x00007f36a23f6af6 in clock_gettime () at /usr/lib/libc.so.6
#2  0x00007f369fa195e2 in  () at /usr/lib/libQt5Core.so.5
#3  0x00007f369fa17d7a in QTimerInfoList::updateCurrentTime() () at /usr/lib/libQt5Core.so.5
#4  0x00007f369fa18356 in QTimerInfoList::timerWait(timespec&) () at /usr/lib/libQt5Core.so.5
#5  0x00007f369fa172c5 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#6  0x00007f369f9bd48b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#7  0x00007f369f7d627e in QThread::exec() () at /usr/lib/libQt5Core.so.5
#8  0x00007f3699037376 in  () at /usr/lib/libQt5DBus.so.5
#9  0x00007f369f7dafcb in  () at /usr/lib/libQt5Core.so.5
#10 0x00007f369b38e08a in start_thread () at /usr/lib/libpthread.so.0
#11 0x00007f36a23e924f in clone () at /usr/lib/libc.so.6

Thread 2 (Thread 0x7f368931a700 (LWP 564)):
#0  0x00007f36a23ded4b in poll () at /usr/lib/libc.so.6
#1  0x00007f36a14dc8e0 in  () at /usr/lib/libxcb.so.1
#2  0x00007f36a14de679 in xcb_wait_for_event () at /usr/lib/libxcb.so.1
#3  0x00007f368a1f585a in  () at /usr/lib/libQt5XcbQpa.so.5
#4  0x00007f369f7dafcb in  () at /usr/lib/libQt5Core.so.5
#5  0x00007f369b38e08a in start_thread () at /usr/lib/libpthread.so.0
#6  0x00007f36a23e924f in clone () at /usr/lib/libc.so.6

Thread 1 (Thread 0x7f36a2a5f840 (LWP 548)):
#0  0x00007ffd37938b52 in clock_gettime ()
#1  0x00007f36a23f6af6 in clock_gettime () at /usr/lib/libc.so.6
#2  0x00007f369fa195e2 in  () at /usr/lib/libQt5Core.so.5
#3  0x00007f369fa17d7a in QTimerInfoList::updateCurrentTime() () at /usr/lib/libQt5Core.so.5
#4  0x00007f369fa18356 in QTimerInfoList::timerWait(timespec&) () at /usr/lib/libQt5Core.so.5
#5  0x00007f369fa172c5 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#6  0x00007f368a25a8ce in  () at /usr/lib/libQt5XcbQpa.so.5
#7  0x00007f369f9bd48b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#8  0x00007f369f9c64d8 in QCoreApplication::exec() () at /usr/lib/libQt5Core.so.5
#9  0x00007f36a26b26e3 in kdemain () at /usr/lib/libkdeinit5_kwin_x11.so
#10 0x00007f36a2313f6a in __libc_start_main () at /usr/lib/libc.so.6
#11 0x0000557b3f2637aa in _start ()

Reported using DrKonqi