Application: kwin_x11 (5.16.4)

Qt Version: 5.12.4
Frameworks Version: 5.61.0
Operating System: Linux 5.2.16-200.fc30.x86_64 x86_64
Distribution (Platform): Fedora RPMs

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

Black screen after unlocking my PC. I waited several seconds and nothing appeared(except the mouse cursor). 

It's happened several times now but happens only after leaving the PC idle for extended periods

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 0x7f53df168640 (LWP 2220))]

Thread 6 (Thread 0x7f53c8a2d700 (LWP 29866)):
#0  0x00007fff36923625 in  ()
#1  0x00007f53e614932b in clock_gettime@GLIBC_2.2.5 () at /lib64/libc.so.6
#2  0x00007f53e4ced3e5 in  () at /lib64/libQt5Core.so.5
#3  0x00007f53e4cebf1d in QTimerInfoList::updateCurrentTime() () at /lib64/libQt5Core.so.5
#4  0x00007f53e4cecb29 in QTimerInfoList::activateTimers() () at /lib64/libQt5Core.so.5
#5  0x00007f53e4ceb2bf in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#6  0x00007f53e4c979eb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#7  0x00007f53e4af0635 in QThread::exec() () at /lib64/libQt5Core.so.5
#8  0x00007f53e4af1786 in  () at /lib64/libQt5Core.so.5
#9  0x00007f53e40254c0 in start_thread () at /lib64/libpthread.so.0
#10 0x00007f53e6182553 in clone () at /lib64/libc.so.6

Thread 5 (Thread 0x7f53ca35d700 (LWP 2578)):
#0  0x00007f53e6177bd6 in ppoll () at /lib64/libc.so.6
#1  0x00007f53e4cea099 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /lib64/libQt5Core.so.5
#2  0x00007f53e4ceb194 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#3  0x00007f53e4c979eb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#4  0x00007f53e4af0635 in QThread::exec() () at /lib64/libQt5Core.so.5
#5  0x00007f53e379ba69 in  () at /lib64/libQt5Qml.so.5
#6  0x00007f53e4af1786 in  () at /lib64/libQt5Core.so.5
#7  0x00007f53e40254c0 in start_thread () at /lib64/libpthread.so.0
#8  0x00007f53e6182553 in clone () at /lib64/libc.so.6

Thread 4 (Thread 0x7f53b62da700 (LWP 2441)):
#0  0x00007f53e402b3c5 in pthread_cond_wait@@GLIBC_2.3.2 () at /lib64/libpthread.so.0
#1  0x00007f53e45646ea in  () at /lib64/libQt5Script.so.5
#2  0x00007f53e456470f in  () at /lib64/libQt5Script.so.5
#3  0x00007f53e40254c0 in start_thread () at /lib64/libpthread.so.0
#4  0x00007f53e6182553 in clone () at /lib64/libc.so.6

Thread 3 (Thread 0x7f53cb59e700 (LWP 2380)):
#0  0x00007f53e6177bd6 in ppoll () at /lib64/libc.so.6
#1  0x00007f53e4cea099 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /lib64/libQt5Core.so.5
#2  0x00007f53e4ceb194 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#3  0x00007f53e4c979eb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#4  0x00007f53e4af0635 in QThread::exec() () at /lib64/libQt5Core.so.5
#5  0x00007f53e379ba69 in  () at /lib64/libQt5Qml.so.5
#6  0x00007f53e4af1786 in  () at /lib64/libQt5Core.so.5
#7  0x00007f53e40254c0 in start_thread () at /lib64/libpthread.so.0
#8  0x00007f53e6182553 in clone () at /lib64/libc.so.6

Thread 2 (Thread 0x7f53d124e700 (LWP 2338)):
#0  0x00007f53e6177bd6 in ppoll () at /lib64/libc.so.6
#1  0x00007f53e4cea099 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () at /lib64/libQt5Core.so.5
#2  0x00007f53e4ceb194 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#3  0x00007f53e4c979eb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#4  0x00007f53e4af0635 in QThread::exec() () at /lib64/libQt5Core.so.5
#5  0x00007f53e31aef4a in  () at /lib64/libQt5DBus.so.5
#6  0x00007f53e4af1786 in  () at /lib64/libQt5Core.so.5
#7  0x00007f53e40254c0 in start_thread () at /lib64/libpthread.so.0
#8  0x00007f53e6182553 in clone () at /lib64/libc.so.6

Thread 1 (Thread 0x7f53df168640 (LWP 2220)):
[KCrash Handler]
#6  0x00005561a9fc9010 in  ()
#7  0x00007f53cb5bc0d4 in KWin::SceneOpenGL::createScene(QObject*) () at /usr/lib64/qt5/plugins/org.kde.kwin.scenes/KWinSceneOpenGL.so
#8  0x00007f53cb5bf83d in KWin::OpenGLFactory::create(QObject*) const () at /usr/lib64/qt5/plugins/org.kde.kwin.scenes/KWinSceneOpenGL.so
#9  0x00007f53e5eeb7e3 in KWin::Compositor::slotCompositingOptionsInitialized() () at /lib64/libkwin.so.5
#10 0x00007f53e5eec803 in KWin::Compositor::setup() () at /lib64/libkwin.so.5
#11 0x00007f53e4cc3bfa in QObject::event(QEvent*) () at /lib64/libQt5Core.so.5
#12 0x00007f53e55fbaf6 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /lib64/libQt5Widgets.so.5
#13 0x00007f53e5604e80 in QApplication::notify(QObject*, QEvent*) () at /lib64/libQt5Widgets.so.5
#14 0x00007f53e4c98ae8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /lib64/libQt5Core.so.5
#15 0x00007f53e4c9ba93 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /lib64/libQt5Core.so.5
#16 0x00007f53e4ceafa7 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#17 0x00007f53d206dfa2 in  () at /lib64/libQt5XcbQpa.so.5
#18 0x00007f53e4c979eb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /lib64/libQt5Core.so.5
#19 0x00007f53e4c9f726 in QCoreApplication::exec() () at /lib64/libQt5Core.so.5
#20 0x00007f53e6256a8d in kdemain () at /lib64/libkdeinit5_kwin_x11.so
#21 0x00007f53e60a9f43 in __libc_start_main () at /lib64/libc.so.6
#22 0x00005561a853b0ae in _start ()
[Inferior 1 (process 2220) detached]

Reported using DrKonqi