Application: kwin_x11 (5.21.4)

Qt Version: 5.15.2
Frameworks Version: 5.81.0
Operating System: Linux 5.4.0-71-generic x86_64
Windowing System: X11
Drkonqi Version: 5.21.4
Distribution: KDE neon User Edition 5.21

-- Information about the crash:
- What I was doing when the application crashed:
I had the Oracle VM VirtualBox Manager Version 6.1.18 r142142 (Qt5.15.2) open, with no VMs running, and working in the settings dialog of a virtual machine. Then, I saved the settings, with the dialog windows closing 
- Unusual behavior I noticed:
Right after it closed, both screens, a laptop screen, and an LCD connected via HDMI, went black for a few seconds. Then, the desktop returned to the way it looked before. None of my open applications crashed.

The reporter is unsure if this crash is reproducible.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault

[New LWP 2108]
[New LWP 2109]
[New LWP 2110]
[New LWP 2111]
[New LWP 2112]
[New LWP 2113]
[New LWP 2175]
[New LWP 2284]
[New LWP 2925]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
0x00007f6a48668aff in __GI___poll (fds=0x7ffd4e1d43e8, nfds=1, timeout=1000) at ../sysdeps/unix/sysv/linux/poll.c:29
[Current thread is 1 (Thread 0x7f6a42a798c0 (LWP 2105))]

Thread 10 (Thread 0x7f696bfff700 (LWP 2925)):
#0  0x00007f6a48668bf6 in __ppoll (fds=0x7f6964000d78, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:44
#1  0x00007f6a48c2fef9 in qt_safe_poll(pollfd*, unsigned long, timespec const*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f6a48c315a3 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f6a48bd81eb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f6a489f2a52 in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f6a47465fa9 in ?? () from /lib/x86_64-linux-gnu/libQt5Qml.so.5
#6  0x00007f6a489f3bec in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f6a47bd5609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#8  0x00007f6a48675293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 9 (Thread 0x7f6a0f7fe700 (LWP 2284)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x7f6a483bdfd8) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x7f6a483bdf88, cond=0x7f6a483bdfb0) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x7f6a483bdfb0, mutex=0x7f6a483bdf88) at pthread_cond_wait.c:638
#3  0x00007f6a482c063a in ?? () from /lib/x86_64-linux-gnu/libQt5Script.so.5
#4  0x00007f6a482c065f in ?? () from /lib/x86_64-linux-gnu/libQt5Script.so.5
#5  0x00007f6a47bd5609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f6a48675293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x7f6a2de4a700 (LWP 2175)):
#0  0x00007f6a48c338de in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#1  0x00007f6a48c3215d in QTimerInfoList::updateCurrentTime() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f6a48c32739 in QTimerInfoList::timerWait(timespec&) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f6a48c317b4 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f6a48bd81eb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f6a489f2a52 in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f6a47465fa9 in ?? () from /lib/x86_64-linux-gnu/libQt5Qml.so.5
#7  0x00007f6a489f3bec in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f6a47bd5609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007f6a48675293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7f6a3889f700 (LWP 2113)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5652018b6db8) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5652018b6d68, cond=0x5652018b6d90) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x5652018b6d90, mutex=0x5652018b6d68) at pthread_cond_wait.c:638
#3  0x00007f6a3ad5eb5b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#4  0x00007f6a3ad5e75b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#5  0x00007f6a47bd5609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f6a48675293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7f6a390a0700 (LWP 2112)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5652018b6db8) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5652018b6d68, cond=0x5652018b6d90) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x5652018b6d90, mutex=0x5652018b6d68) at pthread_cond_wait.c:638
#3  0x00007f6a3ad5eb5b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#4  0x00007f6a3ad5e75b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#5  0x00007f6a47bd5609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f6a48675293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f6a398a1700 (LWP 2111)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5652018b6db8) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5652018b6d68, cond=0x5652018b6d90) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x5652018b6d90, mutex=0x5652018b6d68) at pthread_cond_wait.c:638
#3  0x00007f6a3ad5eb5b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#4  0x00007f6a3ad5e75b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#5  0x00007f6a47bd5609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f6a48675293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f6a3a0a2700 (LWP 2110)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5652018b6db8) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5652018b6d68, cond=0x5652018b6d90) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x5652018b6d90, mutex=0x5652018b6d68) at pthread_cond_wait.c:638
#3  0x00007f6a3ad5eb5b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#4  0x00007f6a3ad5e75b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#5  0x00007f6a47bd5609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f6a48675293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f6a3a8a3700 (LWP 2109)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5652018b5e6c) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5652018b5e18, cond=0x5652018b5e40) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x5652018b5e40, mutex=0x5652018b5e18) at pthread_cond_wait.c:638
#3  0x00007f6a3ad5eb5b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#4  0x00007f6a3ad5e75b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#5  0x00007f6a47bd5609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f6a48675293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f6a41361700 (LWP 2108)):
#0  0x00007f6a48c338a0 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#1  0x00007f6a48c3215d in QTimerInfoList::updateCurrentTime() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007f6a48c32739 in QTimerInfoList::timerWait(timespec&) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007f6a48c317b4 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f6a48bd81eb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f6a489f2a52 in QThread::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f6a48e95f4b in ?? () from /lib/x86_64-linux-gnu/libQt5DBus.so.5
#7  0x00007f6a489f3bec in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f6a47bd5609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007f6a48675293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f6a42a798c0 (LWP 2105)):
[KCrash Handler]
#4  0x0000000000000000 in ?? ()
#5  0x00007f6a4849a957 in ?? () from /lib/x86_64-linux-gnu/libkwin4_effect_builtins.so.1
#6  0x00007f6a4849b75d in ?? () from /lib/x86_64-linux-gnu/libkwin4_effect_builtins.so.1
#7  0x00007f6a4a015857 in KWin::EffectsHandlerImpl::paintWindow (this=0x56520209acc0, w=0x56520224f0f0, mask=1, region=..., data=...) at ./effects.cpp:421
#8  0x00007f6a484174fa in KWin::AnimationEffect::paintWindow(KWin::EffectWindow*, int, QRegion, KWin::WindowPaintData&) () from /lib/x86_64-linux-gnu/libkwineffects.so.13
#9  0x00007f6a4a015857 in KWin::EffectsHandlerImpl::paintWindow (this=0x56520209acc0, w=0x56520224f0f0, mask=1, region=..., data=...) at ./effects.cpp:421
#10 0x00007f6a484174fa in KWin::AnimationEffect::paintWindow(KWin::EffectWindow*, int, QRegion, KWin::WindowPaintData&) () from /lib/x86_64-linux-gnu/libkwineffects.so.13
#11 0x00007f6a4a015857 in KWin::EffectsHandlerImpl::paintWindow (this=0x56520209acc0, w=0x56520224f0f0, mask=1, region=..., data=...) at ./effects.cpp:421
#12 0x00007f6a484174fa in KWin::AnimationEffect::paintWindow(KWin::EffectWindow*, int, QRegion, KWin::WindowPaintData&) () from /lib/x86_64-linux-gnu/libkwineffects.so.13
#13 0x00007f6a4a015857 in KWin::EffectsHandlerImpl::paintWindow (this=this@entry=0x56520209acc0, w=0x56520224f0f0, mask=mask@entry=1, region=..., data=...) at ./effects.cpp:421
#14 0x00007f6a4a0a7285 in KWin::Scene::paintWindow (this=0x565201a86560, w=0x5652022439b0, mask=1, _region=..., quads=...) at ./scene.cpp:514
#15 0x00007f6a4a0a4684 in KWin::Scene::paintSimpleScreen (this=<optimized out>, orig_mask=0, region=...) at ./scene.cpp:426
#16 0x00007f6a4a09f456 in KWin::Scene::finalPaintScreen (this=0x565201a86560, mask=<optimized out>, region=..., data=...) at ./scene.cpp:225
#17 0x00007f6a4a015662 in KWin::EffectsHandlerImpl::paintScreen (this=0x56520209acc0, mask=<optimized out>, region=..., data=...) at ./effects.cpp:378
#18 0x00007f6a4a015662 in KWin::EffectsHandlerImpl::paintScreen (this=0x56520209acc0, mask=<optimized out>, region=..., data=...) at ./effects.cpp:378
#19 0x00007f6a4a015662 in KWin::EffectsHandlerImpl::paintScreen (this=0x56520209acc0, mask=<optimized out>, region=..., data=...) at ./effects.cpp:378
#20 0x00007f6a4a015662 in KWin::EffectsHandlerImpl::paintScreen (this=0x56520209acc0, mask=<optimized out>, region=..., data=...) at ./effects.cpp:378
#21 0x00007f6a4a015662 in KWin::EffectsHandlerImpl::paintScreen (this=0x56520209acc0, mask=<optimized out>, region=..., data=...) at ./effects.cpp:378
#22 0x00007f6a4a015662 in KWin::EffectsHandlerImpl::paintScreen (this=0x56520209acc0, mask=<optimized out>, region=..., data=...) at ./effects.cpp:378
#23 0x00007f6a4a0a6591 in KWin::Scene::paintScreen (this=this@entry=0x565201a86560, mask=mask@entry=0x7ffd4e1d5314, damage=..., repaint=..., updateRegion=updateRegion@entry=0x7ffd4e1d5318, validRegion=validRegion@entry=0x7ffd4e1d5320, renderLoop=0x5652018c30e0, projection=..., outputGeometry=..., screenScale=screenScale@entry=1) at ./scene.cpp:197
#24 0x00007f6a3802fa53 in KWin::SceneOpenGL::paint (this=0x565201a86560, screenId=-1, damage=..., toplevels=..., renderLoop=0x5652018c30e0) at ./plugins/scenes/opengl/scene_opengl.h:114
#25 0x00007f6a49fd9a51 in KWin::Compositor::handleFrameRequested (renderLoop=0x5652018c30e0, this=<optimized out>) at ./composite.cpp:665
#26 KWin::Compositor::handleFrameRequested (this=<optimized out>, renderLoop=0x5652018c30e0) at ./composite.cpp:589
#27 0x00007f6a48c106fe in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#28 0x00007f6a49f94ae6 in KWin::RenderLoop::frameRequested (this=<optimized out>, _t1=<optimized out>) at ./obj-x86_64-linux-gnu/kwin_autogen/EWIEGA46WW/moc_renderloop.cpp:193
#29 0x00007f6a4a0910b7 in KWin::RenderLoopPrivate::dispatch (this=0x5652018554e0) at ./renderloop.cpp:143
#30 0x00007f6a48c106fe in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#31 0x00007f6a48c1522e in QTimer::timeout(QTimer::QPrivateSignal) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#32 0x00007f6a48c07195 in QObject::event(QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#33 0x00007f6a4977adc3 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#34 0x00007f6a49783bb8 in QApplication::notify(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#35 0x00007f6a48bd96da in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#36 0x00007f6a48c33330 in QTimerInfoList::activateTimers() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#37 0x00007f6a48c316f7 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#38 0x00007f6a4239d132 in ?? () from /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#39 0x00007f6a48bd81eb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#40 0x00007f6a48be0394 in QCoreApplication::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#41 0x0000565200463acd in main (argc=<optimized out>, argv=0x7ffd4e1d5e28) at ./main_x11.cpp:491
[Inferior 1 (process 2105) detached]

Possible duplicates by query: bug 434453, bug 431783, bug 430699, bug 430648, bug 430160.

Reported using DrKonqi