Application: kwin_x11 (5.6.1)

Qt Version: 5.5.1
Frameworks Version: 5.20.0
Operating System: Linux 4.5.0-sabayon x86_64
Distribution: "Sabayon Linux amd64 16.04"

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

Had launched POL Diablo II LOD and when I saw the low-res desktop I attempted to correct by switching to an open app of nvidia-settings to change back to hi-res for resolving. While I was investigating the failure to launch fullscreen (which has worked correctly for me recently but I have been having Plasma crashes with KDE in general also recently - the main reason that I now have some debug info & an account in case I ever can properly report that Plasmashell segfault), I noticed the icon in the systray for CRA & that's when I knew about the kwin crash).

- Unusual behavior I noticed:

Screen switched to 800 x 600 but I was left with not just a desktop but a desktop exhibiting the behavoir of KDE in midst of an Alt-Tab operation (which I had not done at that point although I did later to reach an existing open instance of nvidia-settings).

-Distro: Sabayon

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 0x7fee51a1c880 (LWP 2406))]

Thread 4 (Thread 0x7fee328e2700 (LWP 2411)):
#0  0x00007fee515165cd in poll () from /lib64/libc.so.6
#1  0x00007fee4f71fc6a in _xcb_conn_wait () from /usr/lib64/libxcb.so.1
#2  0x00007fee4f7220cf in xcb_wait_for_event () from /usr/lib64/libxcb.so.1
#3  0x00007fee333cb559 in ?? () from /usr/lib64/libQt5XcbQpa.so.5
#4  0x00007fee4f9dc893 in QThreadPrivate::start(void*) () from /usr/lib64/libQt5Core.so.5
#5  0x00007fee50b1051c in start_thread () from /lib64/libpthread.so.0
#6  0x00007fee515201ad in clone () from /lib64/libc.so.6

Thread 3 (Thread 0x7fee2adee700 (LWP 2421)):
#0  0x00007fee515185a3 in select () from /lib64/libc.so.6
#1  0x00007fee4fbbfbf1 in qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) () from /usr/lib64/libQt5Core.so.5
#2  0x00007fee4fbc123b in QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) () from /usr/lib64/libQt5Core.so.5
#3  0x00007fee4fbc174d in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#4  0x00007fee4fb781fa in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#5  0x00007fee4f9d810c in QThread::exec() () from /usr/lib64/libQt5Core.so.5
#6  0x00007fee4a2df4a5 in QQmlThreadPrivate::run() () from /usr/lib64/libQt5Qml.so.5
#7  0x00007fee4f9dc893 in QThreadPrivate::start(void*) () from /usr/lib64/libQt5Core.so.5
#8  0x00007fee50b1051c in start_thread () from /lib64/libpthread.so.0
#9  0x00007fee515201ad in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7fee28843700 (LWP 2423)):
#0  0x00007fee50b15e7f in pthread_cond_wait () from /lib64/libpthread.so.0
#1  0x00007fee4ebab0c4 in QTWTF::TCMalloc_PageHeap::scavengerThread() () from /usr/lib64/libQt5Script.so.5
#2  0x00007fee4ebab109 in QTWTF::TCMalloc_PageHeap::runScavengerThread(void*) () from /usr/lib64/libQt5Script.so.5
#3  0x00007fee50b1051c in start_thread () from /lib64/libpthread.so.0
#4  0x00007fee515201ad in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7fee51a1c880 (LWP 2406)):
[KCrash Handler]
#6  0x00007fee514c2979 in __memcpy_sse2_unaligned () from /lib64/libc.so.6
#7  0x00007fee4af46a22 in KWin::GLVertexBuffer::setData(int, int, float const*, float const*) () from /usr/lib64/libkwinglutils.so.8
#8  0x00007fee510d10ce in KWin::SceneOpenGL2::doPaintBackground(QVector<float> const&) () from /usr/lib64/libkwin.so.5
#9  0x00007fee510d6905 in KWin::SceneOpenGL::paintBackground(QRegion) () from /usr/lib64/libkwin.so.5
#10 0x00007fee510bd493 in KWin::Scene::paintSimpleScreen(int, QRegion) () from /usr/lib64/libkwin.so.5
#11 0x00007fee510d1063 in KWin::SceneOpenGL2::paintSimpleScreen(int, QRegion) () from /usr/lib64/libkwin.so.5
#12 0x00007fee510bf0f5 in KWin::Scene::finalPaintScreen(int, QRegion, KWin::ScreenPaintData&) () from /usr/lib64/libkwin.so.5
#13 0x00007fee510e8a6f in KWin::EffectsHandlerImpl::paintScreen(int, QRegion, KWin::ScreenPaintData&) () from /usr/lib64/libkwin.so.5
#14 0x00007fee4f1c769f in KWin::Effect::paintScreen(int, QRegion, KWin::ScreenPaintData&) () from /usr/lib64/libkwineffects.so.8
#15 0x00007fee510e8a2d in KWin::EffectsHandlerImpl::paintScreen(int, QRegion, KWin::ScreenPaintData&) () from /usr/lib64/libkwin.so.5
#16 0x00007fee4f1c769f in KWin::Effect::paintScreen(int, QRegion, KWin::ScreenPaintData&) () from /usr/lib64/libkwineffects.so.8
#17 0x00007fee510e8a2d in KWin::EffectsHandlerImpl::paintScreen(int, QRegion, KWin::ScreenPaintData&) () from /usr/lib64/libkwin.so.5
#18 0x00007fee510bed9f in KWin::Scene::paintScreen(int*, QRegion const&, QRegion const&, QRegion*, QRegion*, QMatrix4x4 const&) () from /usr/lib64/libkwin.so.5
#19 0x00007fee510d7315 in KWin::SceneOpenGL::paint(QRegion, QList<KWin::Toplevel*>) () from /usr/lib64/libkwin.so.5
#20 0x00007fee510b3109 in KWin::Compositor::performCompositing() () from /usr/lib64/libkwin.so.5
#21 0x00007fee4fba0b7b in QObject::event(QEvent*) () from /usr/lib64/libQt5Core.so.5
#22 0x00007fee503b2e7c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#23 0x00007fee503b7ff0 in QApplication::notify(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#24 0x00007fee4fb794ed in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib64/libQt5Core.so.5
#25 0x00007fee4fbc2d8d in QTimerInfoList::activateTimers() () from /usr/lib64/libQt5Core.so.5
#26 0x00007fee4fbc171b in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#27 0x00007fee3342a9fd in ?? () from /usr/lib64/libQt5XcbQpa.so.5
#28 0x00007fee4fb781fa in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#29 0x00007fee4fb7f0ed in QCoreApplication::exec() () from /usr/lib64/libQt5Core.so.5
#30 0x00007fee517e0788 in kdemain () from /usr/lib64/libkdeinit5_kwin_x11.so
#31 0x00007fee5144ba94 in __libc_start_main () from /lib64/libc.so.6
#32 0x00000000004007f9 in _start ()

Possible duplicates by query: bug 359374, bug 355103, bug 352423, bug 350872, bug 350076.

Reported using DrKonqi