Application: kwin_x11 (5.6.4)
 (Compiled from sources)
Qt Version: 5.5.1
Frameworks Version: 5.22.0
Operating System: Linux 4.6.0-gentoo x86_64
Distribution: "Gentoo Base System release 2.2"

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

Two screens, kodi playing fullscreen on one, browser on other.
Focus on browser, press alt+tab to switch window.
Kwin crash.

DrKonqui found quite a few possible dupes, but I'm not sure if it actually is one. (those I quickly browsed mentioned a fix in qt 5.5, which I have)

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin_x11), signal: Aborted
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f1c39cf7840 (LWP 5958))]

Thread 7 (Thread 0x7f1c22e2d700 (LWP 5961)):
#0  0x00007f1c395ed57d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f1c37a9ca92 in poll (__timeout=-1, __nfds=1, __fds=0x7f1c22e2cc80) at /usr/include/bits/poll2.h:46
#2  _xcb_conn_wait (c=c@entry=0x24a2ab0, cond=cond@entry=0x24a2af0, vector=vector@entry=0x0, count=count@entry=0x0) at /var/tmp/portage/x11-libs/libxcb-1.11.1/work/libxcb-1.11.1/src/xcb_conn.c:459
#3  0x00007f1c37a9e67f in xcb_wait_for_event (c=0x24a2ab0) at /var/tmp/portage/x11-libs/libxcb-1.11.1/work/libxcb-1.11.1/src/xcb_in.c:693
#4  0x00007f1c236d1719 in QXcbEventReader::run (this=0x24b5ae0) at qxcbconnection.cpp:1229
#5  0x00007f1c37d51b63 in QThreadPrivate::start(void*) () from /usr/lib64/libQt5Core.so.5
#6  0x00007f1c398af5c4 in start_thread (arg=0x7f1c22e2d700) at pthread_create.c:334
#7  0x00007f1c395f639d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 6 (Thread 0x7f1c1bec1700 (LWP 5969)):
#0  pthread_cond_wait () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f1c21a3e293 in radeon_drm_cs_emit_ioctl () from /usr/lib64/dri/r600_dri.so
#2  0x00007f1c21a3dab7 in impl_thrd_routine () from /usr/lib64/dri/r600_dri.so
#3  0x00007f1c398af5c4 in start_thread (arg=0x7f1c1bec1700) at pthread_create.c:334
#4  0x00007f1c395f639d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 5 (Thread 0x7f1c1938d700 (LWP 5975)):
#0  pthread_cond_timedwait () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:225
#1  0x00007f1c37d52118 in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib64/libQt5Core.so.5
#2  0x00007f1c37d4f197 in QThreadPoolThread::run() () from /usr/lib64/libQt5Core.so.5
#3  0x00007f1c37d51b63 in QThreadPrivate::start(void*) () from /usr/lib64/libQt5Core.so.5
#4  0x00007f1c398af5c4 in start_thread (arg=0x7f1c1938d700) at pthread_create.c:334
#5  0x00007f1c395f639d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 4 (Thread 0x7f1c13fff700 (LWP 5976)):
#0  0x00007f1c395ef203 in select () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f1c37f34ad9 in qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) () from /usr/lib64/libQt5Core.so.5
#2  0x00007f1c37f36033 in QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) () from /usr/lib64/libQt5Core.so.5
#3  0x00007f1c37f3644b in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#4  0x00007f1c37eed75b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#5  0x00007f1c37d4d51a in QThread::exec() () from /usr/lib64/libQt5Core.so.5
#6  0x00007f1c3238f548 in QQmlThreadPrivate::run (this=0x270c4d0) at qml/ftw/qqmlthread.cpp:141
#7  0x00007f1c37d51b63 in QThreadPrivate::start(void*) () from /usr/lib64/libQt5Core.so.5
#8  0x00007f1c398af5c4 in start_thread (arg=0x7f1c13fff700) at pthread_create.c:334
#9  0x00007f1c395f639d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7f1c12ffe700 (LWP 5977)):
#0  pthread_cond_timedwait () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:225
#1  0x00007f1c37d52118 in QWaitCondition::wait(QMutex*, unsigned long) () from /usr/lib64/libQt5Core.so.5
#2  0x00007f1c37d4f197 in QThreadPoolThread::run() () from /usr/lib64/libQt5Core.so.5
#3  0x00007f1c37d51b63 in QThreadPrivate::start(void*) () from /usr/lib64/libQt5Core.so.5
#4  0x00007f1c398af5c4 in start_thread (arg=0x7f1c12ffe700) at pthread_create.c:334
#5  0x00007f1c395f639d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f1c127fd700 (LWP 5978)):
#0  pthread_cond_wait () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f1c36e6911b in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0x7f1c36f50c60 <QTWTF::pageheap_memory>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#2  0x00007f1c36e69149 in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=<optimized out>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#3  0x00007f1c398af5c4 in start_thread (arg=0x7f1c127fd700) at pthread_create.c:334
#4  0x00007f1c395f639d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f1c39cf7840 (LWP 5958)):
[KCrash Handler]
#6  0x00007f1c39541ff7 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:55
#7  0x00007f1c3954335a in __GI_abort () at abort.c:89
#8  0x00007f1c37d4215e in QMessageLogger::fatal(char const*, ...) const () from /usr/lib64/libQt5Core.so.5
#9  0x00007f1c236e7992 in QXcbWindow::create (this=this@entry=0x2e27ff0) at qxcbwindow.cpp:462
#10 0x00007f1c39ede409 in QXcbEglWindow::create (this=0x2e27ff0) at qxcbeglwindow.cpp:83
#11 0x00007f1c236d2f72 in QXcbIntegration::createPlatformWindow (this=<optimized out>, window=<optimized out>) at qxcbintegration.cpp:201
#12 0x00007f1c3821570b in QWindowPrivate::create (this=0x2d66220, recursive=recursive@entry=false) at kernel/qwindow.cpp:392
#13 0x00007f1c3821580b in QWindow::create (this=this@entry=0x2d64b50) at kernel/qwindow.cpp:548
#14 0x00007f1c38215898 in QWindow::winId (this=0x2d64b50) at kernel/qwindow.cpp:567
#15 0x00007f1c11765cd6 in PlasmaQuick::DialogPrivate::updateTheme() () from /usr/lib64/libKF5PlasmaQuick.so.5
#16 0x00007f1c11767b67 in PlasmaQuick::Dialog::componentComplete() () from /usr/lib64/libKF5PlasmaQuick.so.5
#17 0x00007f1c323857db in QQmlObjectCreator::finalize (this=0x2634a70, interrupt=...) at qml/qqmlobjectcreator.cpp:1207
#18 0x00007f1c323149eb in QQmlComponentPrivate::complete (enginePriv=0x270c270, state=state@entry=0x2866950) at qml/qqmlcomponent.cpp:928
#19 0x00007f1c32314aa7 in QQmlComponentPrivate::completeCreate (this=0x28668b0) at qml/qqmlcomponent.cpp:964
#20 0x00007f1c32314930 in QQmlComponent::create (this=0x26dcc00, context=0x25edc90) at qml/qqmlcomponent.cpp:791
#21 0x00007f1c3924cff7 in KWin::TabBox::TabBoxHandlerPrivate::createSwitcherItem(bool) () from /usr/lib64/libkwin.so.5
#22 0x00007f1c3924e47c in KWin::TabBox::TabBoxHandlerPrivate::show() () from /usr/lib64/libkwin.so.5
#23 0x00007f1c3924e6d9 in KWin::TabBox::TabBoxHandler::show() () from /usr/lib64/libkwin.so.5
#24 0x00007f1c392630dd in KWin::TabBox::TabBox::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) () from /usr/lib64/libkwin.so.5
#25 0x00007f1c37f14be1 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib64/libQt5Core.so.5
#26 0x00007f1c37f20e02 in QTimer::timerEvent(QTimerEvent*) () from /usr/lib64/libQt5Core.so.5
#27 0x00007f1c37f15b14 in QObject::event(QEvent*) () from /usr/lib64/libQt5Core.so.5
#28 0x00007f1c386cf8fc in QApplicationPrivate::notify_helper (this=this@entry=0x249aa30, receiver=receiver@entry=0x2561b68, e=e@entry=0x7ffdf19420b0) at kernel/qapplication.cpp:3716
#29 0x00007f1c386d4748 in QApplication::notify (this=0x7ffdf1942300, receiver=0x2561b68, e=0x7ffdf19420b0) at kernel/qapplication.cpp:3499
#30 0x00007f1c37eeeb0d in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib64/libQt5Core.so.5
#31 0x00007f1c37f37b7d in QTimerInfoList::activateTimers() () from /usr/lib64/libQt5Core.so.5
#32 0x00007f1c37f364d8 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#33 0x00007f1c237315fd in QUnixEventDispatcherQPA::processEvents (this=<optimized out>, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#34 0x00007f1c37eed75b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#35 0x00007f1c37ef4586 in QCoreApplication::exec() () from /usr/lib64/libQt5Core.so.5
#36 0x00007f1c39ac8773 in kdemain () from /usr/lib64/libkdeinit5_kwin_x11.so
#37 0x00007f1c3952f6a5 in __libc_start_main (main=0x4007d0 <main>, argc=3, argv=0x7ffdf1942478, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffdf1942468) at libc-start.c:289
#38 0x0000000000400809 in _start ()

Possible duplicates by query: bug 362635, bug 362567, bug 362228, bug 360548, bug 355457.

Reported using DrKonqi