Application: kwin_x11 (5.3.1)

Qt Version: 5.4.2
Operating System: Linux 4.0.4-303.fc22.x86_64 x86_64
Distribution: "Fedora release 22 (Twenty Two)"

-- Information about the crash:
After switching a new Fedora 22 installation to use the nvidia driver and configuring the monitors in a 2x2 configuration, KDE fails to initialize and prompts to fall back to an alternate window manager.

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[KCrash Handler]
#5  0x00007f20afc91860 in xcb_setup_vendor_end () from /lib64/libxcb.so.1
#6  0x00007f20afc918b9 in xcb_setup_pixmap_formats_iterator () from /lib64/libxcb.so.1
#7  0x00007f20afc918f9 in xcb_setup_roots_iterator () from /lib64/libxcb.so.1
#8  0x00007f20b1752587 in NETRootInfo::NETRootInfo(xcb_connection_t*, unsigned int, char const*, QFlags<NET::Property>, QFlags<NET::WindowTypeMask>, QFlags<NET::State>, QFlags<NET::Property2>, QFlags<NET::Action>, int, bool) () from /lib64/libKF5WindowSystem.so.5
#9  0x00007f20b9658301 in KWin::RootInfo::create() () from /lib64/libkwin.so.5
#10 0x00007f20b962d68c in KWin::Workspace::init() () from /lib64/libkwin.so.5
#11 0x00007f20b962ee0b in KWin::Workspace::Workspace(QString const&) () from /lib64/libkwin.so.5
#12 0x00007f20b96697f0 in KWin::Application::createWorkspace() () from /lib64/libkwin.so.5
#13 0x00007f20b9a5e2ac in QtPrivate::QFunctorSlotObject<KWin::ApplicationX11::performStartup()::{lambda()#2}, 0, QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase*, QObject*, void**, bool*) () from /lib64/libkdeinit5_kwin_x11.so
#14 0x00007f20b0154f07 in QMetaObject::activate(QObject*, int, int, void**) () from /lib64/libQt5Core.so.5
#15 0x00007f20b17360bb in KSelectionOwner::Private::claimSucceeded() () from /lib64/libKF5WindowSystem.so.5
#16 0x00007f20b1736901 in KSelectionOwner::filterEvent(void*) () from /lib64/libKF5WindowSystem.so.5
#17 0x00007f20b012104f in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*) () from /lib64/libQt5Core.so.5
#18 0x00007f20974dd12e in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) () from /usr/lib64/qt5/plugins/platforms/libqxcb.so
#19 0x00007f20974de183 in QXcbConnection::processXcbEvents() () from /usr/lib64/qt5/plugins/platforms/libqxcb.so
#20 0x00007f20b0155f41 in QObject::event(QEvent*) () from /lib64/libQt5Core.so.5
#21 0x00007f20b0de677c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5
#22 0x00007f20b0debe20 in QApplication::notify(QObject*, QEvent*) () from /lib64/libQt5Widgets.so.5
#23 0x00007f20b012467b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /lib64/libQt5Core.so.5
#24 0x00007f20b01267b7 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /lib64/libQt5Core.so.5
#25 0x00007f20b01790f2 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#26 0x00007f20975321ed in QUnixEventDispatcherQPA::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/qt5/plugins/platforms/libqxcb.so
#27 0x00007f20b0121eba in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQt5Core.so.5
#28 0x00007f20b0129a2c in QCoreApplication::exec() () from /lib64/libQt5Core.so.5
#29 0x00007f20b9a5fb07 in kdemain () from /lib64/libkdeinit5_kwin_x11.so
#30 0x00007f20aeb5a790 in __libc_start_main () from /lib64/libc.so.6
#31 0x0000000000400c89 in _start ()

Reported using DrKonqi