Application: kwin_x11 (5.2.2)

Qt Version: 5.4.1
Operating System: Linux 3.19.0-15-generic x86_64
Distribution: Ubuntu 15.04

-- Information about the crash:
- What I was doing when the application crashed:
I have 4 monitors on 2 Nvidia graphics cards and two XScreens. If I enable Xinerama and reboot the login page shows up, but when I log in KWin crashes.

- Unusual behavior I noticed:
After the login button is pressed the login graphics are displayed on only XScreen 0, once the progrss bars get to what is seemingly 100% KWin crashes.
- Custom settings of the application:
4 monitors, 2 XScreens, Xinerama 1 in xorg.conf

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[KCrash Handler]
#6  0x00007f7dea0cb000 in xcb_setup_vendor_end () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#7  0x00007f7dea0cb059 in xcb_setup_pixmap_formats_iterator () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#8  0x00007f7dea0cb099 in xcb_setup_roots_iterator () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#9  0x00007f7deb8eb0f8 in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#10 0x00007f7deb8f3371 in ?? () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#11 0x00007f7dec098aa6 in ?? () from /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so
#12 0x00007f7dea5ee35a in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007f7deb436a9b in KSelectionOwner::Private::claimSucceeded() () from /usr/lib/x86_64-linux-gnu/libKF5WindowSystem.so.5
#14 0x00007f7deb437221 in KSelectionOwner::filterEvent(void*) () from /usr/lib/x86_64-linux-gnu/libKF5WindowSystem.so.5
#15 0x00007f7dea5ba510 in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#16 0x00007f7dd546c02d in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#17 0x00007f7dd546d4bb in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#18 0x00007f7dea5ef73a in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#19 0x00007f7deaec7b2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#20 0x00007f7deaecd000 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#21 0x00007f7dea5bdc2b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007f7dea5bfc9b in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#23 0x00007f7dea614112 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#24 0x00007f7dd54c396d in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#25 0x00007f7dea5bb3e2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#26 0x00007f7dea5c302c in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#27 0x00007f7dec0998c3 in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so
#28 0x00007f7debceba40 in __libc_start_main (main=0x400790 <main>, argc=3, argv=0x7fffcb009498, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffcb009488) at libc-start.c:289
#29 0x00000000004007c9 in _start ()

Reported using DrKonqi