Application: systemsettings5 (5.2.2)

Qt Version: 5.4.1
Operating System: Linux 3.19.0-22-generic x86_64
Distribution: Ubuntu 15.04

-- Information about the crash:
- install kubuntu 15.04
- update and upgrade packages
- install fgrlx-updates driver from driver manager
- reboot
* after reboot effects were broken
- go to system settings -> display settings -> compositor
- change EGL to GLX (OpenGL interface)
* rendering backend is OpenGL 3.1
* vsync is "Automatic"
* additional options are turned off

The crash can be reproduced sometimes.

-- Backtrace:
Application: System Settings (systemsettings5), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f94b0b9f780 (LWP 1756))]

Thread 3 (Thread 0x7f94a1187700 (LWP 1758)):
#0  0x00007f94ad2b38dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f94ab5a9b72 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f94ab5ab64f in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f94a3f63099 in QXcbEventReader::run (this=0x2014880) at qxcbconnection.cpp:1105
#4  0x00007f94ad93bb0e in QThreadPrivate::start (arg=0x2014880) at thread/qthread_unix.cpp:337
#5  0x00007f94aa4a76aa in start_thread (arg=0x7f94a1187700) at pthread_create.c:333
#6  0x00007f94ad2beeed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f948e724700 (LWP 1908)):
#0  0x00007f94ad2b50b7 in ioctl () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f9492b37919 in uki_firegl_MicroSleep () from /usr/lib/libatiuki.so.1
#2  0x00007f9494a6c920 in ?? () from /usr/lib/dri/fglrx_dri.so
#3  0x00007f94941fdd72 in ?? () from /usr/lib/dri/fglrx_dri.so
#4  0x00007f94941fddc5 in ?? () from /usr/lib/dri/fglrx_dri.so
#5  0x00007f94aa4a76aa in start_thread (arg=0x7f948e724700) at pthread_create.c:333
#6  0x00007f94ad2beeed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f94b0b9f780 (LWP 1756)):
[KCrash Handler]
#6  0x00007f94ac3bcde0 in QQuickWindow::maybeUpdate() () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#7  0x00007f94ac3a8e28 in QQuickItemPrivate::dirty(QQuickItemPrivate::DirtyType) () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#8  0x00007f94ac3b3045 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#9  0x00007f94adbab73a in QObject::event (this=0x31cf6c0, e=<optimized out>) at kernel/qobject.cpp:1245
#10 0x00007f94ac3b1b6b in QQuickItem::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#11 0x00007f94ae973b2c in QApplicationPrivate::notify_helper (this=0x1ffae70, receiver=0x31cf6c0, e=0x7f947820aa40) at kernel/qapplication.cpp:3720
#12 0x00007f94ae979000 in QApplication::notify (this=0x7ffd88cf46e0, receiver=0x31cf6c0, e=0x7f947820aa40) at kernel/qapplication.cpp:3503
#13 0x00007f94adb79c2b in QCoreApplication::notifyInternal (this=0x7ffd88cf46e0, receiver=0x31cf6c0, event=event@entry=0x7f947820aa40) at kernel/qcoreapplication.cpp:935
#14 0x00007f94adb7bc9b in sendEvent (event=0x7f947820aa40, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:228
#15 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x1ffa0c0) at kernel/qcoreapplication.cpp:1552
#16 0x00007f94adb7c298 in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1410
#17 0x00007f94adbd2843 in postEventSourceDispatch (s=0x2043e90) at kernel/qeventdispatcher_glib.cpp:271
#18 0x00007f94a9f81c3d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#19 0x00007f94a9f81f20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#20 0x00007f94a9f81fcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007f94adbd2c57 in QEventDispatcherGlib::processEvents (this=0x203b8e0, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#22 0x00007f94adb773e2 in QEventLoop::exec (this=this@entry=0x7ffd88cf45c0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#23 0x00007f94adb7f02c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1188
#24 0x00007f94ae3ab31c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1510
#25 0x00007f94ae96f7a5 in QApplication::exec () at kernel/qapplication.cpp:2956
#26 0x000000000040eebc in main (argc=1, argv=<optimized out>) at ../../app/main.cpp:54

Reported using DrKonqi