Application: kcmshell5 (5.2.1)

Qt Version: 5.4.1
Operating System: Linux 3.19.0-9-generic x86_64
Distribution: Ubuntu Vivid Vervet (development branch)

-- Information about the crash:
- What I was doing when the application crashed:
Checking keyboard settings - layout got changed by itself... was using Slovenian (SI) layout and after restart, keyboard changed to US layout (even my only keyboard was SI), applying SI layout does not help, I add US as well... can not change back to SI... 
system settings just crashed...

- Unusual behavior I noticed:

System settings are crashing like a LOT!!! 
Plasma sometimes crash and can not load GUI
Plasma crash when I woke up laptop (HP EliteBook 8570p - fullHD, radeon) from docking station...
Plasma sometimes change working area on desktop (only part of resolution is usable) ...

Really unstable...!
In 2 days of usage like 20 crashes...
First I was upgrading from 14.04 ... - was not stable at all...
Than I tryed clean Install to 15.04... same situation...
I was hoping on some more stability over 14.04 / 14.10 ... but It does not look any better at  all...
I really hope Kubuntu would be useful (stable) in near future.

Best regards,
Sebastjan

The crash can be reproduced sometimes.

-- Backtrace:
Application: KDE Control Module (kcmshell5), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f00fb7df800 (LWP 16262))]

Thread 3 (Thread 0x7f00e855b700 (LWP 16263)):
#0  0x00007f00fb2bd8dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f00f43dbb72 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f00f43dd64f in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f00ea47f049 in QXcbEventReader::run (this=0x1b6e970) at qxcbconnection.cpp:1105
#4  0x00007f00f9346b0e in QThreadPrivate::start (arg=0x1b6e970) at thread/qthread_unix.cpp:337
#5  0x00007f00f8d7d6aa in start_thread (arg=0x7f00e855b700) at pthread_create.c:333
#6  0x00007f00fb2c8eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f00dd7e2700 (LWP 16268)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f00de212d7b in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#2  0x00007f00de212507 in ?? () from /usr/lib/x86_64-linux-gnu/dri/r600_dri.so
#3  0x00007f00f8d7d6aa in start_thread (arg=0x7f00dd7e2700) at pthread_create.c:333
#4  0x00007f00fb2c8eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f00fb7df800 (LWP 16262)):
[KCrash Handler]
#6  0x00007f00e66dff68 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/kcm_keyboard.so
#7  0x00007f00e673b1ed in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/kcm_keyboard.so
#8  0x00007f00f95b5999 in QMetaObject::activate (sender=sender@entry=0x1d26860, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=2, argv=argv@entry=0x7ffc81b26c50) at kernel/qobject.cpp:3716
#9  0x00007f00f95b6027 in QMetaObject::activate (sender=sender@entry=0x1d26860, m=m@entry=0x7f00f9e7ba60 <QAbstractButton::staticMetaObject>, local_signal_index=local_signal_index@entry=2, argv=argv@entry=0x7ffc81b26c50) at kernel/qobject.cpp:3582
#10 0x00007f00f9cf0012 in QAbstractButton::clicked (this=this@entry=0x1d26860, _t1=false) at .moc/moc_qabstractbutton.cpp:298
#11 0x00007f00f9a3d675 in QAbstractButtonPrivate::emitClicked (this=0x1cd9460) at widgets/qabstractbutton.cpp:534
#12 0x00007f00f9a3e299 in QAbstractButtonPrivate::click (this=0x1cd9460) at widgets/qabstractbutton.cpp:527
#13 0x00007f00f9a3e454 in QAbstractButton::mouseReleaseEvent (this=0x1d26860, e=0x7ffc81b27110) at widgets/qabstractbutton.cpp:1132
#14 0x00007f00f99851e8 in QWidget::event (this=0x1d26860, event=0x7ffc81b27110) at kernel/qwidget.cpp:9022
#15 0x00007f00f9941b2c in QApplicationPrivate::notify_helper (this=0x1b539d0, receiver=0x1d26860, e=0x7ffc81b27110) at kernel/qapplication.cpp:3720
#16 0x00007f00f99478eb in QApplication::notify (this=0x7ffc81b26e50, receiver=0x7ffc81b26e70, e=0x7ffc81b27110) at kernel/qapplication.cpp:3280
#17 0x00007f00f9584bfb in QCoreApplication::notifyInternal (this=0x7ffc81b27a40, receiver=receiver@entry=0x1d26860, event=event@entry=0x7ffc81b27110) at kernel/qcoreapplication.cpp:935
#18 0x00007f00f99463da in sendSpontaneousEvent (event=0x7ffc81b27110, receiver=0x1d26860) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#19 QApplicationPrivate::sendMouseEvent (receiver=0x1d26860, event=0x7ffc81b27110, alienWidget=0x1d26860, nativeWidget=0x1c33f70, buttonDown=<optimized out>, lastMouseReceiver=..., spontaneous=true) at kernel/qapplication.cpp:2751
#20 0x00007f00f999dcc0 in QWidgetWindow::handleMouseEvent (this=0x1da4ba0, event=0x7ffc81b27520) at kernel/qwidgetwindow.cpp:543
#21 0x00007f00f999fe33 in QWidgetWindow::event (this=0x1da4ba0, event=0x7ffc81b27520) at kernel/qwidgetwindow.cpp:210
#22 0x00007f00f9941b2c in QApplicationPrivate::notify_helper (this=0x1b539d0, receiver=0x1da4ba0, e=0x7ffc81b27520) at kernel/qapplication.cpp:3720
#23 0x00007f00f9947000 in QApplication::notify (this=0x7ffc81b27a40, receiver=0x1da4ba0, e=0x7ffc81b27520) at kernel/qapplication.cpp:3503
#24 0x00007f00f9584bfb in QCoreApplication::notifyInternal (this=0x7ffc81b27a40, receiver=0x1da4ba0, event=0x7ffc81b27520) at kernel/qcoreapplication.cpp:935
#25 0x00007f00f788ff82 in sendSpontaneousEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#26 QGuiApplicationPrivate::processMouseEvent (e=0x1f7c560) at kernel/qguiapplication.cpp:1774
#27 0x00007f00f7891b45 in QGuiApplicationPrivate::processWindowSystemEvent (e=e@entry=0x1f7c560) at kernel/qguiapplication.cpp:1576
#28 0x00007f00f787634f in QWindowSystemInterface::sendWindowSystemEvents (flags=...) at kernel/qwindowsysteminterface.cpp:572
#29 0x00007f00ea4a94f0 in userEventSourceDispatch (source=<optimized out>) at eventdispatchers/qeventdispatcher_glib.cpp:70
#30 0x00007f00f3cb7c3d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#31 0x00007f00f3cb7f20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#32 0x00007f00f3cb7fcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#33 0x00007f00f95ddbe7 in QEventDispatcherGlib::processEvents (this=0x1ba7c50, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#34 0x00007f00f95823b2 in QEventLoop::exec (this=this@entry=0x7ffc81b278d0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#35 0x00007f00f9b434b5 in QDialog::exec (this=0x1c33f70) at dialogs/qdialog.cpp:541
#36 0x00007f00fb5949cb in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_kcmshell5.so
#37 0x00007f00fb1e2a40 in __libc_start_main (main=0x400730 <main>, argc=2, argv=0x7ffc81b27b88, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffc81b27b78) at libc-start.c:289
#38 0x000000000040075e in _start ()

Reported using DrKonqi