Application: kcmshell5 (5.2.2)

Qt Version: 5.4.1
Operating System: Linux 3.19.0-43-generic x86_64
Distribution: Ubuntu 15.04

-- Information about the crash:
- What I was doing when the application crashed:
Plugged int external monitor (1920x1080)
Opened "Display Configuraiton" window
Updated alignment of displays (display was already working), hit OK.
Screen flicker and KDE desktop crashed.

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 0x7f577155d800 (LWP 2091))]

Thread 3 (Thread 0x7f575cf52700 (LWP 2092)):
#0  0x00007f57710508dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f576973eb72 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f576974064f in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f575ee76099 in QXcbEventReader::run (this=0x114fda0) at qxcbconnection.cpp:1105
#4  0x00007f576f0d3b0e in QThreadPrivate::start (arg=0x114fda0) at thread/qthread_unix.cpp:337
#5  0x00007f576eb0a6aa in start_thread (arg=0x7f575cf52700) at pthread_create.c:333
#6  0x00007f577105beed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f5752066700 (LWP 2096)):
#0  0x00007f57710508dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f576901aebc in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f576901afcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f576f36ac6c in QEventDispatcherGlib::processEvents (this=0x7f57440008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#4  0x00007f576f30f3e2 in QEventLoop::exec (this=this@entry=0x7f5752065da0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#5  0x00007f576f0ceb44 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:503
#6  0x00007f576e514f65 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#7  0x00007f576f0d3b0e in QThreadPrivate::start (arg=0x139b490) at thread/qthread_unix.cpp:337
#8  0x00007f576eb0a6aa in start_thread (arg=0x7f5752066700) at pthread_create.c:333
#9  0x00007f577105beed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f577155d800 (LWP 2091)):
[KCrash Handler]
#6  0x00007f5756e59df4 in isEmpty (this=0x30) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qstring.h:791
#7  KScreen::ConfigOperation::hasError (this=this@entry=0x15c97d0) at ../../src/configoperation.cpp:76
#8  0x00007f5756e5a026 in KScreen::ConfigOperation::exec (this=0x15c97d0) at ../../src/configoperation.cpp:109
#9  0x00007f575708d33c in KCMKScreen::save (this=0x15c97d0) at ../../../kcm/src/kcm_kscreen.cpp:144
#10 0x00007f5770d34077 in KCModuleProxy::save (this=this@entry=0x12198f0) at ../../src/kcmoduleproxy.cpp:272
#11 0x00007f5770d312f0 in KCMultiDialogPrivate::apply (this=<optimized out>) at ../../src/kcmultidialog.cpp:323
#12 0x00007f5770d31695 in KCMultiDialog::qt_static_metacall (_o=0x15c97d0, _c=QMetaObject::ReadProperty, _id=1, _a=0x0) at ./moc_kcmultidialog.cpp:112
#13 0x00007f576f3429c9 in QMetaObject::activate (sender=sender@entry=0x121af70, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=2, argv=argv@entry=0x7ffc883e5c30) at kernel/qobject.cpp:3716
#14 0x00007f576f343057 in QMetaObject::activate (sender=sender@entry=0x121af70, m=m@entry=0x7f576fc08a60 <QAbstractButton::staticMetaObject>, local_signal_index=local_signal_index@entry=2, argv=argv@entry=0x7ffc883e5c30) at kernel/qobject.cpp:3582
#15 0x00007f576fa7d012 in QAbstractButton::clicked (this=this@entry=0x121af70, _t1=false) at .moc/moc_qabstractbutton.cpp:298
#16 0x00007f576f7ca675 in QAbstractButtonPrivate::emitClicked (this=0x121afb0) at widgets/qabstractbutton.cpp:534
#17 0x00007f576f7cb299 in QAbstractButtonPrivate::click (this=0x121afb0) at widgets/qabstractbutton.cpp:527
#18 0x00007f576f7cb454 in QAbstractButton::mouseReleaseEvent (this=0x121af70, e=0x7ffc883e60f0) at widgets/qabstractbutton.cpp:1132
#19 0x00007f576f7121e8 in QWidget::event (this=0x121af70, event=0x7ffc883e60f0) at kernel/qwidget.cpp:9022
#20 0x00007f576f6ceb2c in QApplicationPrivate::notify_helper (this=0x1139e70, receiver=0x121af70, e=0x7ffc883e60f0) at kernel/qapplication.cpp:3720
#21 0x00007f576f6d48eb in QApplication::notify (this=0x7ffc883e5e30, receiver=0x7ffc883e5e50, e=0x7ffc883e60f0) at kernel/qapplication.cpp:3280
#22 0x00007f576f311c2b in QCoreApplication::notifyInternal (this=0x7ffc883e6a20, receiver=receiver@entry=0x121af70, event=event@entry=0x7ffc883e60f0) at kernel/qcoreapplication.cpp:935
#23 0x00007f576f6d33da in sendSpontaneousEvent (event=0x7ffc883e60f0, receiver=0x121af70) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#24 QApplicationPrivate::sendMouseEvent (receiver=0x121af70, event=0x7ffc883e60f0, alienWidget=0x121af70, nativeWidget=0x1203f60, buttonDown=<optimized out>, lastMouseReceiver=..., spontaneous=true) at kernel/qapplication.cpp:2751
#25 0x00007f576f72acc0 in QWidgetWindow::handleMouseEvent (this=0x12909b0, event=0x7ffc883e6500) at kernel/qwidgetwindow.cpp:543
#26 0x00007f576f72ce33 in QWidgetWindow::event (this=0x12909b0, event=0x7ffc883e6500) at kernel/qwidgetwindow.cpp:210
#27 0x00007f576f6ceb2c in QApplicationPrivate::notify_helper (this=0x1139e70, receiver=0x12909b0, e=0x7ffc883e6500) at kernel/qapplication.cpp:3720
#28 0x00007f576f6d4000 in QApplication::notify (this=0x7ffc883e6a20, receiver=0x12909b0, e=0x7ffc883e6500) at kernel/qapplication.cpp:3503
#29 0x00007f576f311c2b in QCoreApplication::notifyInternal (this=0x7ffc883e6a20, receiver=0x12909b0, event=0x7ffc883e6500) at kernel/qcoreapplication.cpp:935
#30 0x00007f576cbf0f82 in sendSpontaneousEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#31 QGuiApplicationPrivate::processMouseEvent (e=0x2f5d770) at kernel/qguiapplication.cpp:1774
#32 0x00007f576cbf2b45 in QGuiApplicationPrivate::processWindowSystemEvent (e=e@entry=0x2f5d770) at kernel/qguiapplication.cpp:1576
#33 0x00007f576cbd734f in QWindowSystemInterface::sendWindowSystemEvents (flags=...) at kernel/qwindowsysteminterface.cpp:572
#34 0x00007f575eea0590 in userEventSourceDispatch (source=<optimized out>) at eventdispatchers/qeventdispatcher_glib.cpp:70
#35 0x00007f576901ac3d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#36 0x00007f576901af20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#37 0x00007f576901afcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#38 0x00007f576f36ac57 in QEventDispatcherGlib::processEvents (this=0x1175060, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#39 0x00007f576f30f3e2 in QEventLoop::exec (this=this@entry=0x7ffc883e68b0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#40 0x00007f576f8d04b5 in QDialog::exec (this=0x1203f60) at dialogs/qdialog.cpp:541
#41 0x00007f57713279cb in kdemain (_argc=<optimized out>, _argv=<optimized out>) at ../../kcmshell/main.cpp:307
#42 0x00007f5770f75a40 in __libc_start_main (main=0x400730 <main(int, char**)>, argc=2, argv=0x7ffc883e6b68, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffc883e6b58) at libc-start.c:289
#43 0x0000000000400769 in _start ()

Reported using DrKonqi