Application: systemsettings5 (5.2.2)

Qt Version: 5.4.1
Operating System: Linux 3.19.0-28-generic x86_64
Distribution: Ubuntu 15.04

-- Information about the crash:
Attempted to use system settings to change dual monitor setting and lost the second monitor on system settings.  Both monitors display the same desktop but only one shows up in system settings so cannot separate them.

The crash can be reproduced every time.

-- 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 0x7f90bbae0780 (LWP 6330))]

Thread 4 (Thread 0x7f90ab258700 (LWP 6331)):
#0  0x00007f90b82438dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f90b655db72 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f90b655f64f in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f90ad7a3099 in QXcbEventReader::run (this=0x1503780) at qxcbconnection.cpp:1105
#4  0x00007f90b88c4b0e in QThreadPrivate::start (arg=0x1503780) at thread/qthread_unix.cpp:337
#5  0x00007f90b54776aa in start_thread (arg=0x7f90ab258700) at pthread_create.c:333
#6  0x00007f90b824eeed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7f90896fc700 (LWP 6357)):
#0  0x00007f90b823f49d in read () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f90b4f9c2f0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f90b4f5896c in g_main_context_check () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f90b4f58e60 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f90b4f59242 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f90934f5af6 in ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
#6  0x00007f90b4f7f955 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#7  0x00007f90b54776aa in start_thread (arg=0x7f90896fc700) at pthread_create.c:333
#8  0x00007f90b824eeed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f908669e700 (LWP 6372)):
#0  0x00007f90b88bce0f in testAndSetRelaxed<QMutexData*> (currentValue=<synthetic pointer>, newValue=0x0, expectedValue=0x1, _q_value=@0x40038c8: 0x0) at ../../include/QtCore/../../src/corelib/arch/qatomic_x86.h:259
#1  testAndSetRelease<QMutexData*, QMutexData*> (currentValue=<synthetic pointer>, newValue=0x0, expectedValue=0x1, _q_value=@0x40038c8: 0x0) at ../../include/QtCore/../../src/corelib/thread/qgenericatomic.h:175
#2  testAndSetRelease (currentValue=<synthetic pointer>, newValue=0x0, expectedValue=0x1, this=this@entry=0x40038c8) at ../../include/QtCore/../../src/corelib/thread/qbasicatomic.h:272
#3  fastTryUnlock (current=<synthetic pointer>, this=this@entry=0x40038c8) at thread/qmutex.h:85
#4  QMutex::unlock (this=this@entry=0x40038c8) at thread/qmutex.cpp:264
#5  0x00007f90b8b5b1ed in unlock (this=<synthetic pointer>) at ../../include/QtCore/../../src/corelib/thread/qmutex.h:138
#6  ~QMutexLocker (this=<synthetic pointer>, __in_chrg=<optimized out>) at ../../include/QtCore/../../src/corelib/thread/qmutex.h:132
#7  canWaitLocked (this=0x40038a0) at ../../include/QtCore/5.4.1/QtCore/private/../../../../../src/corelib/thread/qthread_p.h:244
#8  postEventSourcePrepare (s=0x7f90781b8550, timeout=0x7f908669dc54) at kernel/qeventdispatcher_glib.cpp:254
#9  0x00007f90b4f583fd in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#10 0x00007f90b4f58de8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#11 0x00007f90b4f58fcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#12 0x00007f90b8b5bc6c in QEventDispatcherGlib::processEvents (this=0x7f90782039a0, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#13 0x00007f90b8b003e2 in QEventLoop::exec (this=this@entry=0x7f908669de20, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#14 0x00007f90b88bfb44 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:503
#15 0x00007f90b788af65 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#16 0x00007f90b88c4b0e in QThreadPrivate::start (arg=0x2f56ea0) at thread/qthread_unix.cpp:337
#17 0x00007f90b54776aa in start_thread (arg=0x7f908669e700) at pthread_create.c:333
#18 0x00007f90b824eeed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f90bbae0780 (LWP 6330)):
[KCrash Handler]
#6  0x00007f9088027df4 in isEmpty (this=0x4005d) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qstring.h:791
#7  KScreen::ConfigOperation::hasError (this=this@entry=0x397ecd0) at ../../src/configoperation.cpp:76
#8  0x00007f9088028026 in KScreen::ConfigOperation::exec (this=0x397ecd0) at ../../src/configoperation.cpp:109
#9  0x00007f908825b33c in KCMKScreen::save (this=0x397ecd0) at ../../../kcm/src/kcm_kscreen.cpp:144
#10 0x00007f90bb657077 in KCModuleProxy::save (this=<optimized out>) at ../../src/kcmoduleproxy.cpp:272
#11 0x00007f90bb887c13 in ModuleView::moduleSave (this=<optimized out>, module=<optimized out>) at ../../core/ModuleView.cpp:295
#12 0x00007f90bb88892e in ModuleView::moduleSave (this=<optimized out>) at ../../core/ModuleView.cpp:286
#13 0x00007f90bb88b585 in ModuleView::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=0x7ffc85ed8a20) at moc_ModuleView.cpp:120
#14 0x00007f90b8b339c9 in QMetaObject::activate (sender=sender@entry=0x17d9830, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=2, argv=argv@entry=0x7ffc85ed8a20) at kernel/qobject.cpp:3716
#15 0x00007f90b8b34057 in QMetaObject::activate (sender=sender@entry=0x17d9830, m=m@entry=0x7f90b9e28a60 <QAbstractButton::staticMetaObject>, local_signal_index=local_signal_index@entry=2, argv=argv@entry=0x7ffc85ed8a20) at kernel/qobject.cpp:3582
#16 0x00007f90b9c9d012 in QAbstractButton::clicked (this=this@entry=0x17d9830, _t1=false) at .moc/moc_qabstractbutton.cpp:298
#17 0x00007f90b99ea675 in QAbstractButtonPrivate::emitClicked (this=0x17d9870) at widgets/qabstractbutton.cpp:534
#18 0x00007f90b99eb299 in QAbstractButtonPrivate::click (this=0x17d9870) at widgets/qabstractbutton.cpp:527
#19 0x00007f90b99eb454 in QAbstractButton::mouseReleaseEvent (this=0x17d9830, e=0x7ffc85ed8ee0) at widgets/qabstractbutton.cpp:1132
#20 0x00007f90b99321e8 in QWidget::event (this=0x17d9830, event=0x7ffc85ed8ee0) at kernel/qwidget.cpp:9022
#21 0x00007f90b98eeb2c in QApplicationPrivate::notify_helper (this=0x14ecb10, receiver=0x17d9830, e=0x7ffc85ed8ee0) at kernel/qapplication.cpp:3720
#22 0x00007f90b98f48eb in QApplication::notify (this=0x7ffc85ed8c20, receiver=0x7ffc85ed8c40, e=0x7ffc85ed8ee0) at kernel/qapplication.cpp:3280
#23 0x00007f90b8b02c2b in QCoreApplication::notifyInternal (this=0x7ffc85ed97b0, receiver=receiver@entry=0x17d9830, event=event@entry=0x7ffc85ed8ee0) at kernel/qcoreapplication.cpp:935
#24 0x00007f90b98f33da in sendSpontaneousEvent (event=0x7ffc85ed8ee0, receiver=0x17d9830) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#25 QApplicationPrivate::sendMouseEvent (receiver=0x17d9830, event=0x7ffc85ed8ee0, alienWidget=0x17d9830, nativeWidget=0x17d8a60, buttonDown=<optimized out>, lastMouseReceiver=..., spontaneous=true) at kernel/qapplication.cpp:2751
#26 0x00007f90b994acc0 in QWidgetWindow::handleMouseEvent (this=0x1aed8c0, event=0x7ffc85ed92f0) at kernel/qwidgetwindow.cpp:543
#27 0x00007f90b994ce33 in QWidgetWindow::event (this=0x1aed8c0, event=0x7ffc85ed92f0) at kernel/qwidgetwindow.cpp:210
#28 0x00007f90b98eeb2c in QApplicationPrivate::notify_helper (this=0x14ecb10, receiver=0x1aed8c0, e=0x7ffc85ed92f0) at kernel/qapplication.cpp:3720
#29 0x00007f90b98f4000 in QApplication::notify (this=0x7ffc85ed97b0, receiver=0x1aed8c0, e=0x7ffc85ed92f0) at kernel/qapplication.cpp:3503
#30 0x00007f90b8b02c2b in QCoreApplication::notifyInternal (this=0x7ffc85ed97b0, receiver=0x1aed8c0, event=0x7ffc85ed92f0) at kernel/qcoreapplication.cpp:935
#31 0x00007f90b9331f82 in sendSpontaneousEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#32 QGuiApplicationPrivate::processMouseEvent (e=0x3980640) at kernel/qguiapplication.cpp:1774
#33 0x00007f90b9333b45 in QGuiApplicationPrivate::processWindowSystemEvent (e=e@entry=0x3980640) at kernel/qguiapplication.cpp:1576
#34 0x00007f90b931834f in QWindowSystemInterface::sendWindowSystemEvents (flags=...) at kernel/qwindowsysteminterface.cpp:572
#35 0x00007f90ad7cd590 in userEventSourceDispatch (source=<optimized out>) at eventdispatchers/qeventdispatcher_glib.cpp:70
#36 0x00007f90b4f58c3d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#37 0x00007f90b4f58f20 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#38 0x00007f90b4f58fcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#39 0x00007f90b8b5bc57 in QEventDispatcherGlib::processEvents (this=0x1529120, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#40 0x00007f90b8b003e2 in QEventLoop::exec (this=this@entry=0x7ffc85ed9690, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#41 0x00007f90b8b0802c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1188
#42 0x00007f90b932931c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1510
#43 0x00007f90b98ea7a5 in QApplication::exec () at kernel/qapplication.cpp:2956
#44 0x000000000040eebc in main (argc=1, argv=<optimized out>) at ../../app/main.cpp:54

Reported using DrKonqi