Application: kwin_x11 (5.3.1)

Qt Version: 5.4.1
Operating System: Linux 3.19.0-18-generic x86_64
Distribution: Ubuntu 15.04

-- Information about the crash:
- What I was doing when the application crashed:
Manualy changed from to external monitors to the internal laptop monitor. 

Disabled both extarnal monitor, enabled laptop monitor, and set this to default, before hitting Apply.

Screen flikered, before chrash dialog apeared. 

Have had a loth of problems with changing monitors after upgrade to Kubuntu 15.04. 

(Squize my english, not my mother thoung.)

The crash can be reproduced sometimes.

-- Backtrace:
Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fee976de800 (LWP 2699))]

Thread 5 (Thread 0x7fee73b9c700 (LWP 2721)):
#0  0x00007fee971b249d in read () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fee8e2812f0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fee8e23d96c in g_main_context_check () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fee8e23de60 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fee8e23e242 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fee7a4b1ae6 in ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
#6  0x00007fee8e264955 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#7  0x00007fee96a336aa in start_thread (arg=0x7fee73b9c700) at pthread_create.c:333
#8  0x00007fee971c1eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 4 (Thread 0x7fee7339b700 (LWP 2723)):
#0  0x00007fee971b68dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fee8e23debc in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fee8e23dfcc in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fee8e23e009 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fee8e264955 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fee96a336aa in start_thread (arg=0x7fee7339b700) at pthread_create.c:333
#6  0x00007fee971c1eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7fee710a3700 (LWP 2741)):
#0  0x00007fee971b8743 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fee957a6101 in qt_safe_select (nfds=23, fdread=fdread@entry=0x7fee60000a78, fdwrite=fdwrite@entry=0x7fee60000d08, fdexcept=fdexcept@entry=0x7fee60000f98, orig_timeout=orig_timeout@entry=0x0) at kernel/qcore_unix.cpp:75
#2  0x00007fee957a7cd2 in select (timeout=0x0, exceptfds=0x7fee60000f98, writefds=0x7fee60000d08, readfds=0x7fee60000a78, nfds=<optimized out>, this=0x7fee600008c0) at kernel/qeventdispatcher_unix.cpp:320
#3  QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7fee600008e0, flags=..., flags@entry=..., timeout=timeout@entry=0x0) at kernel/qeventdispatcher_unix.cpp:196
#4  0x00007fee957a8275 in QEventDispatcherUNIX::processEvents (this=0x7fee600008c0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#5  0x00007fee9574f3e2 in QEventLoop::exec (this=this@entry=0x7fee710a2da0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007fee9550eb44 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:503
#7  0x00007fee8f371f65 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007fee95513b0e in QThreadPrivate::start (arg=0x1e948b0) at thread/qthread_unix.cpp:337
#9  0x00007fee96a336aa in start_thread (arg=0x7fee710a3700) at pthread_create.c:333
#10 0x00007fee971c1eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7fee589a9700 (LWP 2755)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fee94317644 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007fee94317689 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007fee96a336aa in start_thread (arg=0x7fee589a9700) at pthread_create.c:333
#4  0x00007fee971c1eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7fee976de800 (LWP 2699)):
[KCrash Handler]
#6  QScreen::handle (this=0x0) at kernel/qscreen.cpp:85
#7  0x00007fee81551545 in QXcbWindow::QXcbWindow (this=0x3677830, window=0x1bb0330) at qxcbwindow.cpp:260
#8  0x00007fee8153e5c1 in QXcbIntegration::createPlatformWindow (this=<optimized out>, window=0x1bb0330) at qxcbintegration.cpp:194
#9  0x00007fee95aa3786 in QWindowPrivate::create (this=0x3035760, recursive=recursive@entry=false) at kernel/qwindow.cpp:395
#10 0x00007fee95aa397b in QWindow::create (this=this@entry=0x1bb0330) at kernel/qwindow.cpp:539
#11 0x00007fee95aa3b28 in QWindow::winId (this=0x1bb0330) at kernel/qwindow.cpp:558
#12 0x00007fedc9b0bb50 in PlasmaQuick::DialogPrivate::updateInputShape (this=0x2e0cbb0) at ../../../src/plasmaquick/dialog.cpp:542
#13 0x00007fee957829c9 in QMetaObject::activate (sender=sender@entry=0x1bb0330, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=12, argv=argv@entry=0x7ffcc330e040) at kernel/qobject.cpp:3716
#14 0x00007fee95783057 in QMetaObject::activate (sender=sender@entry=0x1bb0330, m=m@entry=0x7fee95eeab80 <QWindow::staticMetaObject>, local_signal_index=local_signal_index@entry=12, argv=argv@entry=0x7ffcc330e040) at kernel/qobject.cpp:3582
#15 0x00007fee95aa31c2 in QWindow::visibleChanged (this=this@entry=0x1bb0330, _t1=_t1@entry=true) at .moc/moc_qwindow.cpp:710
#16 0x00007fee95aa64b7 in QWindow::setVisible (this=this@entry=0x1bb0330, visible=visible@entry=true) at kernel/qwindow.cpp:471
#17 0x00007fedc9b0ba00 in PlasmaQuick::Dialog::setVisible (this=this@entry=0x1bb0330, visible=<optimized out>) at ../../../src/plasmaquick/dialog.cpp:1225
#18 0x00007fedc9b1005a in PlasmaQuick::Dialog::qt_metacall (this=0x1bb0330, _c=QMetaObject::WriteProperty, _id=9, _a=0x7ffcc330e1b0) at ./moc_dialog.cpp:376
#19 0x00007fee8f2e9b7f in QQmlPropertyPrivate::write(QObject*, QQmlPropertyData const&, QVariant const&, QQmlContextData*, QFlags<QQmlPropertyPrivate::WriteFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#20 0x00007fee8f2eb5fb in QQmlPropertyPrivate::writeValueProperty(QObject*, QQmlPropertyData const&, QVariant const&, QQmlContextData*, QFlags<QQmlPropertyPrivate::WriteFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#21 0x00007fee8f2ebd31 in QQmlPropertyPrivate::writeBinding(QObject*, QQmlPropertyData const&, QQmlContextData*, QQmlJavaScriptExpression*, QV4::ValueRef, bool, QFlags<QQmlPropertyPrivate::WriteFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#22 0x00007fee8f36051c in QQmlBinding::update(QFlags<QQmlPropertyPrivate::WriteFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#23 0x00007fee8f360c7e in QQmlBinding::expressionChanged(QQmlJavaScriptExpression*) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#24 0x00007fee8f33a497 in QQmlNotifier::emitNotify(QQmlNotifierEndpoint*, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#25 0x00007fee8f2d710c in QQmlData::signalEmitted(QAbstractDeclarativeData*, QObject*, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#26 0x00007fee95782141 in QMetaObject::activate (sender=0x2feea60, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3603
#27 0x00007fee95783057 in QMetaObject::activate (sender=<optimized out>, m=m@entry=0x7fee970b5220 <KWin::TabBox::SwitcherItem::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3582
#28 0x00007fee96e156a0 in KWin::TabBox::SwitcherItem::visibleChanged (this=<optimized out>) at moc_switcheritem.cpp:244
#29 0x00007fee96def16f in KWin::TabBox::SwitcherItem::setVisible (this=<optimized out>, visible=visible@entry=true) at ../tabbox/switcheritem.cpp:75
#30 0x00007fee96df2e61 in KWin::TabBox::TabBoxHandlerPrivate::show (this=<optimized out>) at ../tabbox/tabboxhandler.cpp:340
#31 0x00007fee96df3039 in KWin::TabBox::TabBoxHandler::show (this=0x1d69d30) at ../tabbox/tabboxhandler.cpp:378
#32 0x00007fee96de4076 in KWin::TabBox::TabBox::show (this=<optimized out>) at ../tabbox/tabbox.cpp:736
#33 0x00007fee96e17295 in KWin::TabBox::TabBox::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at moc_tabbox.cpp:174
#34 0x00007fee957829c9 in QMetaObject::activate (sender=sender@entry=0x1d87b98, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3716
#35 0x00007fee95783057 in QMetaObject::activate (sender=sender@entry=0x1d87b98, m=m@entry=0x7fee959ac580 <QTimer::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3582
#36 0x00007fee95802610 in QTimer::timeout (this=this@entry=0x1d87b98) at .moc/moc_qtimer.cpp:192
#37 0x00007fee95790918 in QTimer::timerEvent (this=0x1d87b98, e=<optimized out>) at kernel/qtimer.cpp:247
#38 0x00007fee957836f3 in QObject::event (this=0x1d87b98, e=<optimized out>) at kernel/qobject.cpp:1267
#39 0x00007fee9605bb2c in QApplicationPrivate::notify_helper (this=0x1b42450, receiver=0x1d87b98, e=0x7ffcc330ebc0) at kernel/qapplication.cpp:3720
#40 0x00007fee96061000 in QApplication::notify (this=0x7ffcc330ee00, receiver=0x1d87b98, e=0x7ffcc330ebc0) at kernel/qapplication.cpp:3503
#41 0x00007fee95751c2b in QCoreApplication::notifyInternal (this=0x7ffcc330ee00, receiver=0x1d87b98, event=event@entry=0x7ffcc330ebc0) at kernel/qcoreapplication.cpp:935
#42 0x00007fee957a9ae5 in sendEvent (event=0x7ffcc330ebc0, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:228
#43 QTimerInfoList::activateTimers (this=0x1bde9c8) at kernel/qtimerinfo_unix.cpp:635
#44 0x00007fee957a76a0 in QEventDispatcherUNIX::activateTimers (this=this@entry=0x1bde120) at kernel/qeventdispatcher_unix.cpp:549
#45 0x00007fee957a8243 in QEventDispatcherUNIX::processEvents (this=0x1bde120, flags=flags@entry=...) at kernel/qeventdispatcher_unix.cpp:611
#46 0x00007fee8159396d in QUnixEventDispatcherQPA::processEvents (this=<optimized out>, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#47 0x00007fee9574f3e2 in QEventLoop::exec (this=this@entry=0x7ffcc330ed20, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#48 0x00007fee9575702c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1188
#49 0x00007fee95a9631c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1510
#50 0x00007fee960577a5 in QApplication::exec () at kernel/qapplication.cpp:2956
#51 0x00007fee9748a320 in kdemain (argc=1, argv=0x7ffcc330ef68) at ../main_x11.cpp:300
#52 0x00007fee970dba40 in __libc_start_main (main=0x4007a0 <main(int, char**)>, argc=1, argv=0x7ffcc330ef68, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffcc330ef58) at libc-start.c:289
#53 0x00000000004007d9 in _start ()

Reported using DrKonqi