Application: kwin_x11 (5.3.1)

Qt Version: 5.4.1
Operating System: Linux 3.19.0-20-generic x86_64
Distribution: Ubuntu 15.04

-- Information about the crash:
- What I was doing when the application crashed:
I have plugged in HDMI cable (additional monitor). Also same issue appear if I unplug HDMI cable. 
My additional monitor is simle DELL monitor used as second monitor (extended desktop)

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 0x7fe2959e9800 (LWP 14902))]

Thread 4 (Thread 0x7fe27eb8c700 (LWP 14903)):
#0  0x00007fe2954b98dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fe29355db72 in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007fe29355f64f in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007fe27f83f099 in QXcbEventReader::run (this=0x25dec00) at qxcbconnection.cpp:1105
#4  0x00007fe293816b0e in QThreadPrivate::start (arg=0x25dec00) at thread/qthread_unix.cpp:337
#5  0x00007fe294d366aa in start_thread (arg=0x7fe27eb8c700) at pthread_create.c:333
#6  0x00007fe2954c4eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7fe2775bb700 (LWP 14921)):
#0  0x00007fe2954bb743 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fe293aa9101 in qt_safe_select (nfds=15, fdread=fdread@entry=0x7fe268000a78, fdwrite=fdwrite@entry=0x7fe268000d08, fdexcept=fdexcept@entry=0x7fe268000f98, orig_timeout=orig_timeout@entry=0x0) at kernel/qcore_unix.cpp:75
#2  0x00007fe293aaacd2 in select (timeout=0x0, exceptfds=0x7fe268000f98, writefds=0x7fe268000d08, readfds=0x7fe268000a78, nfds=<optimized out>, this=0x7fe2680008c0) at kernel/qeventdispatcher_unix.cpp:320
#3  QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7fe2680008e0, flags=..., flags@entry=..., timeout=timeout@entry=0x0) at kernel/qeventdispatcher_unix.cpp:196
#4  0x00007fe293aab275 in QEventDispatcherUNIX::processEvents (this=0x7fe2680008c0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#5  0x00007fe293a523e2 in QEventLoop::exec (this=this@entry=0x7fe2775bada0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007fe293811b44 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:503
#7  0x00007fe28d674f65 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007fe293816b0e in QThreadPrivate::start (arg=0x27eaa50) at thread/qthread_unix.cpp:337
#9  0x00007fe294d366aa in start_thread (arg=0x7fe2775bb700) at pthread_create.c:333
#10 0x00007fe2954c4eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7fe26f7fe700 (LWP 14940)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fe29261a644 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007fe29261a689 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007fe294d366aa in start_thread (arg=0x7fe26f7fe700) at pthread_create.c:333
#4  0x00007fe2954c4eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7fe2959e9800 (LWP 14902)):
[KCrash Handler]
#6  QScreen::handle (this=0x0) at kernel/qscreen.cpp:85
#7  0x00007fe27f853545 in QXcbWindow::QXcbWindow (this=0x30b8520, window=0x31edbf0) at qxcbwindow.cpp:260
#8  0x00007fe27f8405c1 in QXcbIntegration::createPlatformWindow (this=<optimized out>, window=0x31edbf0) at qxcbintegration.cpp:194
#9  0x00007fe293da6786 in QWindowPrivate::create (this=0x306f9e0, recursive=recursive@entry=false) at kernel/qwindow.cpp:395
#10 0x00007fe293da697b in QWindow::create (this=this@entry=0x31edbf0) at kernel/qwindow.cpp:539
#11 0x00007fe293da6b28 in QWindow::winId (this=0x31edbf0) at kernel/qwindow.cpp:558
#12 0x00007fe2950879cf in KWin::AbstractThumbnailItem::findParentEffectWindow (this=0x3340760) at ../thumbnailitem.cpp:79
#13 0x00007fe295087b99 in KWin::AbstractThumbnailItem::effectWindowAdded (this=0x3340760) at ../thumbnailitem.cpp:90
#14 0x00007fe29511dfb5 in KWin::AbstractThumbnailItem::qt_static_metacall (_o=0x0, _c=QMetaObject::ResetProperty, _id=55922096, _a=0x7fe295782c00 <main_arena>) at moc_thumbnailitem.cpp:130
#15 0x00007fe293a859c9 in QMetaObject::activate (sender=0x2dc62c0, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=6, argv=argv@entry=0x7fffa5a6a5f0) at kernel/qobject.cpp:3716
#16 0x00007fe293a86057 in QMetaObject::activate (sender=<optimized out>, m=m@entry=0x7fe293243ac0 <KWin::EffectsHandler::staticMetaObject>, local_signal_index=local_signal_index@entry=6, argv=argv@entry=0x7fffa5a6a5f0) at kernel/qobject.cpp:3582
#17 0x00007fe293035242 in KWin::EffectsHandler::windowAdded (this=<optimized out>, _t1=0x3028550) at moc_kwineffects.cpp:1236
#18 0x00007fe293a8535a in call (a=0x7fffa5a6a730, r=0x2dc62c0, this=0x2ef6160) at ../../include/QtCore/../../src/corelib/kernel/qobject_impl.h:124
#19 QMetaObject::activate (sender=sender@entry=0x2ebb4a0, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=7, argv=argv@entry=0x7fffa5a6a730) at kernel/qobject.cpp:3702
#20 0x00007fe293a86057 in QMetaObject::activate (sender=sender@entry=0x2ebb4a0, m=m@entry=0x7fe2953b8120 <KWin::Toplevel::staticMetaObject>, local_signal_index=local_signal_index@entry=7, argv=argv@entry=0x7fffa5a6a730) at kernel/qobject.cpp:3582
#21 0x00007fe295118f12 in KWin::Toplevel::windowShown (this=this@entry=0x2ebb4a0, _t1=_t1@entry=0x2ebb4a0) at moc_toplevel.cpp:672
#22 0x00007fe29504f13f in KWin::Toplevel::setReadyForPainting (this=0x2ebb4a0) at ../toplevel.cpp:259
#23 0x00007fe29511f615 in KWin::Toplevel::qt_static_metacall (_o=0x0, _c=QMetaObject::ResetProperty, _id=55922096, _a=0x7fe295782c00 <main_arena>) at moc_toplevel.cpp:336
#24 0x00007fe293a859c9 in QMetaObject::activate (sender=sender@entry=0x35b7b90, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3716
#25 0x00007fe293a86057 in QMetaObject::activate (sender=sender@entry=0x35b7b90, m=m@entry=0x7fe293cac080 <QSingleShotTimer::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3582
#26 0x00007fe293a936ab in timeout (this=0x35b7b90) at .moc/qtimer.moc:122
#27 QSingleShotTimer::timerEvent (this=0x35b7b90) at kernel/qtimer.cpp:318
#28 0x00007fe293a866f3 in QObject::event (this=0x35b7b90, e=<optimized out>) at kernel/qobject.cpp:1267
#29 0x00007fe29435eb2c in QApplicationPrivate::notify_helper (this=0x25ccd10, receiver=0x35b7b90, e=0x7fffa5a6aba0) at kernel/qapplication.cpp:3720
#30 0x00007fe294364000 in QApplication::notify (this=0x7fffa5a6ade0, receiver=0x35b7b90, e=0x7fffa5a6aba0) at kernel/qapplication.cpp:3503
#31 0x00007fe293a54c2b in QCoreApplication::notifyInternal (this=0x7fffa5a6ade0, receiver=0x35b7b90, event=event@entry=0x7fffa5a6aba0) at kernel/qcoreapplication.cpp:935
#32 0x00007fe293aacae5 in sendEvent (event=0x7fffa5a6aba0, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:228
#33 QTimerInfoList::activateTimers (this=0x26028f8) at kernel/qtimerinfo_unix.cpp:635
#34 0x00007fe293aaa6a0 in QEventDispatcherUNIX::activateTimers (this=this@entry=0x25faf10) at kernel/qeventdispatcher_unix.cpp:549
#35 0x00007fe293aab243 in QEventDispatcherUNIX::processEvents (this=0x25faf10, flags=flags@entry=...) at kernel/qeventdispatcher_unix.cpp:611
#36 0x00007fe27f89596d in QUnixEventDispatcherQPA::processEvents (this=<optimized out>, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#37 0x00007fe293a523e2 in QEventLoop::exec (this=this@entry=0x7fffa5a6ad00, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#38 0x00007fe293a5a02c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1188
#39 0x00007fe293d9931c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1510
#40 0x00007fe29435a7a5 in QApplication::exec () at kernel/qapplication.cpp:2956
#41 0x00007fe29578d320 in kdemain (argc=1, argv=0x7fffa5a6af48) at ../main_x11.cpp:300
#42 0x00007fe2953dea40 in __libc_start_main (main=0x4007a0 <main(int, char**)>, argc=1, argv=0x7fffa5a6af48, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffa5a6af38) at libc-start.c:289
#43 0x00000000004007d9 in _start ()

Reported using DrKonqi