Application: kwin_x11 (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:
i was using dual monitor system with dockstation, 
and manually suspended laptop with hotkey.
--
then resume at another dockstation without second monitor.

-- 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 0x7f1452258800 (LWP 2191))]

Thread 4 (Thread 0x7f1431f17700 (LWP 2221)):
#0  0x00007f1451d2b743 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f1450575101 in qt_safe_select (nfds=17, fdread=fdread@entry=0x7f1428000a98, fdwrite=fdwrite@entry=0x7f1428000d28, fdexcept=fdexcept@entry=0x7f1428000fb8, orig_timeout=orig_timeout@entry=0x0) at kernel/qcore_unix.cpp:75
#2  0x00007f1450576cd2 in select (timeout=0x0, exceptfds=0x7f1428000fb8, writefds=0x7f1428000d28, readfds=0x7f1428000a98, nfds=<optimized out>, this=0x7f14280008e0) at kernel/qeventdispatcher_unix.cpp:320
#3  QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7f1428000900, flags=..., flags@entry=..., timeout=timeout@entry=0x0) at kernel/qeventdispatcher_unix.cpp:196
#4  0x00007f1450577275 in QEventDispatcherUNIX::processEvents (this=0x7f14280008e0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#5  0x00007f145051e3e2 in QEventLoop::exec (this=this@entry=0x7f1431f16da0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007f14502ddb44 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:503
#7  0x00007f144a190f65 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007f14502e2b0e in QThreadPrivate::start (arg=0x1072000) at thread/qthread_unix.cpp:337
#9  0x00007f144935d6aa in start_thread (arg=0x7f1431f17700) at pthread_create.c:333
#10 0x00007f1451d34eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7f14237fe700 (LWP 2246)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f144f0e7644 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007f144f0e7689 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007f144935d6aa in start_thread (arg=0x7f14237fe700) at pthread_create.c:333
#4  0x00007f1451d34eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f138ef20700 (LWP 2989)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f14502e3c6b in wait (time=18446744073709551615, this=0x1fbc3b0) at thread/qwaitcondition_unix.cpp:128
#2  QWaitCondition::wait (this=<optimized out>, mutex=0x1f776b0, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:200
#3  0x00007f144f36efab in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#4  0x00007f144f36f3a0 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Quick.so.5
#5  0x00007f14502e2b0e in QThreadPrivate::start (arg=0x1f77630) at thread/qthread_unix.cpp:337
#6  0x00007f144935d6aa in start_thread (arg=0x7f138ef20700) at pthread_create.c:333
#7  0x00007f1451d34eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f1452258800 (LWP 2191)):
[KCrash Handler]
#6  QScreen::handle (this=0x0) at kernel/qscreen.cpp:85
#7  0x00007f143afcb545 in QXcbWindow::QXcbWindow (this=0x20e6510, window=0x1cfcea0) at qxcbwindow.cpp:260
#8  0x00007f143afb85c1 in QXcbIntegration::createPlatformWindow (this=<optimized out>, window=0x1cfcea0) at qxcbintegration.cpp:194
#9  0x00007f1450872786 in QWindowPrivate::create (this=0x1cfe490, recursive=recursive@entry=false) at kernel/qwindow.cpp:395
#10 0x00007f145087297b in QWindow::create (this=this@entry=0x1cfcea0) at kernel/qwindow.cpp:539
#11 0x00007f1450872b28 in QWindow::winId (this=0x1cfcea0) at kernel/qwindow.cpp:558
#12 0x00007f145190ec9f in KWin::AbstractThumbnailItem::findParentEffectWindow (this=0x2871a70) at ../thumbnailitem.cpp:79
#13 0x00007f145190ee69 in KWin::AbstractThumbnailItem::effectWindowAdded (this=0x2871a70) at ../thumbnailitem.cpp:90
#14 0x00007f145190ef47 in KWin::AbstractThumbnailItem::compositingToggled (this=0x2871a70) at ../thumbnailitem.cpp:59
#15 0x00007f1451999135 in KWin::AbstractThumbnailItem::qt_static_metacall (_o=0x0, _c=60, _id=13964648, _a=0xff8000) at moc_thumbnailitem.cpp:131
#16 0x00007f14505519c9 in QMetaObject::activate (sender=sender@entry=0xe683d0, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7fffafd843f0) at kernel/qobject.cpp:3716
#17 0x00007f1450552057 in QMetaObject::activate (sender=sender@entry=0xe683d0, m=m@entry=0x7f1451c22f60 <KWin::Compositor::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7fffafd843f0) at kernel/qobject.cpp:3582
#18 0x00007f145199195f in KWin::Compositor::compositingToggled (this=this@entry=0xe683d0, _t1=_t1@entry=true) at moc_composite.cpp:331
#19 0x00007f14518d76a5 in KWin::Compositor::slotCompositingOptionsInitialized (this=this@entry=0xe683d0) at ../composite.cpp:295
#20 0x00007f14518d8370 in KWin::Compositor::setup (this=0xe683d0) at ../composite.cpp:171
#21 0x00007f14518d85d5 in KWin::Compositor::setup (this=<optimized out>) at ../composite.cpp:146
#22 0x00007f14519966e5 in KWin::Compositor::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at moc_composite.cpp:261
#23 0x00007f145055273a in QObject::event (this=0xe683d0, e=<optimized out>) at kernel/qobject.cpp:1245
#24 0x00007f1450e2ab2c in QApplicationPrivate::notify_helper (this=0xd6d360, receiver=0xe683d0, e=0x1cd4d60) at kernel/qapplication.cpp:3720
#25 0x00007f1450e30000 in QApplication::notify (this=0x7fffafd84b50, receiver=0xe683d0, e=0x1cd4d60) at kernel/qapplication.cpp:3503
#26 0x00007f1450520c2b in QCoreApplication::notifyInternal (this=0x7fffafd84b50, receiver=0xe683d0, event=event@entry=0x1cd4d60) at kernel/qcoreapplication.cpp:935
#27 0x00007f1450522c9b in sendEvent (event=0x1cd4d60, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:228
#28 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0xd5d8c0) at kernel/qcoreapplication.cpp:1552
#29 0x00007f1450577112 in QEventDispatcherUNIX::processEvents (this=0xdb3aa0, flags=flags@entry=...) at kernel/qeventdispatcher_unix.cpp:579
#30 0x00007f143b00d96d in QUnixEventDispatcherQPA::processEvents (this=<optimized out>, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#31 0x00007f145051e3e2 in QEventLoop::exec (this=this@entry=0x7fffafd84a70, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#32 0x00007f145052602c in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1188
#33 0x00007f145086531c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1510
#34 0x00007f1450e267a5 in QApplication::exec () at kernel/qapplication.cpp:2956
#35 0x00007f1451ffc8c3 in kdemain (argc=1, argv=0x7fffafd84ca8) at ../main_x11.cpp:294
#36 0x00007f1451c4ea40 in __libc_start_main (main=0x400790 <main(int, char**)>, argc=3, argv=0x7fffafd84ca8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffafd84c98) at libc-start.c:289
#37 0x00000000004007c9 in _start ()

Reported using DrKonqi