Application: kwin_x11 (5.2.2)

Qt Version: 5.4.1
Operating System: Linux 3.19.0-15-generic x86_64
Distribution: Ubuntu 15.04

-- Information about the crash:
- What I was doing when the application crashed:

It happens every time I connect HDMI display for the first time after booting.

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 0x7fd9e895c800 (LWP 9729))]

Thread 5 (Thread 0x7fd9cac3f700 (LWP 9741)):
#0  0x00007fd9e69e7e0f in QMutex::unlock() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#1  0x00007fd9e6c84142 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007fd9e6c2b3e2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007fd9e69eab44 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007fd9e089df65 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#5  0x00007fd9e69efb0e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007fd9dfa6a6aa in start_thread (arg=0x7fd9cac3f700) at pthread_create.c:333
#7  0x00007fd9e8441eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 4 (Thread 0x7fd9bbee7700 (LWP 9749)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fd9e57f4644 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007fd9e57f4689 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007fd9dfa6a6aa in start_thread (arg=0x7fd9bbee7700) at pthread_create.c:333
#4  0x00007fd9e8441eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7fd9cbfff700 (LWP 10078)):
#0  0x00007fd9e8438743 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fd9e6c82101 in qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007fd9e6c83cd2 in QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007fd9e6c84275 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007fd9e6c2b3e2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fd9e69eab44 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007fd9e089df65 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#7  0x00007fd9e69efb0e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007fd9dfa6a6aa in start_thread (arg=0x7fd9cbfff700) at pthread_create.c:333
#9  0x00007fd9e8441eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7fd9c88ee700 (LWP 10149)):
#0  0x00007fd9e8438743 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fd9e6c82101 in qt_safe_select(int, fd_set*, fd_set*, fd_set*, timespec const*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#2  0x00007fd9e6c83cd2 in QEventDispatcherUNIXPrivate::doSelect(QFlags<QEventLoop::ProcessEventsFlag>, timespec*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#3  0x00007fd9e6c84275 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007fd9e6c2b3e2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fd9e69eab44 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007fd9e089df65 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#7  0x00007fd9e69efb0e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007fd9dfa6a6aa in start_thread (arg=0x7fd9c88ee700) at pthread_create.c:333
#9  0x00007fd9e8441eed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7fd9e895c800 (LWP 9729)):
[KCrash Handler]
#6  0x00007fd9e6fa1690 in QScreen::handle() const () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#7  0x00007fd9d36af545 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#8  0x00007fd9d369c5c1 in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#9  0x00007fd9e6f7f786 in QWindowPrivate::create(bool) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#10 0x00007fd9e6f7fb28 in QWindow::winId() const () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#11 0x00007fd9e801bc9f in KWin::AbstractThumbnailItem::findParentEffectWindow (this=0x2452290) at ../thumbnailitem.cpp:79
#12 0x00007fd9e801be69 in KWin::AbstractThumbnailItem::effectWindowAdded (this=0x2452290) at ../thumbnailitem.cpp:90
#13 0x00007fd9e80a6125 in KWin::AbstractThumbnailItem::qt_static_metacall (_o=0x0, _c=QMetaObject::ResetProperty, _id=37042000, _a=0x7fd9e86ffc00 <main_arena>) at moc_thumbnailitem.cpp:130
#14 0x00007fd9e6c5e9c9 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#15 0x00007fd9e620dfb2 in KWin::EffectsHandler::windowAdded (this=<optimized out>, _t1=0x2271fd0) at moc_kwineffects.cpp:1195
#16 0x00007fd9e6c5e35a in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#17 0x00007fd9e80a0fc2 in KWin::Toplevel::windowShown (this=this@entry=0x1fcf230, _t1=_t1@entry=0x1fcf230) at moc_toplevel.cpp:656
#18 0x00007fd9e7fe7ddf in KWin::Toplevel::setReadyForPainting (this=this@entry=0x1fcf230) at ../toplevel.cpp:245
#19 0x00007fd9e7f9a32f in KWin::Client::syncEvent (this=0x1fcf230, e=<optimized out>) at ../events.cpp:1561
#20 0x00007fd9e7f9d301 in KWin::Workspace::workspaceEvent (this=0x735cf0, e=0x7fd9cc0055b0) at ../events.cpp:556
#21 0x00007fd9e6c2a510 in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007fd9d369a02d in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#23 0x00007fd9d369b4bb in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#24 0x00007fd9e6c5f73a in QObject::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#25 0x00007fd9e7537b2c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#26 0x00007fd9e753d000 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#27 0x00007fd9e6c2dc2b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#28 0x00007fd9e6c2fc9b in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#29 0x00007fd9e6c84112 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#30 0x00007fd9d36f196d in ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqxcb.so
#31 0x00007fd9e6c2b3e2 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#32 0x00007fd9e6c3302c in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#33 0x00007fd9e87098c3 in kdemain (argc=1, argv=0x7ffd40413518) at ../main_x11.cpp:294
#34 0x00007fd9e835ba40 in __libc_start_main (main=0x400790 <main(int, char**)>, argc=1, argv=0x7ffd40413518, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffd40413508) at libc-start.c:289
#35 0x00000000004007c9 in _start ()

Reported using DrKonqi