Application: kwin_x11 (5.5.90)
 (Compiled from sources)
Qt Version: 5.5.1
Operating System: Linux 4.2.0-22-generic x86_64
Distribution: Ubuntu 15.10

-- Information about the crash:
- What I was doing when the application crashed:
I was in VLC player settings when it suddenly opened a fullscreen player window I was unable to exit from (eg. double click the window did nothing), so I invoked Present Windows by screen corner to closethe VLC fullscreen window. After I closed it, VLC quit and KWin crashed.

-- 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 0x7f2f2d000840 (LWP 1798))]

Thread 5 (Thread 0x7f2f15045700 (LWP 1814)):
#0  0x00007f2f2cb018dd in poll () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f2f2aab3bd2 in poll (__timeout=-1, __nfds=1, __fds=0x7f2f15044c80) at /usr/include/x86_64-linux-gnu/bits/poll2.h:46
#2  _xcb_conn_wait (c=c@entry=0xb49e00, cond=cond@entry=0xb49e40, vector=vector@entry=0x0, count=count@entry=0x0) at ../../src/xcb_conn.c:459
#3  0x00007f2f2aab574f in xcb_wait_for_event (c=0xb49e00) at ../../src/xcb_in.c:623
#4  0x00007f2f158e57e9 in QXcbEventReader::run (this=0xb544c0) at qxcbconnection.cpp:1229
#5  0x00007f2f2ad70a6e in QThreadPrivate::start (arg=0xb544c0) at thread/qthread_unix.cpp:331
#6  0x00007f2f2bfe56aa in start_thread (arg=0x7f2f15045700) at pthread_create.c:333
#7  0x00007f2f2cb0ceed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 4 (Thread 0x7f2f0d63d700 (LWP 1850)):
#0  0x00007f2f2cb03743 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f2f2afa3b7f in qt_safe_select (nfds=12, fdread=fdread@entry=0x7f2f00000a78, fdwrite=fdwrite@entry=0x7f2f00000d08, fdexcept=fdexcept@entry=0x7f2f00000f98, orig_timeout=orig_timeout@entry=0x0) at kernel/qcore_unix.cpp:75
#2  0x00007f2f2afa567e in QEventDispatcherUNIX::select (timeout=0x0, exceptfds=0x7f2f00000f98, writefds=0x7f2f00000d08, readfds=0x7f2f00000a78, nfds=<optimized out>, this=0x7f2f000008c0) at kernel/qeventdispatcher_unix.cpp:320
#3  QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7f2f000008e0, flags=..., flags@entry=..., timeout=timeout@entry=0x0) at kernel/qeventdispatcher_unix.cpp:196
#4  0x00007f2f2afa5bae in QEventDispatcherUNIX::processEvents (this=0x7f2f000008c0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#5  0x00007f2f2af4f50a in QEventLoop::exec (this=this@entry=0x7f2f0d63cd60, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007f2f2ad6bac4 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:503
#7  0x00007f2f256e8c35 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007f2f2ad70a6e in QThreadPrivate::start (arg=0xd8c300) at thread/qthread_unix.cpp:331
#9  0x00007f2f2bfe56aa in start_thread (arg=0x7f2f0d63d700) at pthread_create.c:333
#10 0x00007f2f2cb0ceed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7f2f061c3700 (LWP 1865)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f2f29e89194 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#2  0x00007f2f29e891d9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Script.so.5
#3  0x00007f2f2bfe56aa in start_thread (arg=0x7f2f061c3700) at pthread_create.c:333
#4  0x00007f2f2cb0ceed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f2f0e2db700 (LWP 15903)):
#0  0x00007f2f2cb03743 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f2f2afa3b7f in qt_safe_select (nfds=11, fdread=fdread@entry=0x7f2f0811c978, fdwrite=fdwrite@entry=0x7f2f0811cc08, fdexcept=fdexcept@entry=0x7f2f0811ce98, orig_timeout=orig_timeout@entry=0x0) at kernel/qcore_unix.cpp:75
#2  0x00007f2f2afa567e in QEventDispatcherUNIX::select (timeout=0x0, exceptfds=0x7f2f0811ce98, writefds=0x7f2f0811cc08, readfds=0x7f2f0811c978, nfds=<optimized out>, this=0x7f2f08033040) at kernel/qeventdispatcher_unix.cpp:320
#3  QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7f2f0811c7e0, flags=..., flags@entry=..., timeout=timeout@entry=0x0) at kernel/qeventdispatcher_unix.cpp:196
#4  0x00007f2f2afa5bae in QEventDispatcherUNIX::processEvents (this=0x7f2f08033040, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#5  0x00007f2f2af4f50a in QEventLoop::exec (this=this@entry=0x7f2f0e2dad60, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007f2f2ad6bac4 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:503
#7  0x00007f2f256e8c35 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007f2f2ad70a6e in QThreadPrivate::start (arg=0x170a3c0) at thread/qthread_unix.cpp:331
#9  0x00007f2f2bfe56aa in start_thread (arg=0x7f2f0e2db700) at pthread_create.c:333
#10 0x00007f2f2cb0ceed in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f2f2d000840 (LWP 1798)):
[KCrash Handler]
#6  0x00007f2f2af62835 in QMetaObject::invokeMethod (obj=0x1777790, member=0x7f2f2a513a6c "addRepaintFull", type=1696672464, ret=..., val0=..., val1=..., val2=..., val3=..., val4=..., val5=..., val6=..., val7=..., val8=..., val9=...) at kernel/qmetaobject.cpp:1464
#7  0x00007f2f2a4f8742 in QMetaObject::invokeMethod(QObject*, char const*, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument, QGenericArgument) () from /usr/lib/x86_64-linux-gnu/libkwineffects.so.7
#8  0x00007f2f2a4f21a4 in KWin::EffectWindow::addRepaintFull() () from /usr/lib/x86_64-linux-gnu/libkwineffects.so.7
#9  0x00007f2f2a02b362 in KWin::PresentWindowsEffect::setHighlightedWindow(KWin::EffectWindow*) () from /usr/lib/x86_64-linux-gnu/libkwin4_effect_builtins.so.1
#10 0x00007f2f2a02472f in KWin::PresentWindowsEffect::windowInputMouseEvent(QEvent*) () from /usr/lib/x86_64-linux-gnu/libkwin4_effect_builtins.so.1
#11 0x00007f2f2c62dccb in KWin::EffectsHandlerImpl::checkInputWindowEvent(xcb_motion_notify_event_t*) () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#12 0x00007f2f2c585d6a in KWin::Workspace::workspaceEvent(xcb_generic_event_t*) () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#13 0x00007f2f2c57a52a in KWin::XcbEventFilter::nativeEventFilter(QByteArray const&, void*, long*) () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#14 0x00007f2f2af4e69f in QAbstractEventDispatcher::filterNativeEvent (this=<optimized out>, eventType=..., message=message@entry=0x7f2f10001840, result=result@entry=0x7fff652134a8) at kernel/qabstracteventdispatcher.cpp:460
#15 0x00007f2f158e9254 in QXcbConnection::handleXcbEvent (this=this@entry=0xb48660, event=event@entry=0x7f2f10001840) at qxcbconnection.cpp:1020
#16 0x00007f2f158ea003 in QXcbConnection::processXcbEvents (this=0xb48660) at qxcbconnection.cpp:1502
#17 0x00007f2f2af817b1 in QObject::event (this=0xb48660, e=<optimized out>) at kernel/qobject.cpp:1239
#18 0x00007f2f2b8469dc in QApplicationPrivate::notify_helper (this=this@entry=0xb41400, receiver=receiver@entry=0xb48660, e=e@entry=0x7f2f10002810) at kernel/qapplication.cpp:3716
#19 0x00007f2f2b84bea6 in QApplication::notify (this=0x7fff65213b20, receiver=0xb48660, e=0x7f2f10002810) at kernel/qapplication.cpp:3499
#20 0x00007f2f2c578fdd in KWin::Application::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libkwin.so.5
#21 0x00007f2f2af51d7b in QCoreApplication::notifyInternal (this=0x7fff65213b20, receiver=0xb48660, event=event@entry=0x7f2f10002810) at kernel/qcoreapplication.cpp:965
#22 0x00007f2f2af54176 in QCoreApplication::sendEvent (event=0x7f2f10002810, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:224
#23 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0xb31670) at kernel/qcoreapplication.cpp:1593
#24 0x00007f2f2afa5a72 in QEventDispatcherUNIX::processEvents (this=0xb72610, flags=flags@entry=...) at kernel/qeventdispatcher_unix.cpp:579
#25 0x00007f2f1594ca1d in QUnixEventDispatcherQPA::processEvents (this=<optimized out>, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#26 0x00007f2f2af4f50a in QEventLoop::exec (this=this@entry=0x7fff65213a10, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#27 0x00007f2f2af575ec in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1229
#28 0x00007f2f2cdd5735 in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_kwin_x11.so
#29 0x00000000004008d8 in main ()

Reported using DrKonqi