Application: kwin (4.4.2 (KDE 4.4.2))
KDE Platform Version: 4.4.2 (KDE 4.4.2)
Qt Version: 4.6.2
Operating System: Linux 2.6.31-14-generic i686
Distribution: Ubuntu 10.04 LTS

-- Information about the crash:
I was alt-tabbing between windows within the same virtual desktop.  Both were gtk apps (eclipse and google-chrome).  The system was under decently heavy load.  I am using the free radeon x driver.

 -- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
[Current thread is 1 (Thread 0xb773d720 (LWP 13195))]

Thread 2 (Thread 0xab736b70 (LWP 13196)):
#0  0x00cece16 in clock_gettime () from /lib/tls/i686/cmov/librt.so.1
#1  0x033586fb in qt_gettime () at kernel/qcore_unix.cpp:111
#2  0x0335d825 in QTimerInfoList::updateCurrentTime (this=0x92b8484) at kernel/qeventdispatcher_unix.cpp:340
#3  0x0335d86a in QTimerInfoList::timerWait (this=0x92b8484, tm=...) at kernel/qeventdispatcher_unix.cpp:443
#4  0x0335b818 in timerSourcePrepareHelper (src=<value optimized out>, timeout=0xab7360bc) at kernel/qeventdispatcher_glib.cpp:136
#5  0x0335b8a5 in timerSourcePrepare (source=0x0, timeout=0xcf0ff4) at kernel/qeventdispatcher_glib.cpp:169
#6  0x07661aca in g_main_context_prepare () from /lib/libglib-2.0.so.0
#7  0x07661ee9 in ?? () from /lib/libglib-2.0.so.0
#8  0x076624b8 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#9  0x0335b60f in QEventDispatcherGlib::processEvents (this=0x92dcd68, flags=...) at kernel/qeventdispatcher_glib.cpp:414
#10 0x0332e059 in QEventLoop::processEvents (this=0xab736280, flags=) at kernel/qeventloop.cpp:149
#11 0x0332e4aa in QEventLoop::exec (this=0xab736280, flags=...) at kernel/qeventloop.cpp:201
#12 0x0322a5a8 in QThread::exec (this=0x92aeca8) at thread/qthread.cpp:487
#13 0x0330dc1b in QInotifyFileSystemWatcherEngine::run (this=0x92aeca8) at io/qfilesystemwatcher_inotify.cpp:248
#14 0x0322d32e in QThreadPrivate::start (arg=0x92aeca8) at thread/qthread_unix.cpp:248
#15 0x0026c96e in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#16 0x00eaaa0e in clone () from /lib/tls/i686/cmov/libc.so.6

Thread 1 (Thread 0xb773d720 (LWP 13195)):
[KCrash Handler]
#6  0x001b8b83 in QList<KWin::WindowQuad>::node_destruct (this=0xbfe043f0, data=0xf343c0) at /usr/include/qt4/QtCore/qlist.h:402
#7  QList<KWin::WindowQuad>::free (this=0xbfe043f0, data=0xf343c0) at /usr/include/qt4/QtCore/qlist.h:646
#8  0x001b8c4c in QList<KWin::WindowQuad>::detach_helper (this=0xbfe043f0) at /usr/include/qt4/QtCore/qlist.h:614
#9  0x001b07e2 in QList<KWin::WindowQuad>::operator= (this=0xbfe043a0, w=0x91b7158) at /usr/include/qt4/QtCore/qlist.h:416
#10 operator= (this=0xbfe043a0, w=0x91b7158) at ../../../kwin/lib/kwineffects.h:1066
#11 WindowPaintData (this=0xbfe043a0, w=0x91b7158) at ../../../kwin/lib/kwineffects.cpp:78
#12 0x0474f237 in KWin::CoverSwitchEffect::paintFrontWindow (this=0x92665b0, frontWindow=0x91b7158, width=1440, leftWindows=0, rightWindows=0, reflectedWindow=true)
    at ../../../kwin/effects/coverswitch/coverswitch.cpp:785
#13 0x0474f9ab in KWin::CoverSwitchEffect::paintScene (this=0x92665b0, frontWindow=0x91b7158, leftWindows=..., rightWindows=..., reflectedWindows=true)
    at ../../../kwin/effects/coverswitch/coverswitch.cpp:459
#14 0x04750779 in KWin::CoverSwitchEffect::paintScreen (this=0x92665b0, mask=32, region=..., data=...) at ../../../kwin/effects/coverswitch/coverswitch.cpp:252
#15 0x00dbfd30 in KWin::EffectsHandlerImpl::paintScreen (this=0x92246c0, mask=32, region=..., data=...) at ../../kwin/effects.cpp:122
#16 0x001ad426 in KWin::Effect::paintScreen (this=0x92540e8, mask=32, region=..., data=...) at ../../../kwin/lib/kwineffects.cpp:227
#17 0x00dbfd30 in KWin::EffectsHandlerImpl::paintScreen (this=0x92246c0, mask=32, region=..., data=...) at ../../kwin/effects.cpp:122
#18 0x001ad426 in KWin::Effect::paintScreen (this=0x929c288, mask=32, region=..., data=...) at ../../../kwin/lib/kwineffects.cpp:227
#19 0x00dbfd30 in KWin::EffectsHandlerImpl::paintScreen (this=0x92246c0, mask=32, region=..., data=...) at ../../kwin/effects.cpp:122
#20 0x04778419 in KWin::TrackMouseEffect::paintScreen (this=0x925eb80, mask=32, region=..., data=...) at ../../../kwin/effects/trackmouse/trackmouse.cpp:71
#21 0x00dbfd30 in KWin::EffectsHandlerImpl::paintScreen (this=0x92246c0, mask=32, region=..., data=...) at ../../kwin/effects.cpp:122
#22 0x001ad426 in KWin::Effect::paintScreen (this=0x9282a18, mask=32, region=..., data=...) at ../../../kwin/lib/kwineffects.cpp:227
#23 0x00dbfd30 in KWin::EffectsHandlerImpl::paintScreen (this=0x92246c0, mask=32, region=..., data=...) at ../../kwin/effects.cpp:122
#24 0x0474c133 in KWin::ZoomEffect::paintScreen (this=0x9279210, mask=32, region=..., data=...) at ../../../kwin/effects/zoom/zoom.cpp:73
#25 0x00dbfd30 in KWin::EffectsHandlerImpl::paintScreen (this=0x92246c0, mask=32, region=..., data=...) at ../../kwin/effects.cpp:122
#26 0x00da7ca4 in KWin::Scene::paintScreen (this=0x91de7d0, mask=0xbfe04ad8, region=0xbfe04ba4) at ../../kwin/scene.cpp:134
#27 0x00db953a in KWin::SceneOpenGL::paint (this=0x91de7d0, damage=..., toplevels=...) at ../../kwin/scene_opengl.cpp:748
#28 0x00da2604 in KWin::Workspace::performCompositing (this=0x91ca188) at ../../kwin/composite.cpp:424
#29 0x00d1a4a6 in KWin::Workspace::qt_metacall (this=0x91ca188, _c=QMetaObject::InvokeMetaMethod, _id=173, _a=0xbfe04ccc) at ./workspace.moc:535
#30 0x03334c9a in QMetaObject::metacall (object=0x91ca188, cl=15942592, idx=173, argv=0xbfe04ccc) at kernel/qmetaobject.cpp:237
#31 0x033433d5 in QMetaObject::activate (sender=0x91ca410, m=0x34435a4, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3293
#32 0x03394aa7 in QTimer::timeout (this=0x91ca410) at .moc/release-shared/moc_qtimer.cpp:134
#33 0x0334b60e in QTimer::timerEvent (this=0x91ca410, e=0xbfe05220) at kernel/qtimer.cpp:271
#34 0x03340254 in QObject::event (this=0x91ca410, e=0x982adb0) at kernel/qobject.cpp:1212
#35 0x069014dc in QApplicationPrivate::notify_helper (this=0x90fb7a8, receiver=0x91ca410, e=0xbfe05220) at kernel/qapplication.cpp:4300
#36 0x0690805e in QApplication::notify (this=0xbfe05598, receiver=0x91ca410, e=0xbfe05220) at kernel/qapplication.cpp:3704
#37 0x004b5f2a in KApplication::notify (this=0xbfe05598, receiver=0x91ca410, event=0xbfe05220) at ../../kdeui/kernel/kapplication.cpp:302
#38 0x00d36def in KWin::Application::notify (this=0xbfe05598, o=0x91ca410, e=0xbfe05220) at ../../kwin/main.cpp:370
#39 0x0332fa3b in QCoreApplication::notifyInternal (this=0xbfe05598, receiver=0x91ca410, event=0xbfe05220) at kernel/qcoreapplication.cpp:704
#40 0x0335ed66 in QCoreApplication::sendEvent (this=0x90fe784) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#41 QTimerInfoList::activateTimers (this=0x90fe784) at kernel/qeventdispatcher_unix.cpp:603
#42 0x0335b917 in timerSourceDispatch (source=0x90fe7b8) at kernel/qeventdispatcher_glib.cpp:184
#43 idleTimerSourceDispatch (source=0x90fe7b8) at kernel/qeventdispatcher_glib.cpp:231
#44 0x0765e5e5 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#45 0x076622d8 in ?? () from /lib/libglib-2.0.so.0
#46 0x076624b8 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#47 0x0335b5d5 in QEventDispatcherGlib::processEvents (this=0x90e5de8, flags=...) at kernel/qeventdispatcher_glib.cpp:412
#48 0x069c1135 in QGuiEventDispatcherGlib::processEvents (this=0x90e5de8, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#49 0x0332e059 in QEventLoop::processEvents (this=0xbfe054e4, flags=) at kernel/qeventloop.cpp:149
#50 0x0332e4aa in QEventLoop::exec (this=0xbfe054e4, flags=...) at kernel/qeventloop.cpp:201
#51 0x0333269f in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#52 0x06901577 in QApplication::exec () at kernel/qapplication.cpp:3579
#53 0x00d38a00 in kdemain (argc=3, argv=0xbfe057a4) at ../../kwin/main.cpp:526
#54 0x0804860b in main (argc=3, argv=0xbfe057a4) at kwin_dummy.cpp:3

Reported using DrKonqi