Application that crashed: kwin
Version of the application: 4.3.1 (KDE 4.3.1)
KDE Version: 4.3.1 (KDE 4.3.1)
Qt Version: 4.5.2
Operating System: Linux 2.6.28-15-generic i686
Distribution: Ubuntu 9.04

What I was doing when the application crashed:
KWin crashes when I switch (ALT-Tab) between two OpenOffice windows. One is a rather large document in which the search window is activated, the other is an ordinary small document. The crash only seems to be reproducible when the search window is open in the first document and even then the crash does not happen every time.
I use the CoverSwitch effect for window-switching which led me to believe this bug could be related to the other one.

 -- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
[KCrash Handler]
#6  WindowPaintData (this=0xbffbe9b8, w=0x400001) at /build/buildd/kdebase-workspace-4.3.1/kwin/lib/kwineffects.cpp:76
#7  0xb1f48087 in KWin::CoverSwitchEffect::paintWindows (this=0x92584d8, windows=0x9258538, left=true, reflectedWindows=false, additionalWindow=0x0)
    at /build/buildd/kdebase-workspace-4.3.1/kwin/effects/coverswitch/coverswitch.cpp:886
#8  0xb1f488c9 in KWin::CoverSwitchEffect::paintScene (this=0x92584d8, frontWindow=0x96363d8, leftWindows=0x9258538, rightWindows=0x925853c, reflectedWindows=false)
    at /build/buildd/kdebase-workspace-4.3.1/kwin/effects/coverswitch/coverswitch.cpp:427
#9  0xb1f4f195 in KWin::CoverSwitchEffect::paintScreen (this=0x92584d8, mask=32, region={d = 0xbffbed48, static shared_empty = {ref = {_q_value = 582}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbffbeea8) at /build/buildd/kdebase-workspace-4.3.1/kwin/effects/coverswitch/coverswitch.cpp:308
#10 0xb7f6e2bf in KWin::EffectsHandlerImpl::paintScreen (this=0x9103d38, mask=32, region={d = 0xbffbed88, static shared_empty = {ref = {_q_value = 582}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbffbeea8) at /build/buildd/kdebase-workspace-4.3.1/kwin/effects.cpp:122
#11 0xb7e90cf6 in KWin::Effect::paintScreen (this=0x91f0ff0, mask=32, region={d = 0xbffbedc8, static shared_empty = {ref = {_q_value = 582}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbffbeea8) at /build/buildd/kdebase-workspace-4.3.1/kwin/lib/kwineffects.cpp:206
#12 0xb7f6e2bf in KWin::EffectsHandlerImpl::paintScreen (this=0x9103d38, mask=32, region={d = 0xbffbee1c, static shared_empty = {ref = {_q_value = 582}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbffbeea8) at /build/buildd/kdebase-workspace-4.3.1/kwin/effects.cpp:122
#13 0xb1f45ddd in KWin::ZoomEffect::paintScreen (this=0x9250dc8, mask=32, region={d = 0xbffbee68, static shared_empty = {ref = {_q_value = 582}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbffbeea8) at /build/buildd/kdebase-workspace-4.3.1/kwin/effects/zoom/zoom.cpp:73
#14 0xb7f6e2bf in KWin::EffectsHandlerImpl::paintScreen (this=0x9103d38, mask=32, region={d = 0xbffbef00, static shared_empty = {ref = {_q_value = 582}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbffbeea8) at /build/buildd/kdebase-workspace-4.3.1/kwin/effects.cpp:122
#15 0xb7f57850 in KWin::Scene::paintScreen (this=0x90a75e8, mask=0xbffbef84, region=0xbffbf044) at /build/buildd/kdebase-workspace-4.3.1/kwin/scene.cpp:134
#16 0xb7f673ba in KWin::SceneOpenGL::paint (this=0x90a75e8, damage={d = 0xbffbf044, static shared_empty = {ref = {_q_value = 582}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, toplevels=
        {{p = {static shared_null = {ref = {_q_value = 5619}, alloc = 0, begin = 0, end = 0, sharable = 1, array = {0x0}}, d = 0xbffbf040}, d = 0xbffbf040}})
    at /build/buildd/kdebase-workspace-4.3.1/kwin/scene_opengl.cpp:746
#17 0xb7f5253b in KWin::Workspace::performCompositing (this=0x9108d20) at /build/buildd/kdebase-workspace-4.3.1/kwin/composite.cpp:420
#18 0xb7ee2ddd in KWin::Workspace::qt_metacall (this=0x9108d20, _c=QMetaObject::InvokeMetaMethod, _id=149, _a=0xbffbf118)
    at /build/buildd/kdebase-workspace-4.3.1/obj-i486-linux-gnu/kwin/workspace.moc:473
#19 0xb6b691b8 in QMetaObject::activate (sender=0x9108f84, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3113
#20 0xb6b69e42 in QMetaObject::activate (sender=0x9108f84, m=0xb6c46904, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3187
#21 0xb6ba5687 in QTimer::timeout (this=0x9108f84) at .moc/release-shared/moc_qtimer.cpp:128
#22 0xb6b6f5ce in QTimer::timerEvent (this=0x9108f84, e=0xbffbf5bc) at kernel/qtimer.cpp:261
#23 0xb6b6416f in QObject::event (this=0x9108f84, e=0xbffbf5bc) at kernel/qobject.cpp:1075
#24 0xb6ddfd3c in QApplicationPrivate::notify_helper (this=0x9004020, receiver=0x9108f84, e=0xbffbf5bc) at kernel/qapplication.cpp:4056
#25 0xb6de803e in QApplication::notify (this=0xbffbf894, receiver=0x9108f84, e=0xbffbf5bc) at kernel/qapplication.cpp:3603
#26 0xb7ada85d in KApplication::notify (this=0xbffbf894, receiver=0x9108f84, event=0xbffbf5bc) at /build/buildd/kde4libs-4.3.1/kdeui/kernel/kapplication.cpp:302
#27 0xb7efa7ed in KWin::Application::notify (this=0xbffbf894, o=0x9108f84, e=0xbffbf5bc) at /build/buildd/kdebase-workspace-4.3.1/kwin/main.cpp:366
#28 0xb6b53bcb in QCoreApplication::notifyInternal (this=0xbffbf894, receiver=0x9108f84, event=0xbffbf5bc) at kernel/qcoreapplication.cpp:610
#29 0xb6b82d51 in QTimerInfoList::activateTimers (this=0x9006dcc) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#30 0xb6b7f3a0 in timerSourceDispatch (source=0x9006d98) at kernel/qeventdispatcher_glib.cpp:165
#31 0xb4f1bb88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#32 0xb4f1f0eb in ?? () from /usr/lib/libglib-2.0.so.0
#33 0xb4f1f268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#34 0xb6b7f2f8 in QEventDispatcherGlib::processEvents (this=0x8fee740, flags={i = -1074006216}) at kernel/qeventdispatcher_glib.cpp:327
#35 0xb6e81a75 in QGuiEventDispatcherGlib::processEvents (this=0x8fee740, flags={i = -1074006168}) at kernel/qguieventdispatcher_glib.cpp:202
#36 0xb6b521fa in QEventLoop::processEvents (this=0xbffbf7e0, flags={i = -1074006104}) at kernel/qeventloop.cpp:149
#37 0xb6b52642 in QEventLoop::exec (this=0xbffbf7e0, flags={i = -1074006040}) at kernel/qeventloop.cpp:201
#38 0xb6b54ae9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#39 0xb6ddfbb7 in QApplication::exec () at kernel/qapplication.cpp:3525
#40 0xb7efd063 in kdemain (argc=3, argv=0xbffbfa74) at /build/buildd/kdebase-workspace-4.3.1/kwin/main.cpp:522
#41 0x08048742 in main (argc=) at /build/buildd/kdebase-workspace-4.3.1/obj-i486-linux-gnu/kwin/kwin_dummy.cpp:3

This bug may be a duplicate of or related to bug 194524

Reported using DrKonqi