Application that crashed: kwin
Version of the application: 4.2.90 (KDE 4.2.90 (KDE 4.3 Beta2)) "release 138"
KDE Version: 4.2.90 (KDE 4.2.90 (KDE 4.3 Beta2)) "release 139"
Qt Version: 4.5.1
Operating System: Linux 2.6.30-rc6-git3-4-default i686
Distribution: "openSUSE 11.2 Milestone 2 (i586)"

What I was doing when the application crashed:
I started Kontact and Kwallet asksed for password in background. When I tried to switch with Alt+Tab KWin crashed.
I use preset Ultimate for effects.

 -- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
[KCrash Handler]
#6  0x07000038 in ?? ()
#7  0xb7e85e9e in KWin::WindowPaintData::WindowPaintData(struct KWin::EffectWindow *) (this=0xbf962350, w=0x85ffbc0) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/lib/kwineffects.cpp:76
#8  0xb151cb27 in KWin::BoxSwitchEffect::paintWindowThumbnail (this=0x82b49b8, w=0x85ffbc0) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/effects/boxswitch/boxswitch.cpp:747
#9  0xb151e9f4 in KWin::BoxSwitchEffect::paintScreen (this=0x82b49b8, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/effects/boxswitch/boxswitch.cpp:157
#10 0xb7f6d8f5 in KWin::EffectsHandlerImpl::paintScreen (this=0x81ad450, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/effects.cpp:122
#11 0xb7e8353a in KWin::Effect::paintScreen (this=0x82b4b10, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/lib/kwineffects.cpp:206
#12 0xb7f6d8f5 in KWin::EffectsHandlerImpl::paintScreen (this=0x81ad450, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/effects.cpp:122
#13 0xb7e8353a in KWin::Effect::paintScreen (this=0x82b1e58, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/lib/kwineffects.cpp:206
#14 0xb7f6d8f5 in KWin::EffectsHandlerImpl::paintScreen (this=0x81ad450, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/effects.cpp:122
#15 0xb7e8353a in KWin::Effect::paintScreen (this=0x8246fc8, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/lib/kwineffects.cpp:206
#16 0xb7f6d8f5 in KWin::EffectsHandlerImpl::paintScreen (this=0x81ad450, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/effects.cpp:122
#17 0xb155ffaa in KWin::ZoomEffect::paintScreen (this=0x817d870, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/effects/zoom/zoom.cpp:73
#18 0xb7f6d8f5 in KWin::EffectsHandlerImpl::paintScreen (this=0x81ad450, mask=0, region={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, 
    data=@0xbf962870) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/effects.cpp:122
#19 0xb7f55fed in KWin::Scene::paintScreen (this=0x8179d88, mask=0xbf962958, region=0xbf962a28) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/scene.cpp:134
#20 0xb7f65ef0 in KWin::SceneOpenGL::paint (this=0x8179d88, damage={d = 0x8365a68, static shared_empty = {ref = {_q_value = 326}, rgn = 0x0, xrectangles = 0x0, qt_rgn = 0x0}}, toplevels=
        {{p = {static shared_null = {ref = {_q_value = 5658}, alloc = 0, begin = 0, end = 0, sharable = 1, array = {0x0}}, d = 0x85fe9d0}, d = 0x85fe9d0}})
    at /usr/src/debug/kdebase-workspace-4.2.90/kwin/scene_opengl.cpp:746
#21 0xb7f50b98 in KWin::Workspace::performCompositing (this=0x81c3a70) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/composite.cpp:412
#22 0xb7edf75e in KWin::Workspace::qt_metacall (this=0x81c3a70, _c=QMetaObject::InvokeMetaMethod, _id=153, _a=0xbf962b1c) at /usr/src/debug/kdebase-workspace-4.2.90/build/kwin/workspace.moc:473
#23 0xb6a64039 in QMetaObject::activate (sender=0x81c3cd4, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3120
#24 0xb6a64d55 in QMetaObject::activate (sender=0x81c3cd4, m=0xb6b41904, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3194
#25 0xb6aa04f5 in QTimer::timeout (this=0x81c3cd4) at .moc/release-shared/moc_qtimer.cpp:128
#26 0xb6a69986 in QTimer::timerEvent (this=0x81c3cd4, e=0xbf962fc4) at kernel/qtimer.cpp:261
#27 0xb6a5db6b in QObject::event (this=0x81c3cd4, e=0xbf962fc4) at kernel/qobject.cpp:1082
#28 0xb6cd3a2c in QApplicationPrivate::notify_helper (this=0x807be48, receiver=0x81c3cd4, e=0xbf962fc4) at kernel/qapplication.cpp:4057
#29 0xb6cdb5ee in QApplication::notify (this=0xbf963328, receiver=0x81c3cd4, e=0xbf962fc4) at kernel/qapplication.cpp:3604
#30 0xb7a404d1 in KApplication::notify (this=0xbf963328, receiver=0x81c3cd4, event=0xbf962fc4) at /usr/src/debug/kdelibs-4.2.90/kdeui/kernel/kapplication.cpp:302
#31 0xb7ef6231 in KWin::Application::notify (this=0xbf963328, o=0x81c3cd4, e=0xbf962fc4) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/main.cpp:370
#32 0xb6a4d62e in QCoreApplication::notifyInternal (this=0xbf963328, receiver=0x81c3cd4, event=0xbf962fc4) at kernel/qcoreapplication.cpp:610
#33 0xb6a7ca66 in QCoreApplication::sendEvent (event=<value optimized out>, receiver=<value optimized out>) at kernel/qcoreapplication.h:213
#34 QTimerInfoList::activateTimers (event=<value optimized out>, receiver=<value optimized out>) at kernel/qeventdispatcher_unix.cpp:586
#35 0xb6a79a9e in timerSourceDispatch (source=0x807f000) at kernel/qeventdispatcher_glib.cpp:164
#36 0xb4c6e6f2 in g_main_dispatch (context=<value optimized out>) at gmain.c:1814
#37 IA__g_main_context_dispatch (context=<value optimized out>) at gmain.c:2367
#38 0xb4c71d60 in g_main_context_iterate (context=0x807e100, block=<value optimized out>, dispatch=1, self=0x807bfc0) at gmain.c:2448
#39 0xb4c71eae in IA__g_main_context_iteration (context=0x807e100, may_block=1) at gmain.c:2511
#40 0xb6a799e8 in QEventDispatcherGlib::processEvents (this=0x807be28, flags={i = 36}) at kernel/qeventdispatcher_glib.cpp:324
#41 0xb6d7629a in QGuiEventDispatcherGlib::processEvents (this=0x807be28, flags={i = 36}) at kernel/qguieventdispatcher_glib.cpp:202
#42 0xb6a4bc1d in QEventLoop::processEvents (this=0xbf963274, flags=) at kernel/qeventloop.cpp:149
#43 0xb6a4c069 in QEventLoop::exec (this=0xbf963274, flags={i = 0}) at kernel/qeventloop.cpp:200
#44 0xb6a4e430 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#45 0xb6cd3894 in QApplication::exec () at kernel/qapplication.cpp:3526
#46 0xb7ef8c1e in kdemain (argc=3, argv=0xbf963514) at /usr/src/debug/kdebase-workspace-4.2.90/kwin/main.cpp:525
#47 0x080487bb in main (argc=3, argv=0xbf963514) at /usr/src/debug/kdebase-workspace-4.2.90/build/kwin/kwin_dummy.cpp:3

This bug may be a duplicate of or related to bug 184602

Reported using DrKonqi