Application that crashed: kwin
Version of the application: 4.3.2 (KDE 4.3.2)
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.2
Operating System: Linux 2.6.31-16-generic x86_64
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
Kwin crashs when using alt-tab to switch between windows. Window switching effect used: Flip Switch

 -- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
The current source language is "auto; currently c".
[KCrash Handler]
#5  KWin::FlipSwitchEffect::paintScreen (this=0x1fad9b0, mask=<value optimized out>, region=<value optimized out>, data=<value optimized out>) at ../../../kwin/effects/flipswitch/flipswitch.cpp:199
#6  0x00007fb977cef57b in KWin::EffectsHandlerImpl::paintScreen (this=0x18f9440, mask=32, region=) at ../../kwin/effects.cpp:122
#7  0x00007fb95bb9f31d in KWin::DesktopGridEffect::paintScreen (this=<value optimized out>, mask=<value optimized out>, region=<value optimized out>, data=...)
    at ../../../kwin/effects/desktopgrid/desktopgrid.cpp:140
#8  0x00007fb977cef57b in KWin::EffectsHandlerImpl::paintScreen (this=0x18f9440, mask=32, region=) at ../../kwin/effects.cpp:122
#9  0x00007fb95bbd05b5 in KWin::SlideEffect::paintScreen (this=<value optimized out>, mask=<value optimized out>, region=<value optimized out>, data=...) at ../../../kwin/effects/slide/slide.cpp:86
#10 0x00007fb977cef57b in KWin::EffectsHandlerImpl::paintScreen (this=0x18f9440, mask=32, region=) at ../../kwin/effects.cpp:122
#11 0x00007fb976827e9f in KWin::Effect::paintScreen (this=<value optimized out>, mask=32, region=<value optimized out>, data=...) at ../../../kwin/lib/kwineffects.cpp:206
#12 0x00007fb977cef57b in KWin::EffectsHandlerImpl::paintScreen (this=0x18f9440, mask=32, region=) at ../../kwin/effects.cpp:122
#13 0x00007fb976827e9f in KWin::Effect::paintScreen (this=<value optimized out>, mask=32, region=<value optimized out>, data=...) at ../../../kwin/lib/kwineffects.cpp:206
#14 0x00007fb977cef57b in KWin::EffectsHandlerImpl::paintScreen (this=0x18f9440, mask=32, region=) at ../../kwin/effects.cpp:122
#15 0x00007fb976827e9f in KWin::Effect::paintScreen (this=<value optimized out>, mask=32, region=<value optimized out>, data=...) at ../../../kwin/lib/kwineffects.cpp:206
#16 0x00007fb977cef57b in KWin::EffectsHandlerImpl::paintScreen (this=0x18f9440, mask=32, region=) at ../../kwin/effects.cpp:122
#17 0x00007fb976827e9f in KWin::Effect::paintScreen (this=<value optimized out>, mask=32, region=<value optimized out>, data=...) at ../../../kwin/lib/kwineffects.cpp:206
#18 0x00007fb977cef57b in KWin::EffectsHandlerImpl::paintScreen (this=0x18f9440, mask=32, region=) at ../../kwin/effects.cpp:122
#19 0x00007fb95bbd7731 in KWin::ZoomEffect::paintScreen (this=<value optimized out>, mask=32, region=) at ../../../kwin/effects/zoom/zoom.cpp:73
#20 0x00007fb977cef57b in KWin::EffectsHandlerImpl::paintScreen (this=0x18f9440, mask=32, region=) at ../../kwin/effects.cpp:122
#21 0x00007fb977cda715 in KWin::Scene::paintScreen (this=0x17ca070, mask=0x7fff7b49317c, region=0x7fff7b493290) at ../../kwin/scene.cpp:134
#22 0x00007fb977ce8dc3 in KWin::SceneOpenGL::paint (this=0x17ca070, damage=<value optimized out>, toplevels=<value optimized out>) at ../../kwin/scene_opengl.cpp:746
#23 0x00007fb977cd657e in KWin::Workspace::performCompositing (this=<value optimized out>) at ../../kwin/composite.cpp:420
#24 0x00007fb977c728b6 in KWin::Workspace::qt_metacall (this=0x18b2940, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff7b493430) at ./workspace.moc:473
#25 0x00007fb973d22ddc in QMetaObject::activate (sender=0x18b2d68, from_signal_index=<value optimized out>, to_signal_index=<value optimized out>, argv=0x22d7d0) at kernel/qobject.cpp:3113
#26 0x00007fb973d1cd83 in QObject::event (this=0x18b2d68, e=0x1e7fdd0) at kernel/qobject.cpp:1075
#27 0x00007fb974411efc in QApplicationPrivate::notify_helper (this=0x16322a0, receiver=0x18b2d68, e=0x7fff7b493a30) at kernel/qapplication.cpp:4056
#28 0x00007fb9744191ce in QApplication::notify (this=0x7fff7b493d90, receiver=0x18b2d68, e=0x7fff7b493a30) at kernel/qapplication.cpp:4021
#29 0x00007fb9774d8ab6 in KApplication::notify (this=0x7fff7b493d90, receiver=0x18b2d68, event=0x7fff7b493a30) at ../../kdeui/kernel/kapplication.cpp:302
#30 0x00007fb973d0dc2c in QCoreApplication::notifyInternal (this=0x7fff7b493d90, receiver=0x18b2d68, event=0x7fff7b493a30) at kernel/qcoreapplication.cpp:610
#31 0x00007fb973d38862 in QCoreApplication::sendEvent (this=0x1636000) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#32 QTimerInfoList::activateTimers (this=0x1636000) at kernel/qeventdispatcher_unix.cpp:572
#33 0x00007fb973d3625d in timerSourceDispatch (source=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:165
#34 0x00007fb96d7cbbce in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#35 0x00007fb96d7cf598 in ?? () from /lib/libglib-2.0.so.0
#36 0x00007fb96d7cf6c0 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#37 0x00007fb973d361a6 in QEventDispatcherGlib::processEvents (this=0x1617e90, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#38 0x00007fb9744a64be in QGuiEventDispatcherGlib::processEvents (this=0x1e7fe80, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#39 0x00007fb973d0c532 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#40 0x00007fb973d0c904 in QEventLoop::exec (this=0x7fff7b493cd0, flags=) at kernel/qeventloop.cpp:201
#41 0x00007fb973d0eab9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#42 0x00007fb977c89094 in kdemain (argc=<value optimized out>, argv=<value optimized out>) at ../../kwin/main.cpp:522
#43 0x00007fb9778f3abd in __libc_start_main (main=<value optimized out>, argc=<value optimized out>, ubp_av=<value optimized out>, init=<value optimized out>, fini=<value optimized out>, 
    rtld_fini=<value optimized out>, stack_end=0x7fff7b494278) at libc-start.c:220
#44 0x0000000000400679 in _start () at ../sysdeps/x86_64/elf/start.S:113

This bug may be a duplicate of or related to bug 216555

Reported using DrKonqi