Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.00 (KDE 4.3.0)
Qt Version: 4.5.2
Operating System: Linux 2.6.30.5-43.fc11.x86_64 x86_64

What I was doing when the application crashed:
I turned off desktop effects and I uninstalled the proprietary nvidia driver to go back to the nouveau one. It sadly crashed Plasma.

 -- Backtrace:
Application: Plasma-arbeidsområde (plasma-desktop), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f1b7398e860 (LWP 8964))]

Thread 2 (Thread 0x7f1b5d013910 (LWP 8965)):
#0  0x000000308700b2f9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x000000308e85adfb in QWaitConditionPrivate::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#3  0x000000308ac818e4 in QHostInfoAgent::run (this=0x197f230) at kernel/qhostinfo.cpp:260
#4  0x000000308e859d45 in QThreadPrivate::start (arg=0x197f230) at thread/qthread_unix.cpp:188
#5  0x000000308700686a in start_thread () from /lib64/libpthread.so.0
#6  0x00000030864de3bd in clone () from /lib64/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f1b7398e860 (LWP 8964)):
[KCrash Handler]
#5  0x0000003e2370a034 in QGraphicsItem::isWidget (this=0x1cdd350) at graphicsview/qgraphicsitem.cpp:1143
#6  0x0000003e2370c739 in QGraphicsItem::isWindow (this=0x1cdd350) at graphicsview/qgraphicsitem.cpp:1156
#7  0x0000003e2373fc59 in QGraphicsScene::event (this=0x13cfe60, event=<value optimized out>) at graphicsview/qgraphicsscene.cpp:3850
#8  0x0000003e2318f69c in QApplicationPrivate::notify_helper (this=0x13d7480, receiver=0x13cfe60, e=0x7fff9b9f0f60) at kernel/qapplication.cpp:4056
#9  0x0000003e231968fe in QApplication::notify (this=0x13c5820, receiver=0x13cfe60, e=0x7fff9b9f0f60) at kernel/qapplication.cpp:4021
#10 0x0000003540611296 in KApplication::notify (this=0x13c5820, receiver=0x13cfe60, event=0x7fff9b9f0f60) at /usr/src/debug/kdelibs-4.3.0/kdeui/kernel/kapplication.cpp:302
#11 0x000000308e93f59c in QCoreApplication::notifyInternal (this=0x13c5820, receiver=0x13cfe60, event=0x7fff9b9f0f60) at kernel/qcoreapplication.cpp:610
#12 0x0000003e2375142e in QCoreApplication::sendEvent (event=<value optimized out>, receiver=<value optimized out>) at ../../src/corelib/kernel/qcoreapplication.h:213
#13 QGraphicsView::viewportEvent (event=<value optimized out>, receiver=<value optimized out>) at graphicsview/qgraphicsview.cpp:2880
#14 0x000000308e93e8e7 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<value optimized out>, receiver=0x1ce1eb0, event=0x7fff9b9f0f60) at kernel/qcoreapplication.cpp:726
#15 0x0000003e2318f66c in QApplicationPrivate::notify_helper (this=0x13d7480, receiver=0x1ce1eb0, e=0x7fff9b9f0f60) at kernel/qapplication.cpp:4052
#16 0x0000003e231968fe in QApplication::notify (this=0x13c5820, receiver=0x1ce1eb0, e=0x7fff9b9f0f60) at kernel/qapplication.cpp:4021
#17 0x0000003540611296 in KApplication::notify (this=0x13c5820, receiver=0x1ce1eb0, event=0x7fff9b9f0f60) at /usr/src/debug/kdelibs-4.3.0/kdeui/kernel/kapplication.cpp:302
#18 0x000000308e93f59c in QCoreApplication::notifyInternal (this=0x13c5820, receiver=0x1ce1eb0, event=0x7fff9b9f0f60) at kernel/qcoreapplication.cpp:610
#19 0x0000003e231ddf2b in QCoreApplication::sendEvent (event=<value optimized out>, receiver=<value optimized out>) at ../../src/corelib/kernel/qcoreapplication.h:213
#20 QWidget::event (event=<value optimized out>, receiver=<value optimized out>) at kernel/qwidget.cpp:7797
#21 0x0000003e23535916 in QFrame::event (this=0x1cc5730, e=0x7fff9b9f0f60) at widgets/qframe.cpp:559
#22 0x0000003e235c4bf1 in QAbstractScrollArea::event (this=0x1cc5730, e=0x7fff9b9f0f60) at widgets/qabstractscrollarea.cpp:918
#23 0x0000003e2318f69c in QApplicationPrivate::notify_helper (this=0x13d7480, receiver=0x1cc5730, e=0x7fff9b9f0f60) at kernel/qapplication.cpp:4056
#24 0x0000003e231968fe in QApplication::notify (this=0x13c5820, receiver=0x1cc5730, e=0x7fff9b9f0f60) at kernel/qapplication.cpp:4021
#25 0x0000003540611296 in KApplication::notify (this=0x13c5820, receiver=0x1cc5730, event=0x7fff9b9f0f60) at /usr/src/debug/kdelibs-4.3.0/kdeui/kernel/kapplication.cpp:302
#26 0x000000308e93f59c in QCoreApplication::notifyInternal (this=0x13c5820, receiver=0x1cc5730, event=0x7fff9b9f0f60) at kernel/qcoreapplication.cpp:610
#27 0x0000003e23199c6b in QCoreApplication::sendSpontaneousEvent (event=<value optimized out>, receiver=<value optimized out>) at ../../src/corelib/kernel/qcoreapplication.h:216
#28 QApplication::setActiveWindow (event=<value optimized out>, receiver=<value optimized out>) at kernel/qapplication.cpp:2414
#29 0x0000003e231fabfb in QApplication::x11ProcessEvent (this=<value optimized out>, event=0x7fff9b9f2840) at kernel/qapplication_x11.cpp:3464
#30 0x0000003e232227dc in x11EventSourceDispatch (s=<value optimized out>, callback=<value optimized out>, user_data=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:146
#31 0x0000003088837abe in g_main_dispatch (context=<value optimized out>) at gmain.c:1824
#32 IA__g_main_context_dispatch (context=<value optimized out>) at gmain.c:2377
#33 0x000000308883b278 in g_main_context_iterate (context=0x13d9d20, block=<value optimized out>, dispatch=<value optimized out>, self=<value optimized out>) at gmain.c:2455
#34 0x000000308883b3a0 in IA__g_main_context_iteration (context=0x13d9d20, may_block=1) at gmain.c:2518
#35 0x000000308e967936 in QEventDispatcherGlib::processEvents (this=0x13ad4e0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#36 0x0000003e23221f8e in QGuiEventDispatcherGlib::processEvents (this=0x1cdd350, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#37 0x000000308e93ded2 in QEventLoop::processEvents (this=<value optimized out>, flags={i = 36}) at kernel/qeventloop.cpp:149
#38 0x000000308e93e2a4 in QEventLoop::exec (this=0x7fff9b9f2b70, flags={i = 0}) at kernel/qeventloop.cpp:201
#39 0x000000308e940439 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#40 0x000000354163aeaf in kdemain () from /usr/lib64/libkdeinit4_plasma-desktop.so
#41 0x000000308641ea2d in __libc_start_main () from /lib64/libc.so.6
#42 0x0000000000400779 in _start ()

Reported using DrKonqi