Application that crashed: kontact
Version of the application: 4.3.0 pre
KDE Version: 4.2.90 (KDE 4.2.90 (KDE 4.3 Beta2))
Qt Version: 4.5.1
Operating System: Linux 2.6.30-9-generic i686
Distribution: Ubuntu karmic (development branch)

What I was doing when the application crashed:
Actions taken: I click send in Kmail composer window, switched to todo component and entered some text in filter field. I can't say which of the actions caused the crash.

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[KCrash Handler]
#6  KOTodoViewSortFilterProxyModel::filterAcceptsRow (this=0x92a6340, source_row=82, source_parent=@0xbf9e3c50) at ../../korganizer/views/todoview/kotodoviewsortfilterproxymodel.cpp:63
#7  0x012fcf79 in QSortFilterProxyModelPrivate::handle_filter_changed (this=0x92a6358, source_to_proxy=@0x932f8b8, proxy_to_source=@0x932f8b0, source_parent=@0xbf9e3c50, orient=Qt::Vertical)
    at itemviews/qsortfilterproxymodel.cpp:959
#8  0x012fd2ea in QSortFilterProxyModelPrivate::filter_changed (this=0x92a6358) at itemviews/qsortfilterproxymodel.cpp:943
#9  0x012fd71a in QSortFilterProxyModel::qt_metacall (this=0x92a6340, _c=QMetaObject::InvokeMetaMethod, _id=0, _a=0xbf9e3dd8) at .moc/release-shared/moc_qsortfilterproxymodel.cpp:115
#10 0x03a542aa in KOTodoViewSortFilterProxyModel::qt_metacall (this=0x92a6340, _c=QMetaObject::InvokeMetaMethod, _id=21, _a=0xbf9e3dd8) at ./kotodoviewsortfilterproxymodel.moc:62
#11 0x007d9ff3 in QMetaObject::activate (sender=0x92b0f78, from_signal_index=27, to_signal_index=27, argv=0xbf9e3dd8) at kernel/qobject.cpp:3120
#12 0x007dac42 in QMetaObject::activate (sender=0x92b0f78, m=0x3b8181c, local_signal_index=0, argv=0xbf9e3dd8) at kernel/qobject.cpp:3194
#13 0x03a60f83 in KOTodoViewQuickSearch::searchTextChanged (this=0x92b0f78, _t1=@0xbf9e3f38) at ./kotodoviewquicksearch.moc:87
#14 0x03a610a7 in KOTodoViewQuickSearch::qt_metacall (this=0x92b0f78, _c=QMetaObject::InvokeMetaMethod, _id=27, _a=0xbf9e3ef8) at ./kotodoviewquicksearch.moc:73
#15 0x007d9ff3 in QMetaObject::activate (sender=0x92b1298, from_signal_index=27, to_signal_index=27, argv=0xbf9e3ef8) at kernel/qobject.cpp:3120
#16 0x007dac42 in QMetaObject::activate (sender=0x92b1298, m=0x15835e8, local_signal_index=0, argv=0xbf9e3ef8) at kernel/qobject.cpp:3194
#17 0x01132253 in QLineEdit::textChanged (this=0x92b1298, _t1=@0xbf9e3f38) at .moc/release-shared/moc_qlineedit.cpp:228
#18 0x0113766c in QLineEditPrivate::finishChange (this=0x92b12c0, validateFromState=0, update=false, edited=true) at widgets/qlineedit.cpp:2975
#19 0x0113933b in QLineEdit::insert (this=0x92b1298, newText=@0xbf9e3fa4) at widgets/qlineedit.cpp:1408
#20 0x01139f20 in QLineEdit::keyPressEvent (this=0x92b1298, event=0xbf9e4654) at widgets/qlineedit.cpp:2176
#21 0x00482c19 in KLineEdit::keyPressEvent (this=0x92b1298, e=0xbf9e4654) at ../../kdeui/widgets/klineedit.cpp:896
#22 0x00d45b39 in QWidget::event (this=0x92b1298, event=0xbf9e4654) at kernel/qwidget.cpp:7556
#23 0x01137a65 in QLineEdit::event (this=0x92b1298, e=0xbf9e4654) at widgets/qlineedit.cpp:1681
#24 0x004841ea in KLineEdit::event (this=0x92b1298, ev=0xbf9e4654) at ../../kdeui/widgets/klineedit.cpp:1323
#25 0x00cf0aa4 in QApplicationPrivate::notify_helper (this=0x8373500, receiver=0x92b1298, e=0xbf9e4654) at kernel/qapplication.cpp:4057
#26 0x00cf92d8 in QApplication::notify (this=0xbf9e61d4, receiver=0x92b1298, e=0xbf9e4654) at kernel/qapplication.cpp:3663
#27 0x003a402a in KApplication::notify (this=0xbf9e61d4, receiver=0x92b1298, event=0xbf9e4654) at ../../kdeui/kernel/kapplication.cpp:302
#28 0x007c417b in QCoreApplication::notifyInternal (this=0xbf9e61d4, receiver=0x92b1298, event=0xbf9e4654) at kernel/qcoreapplication.cpp:610
#29 0x00cf197e in qt_sendSpontaneousEvent (receiver=0x92b1298, event=0x92ad5c0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#30 0x00d8de40 in QKeyMapper::sendKeyEvent (keyWidget=0x92b1298, grab=false, type=QEvent::KeyPress, code=87, modifiers={i = 0}, text=@0xbf9e47c8, autorepeat=<value optimized out>, 
    count=<value optimized out>, nativeScanCode=25, nativeVirtualKey=119, nativeModifiers=16) at kernel/qkeymapper_x11.cpp:1675
#31 0x00d90369 in QKeyMapperPrivate::translateKeyEvent (this=0x83a2450, keyWidget=0x92b1298, event=0xbf9e5e3c, grab=false) at kernel/qkeymapper_x11.cpp:1645
#32 0x00d649cf in QApplication::x11ProcessEvent (this=0xbf9e61d4, event=0xbf9e5e3c) at kernel/qapplication_x11.cpp:3459
#33 0x00d91ee2 in x11EventSourceDispatch (s=0x8375a08, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#34 0x047b2b18 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#35 0x047b60b0 in ?? () from /usr/lib/libglib-2.0.so.0
#36 0x047b61e3 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#37 0x007eed0c in QEventDispatcherGlib::processEvents (this=0x835d9d0, flags={i = 36}) at kernel/qeventdispatcher_glib.cpp:324
#38 0x00d915c5 in QGuiEventDispatcherGlib::processEvents (this=0x835d9d0, flags={i = 36}) at kernel/qguieventdispatcher_glib.cpp:202
#39 0x007c2729 in QEventLoop::processEvents (this=0xbf9e6134, flags=) at kernel/qeventloop.cpp:149
#40 0x007c2b72 in QEventLoop::exec (this=0xbf9e6134, flags={i = 0}) at kernel/qeventloop.cpp:200
#41 0x007c4ecf in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#42 0x00cf0927 in QApplication::exec () at kernel/qapplication.cpp:3526
#43 0x0804b4d6 in main (argc=1, argv=0xbf9e63d4) at ../../../kontact/src/main.cpp:218

Reported using DrKonqi