Application that crashed: kontact
Version of the application: 4.3.0
KDE Version: 4.3.00 (KDE 4.3.0)
Qt Version: 4.5.2
Operating System: Linux 2.6.28-14-generic i686
Distribution: Ubuntu 9.04

What I was doing when the application crashed:
Upgraded from 4.2.2 to 4.3 today. Problem occurred in 4.2.2 as well: Kontact crashes when creating or changing calendar events (or to dos) either with attendees or recurring details. Initial creation of such an event or task leads to Kontact crashing almost 100% of the time. Further, events with recurrence do not seem to sync to Google through GCALDaemon (separate issue in itself). 

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[KCrash Handler]
#6  0xb72233ec in KCal::IncidenceBase::uid () from /usr/lib/libkcal.so.4
#7  0xac5240f6 in KOEventViewer::changeIncidenceDisplay () from /usr/lib/libkorganizer_eventviewer.so.4
#8  0xaae3ea6e in CalendarView::changeIncidenceDisplay () from /usr/lib/libkorganizerprivate.so.4
#9  0xaae49ab3 in CalendarView::incidenceAdded () from /usr/lib/libkorganizerprivate.so.4
#10 0xaae4ed6f in CalendarView::qt_metacall () from /usr/lib/libkorganizerprivate.so.4
#11 0xb5ba21b8 in QMetaObject::activate (sender=0x9894230, from_signal_index=4, to_signal_index=4, argv=0xbfc2364c) at kernel/qobject.cpp:3113
#12 0xb5ba2e42 in QMetaObject::activate (sender=0x9894230, m=0xace6bdbc, local_signal_index=0, argv=0xbfc2364c) at kernel/qobject.cpp:3187
#13 0xace69003 in KOrg::IncidenceChangerBase::incidenceAdded () from /usr/lib/libkorganizer_interfaces.so.4
#14 0xaaee220c in IncidenceChanger::addIncidence () from /usr/lib/libkorganizerprivate.so.4
#15 0xaae5d241 in ?? () from /usr/lib/libkorganizerprivate.so.4
#16 0xaae59b19 in ?? () from /usr/lib/libkorganizerprivate.so.4
#17 0xb6bb1e2c in KDialog::qt_metacall (this=0x9efa488, _c=3217176416, _id=33, _a=0x9efa488) at /build/buildd/kde4libs-4.3.0/obj-i486-linux-gnu/kdeui/kdialog.moc:184
#18 0xb6c7872a in KPageDialog::qt_metacall (this=0x9efa488, _c=QMetaObject::InvokeMetaMethod, _id=69, _a=0xbfc239ac) at /build/buildd/kde4libs-4.3.0/obj-i486-linux-gnu/kdeui/kpagedialog.moc:64
#19 0xaae5a3fa in ?? () from /usr/lib/libkorganizerprivate.so.4
#20 0xaae5d7da in ?? () from /usr/lib/libkorganizerprivate.so.4
#21 0xb5ba21b8 in QMetaObject::activate (sender=0x994e7a8, from_signal_index=4, to_signal_index=4, argv=0xbfc239ac) at kernel/qobject.cpp:3113
#22 0xb5ba2e42 in QMetaObject::activate (sender=0x994e7a8, m=0xb5c7e878, local_signal_index=0, argv=0xbfc239ac) at kernel/qobject.cpp:3187
#23 0xb5ba5ab3 in QSignalMapper::mapped (this=0x994e7a8, _t1=4) at .moc/release-shared/moc_qsignalmapper.cpp:95
#24 0xb5ba633d in QSignalMapper::map (this=0x994e7a8, sender=0x9664920) at kernel/qsignalmapper.cpp:266
#25 0xb5ba652e in QSignalMapper::map (this=0x994e7a8) at kernel/qsignalmapper.cpp:257
#26 0xb5ba6dfb in QSignalMapper::qt_metacall (this=0x994e7a8, _c=QMetaObject::InvokeMetaMethod, _id=4, _a=0xbfc23b2c) at .moc/release-shared/moc_qsignalmapper.cpp:81
#27 0xb5ba21b8 in QMetaObject::activate (sender=0x9664920, from_signal_index=29, to_signal_index=30, argv=0xbfc23b2c) at kernel/qobject.cpp:3113
#28 0xb5ba25f0 in QMetaObject::activate (sender=0x9664920, m=0xb68c80a4, from_local_signal_index=2, to_local_signal_index=3, argv=0xbfc23b2c) at kernel/qobject.cpp:3207
#29 0xb66def91 in QAbstractButton::clicked (this=0x9664920, _t1=false) at .moc/release-shared/moc_qabstractbutton.cpp:200
#30 0xb64063e9 in QAbstractButtonPrivate::emitClicked (this=0xaeddee0) at widgets/qabstractbutton.cpp:543
#31 0xb6408044 in QAbstractButtonPrivate::click (this=0xaeddee0) at widgets/qabstractbutton.cpp:536
#32 0xb64082d6 in QAbstractButton::mouseReleaseEvent (this=0x9664920, e=0xbfc24108) at widgets/qabstractbutton.cpp:1115
#33 0xb60a4973 in QWidget::event (this=0x9664920, event=0xbfc24108) at kernel/qwidget.cpp:7549
#34 0xb640628e in QAbstractButton::event (this=0x9664920, e=0xbfc24108) at widgets/qabstractbutton.cpp:1077
#35 0xb64b1050 in QPushButton::event (this=0x9664920, e=0xbfc24108) at widgets/qpushbutton.cpp:662
#36 0xb604dd3c in QApplicationPrivate::notify_helper (this=0x8708640, receiver=0x9664920, e=0xbfc24108) at kernel/qapplication.cpp:4056
#37 0xb60569b1 in QApplication::notify (this=0xbfc25a88, receiver=0x9664920, e=0xbfc24108) at kernel/qapplication.cpp:3758
#38 0xb6c475cd in KApplication::notify (this=0xbfc25a88, receiver=0x9664920, event=0xbfc24108) at /build/buildd/kde4libs-4.3.0/kdeui/kernel/kapplication.cpp:302
#39 0xb5b8cbcb in QCoreApplication::notifyInternal (this=0xbfc25a88, receiver=0x9664920, event=0xbfc24108) at kernel/qcoreapplication.cpp:610
#40 0xb6055a1e in QApplicationPrivate::sendMouseEvent (receiver=0x9664920, event=0xbfc24108, alienWidget=0x9664920, nativeWidget=0x9efa488, buttonDown=0xb68cfaa0, lastMouseReceiver=@0xb68cfaa4)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#41 0xb60c5cce in QETWidget::translateMouseEvent (this=0x9efa488, event=0xbfc2579c) at kernel/qapplication_x11.cpp:4409
#42 0xb60c5085 in QApplication::x11ProcessEvent (this=0xbfc25a88, event=0xbfc2579c) at kernel/qapplication_x11.cpp:3428
#43 0xb60f037a in x11EventSourceDispatch (s=0x86f9468, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#44 0xb4c5eb88 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#45 0xb4c620eb in ?? () from /usr/lib/libglib-2.0.so.0
#46 0xb4c62268 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#47 0xb5bb82f8 in QEventDispatcherGlib::processEvents (this=0x86d9028, flags={i = -1077782184}) at kernel/qeventdispatcher_glib.cpp:327
#48 0xb60efa75 in QGuiEventDispatcherGlib::processEvents (this=0x86d9028, flags={i = -1077782136}) at kernel/qguieventdispatcher_glib.cpp:202
#49 0xb5b8b1fa in QEventLoop::processEvents (this=0xbfc25a00, flags={i = -1077782072}) at kernel/qeventloop.cpp:149
#50 0xb5b8b642 in QEventLoop::exec (this=0xbfc25a00, flags={i = -1077782008}) at kernel/qeventloop.cpp:201
#51 0xb5b8dae9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#52 0xb604dbb7 in QApplication::exec () at kernel/qapplication.cpp:3525
#53 0x0804bfef in _start ()

This bug may be a duplicate of or related to bug 199185

Reported using DrKonqi