Application that crashed: kontact
Version of the application: 4.3.2
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.3
Operating System: Linux 2.6.30-gentoo-r7-yuzuki i686

What I was doing when the application crashed:
Saved session tries to start kontact, which reports another instance already running.
If stopped to start the "second" instance, no kontact starts at all, if started anyway, two kontact windows (instances) show up, but crash whenever anything is done (closed, navigated to some mails, etc.)
This is always reproducable with a saved session.
This problem was not in KDE 4.3.1, but I had a similar behaviour some version before that at some point.

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[Current thread is 0 (LWP 4425)]

Thread 2 (Thread 0xaf343b90 (LWP 4556)):
#0  0xb7fd7c50 in ?? () from /lib/ld-linux.so.2
#1  0xb7fd8008 in ?? () from /lib/ld-linux.so.2
#2  0xb7fdd766 in ?? () from /lib/ld-linux.so.2
#3  0xb7fe4740 in ?? () from /lib/ld-linux.so.2
#4  0xb5be9d02 in QEventDispatcherGlib::~QEventDispatcherGlib () from /usr/lib/qt4/libQtCore.so.4
#5  0xb5ad83fd in QThreadPrivate::finish () from /usr/lib/qt4/libQtCore.so.4
#6  0xb5ad8539 in QThreadPrivate::start () from /usr/lib/qt4/libQtCore.so.4
#7  0xb5a564cf in start_thread () from /lib/libpthread.so.0

Thread 1 (Thread 0xb49df700 (LWP 4425)):
[KCrash Handler]
#6  0xb1421566 in KMail::ListJob::slotListEntries () from /usr/lib/libkmailprivate.so.4
#7  0xb142254e in KMail::ListJob::qt_metacall () from /usr/lib/libkmailprivate.so.4
#8  0xb5bd40f4 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#9  0xb5bd4692 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#10 0xb6cd0169 in KIO::ListJob::entries (this=0x888a690, _t1=0x888a690, _t2=@0xbfdb4954) at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2_build/kio/jobclasses.moc:781
#11 0xb6cdcb58 in KIO::ListJobPrivate::slotListEntries (this=0x888a360, list=@0xbfdb4954) at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2/kio/kio/job.cpp:2333
#12 0xb6cdcc60 in KIO::ListJob::qt_metacall (this=0x888a690, _c=QMetaObject::InvokeMetaMethod, _id=6, _a=0xbfdb481c)
    at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2_build/kio/jobclasses.moc:767
#13 0xb5bd40f4 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#14 0xb5bd4692 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#15 0xb6da0733 in KIO::SlaveInterface::listEntries (this=0x87d16c8, _t1=@0xbfdb4954) at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2_build/kio/slaveinterface.moc:179
#16 0xb6da44d9 in KIO::SlaveInterface::dispatch (this=0x87d16c8, _cmd=106, rawdata=@0xbfdb49a4) at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2/kio/kio/slaveinterface.cpp:193
#17 0xb6da0cc7 in KIO::SlaveInterface::dispatch (this=0x87d16c8) at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2/kio/kio/slaveinterface.cpp:91
#18 0xb6d92cad in KIO::Slave::gotInput (this=0x87d16c8) at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2/kio/kio/slave.cpp:322
#19 0xb6d95193 in KIO::Slave::qt_metacall (this=0x87d16c8, _c=QMetaObject::InvokeMetaMethod, _id=2, _a=0xbfdb4aa8)
    at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2_build/kio/slave.moc:76
#20 0xb5bd40f4 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#21 0xb5bd4692 in QMetaObject::activate () from /usr/lib/qt4/libQtCore.so.4
#22 0xb6c9ee77 in KIO::Connection::readyRead (this=0x81cfff8) at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2_build/kio/connection.moc:86
#23 0xb6ca0793 in KIO::ConnectionPrivate::dequeue (this=0x81cfff8) at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2/kio/kio/connection.cpp:82
#24 0xb6ca0b76 in KIO::Connection::qt_metacall (this=0x81cfff8, _c=QMetaObject::InvokeMetaMethod, _id=1, _a=0x864b7a8)
    at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2_build/kio/connection.moc:73
#25 0xb5bcf50b in QMetaCallEvent::placeMetaCall () from /usr/lib/qt4/libQtCore.so.4
#26 0xb5bd12a0 in QObject::event () from /usr/lib/qt4/libQtCore.so.4
#27 0xb6075544 in QApplicationPrivate::notify_helper () from /usr/lib/qt4/libQtGui.so.4
#28 0xb607dd2e in QApplication::notify () from /usr/lib/qt4/libQtGui.so.4
#29 0xb6949e8d in KApplication::notify (this=0xbfdb5228, receiver=0x81cfff8, event=0x880c748) at /var/tmp/portage/kde-base/kdelibs-4.3.2-r3/work/kdelibs-4.3.2/kdeui/kernel/kapplication.cpp:302
#30 0xb5bc200b in QCoreApplication::notifyInternal () from /usr/lib/qt4/libQtCore.so.4
#31 0xb5bc292c in QCoreApplicationPrivate::sendPostedEvents () from /usr/lib/qt4/libQtCore.so.4
#32 0xb5bc2abd in QCoreApplication::sendPostedEvents () from /usr/lib/qt4/libQtCore.so.4
#33 0xb5be952f in postEventSourceDispatch () from /usr/lib/qt4/libQtCore.so.4
#34 0xb513b8fe in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#35 0xb513f13b in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#36 0xb513f2c8 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#37 0xb5be9188 in QEventDispatcherGlib::processEvents () from /usr/lib/qt4/libQtCore.so.4
#38 0xb6103fd5 in QGuiEventDispatcherGlib::processEvents () from /usr/lib/qt4/libQtGui.so.4
#39 0xb5bc07ca in QEventLoop::processEvents () from /usr/lib/qt4/libQtCore.so.4
#40 0xb5bc0992 in QEventLoop::exec () from /usr/lib/qt4/libQtCore.so.4
#41 0xb5bc2b81 in QCoreApplication::exec () from /usr/lib/qt4/libQtCore.so.4
#42 0xb60753c7 in QApplication::exec () from /usr/lib/qt4/libQtGui.so.4
#43 0x0804b74b in main (argc=3, argv=0xbfdb53e4) at /var/tmp/portage/kde-base/kontact-4.3.2/work/kontact-4.3.2/kontact/src/main.cpp:218

This bug may be a duplicate of or related to bug 211733

Reported using DrKonqi