Application that crashed: kmail
Version of the application: 1.12.2
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.2
Operating System: Linux 2.6.31-16-generic i686
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
When I advanced to the next message in my mailbox, KMail become completely unresponsive and its CPU usage went to 100%. After about two minutes, I killed it with a 'kill -HUP', which produced the attached stack dump.

 -- Backtrace:
Application: KMail (kmail), signal: Aborted
[KCrash Handler]
#23 0x066b1aa0 in DwBodyPart::Next() const () from /usr/lib/libmimelib.so.4
#24 0x066b062a in DwBody::_AddBodyPart(DwBodyPart*) () from /usr/lib/libmimelib.so.4
#25 0x066b06f9 in DwBody::AddBodyPart(DwBodyPart*) () from /usr/lib/libmimelib.so.4
#26 0x01056e44 in ?? () from /usr/lib/libkmailprivate.so.4
#27 0x01056d9e in ?? () from /usr/lib/libkmailprivate.so.4
#28 0x01057168 in ?? () from /usr/lib/libkmailprivate.so.4
#29 0x011e8ef9 in ?? () from /usr/lib/libkmailprivate.so.4
#30 0x011ee62f in ?? () from /usr/lib/libkmailprivate.so.4
#31 0x0037e263 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#32 0x0037eec2 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#33 0x00cacfe3 in KJob::result(KJob*) () from /usr/lib/libkdecore.so.5
#34 0x00cad469 in KJob::emitResult() () from /usr/lib/libkdecore.so.5
#35 0x01b02660 in KIO::SimpleJob::slotFinished() () from /usr/lib/libkio.so.5
#36 0x01b02b7a in KIO::TransferJob::slotFinished() () from /usr/lib/libkio.so.5
#37 0x01b008a3 in KIO::TransferJob::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libkio.so.5
#38 0x0037e263 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#39 0x0037eec2 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#40 0x01bcc557 in KIO::SlaveInterface::finished() () from /usr/lib/libkio.so.5
#41 0x01bd044d in KIO::SlaveInterface::dispatch(int, QByteArray const&) () from /usr/lib/libkio.so.5
#42 0x01bcca13 in KIO::SlaveInterface::dispatch() () from /usr/lib/libkio.so.5
#43 0x01bbeaea in KIO::Slave::gotInput() () from /usr/lib/libkio.so.5
#44 0x01bc0ee3 in KIO::Slave::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libkio.so.5
#45 0x0037e263 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#46 0x0037eec2 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#47 0x01ac8f97 in KIO::Connection::readyRead() () from /usr/lib/libkio.so.5
#48 0x01acad5e in ?? () from /usr/lib/libkio.so.5
#49 0x01acae8e in KIO::Connection::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libkio.so.5
#50 0x00376f0b in QMetaCallEvent::placeMetaCall(QObject*) () from /usr/lib/libQtCore.so.4
#51 0x003785fe in QObject::event(QEvent*) () from /usr/lib/libQtCore.so.4
#52 0x0435df54 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#53 0x0436567c in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#54 0x0090dbfa in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#55 0x003686cb in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#56 0x003692b2 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/libQtCore.so.4
#57 0x0036947d in QCoreApplication::sendPostedEvents(QObject*, int) () from /usr/lib/libQtCore.so.4
#58 0x003933ff in ?? () from /usr/lib/libQtCore.so.4
#59 0x0214be88 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#60 0x0214f730 in ?? () from /lib/libglib-2.0.so.0
#61 0x0214f863 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#62 0x0039302c in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#63 0x043febe5 in ?? () from /usr/lib/libQtGui.so.4
#64 0x00366c79 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#65 0x003670ca in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#66 0x0036953f in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#67 0x0435ddd7 in QApplication::exec() () from /usr/lib/libQtGui.so.4
#68 0x0804a702 in _start ()

Reported using DrKonqi