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 x86_64
Distribution: Ubuntu karmic (development branch)

What I was doing when the application crashed:
I have ~ 1000 messages in my local sent mail folder.  I filtered them down to just messages I'd sent to a specific person and was looking through those.  As I clicked between them, it crashed.

 -- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[KCrash Handler]
#5  QAbstractItemView::model (this=0x5e5c9a0) at itemviews/qabstractitemview.cpp:585
#6  0x00007f3f234ec7d5 in QTreeWidgetItem::executePendingSort (this=<value optimized out>) at itemviews/qtreewidget.cpp:2181
#7  0x00007f3f0d7f5305 in KMMimePartTreeItem (this=0x3243a40, parent=0x51d6050, node=0x610c910, description=@0x7fff0ca20fe0, mimetype=@0x7fff0ca20fd0, encoding=<value optimized out>, size=9436, 
    revertOrder=false) at /usr/include/qt4/QtGui/qtreewidget.h:251
#8  0x00007f3f0d835593 in partNode::fillMimePartTree (this=0x610c910, parentItem=0x51d6050, mimePartTree=<value optimized out>, labelDescr=<value optimized out>, labelCntType=<value optimized out>, 
    labelEncoding=<value optimized out>, size=0, revertOrder=220) at ../../kmail/partNode.cpp:496
#9  0x00007f3f0d8239b7 in KMail::ObjectTreeParser::insertAndParseNewChildNode (this=0x7fff0ca21660, startNode=@0x6684f30, content=<value optimized out>, cntDesc=<value optimized out>, append=false)
    at ../../kmail/objecttreeparser.cpp:219
#10 0x00007f3f0d82592d in KMail::ObjectTreeParser::processMessageRfc822Subtype (this=0x7fff0ca21660, node=0x6684f30) at ../../kmail/objecttreeparser.cpp:1411
#11 0x00007f3f0d8232be in KMail::ObjectTreeParser::parseObjectTree (this=0x7fff0ca21660, node=0x6684f30) at ../../kmail/objecttreeparser.cpp:290
#12 0x00007f3f0d8234b5 in KMail::ObjectTreeParser::stdChildHandling (this=0x7fff0ca21bc0, child=0x55cc260) at ../../kmail/objecttreeparser.cpp:1135
#13 0x00007f3f0d8237c4 in KMail::ObjectTreeParser::processMultiPartMixedSubtype (this=0x5e5c9a0, node=<value optimized out>) at ../../kmail/objecttreeparser.cpp:1148
#14 0x00007f3f0d8232be in KMail::ObjectTreeParser::parseObjectTree (this=0x7fff0ca21bc0, node=0x6c802d0) at ../../kmail/objecttreeparser.cpp:290
#15 0x00007f3f0d8275e6 in KMail::ObjectTreeParser::writeOpaqueOrMultipartSignedData (this=<value optimized out>, data=<value optimized out>, sign=<value optimized out>, 
    fromAddress=<value optimized out>, doCheck=<value optimized out>, cleartextData=<value optimized out>, paramSignatures=@0x7fff0ca22360, hideErrors=false) at ../../kmail/objecttreeparser.cpp:642
#16 0x00007f3f0d82a007 in KMail::ObjectTreeParser::processMultiPartSignedSubtype (this=0x7fff0ca22770, node=0x5630350) at ../../kmail/objecttreeparser.cpp:1239
#17 0x00007f3f0d8232be in KMail::ObjectTreeParser::parseObjectTree (this=0x7fff0ca22770, node=0x5630350) at ../../kmail/objecttreeparser.cpp:290
#18 0x00007f3f0d6aa0f9 in KMReaderWin::parseMsg (this=0x22ef280, aMsg=0x674e850) at ../../kmail/kmreaderwin.cpp:1656
#19 0x00007f3f0d6998aa in KMReaderWin::displayMessage (this=0x22ef280) at ../../kmail/kmreaderwin.cpp:1589
#20 0x00007f3f0d699a84 in KMReaderWin::updateReaderWin (this=0x22ef280) at ../../kmail/kmreaderwin.cpp:1529
#21 0x00007f3f0d6a56ad in KMReaderWin::qt_metacall (this=0x22ef280, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff0ca22e70) at ./kmreaderwin.moc:165
#22 0x00007f3f2267274c in QMetaObject::activate (sender=0x22ef318, from_signal_index=<value optimized out>, to_signal_index=<value optimized out>, argv=0x6549190) at kernel/qobject.cpp:3120
#23 0x00007f3f2266c623 in QObject::event (this=0x22ef318, e=0xffffffff) at kernel/qobject.cpp:1082
#24 0x00007f3f22f7427c in QApplicationPrivate::notify_helper (this=0x163f6b0, receiver=0x22ef318, e=0x7fff0ca23470) at kernel/qapplication.cpp:4057
#25 0x00007f3f22f7b54e in QApplication::notify (this=0x7fff0ca237d0, receiver=0x22ef318, e=0x7fff0ca23470) at kernel/qapplication.cpp:4022
#26 0x00007f3f23bd1c16 in KApplication::notify (this=0x7fff0ca237d0, receiver=0x22ef318, event=0x7fff0ca23470) at ../../kdeui/kernel/kapplication.cpp:302
#27 0x00007f3f2265d20c in QCoreApplication::notifyInternal (this=0x7fff0ca237d0, receiver=0x22ef318, event=0x7fff0ca23470) at kernel/qcoreapplication.cpp:610
#28 0x00007f3f22688142 in QTimerInfoList::activateTimers (this=0x1635310) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#29 0x00007f3f22685c1d in timerSourceDispatch (source=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:164
#30 0x00007f3f1c4728fe in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#31 0x00007f3f1c475fd8 in ?? () from /usr/lib/libglib-2.0.so.0
#32 0x00007f3f1c476100 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#33 0x00007f3f22685b66 in QEventDispatcherGlib::processEvents (this=0x1608850, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:324
#34 0x00007f3f2300855e in QGuiEventDispatcherGlib::processEvents (this=0x5e5c9a0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#35 0x00007f3f2265bb12 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#36 0x00007f3f2265bee4 in QEventLoop::exec (this=0x7fff0ca23710, flags=) at kernel/qeventloop.cpp:200
#37 0x00007f3f2265df89 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#38 0x0000000000403f27 in _start ()

Reported using DrKonqi