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 x86_64
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
I don't know whether this is reproducible.  I did this:

1.  Add a new IMAP account (this account has dozens of folders and tens or maybe a hundred thousand messages)
2.  While kmail was reading message information, I opened the settings dialog
3.  Changed folder list to "short", press "apply"
4.  Changed folder list back to "long", press "apply"
5.  Crash

 -- Backtrace:
Application: KMail (kmail), signal: Segmentation fault
The current source language is "auto; currently c".
[Current thread is 1 (Thread 0x7fcadca8b7f0 (LWP 4488))]

Thread 2 (Thread 0x7fcabdcff910 (LWP 4496)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:261
#1  0x00007fcada1824fb in QWaitConditionPrivate::wait (this=<value optimized out>, mutex=0x1530bf8, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=<value optimized out>, mutex=0x1530bf8, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:159
#3  0x00007fcad89fb78c in QHostInfoAgent::run (this=0x1530be0) at kernel/qhostinfo.cpp:260
#4  0x00007fcada181445 in QThreadPrivate::start (arg=0x1530be0) at thread/qthread_unix.cpp:188
#5  0x00007fcad4a99a04 in start_thread (arg=<value optimized out>) at pthread_create.c:300
#6  0x00007fcad996c7bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fcadca8b7f0 (LWP 4488)):
[KCrash Handler]
#5  0x00007fcadb8676d6 in KMail::ISubject::notify (this=0x17f9830) at ../../kmail/isubject.cpp:30
#6  0x00007fcadb552eec in KMMessage::updateBodyPart (this=0x17f9760, partSpecifier=) at ../../kmail/kmmessage.cpp:3235
#7  0x00007fcadb83bbca in KMail::ImapJob::slotGetMessageResult (this=0x1cb5cd0, job=<value optimized out>) at ../../kmail/imapjob.cpp:435
#8  0x00007fcadb84004b in KMail::ImapJob::qt_metacall (this=0x1cb5cd0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffe894fa00) at ./imapjob.moc:82
#9  0x00007fcada27cddc in QMetaObject::activate (sender=0x1cb39f0, from_signal_index=<value optimized out>, to_signal_index=<value optimized out>, argv=0x2) at kernel/qobject.cpp:3113
#10 0x00007fcadbf05af2 in KJob::result (this=0xa9c458, _t1=0x1cb39f0) at ./kjob.moc:188
#11 0x00007fcadbf05e6f in KJob::emitResult (this=0x1cb39f0) at ../../kdecore/jobs/kjob.cpp:304
#12 0x00007fcad4025d93 in KIO::SimpleJob::slotFinished (this=0x1cb39f0) at ../../kio/kio/job.cpp:477
#13 0x00007fcad4026253 in KIO::TransferJob::slotFinished (this=0x1cb39f0) at ../../kio/kio/job.cpp:948
#14 0x00007fcad4024b61 in KIO::TransferJob::qt_metacall (this=0x1cb39f0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffe894fe20) at ./jobclasses.moc:343
#15 0x00007fcada27cddc in QMetaObject::activate (sender=0xa9ca70, from_signal_index=<value optimized out>, to_signal_index=<value optimized out>, argv=0x2) at kernel/qobject.cpp:3113
#16 0x00007fcad40e6a81 in KIO::SlaveInterface::dispatch (this=0xa9ca70, _cmd=104, rawdata=...) at ../../kio/kio/slaveinterface.cpp:175
#17 0x00007fcad40e3333 in KIO::SlaveInterface::dispatch (this=0xa9ca70) at ../../kio/kio/slaveinterface.cpp:91
#18 0x00007fcad40d614d in KIO::Slave::gotInput (this=0xa9ca70) at ../../kio/kio/slave.cpp:322
#19 0x00007fcad40d826c in KIO::Slave::qt_metacall (this=0xa9ca70, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffe89501e0) at ./slave.moc:76
#20 0x00007fcada27cddc in QMetaObject::activate (sender=0x16bafd0, from_signal_index=<value optimized out>, to_signal_index=<value optimized out>, argv=0x2) at kernel/qobject.cpp:3113
#21 0x00007fcad3ff2f57 in KIO::ConnectionPrivate::dequeue (this=0x13f0080) at ../../kio/kio/connection.cpp:82
#22 0x00007fcad3ff307d in KIO::Connection::qt_metacall (this=0x16bafd0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x1c80250) at ./connection.moc:73
#23 0x00007fcada2770f9 in QObject::event (this=0x16bafd0, e=0x1cb3280) at kernel/qobject.cpp:1111
#24 0x00007fcada6faefc in QApplicationPrivate::notify_helper (this=0x866720, receiver=0x16bafd0, e=0x1cb3280) at kernel/qapplication.cpp:4056
#25 0x00007fcada7021ce in QApplication::notify (this=0x7fffe8950cb0, receiver=0x16bafd0, e=0x1cb3280) at kernel/qapplication.cpp:4021
#26 0x00007fcadc4bdab6 in KApplication::notify (this=0x7fffe8950cb0, receiver=0x16bafd0, event=0x1cb3280) at ../../kdeui/kernel/kapplication.cpp:302
#27 0x00007fcada267c2c in QCoreApplication::notifyInternal (this=0x7fffe8950cb0, receiver=0x16bafd0, event=0x1cb3280) at kernel/qcoreapplication.cpp:610
#28 0x00007fcada26880a in QCoreApplication::sendEvent (receiver=0x0, event_type=<value optimized out>, data=0x828d00) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#29 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=<value optimized out>, data=0x828d00) at kernel/qcoreapplication.cpp:1247
#30 0x00007fcada290533 in QCoreApplication::sendPostedEvents (s=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#31 postEventSourceDispatch (s=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:210
#32 0x00007fcad1500bce in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#33 0x00007fcad1504598 in ?? () from /lib/libglib-2.0.so.0
#34 0x00007fcad15046c0 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#35 0x00007fcada2901a6 in QEventDispatcherGlib::processEvents (this=0x828930, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#36 0x00007fcada78f4be in QGuiEventDispatcherGlib::processEvents (this=0xa9c458, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#37 0x00007fcada266532 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#38 0x00007fcada266904 in QEventLoop::exec (this=0x7fffe8950ae0, flags=) at kernel/qeventloop.cpp:201
#39 0x00007fcada268ab9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#40 0x0000000000402fe9 in main (argc=<value optimized out>, argv=<value optimized out>) at ../../kmail/main.cpp:146
The current source language is "auto; currently asm".
The current source language is "auto; currently c".

Reported using DrKonqi