Application: kmail (1.13.6)
KDE Platform Version: 4.6.1 (4.6.1)
Qt Version: 4.7.2
Operating System: Linux 2.6.37-ARCH x86_64
Distribution (Platform): Archlinux Packages

-- Information about the crash:
I noticed that a filter was not entirely pertinent so I added a condition at it, then I pressed Control+J 3-4 times on the first message of the list (which was concerned by the filter) and... crash.
This happened on an IMAP account.

The crash can be reproduced some of the time.

-- Backtrace:
Application: KMail (kmail), signal: Aborted
[KCrash Handler]
#6  0x00007fd4fe655655 in raise () from /lib/libc.so.6
#7  0x00007fd4fe656ad6 in abort () from /lib/libc.so.6
#8  0x00007fd4fef0e65f in qt_message_output(QtMsgType, char const*) () from /usr/lib/libQtCore.so.4
#9  0x00007fd4fef0e7ed in ?? () from /usr/lib/libQtCore.so.4
#10 0x00007fd4fef0e985 in qFatal(char const*, ...) () from /usr/lib/libQtCore.so.4
#11 0x00007fd5005d4ee0 in KMail::MessageProperty::forget (msgBase=0x2338580) at /var/abs/local/extra/kdepim/src/kdepim-4.4.10/kmail/messageproperty.cpp:180
#12 0x00007fd50061b036 in KMMsgBase::~KMMsgBase (this=0x2338580, __in_chrg=<value optimized out>) at /var/abs/local/extra/kdepim/src/kdepim-4.4.10/kmail/kmmsgbase.cpp:128
#13 0x00007fd5005157b9 in KMMessage::~KMMessage (this=0x2338580, __in_chrg=<value optimized out>) at /var/abs/local/extra/kdepim/src/kdepim-4.4.10/kmail/kmmessage.cpp:228
#14 0x00007fd50061d001 in KMMsgList::clear (this=0x2145838, doDelete=true, syncDict=true) at /var/abs/local/extra/kdepim/src/kdepim-4.4.10/kmail/kmmsglist.cpp:37
#15 0x00007fd5005cbeeb in FolderStorage::remove (this=0x21457c0) at /var/abs/local/extra/kdepim/src/kdepim-4.4.10/kmail/folderstorage.cpp:785
#16 0x00007fd5005e9e5d in KMFolderMgr::remove (this=0x1b31e10, aFolder=0x21445a0) at /var/abs/local/extra/kdepim/src/kdepim-4.4.10/kmail/kmfoldermgr.cpp:354
#17 0x00007fd5005d104f in KMail::ActionScheduler::~ActionScheduler (this=0x2557fb0, __in_chrg=<value optimized out>) at /var/abs/local/extra/kdepim/src/kdepim-4.4.10/kmail/actionscheduler.cpp:136
#18 0x00007fd5005d10f9 in KMail::ActionScheduler::~ActionScheduler (this=0x2557fb0, __in_chrg=<value optimized out>) at /var/abs/local/extra/kdepim/src/kdepim-4.4.10/kmail/actionscheduler.cpp:144
#19 0x00007fd4ff014c98 in QObject::event(QEvent*) () from /usr/lib/libQtCore.so.4
#20 0x00007fd4ff4ec6a4 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#21 0x00007fd4ff4f126a in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#22 0x00007fd501560d46 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#23 0x00007fd4ff00090c in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#24 0x00007fd4ff004135 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/libQtCore.so.4
#25 0x00007fd4ff02b873 in ?? () from /usr/lib/libQtCore.so.4
#26 0x00007fd4f635dbf3 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#27 0x00007fd4f635e3d0 in ?? () from /usr/lib/libglib-2.0.so.0
#28 0x00007fd4f635e66d in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#29 0x00007fd4ff02ba0f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#30 0x00007fd4ff59203e in ?? () from /usr/lib/libQtGui.so.4
#31 0x00007fd4fefffca2 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#32 0x00007fd4fefffeec in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#33 0x00007fd4ff0043eb in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#34 0x0000000000402ffb in main (argc=<value optimized out>, argv=<value optimized out>) at /var/abs/local/extra/kdepim/src/kdepim-4.4.10/kmail/main.cpp:156

Reported using DrKonqi