Application: kmail (4.8.2)
KDE Platform Version: 4.8.2 (4.8.2)
Qt Version: 4.8.1
Operating System: Linux 3.2.0-22-generic x86_64
Distribution: Ubuntu precise (development branch)

-- Information about the crash:
- What I was doing when the application crashed:
I was writing an e-mail and clicked on send. After that, the mail became uneditable (text and buttons were grayed out, as normal before sending) and stayed open. I then noticed in top the process virtuoso-t with >170% CPU. After a while I killed it and the process nepomukindexer took over with 50% CPU. Killing that, too, led to the kmail crash. When I tried to start KMail again I got the warning that it was already running on another display.
I hope this helps.

-- Backtrace:
Application: KMail (kmail), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f0302abc7c0 (LWP 14818))]

Thread 4 (Thread 0x7f02e0527700 (LWP 14960)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007f02f4dbedec in WTF::TCMalloc_PageHeap::scavengerThread (this=0x7f02f5787de0) at wtf/FastMalloc.cpp:2495
#2  0x00007f02f4dbef19 in WTF::TCMalloc_PageHeap::runScavengerThread (context=<optimized out>) at wtf/FastMalloc.cpp:1618
#3  0x00007f02fd8f0e9a in start_thread (arg=0x7f02e0527700) at pthread_create.c:308
#4  0x00007f02ffe214bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7f02dfc26700 (LWP 14961)):
#0  0x00007ffff5fff98f in clock_gettime ()
#1  0x00007f02f774815d in __GI_clock_gettime (clock_id=<optimized out>, tp=<optimized out>) at ../sysdeps/unix/clock_gettime.c:116
#2  0x00007f03006d4bb4 in do_gettime (frac=0x7f02dfc25ba8, sec=0x7f02dfc25ba0) at tools/qelapsedtimer_unix.cpp:123
#3  qt_gettime () at tools/qelapsedtimer_unix.cpp:140
#4  0x00007f03007acb8d in QTimerInfoList::updateCurrentTime (this=0x7f02d8002860) at kernel/qeventdispatcher_unix.cpp:343
#5  0x00007f03007acec3 in QTimerInfoList::timerWait (this=0x7f02d8002860, tm=...) at kernel/qeventdispatcher_unix.cpp:450
#6  0x00007f03007ab97c in timerSourcePrepareHelper (src=<optimized out>, timeout=0x7f02dfc25c5c) at kernel/qeventdispatcher_glib.cpp:136
#7  0x00007f02f86ca71e in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#8  0x00007f02f86caf1b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#9  0x00007f02f86cb124 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#10 0x00007f03007ac426 in QEventDispatcherGlib::processEvents (this=0x7f02d80008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#11 0x00007f030077bc82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#12 0x00007f030077bed7 in QEventLoop::exec (this=0x7f02dfc25dc0, flags=...) at kernel/qeventloop.cpp:204
#13 0x00007f030067afa7 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#14 0x00007f030067dfcb in QThreadPrivate::start (arg=0x1aa0ae0) at thread/qthread_unix.cpp:298
#15 0x00007f02fd8f0e9a in start_thread (arg=0x7f02dfc26700) at pthread_create.c:308
#16 0x00007f02ffe214bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#17 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f02dcb35700 (LWP 14972)):
#0  0x00007f02fd8f2f69 in __pthread_mutex_lock (mutex=0x7f028c000a60) at pthread_mutex_lock.c:92
#1  0x00007f02f8706571 in g_mutex_lock () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f02f86cb110 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f03007ac426 in QEventDispatcherGlib::processEvents (this=0x7f028c0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4  0x00007f030077bc82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f030077bed7 in QEventLoop::exec (this=0x7f02dcb34d90, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f030067afa7 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#7  0x00007f030075b9ff in QInotifyFileSystemWatcherEngine::run (this=0x1f60cd0) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007f030067dfcb in QThreadPrivate::start (arg=0x1f60cd0) at thread/qthread_unix.cpp:298
#9  0x00007f02fd8f0e9a in start_thread (arg=0x7f02dcb35700) at pthread_create.c:308
#10 0x00007f02ffe214bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f0302abc7c0 (LWP 14818)):
[KCrash Handler]
#6  deref (this=0x0) at /usr/include/qt4/QtCore/qatomic_x86_64.h:133
#7  operator= (l=..., this=0x26a60c8) at /usr/include/qt4/QtCore/qlist.h:442
#8  Message::ComposerViewBase::slotEmailAddressResolved (this=0x26a6050, job=<optimized out>) at ../../messagecomposer/composerviewbase.cpp:343
#9  0x00007f0300791281 in QMetaObject::activate (sender=0x3ecc480, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7ffff5f32450) at kernel/qobject.cpp:3547
#10 0x00007f0301f02822 in KJob::result (this=<optimized out>, _t1=0x3ecc480) at ./kjob.moc:208
#11 0x00007f0301f02860 in KJob::emitResult (this=0x3ecc480) at ../../kdecore/jobs/kjob.cpp:318
#12 0x00007f02fc217f38 in MessageComposer::EmailAddressResolveJob::start (this=0x3ecc480) at ../../messagecomposer/emailaddressresolvejob.cpp:95
#13 0x00007f02fc1ed3a5 in Message::ComposerViewBase::readyForSending (this=0x26a6050) at ../../messagecomposer/composerviewbase.cpp:290
#14 0x00007f02fc1eea54 in Message::ComposerViewBase::send (this=0x26a6050, method=<optimized out>, saveIn=<optimized out>) at ../../messagecomposer/composerviewbase.cpp:261
#15 0x00007f030190cf9e in KMComposeWin::doDelayedSend (this=0x28ee690, method=MessageSender::SendImmediate, saveIn=MessageSender::SaveInNone) at ../../kmail/kmcomposewin.cpp:2711
#16 0x00007f030190d29b in KMComposeWin::slotDoDelayedSend (this=0x28ee690, job=<optimized out>) at ../../kmail/kmcomposewin.cpp:2669
#17 0x00007f0300791281 in QMetaObject::activate (sender=0x3cdea60, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7ffff5f32d10) at kernel/qobject.cpp:3547
#18 0x00007f0301f02822 in KJob::result (this=<optimized out>, _t1=0x3cdea60) at ./kjob.moc:208
#19 0x00007f0301f02860 in KJob::emitResult (this=0x3cdea60) at ../../kdecore/jobs/kjob.cpp:318
#20 0x00007f030191b631 in AddressValidationJob::Private::slotAliasExpansionDone (this=0x3808cd0, job=<optimized out>) at ../../kmail/addressvalidationjob.cpp:96
#21 0x00007f0300791281 in QMetaObject::activate (sender=0x302c6a0, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7ffff5f33050) at kernel/qobject.cpp:3547
#22 0x00007f0301f02822 in KJob::result (this=<optimized out>, _t1=0x302c6a0) at ./kjob.moc:208
#23 0x00007f0301f02860 in KJob::emitResult (this=0x302c6a0) at ../../kdecore/jobs/kjob.cpp:318
#24 0x00007f02fc215d6b in MessageComposer::AliasesExpandJob::finishExpansion (this=0x302c6a0) at ../../messagecomposer/aliasesexpandjob.cpp:250
#25 0x00007f02fc2168ee in MessageComposer::AliasesExpandJob::slotNicknameExpansionDone (this=0x302c6a0, job=<optimized out>) at ../../messagecomposer/aliasesexpandjob.cpp:204
#26 0x00007f0300791281 in QMetaObject::activate (sender=0x3eec540, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7ffff5f33430) at kernel/qobject.cpp:3547
#27 0x00007f0301f02822 in KJob::result (this=<optimized out>, _t1=0x3eec540) at ./kjob.moc:208
#28 0x00007f0301f02860 in KJob::emitResult (this=0x3eec540) at ../../kdecore/jobs/kjob.cpp:318
#29 0x00007f0300796446 in QObject::event (this=0x3eec540, e=<optimized out>) at kernel/qobject.cpp:1195
#30 0x00007f0300c9f894 in notify_helper (e=0x3e6d060, receiver=0x3eec540, this=0x1412e50) at kernel/qapplication.cpp:4559
#31 QApplicationPrivate::notify_helper (this=0x1412e50, receiver=0x3eec540, e=0x3e6d060) at kernel/qapplication.cpp:4531
#32 0x00007f0300ca4713 in QApplication::notify (this=0x7ffff5f33e70, receiver=0x3eec540, e=0x3e6d060) at kernel/qapplication.cpp:4420
#33 0x00007f03024d8b46 in KApplication::notify (this=0x7ffff5f33e70, receiver=0x3eec540, event=0x3e6d060) at ../../kdeui/kernel/kapplication.cpp:311
#34 0x00007f030077ce9c in QCoreApplication::notifyInternal (this=0x7ffff5f33e70, receiver=0x3eec540, event=0x3e6d060) at kernel/qcoreapplication.cpp:876
#35 0x00007f0300780c6a in sendEvent (event=0x3e6d060, receiver=0x3eec540) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#36 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x13b2220) at kernel/qcoreapplication.cpp:1500
#37 0x00007f03007abf93 in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#38 postEventSourceDispatch (s=<optimized out>) at kernel/qeventdispatcher_glib.cpp:279
#39 0x00007f02f86cac9a in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#40 0x00007f02f86cb060 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#41 0x00007f02f86cb124 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#42 0x00007f03007ac3bf in QEventDispatcherGlib::processEvents (this=0x13b3b00, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#43 0x00007f0300d47d6e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#44 0x00007f030077bc82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#45 0x00007f030077bed7 in QEventLoop::exec (this=0x7ffff5f33d50, flags=...) at kernel/qeventloop.cpp:204
#46 0x00007f0300780f67 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#47 0x0000000000402bd3 in main (argc=<optimized out>, argv=<optimized out>) at ../../kmail/main.cpp:145

Reported using DrKonqi