Application: kmail (4.8.0)
KDE Platform Version: 4.8.1 (4.8.1)
Qt Version: 4.8.0
Operating System: Linux 3.0.0-16-generic x86_64
Distribution: Ubuntu 11.10

-- Information about the crash:
I updated to 4.8.1 soon after the packages were availabe in Kubuntu, which is about two weeks ago. In the last three days, kmail is crashing again and again; I detect no pattern except that it is when Igive kmail focus or change focus (moving to a different inbox, for example). 
4.8.0 was really stable.

The crash can be reproduced some of the time.

-- Backtrace:
Application: KMail (kmail), signal: Aborted
[Current thread is 1 (Thread 0x7f38dd6eb7c0 (LWP 19292))]

Thread 6 (Thread 0x7f38bc7ca700 (LWP 19298)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007f38cfb08c2c in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#2  0x00007f38cfb08d59 in ?? () from /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4
#3  0x00007f38d85f6efc in start_thread (arg=0x7f38bc7ca700) at pthread_create.c:304
#4  0x00007f38daa6159d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 5 (Thread 0x7f38bbec9700 (LWP 19299)):
#0  __lll_lock_wait_private () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:97
#1  0x00007f38da9fe62f in _L_lock_10501 () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007f38da9fc9c1 in __GI___libc_free (mem=0x7f3874000020) at malloc.c:3736
#3  0x00007f38db3e68d4 in QTimerInfoList::unregisterTimer (this=0xeaefa0, timerId=2046820368) at kernel/qeventdispatcher_unix.cpp:507
#4  0x00007f38db3d3f51 in stop (this=0xec9dc0) at kernel/qtimer.cpp:266
#5  QTimer::stop (this=0xec9dc0) at kernel/qtimer.cpp:263
#6  0x00007f38db3d4055 in QTimer::timerEvent (this=0xec9dc0, e=<optimized out>) at kernel/qtimer.cpp:279
#7  0x00007f38db3cf8d9 in QObject::event (this=0xec9dc0, e=<optimized out>) at kernel/qobject.cpp:1157
#8  0x00007f38db8d9104 in notify_helper (e=0x7f38bbec8b50, receiver=0xec9dc0, this=0x89a560) at kernel/qapplication.cpp:4555
#9  QApplicationPrivate::notify_helper (this=0x89a560, receiver=0xec9dc0, e=0x7f38bbec8b50) at kernel/qapplication.cpp:4527
#10 0x00007f38db8ddf83 in QApplication::notify (this=0x7fff7ff8c7a0, receiver=0xec9dc0, e=0x7f38bbec8b50) at kernel/qapplication.cpp:4416
#11 0x00007f38dd1079a6 in KApplication::notify (this=0x7fff7ff8c7a0, receiver=0xec9dc0, event=0x7f38bbec8b50) at ../../kdeui/kernel/kapplication.cpp:311
#12 0x00007f38db3b65fc in QCoreApplication::notifyInternal (this=0x7fff7ff8c7a0, receiver=0xec9dc0, event=0x7f38bbec8b50) at kernel/qcoreapplication.cpp:876
#13 0x00007f38db3e79a2 in sendEvent (event=0x7f38bbec8b50, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#14 QTimerInfoList::activateTimers (this=0xeaefa0) at kernel/qeventdispatcher_unix.cpp:611
#15 0x00007f38db3e536d in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:186
#16 timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:180
#17 0x00007f38db3e5391 in idleTimerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:233
#18 0x00007f38d33f0a5d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#19 0x00007f38d33f1258 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#20 0x00007f38d33f1429 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007f38db3e5b9f in QEventDispatcherGlib::processEvents (this=0xeadd00, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:424
#22 0x00007f38db3b53e2 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#23 0x00007f38db3b5637 in QEventLoop::exec (this=0x7f38bbec8dc0, flags=...) at kernel/qeventloop.cpp:204
#24 0x00007f38db2b5067 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#25 0x00007f38db2b808b in QThreadPrivate::start (arg=0xeacb70) at thread/qthread_unix.cpp:298
#26 0x00007f38d85f6efc in start_thread (arg=0x7f38bbec9700) at pthread_create.c:304
#27 0x00007f38daa6159d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#28 0x0000000000000000 in ?? ()

Thread 4 (Thread 0x7f3878e4b700 (LWP 19302)):
#0  0x00007f38d85fa1fd in __pthread_mutex_unlock_usercnt (mutex=<optimized out>, decr=<optimized out>) at pthread_mutex_unlock.c:52
#1  __pthread_mutex_unlock (mutex=0x13557b8) at pthread_mutex_unlock.c:290
#2  0x00007f38d33ef687 in g_main_context_acquire () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f38d33f0d81 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f38d33f1429 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f38db3e5c06 in QEventDispatcherGlib::processEvents (this=0x1356e90, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00007f38db3b53e2 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007f38db3b5637 in QEventLoop::exec (this=0x7f3878e4ad90, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007f38db2b5067 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#9  0x00007f38db39517f in QInotifyFileSystemWatcherEngine::run (this=0x1354640) at io/qfilesystemwatcher_inotify.cpp:248
#10 0x00007f38db2b808b in QThreadPrivate::start (arg=0x1354640) at thread/qthread_unix.cpp:298
#11 0x00007f38d85f6efc in start_thread (arg=0x7f3878e4b700) at pthread_create.c:304
#12 0x00007f38daa6159d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#13 0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7f3873fff700 (LWP 20567)):
#0  pthread_cond_timedwait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_timedwait.S:216
#1  0x00007f38db2b84ff in wait (time=30000, this=0xf5bda0) at thread/qwaitcondition_unix.cpp:84
#2  QWaitCondition::wait (this=<optimized out>, mutex=0xf5bd18, time=30000) at thread/qwaitcondition_unix.cpp:158
#3  0x00007f38db2ab67f in QThreadPoolThread::run (this=0xf6fd00) at concurrent/qthreadpool.cpp:141
#4  0x00007f38db2b808b in QThreadPrivate::start (arg=0xf6fd00) at thread/qthread_unix.cpp:298
#5  0x00007f38d85f6efc in start_thread (arg=0x7f3873fff700) at pthread_create.c:304
#6  0x00007f38daa6159d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#7  0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f387a3a7700 (LWP 20572)):
#0  __lll_lock_wait_private () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:97
#1  0x00007f38da9fe62f in _L_lock_10501 () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007f38da9fc9c1 in __GI___libc_free (mem=0x7f3874000020) at malloc.c:3736
#3  0x00007f38d41031d1 in Soprano::Error::ErrorCache::~ErrorCache() () from /usr/lib/libsoprano.so.4
#4  0x00007f38cd03e314 in ?? () from /usr/lib/libsopranoclient.so.1
#5  0x00007f38cd03fa03 in ?? () from /usr/lib/libsopranoclient.so.1
#6  0x00007f38d3e320b2 in Nepomuk::MainModel::executeQuery (this=0xcd8e90, query=..., language=Soprano::Query::QueryLanguageSparql, userQueryLanguage=...) at ../../nepomuk/core/nepomukmainmodel.cpp:212
#7  0x00007f38d3e22083 in Nepomuk::ResourceData::load (this=0x7f387404fe60) at ../../nepomuk/core/resourcedata.cpp:417
#8  0x00007f38d3e2295c in Nepomuk::ResourceData::property (this=0x7f387404fe60, uri=...) at ../../nepomuk/core/resourcedata.cpp:265
#9  0x00007f38d3e36893 in Nepomuk::Resource::property (this=0x7f387a3a6cc0, uri=...) at ../../nepomuk/core/resource.cpp:301
#10 0x00007f38d71957da in MessageCore::NepomukResourceRetrieverRunnable::run (this=0x7f3874153240) at ../../messagecore/asyncnepomukresourceretriever.cpp:47
#11 0x00007f38db2ab5b2 in QThreadPoolThread::run (this=0x347a370) at concurrent/qthreadpool.cpp:107
#12 0x00007f38db2b808b in QThreadPrivate::start (arg=0x347a370) at thread/qthread_unix.cpp:298
#13 0x00007f38d85f6efc in start_thread (arg=0x7f387a3a7700) at pthread_create.c:304
#14 0x00007f38daa6159d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#15 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f38dd6eb7c0 (LWP 19292)):
[KCrash Handler]
#6  0x00007f38da9b43a5 in __GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
#7  0x00007f38da9b7b0b in __GI_abort () at abort.c:92
#8  0x00007f38da9edd63 in __libc_message (do_abort=2, fmt=0x7f38daadee58 "*** glibc detected *** %s: %s: 0x%s ***\n") at ../sysdeps/unix/sysv/linux/libc_fatal.c:189
#9  0x00007f38da9f86e6 in malloc_printerr (action=3, str=0x7f38daadef90 "double free or corruption (fasttop)", ptr=<optimized out>) at malloc.c:6283
#10 0x00007f38da9fc9cc in __GI___libc_free (mem=<optimized out>) at malloc.c:3738
#11 0x00007f38d913291e in qMetaTypeDeleteHelper<QDBusMessage> (t=0x7f3874052480) at ../../include/QtCore/../../src/corelib/kernel/qmetatype.h:134
#12 0x00007f38db3c7009 in QMetaCallEvent::~QMetaCallEvent (this=0x7f3874070870, __in_chrg=<optimized out>) at kernel/qobject.cpp:509
#13 0x00007f38db3c7069 in QMetaCallEvent::~QMetaCallEvent (this=0x7f3874070870, __in_chrg=<optimized out>) at kernel/qobject.cpp:518
#14 0x00007f38db3ba3d3 in QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x846220) at kernel/qcoreapplication.cpp:1516
#15 0x00007f38db3e5773 in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#16 postEventSourceDispatch (s=<optimized out>) at kernel/qeventdispatcher_glib.cpp:279
#17 0x00007f38d33f0a5d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#18 0x00007f38d33f1258 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#19 0x00007f38d33f1429 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#20 0x00007f38db3e5b9f in QEventDispatcherGlib::processEvents (this=0x847b00, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:424
#21 0x00007f38db97e21e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=<optimized out>) at kernel/qguieventdispatcher_glib.cpp:204
#22 0x00007f38db3b53e2 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#23 0x00007f38db3b5637 in QEventLoop::exec (this=0x7fff7ff8c680, flags=...) at kernel/qeventloop.cpp:204
#24 0x00007f38db3ba6c7 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#25 0x0000000000402bd3 in main (argc=<optimized out>, argv=<optimized out>) at ../../kmail/main.cpp:145

This bug may be a duplicate of or related to bug 295474.

Possible duplicates by query: bug 296015, bug 295989, bug 295901, bug 295681, bug 295474.

Reported using DrKonqi