Application: kontact (4.6 pre)
KDE Platform Version: 4.5.85 (4.6 Beta2)
Qt Version: 4.7.1
Operating System: Linux 2.6.35.9-64.fc14.x86_64 x86_64
Distribution (Platform): Fedora RPMs

-- Information about the crash:
Sometimes for a reason I can't explain, kmail is not able to propose the good information about unread mails (it indicates 2 unread mails even none where there are numerous); kmail is also unable to go and select the next mail when I am deleting one.
At this moment, I close kontact, trying to get kmail working again. Kontact is configured to open knode as the default application. When I try to select kmail after starting kontact, nothing happen and kontact crashes in a few second.
In normal conditions (without problems of unread mail notification in kmail), restarting kontact does not finish in a crash.

The crash can be reproduced every time.

-- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
[Current thread is 1 (Thread 0x7fb708f50840 (LWP 31678))]

Thread 2 (Thread 0x7fb6fdd5d700 (LWP 31679)):
#0  0x0000003431e0b8c4 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x0000003509b287f4 in WTF::TCMalloc_PageHeap::runScavengerThread(void*) () from /usr/lib64/libQtWebKit.so.4
#2  0x0000003431e06d5b in start_thread () from /lib64/libpthread.so.0
#3  0x00000034312e4aad in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7fb708f50840 (LWP 31678)):
[KCrash Handler]
#6  QMutex::lock (this=0x100000040) at thread/qmutex.cpp:151
#7  0x00000034fe75e63e in QCoreApplication::postEvent (receiver=0x2b169d8, event=0x25dc3d0, priority=0) at kernel/qcoreapplication.cpp:1141
#8  0x000000350c47bf4f in KPIM::ProgressItem::removeChild (this=0x2b169d8, kiddo=0x25ab970) at /usr/src/debug/kdepim-4.5.80/libkdepim/progressmanager.cpp:77
#9  0x000000350c47bf91 in KPIM::ProgressItem::setComplete (this=0x25ab970) at /usr/src/debug/kdepim-4.5.80/libkdepim/progressmanager.cpp:58
#10 0x000000350c47d3dc in KPIM::AgentProgressMonitor::Private::instanceStatusChanged (this=0x25aeb90, instance=...) at /usr/src/debug/kdepim-4.5.80/libkdepim/agentprogressmonitor.cpp:85
#11 0x000000350c47d47a in KPIM::AgentProgressMonitor::qt_metacall (this=0x25a9790, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffad5a4300) at /usr/src/debug/kdepim-4.5.80/x86_64-redhat-linux-gnu/libkdepim/agentprogressmonitor.moc:78
#12 0x00000034fe77004f in QMetaObject::activate (sender=0x19a1220, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x7fffad5a4300) at kernel/qobject.cpp:3272
#13 0x0000003505e8fd85 in Akonadi::AgentManager::instanceStatusChanged (this=<value optimized out>, _t1=<value optimized out>) at /usr/src/debug/kdepimlibs-4.5.85/x86_64-redhat-linux-gnu/akonadi/agentmanager.moc:177
#14 0x0000003505e944d1 in Akonadi::AgentManagerPrivate::agentInstanceStatusChanged (this=0x19a1250, identifier=<value optimized out>, status=0, msg=...) at /usr/src/debug/kdepimlibs-4.5.85/akonadi/agentmanager.cpp:129
#15 0x0000003505e9687e in Akonadi::AgentManager::qt_metacall (this=0x19a1220, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffad5a4480) at /usr/src/debug/kdepimlibs-4.5.85/x86_64-redhat-linux-gnu/akonadi/agentmanager.moc:131
#16 0x00000034fe77004f in QMetaObject::activate (sender=0x18e6640, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x7fffad5a4480) at kernel/qobject.cpp:3272
#17 0x0000003505fb0a6b in OrgFreedesktopAkonadiAgentManagerInterface::agentInstanceStatusChanged (this=<value optimized out>, _t1=<value optimized out>, _t2=0, _t3=<value optimized out>) at /usr/src/debug/kdepimlibs-4.5.85/x86_64-redhat-linux-gnu/akonadi/agentmanagerinterface.moc:280
#18 0x0000003505fb0f18 in OrgFreedesktopAkonadiAgentManagerInterface::qt_metacall (this=0x18e6640, _c=QMetaObject::InvokeMetaMethod, _id=7, _a=0x7fffad5a4e30) at /usr/src/debug/kdepimlibs-4.5.85/x86_64-redhat-linux-gnu/akonadi/agentmanagerinterface.moc:164
#19 0x00000034fec20228 in QDBusConnectionPrivate::deliverCall (this=0x130f1d0, object=0x18e6640, msg=..., metaTypes=..., slotIdx=12) at qdbusintegrator.cpp:919
#20 0x00000034fec2b0ff in QDBusCallDeliveryEvent::placeMetaCall (this=<value optimized out>, object=<value optimized out>) at qdbusintegrator_p.h:103
#21 0x00000034fe76fb4a in QObject::event (this=0x18e6640, e=<value optimized out>) at kernel/qobject.cpp:1211
#22 0x00000034ff9b78c4 in QApplicationPrivate::notify_helper (this=0x1325b00, receiver=0x18e6640, e=0x2407720) at kernel/qapplication.cpp:4445
#23 0x00000034ff9bc3da in QApplication::notify (this=<value optimized out>, receiver=0x18e6640, e=0x2407720) at kernel/qapplication.cpp:4324
#24 0x000000350123cff6 in KApplication::notify (this=0x7fffad5a5900, receiver=0x18e6640, event=0x2407720) at /usr/src/debug/kdelibs-4.5.85/kdeui/kernel/kapplication.cpp:311
#25 0x00000034fe75b7ac in QCoreApplication::notifyInternal (this=0x7fffad5a5900, receiver=0x18e6640, event=0x2407720) at kernel/qcoreapplication.cpp:732
#26 0x00000034fe75ef95 in sendEvent (receiver=0x0, event_type=0, data=0x12f3800) at kernel/qcoreapplication.h:215
#27 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x12f3800) at kernel/qcoreapplication.cpp:1373
#28 0x00000034fe786723 in sendPostedEvents (s=0x13346d0) at kernel/qcoreapplication.h:220
#29 postEventSourceDispatch (s=0x13346d0) at kernel/qeventdispatcher_glib.cpp:277
#30 0x0000003433e41e33 in g_main_dispatch (context=0x1333920) at gmain.c:2149
#31 g_main_context_dispatch (context=0x1333920) at gmain.c:2702
#32 0x0000003433e42610 in g_main_context_iterate (context=0x1333920, block=1, dispatch=1, self=<value optimized out>) at gmain.c:2780
#33 0x0000003433e428ad in g_main_context_iteration (context=0x1333920, may_block=1) at gmain.c:2843
#34 0x00000034fe7868bf in QEventDispatcherGlib::processEvents (this=0x12f2ee0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:415
#35 0x00000034ffa5c59e in QGuiEventDispatcherGlib::processEvents (this=<value optimized out>, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:207
#36 0x00000034fe75ab42 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at kernel/qeventloop.cpp:149
#37 0x00000034fe75ad8c in QEventLoop::exec (this=0x7fffad5a5850, flags=...) at kernel/qeventloop.cpp:201
#38 0x00000034fe75f24b in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1009
#39 0x0000000000403f77 in main (argc=1, argv=0x7fffad5a5ee8) at /usr/src/debug/kdepim-4.5.80/kontact/src/main.cpp:217

Reported using DrKonqi