Application: kontact (4.4.11)
KDE Platform Version: 4.7.4 (4.7.4)
Qt Version: 4.8.1
Operating System: Linux 3.3.0-trunk-amd64 x86_64
Distribution: Debian GNU/Linux testing (wheezy)

-- Information about the crash:
- What I was doing when the application crashed:
I was dragging an event in Calendar in Week view (I use it inside Kontact). Then it crashed.

Another problem is that some events disappeared or were placed in wrong positions after the crash. What I expected: the event I was trying to drag will be in its old position right before the crash, and all other events will be present in right positions.

Before crash happened, I dragged'n'dropped events many times (about 20-40 times in total, I do not remember exactly) over period of few hours. Due to the possibility of partial data loss this bug is especially annoying when it happens.

The crash can be reproduced some of the time.

-- Backtrace:
Application: Kontact (kontact), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[KCrash Handler]
#6  deref (this=0xb0) at /usr/include/qt4/QtCore/qatomic_x86_64.h:133
#7  operator= (l=..., this=0x96379d0) at /usr/include/qt4/QtCore/qlist.h:429
#8  KOAgendaItem::setConflictItems (this=0x9637930, ci=...) at ../../korganizer/views/agendaview/koagendaitem.cpp:686
#9  0x00007fcfdff0510d in KOAgenda::placeSubCells (this=0x6ad5ad0, placeItem=0x9637930) at ../../korganizer/views/agendaview/koagenda.cpp:1284
#10 0x00007fcfdff05c17 in KOAgenda::endItemAction (this=0x6ad5ad0) at ../../korganizer/views/agendaview/koagenda.cpp:1110
#11 0x00007fcfdff07766 in KOAgenda::eventFilter_mouse (this=0x6ad5ad0, object=0xb219bf0, me=0x7fff74f1cf10) at ../../korganizer/views/agendaview/koagenda.cpp:573
#12 0x00007fcfdff03c09 in KOAgenda::eventFilter (this=0x6ad5ad0, object=0xb219bf0, event=<optimized out>) at ../../korganizer/views/agendaview/koagenda.cpp:368
#13 0x00007fd001446338 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<optimized out>, receiver=0xb219bf0, event=0x7fff74f1cf10) at kernel/qcoreapplication.cpp:986
#14 0x00007fd001e6a1cf in notify_helper (e=0x7fff74f1cf10, receiver=0xb219bf0, this=0xea2f00) at kernel/qapplication.cpp:4555
#15 QApplicationPrivate::notify_helper (this=0xea2f00, receiver=0xb219bf0, e=0x7fff74f1cf10) at kernel/qapplication.cpp:4531
#16 0x00007fd001e6f953 in QApplication::notify (this=<optimized out>, receiver=0xb219bf0, e=0x7fff74f1cf10) at kernel/qapplication.cpp:4102
#17 0x00007fd002bc8b26 in KApplication::notify (this=0x7fff74f1dbe0, receiver=0xb219bf0, event=0x7fff74f1cf10) at ../../kdeui/kernel/kapplication.cpp:311
#18 0x00007fd0014461ac in QCoreApplication::notifyInternal (this=0x7fff74f1dbe0, receiver=0xb219bf0, event=0x7fff74f1cf10) at kernel/qcoreapplication.cpp:876
#19 0x00007fd001e6b1d2 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#20 QApplicationPrivate::sendMouseEvent (receiver=0xb219bf0, event=0x7fff74f1cf10, alienWidget=0xb219bf0, nativeWidget=0x6ac0390, buttonDown=0xb219bf0, lastMouseReceiver=..., spontaneous=true) at kernel/qapplication.cpp:3170
#21 0x00007fd001ee7635 in QETWidget::translateMouseEvent (this=0x6ac0390, event=<optimized out>) at kernel/qapplication_x11.cpp:4523
#22 0x00007fd001ee64fa in QApplication::x11ProcessEvent (this=0x7fff74f1dbe0, event=0x7fff74f1d7d0) at kernel/qapplication_x11.cpp:3646
#23 0x00007fd001f0ee62 in x11EventSourceDispatch (s=0xea4500, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#24 0x00007fcffa76a853 in g_main_dispatch (context=0xea0ed0) at /tmp/buildd/glib2.0-2.32.2/./glib/gmain.c:2539
#25 g_main_context_dispatch (context=0xea0ed0) at /tmp/buildd/glib2.0-2.32.2/./glib/gmain.c:3075
#26 0x00007fcffa76aba0 in g_main_context_iterate (dispatch=1, block=<optimized out>, context=0xea0ed0, self=<optimized out>) at /tmp/buildd/glib2.0-2.32.2/./glib/gmain.c:3146
#27 g_main_context_iterate (context=0xea0ed0, block=<optimized out>, dispatch=1, self=<optimized out>) at /tmp/buildd/glib2.0-2.32.2/./glib/gmain.c:3083
#28 0x00007fcffa76ac64 in g_main_context_iteration (context=0xea0ed0, may_block=1) at /tmp/buildd/glib2.0-2.32.2/./glib/gmain.c:3207
#29 0x00007fd0014756cf in QEventDispatcherGlib::processEvents (this=0xe67b60, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#30 0x00007fd001f0eaee in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#31 0x00007fd001444f92 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#32 0x00007fd0014451e7 in QEventLoop::exec (this=0x7fff74f1db70, flags=...) at kernel/qeventloop.cpp:204
#33 0x00007fd00144a277 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#34 0x00000000004038ac in main (argc=1, argv=0x7fff74f1e1c8) at ../../../kontact/src/main.cpp:226

Reported using DrKonqi