I have got an infinite loop at qcoreapplication.cpp line 1446:

while (i < data->postEventList.size())

data->postEventList.d->end is 99539 and growing.

Master backtrace:

#14 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x60ca10) at kernel/qcoreapplication.cpp:1500
#15 0x00007f541b3c0e53 in sendPostedEvents () at kernel/qcoreapplication.h:236
#16 postEventSourceDispatch (s=0x63f2b0) at kernel/qeventdispatcher_glib.cpp:279
#17 0x00007f541358c58d in g_main_dispatch (context=0x63f1c0) at gmain.c:2425
#18 g_main_context_dispatch (context=0x63f1c0) at gmain.c:2995
#19 0x00007f541358cd88 in g_main_context_iterate (context=0x63f1c0, block=<optimized out>, dispatch=1, self=<optimized out>)
    at gmain.c:3073
#20 0x00007f541358cf59 in g_main_context_iteration (context=0x63f1c0, may_block=1) at gmain.c:3136
#21 0x00007f541b3c127f in QEventDispatcherGlib::processEvents (this=0x60c6f0, flags=<optimized out>)
    at kernel/qeventdispatcher_glib.cpp:424
#22 0x00007f541a7ba76e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=<optimized out>)
    at kernel/qguieventdispatcher_glib.cpp:204
#23 0x00007f541b391012 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#24 0x00007f541b391267 in QEventLoop::exec (this=0x7fff882d2bc0, flags=...) at kernel/qeventloop.cpp:204
#25 0x00007f541b395dc5 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#26 0x0000000000403919 in main (argc=3, argv=0x7fff882d3258) at /usr/src/debug/kdepim-4.7.2/kontact/src/main.cpp:218

Partial backtraces on postEvent:

#1  0x00007f541a76a4f0 in QWidget::setVisible (this=0x4917e20, visible=<optimized out>) at kernel/qwidget.cpp:7808
#2  0x00007f541aba43ce in QAbstractScrollAreaPrivate::layoutChildren (this=0x4c964a0) at widgets/qabstractscrollarea.cpp:472
#3  0x00007f541b3ab2b6 in QObject::event (this=0x4893d10, e=<optimized out>) at kernel/qobject.cpp:1204
#4  0x00007f541a76721b in QWidget::event (this=0x4893d10, event=0x75ed650) at kernel/qwidget.cpp:8821
#5  0x00007f541ab22fb6 in QFrame::event (this=0x4893d10, e=0x75ed650) at widgets/qframe.cpp:557
#6  0x00007f541aba5353 in QAbstractScrollArea::event (this=0x4893d10, e=0x75ed650) at widgets/qabstractscrollarea.cpp:996
#7  0x00007f53b55bbcb3 in KHTMLView::event (this=0x4893d10, e=0x75ed650) at /usr/src/debug/kdelibs-4.8.2/khtml/khtmlview.cpp:546
#8  0x00007f541a7170d4 in notify_helper (e=0x75ed650, receiver=0x4893d10, this=0x6462d0) at kernel/qapplication.cpp:4554
#9  QApplicationPrivate::notify_helper (this=0x6462d0, receiver=0x4893d10, e=0x75ed650) at kernel/qapplication.cpp:4526
#10 0x00007f541a71bf53 in QApplication::notify (this=0x7fff882d2c30, receiver=0x4893d10, e=0x75ed650) at kernel/qapplication.cpp:4415
#11 0x00007f541be11886 in KApplication::notify (this=0x7fff882d2c30, receiver=0x4893d10, event=0x75ed650)
    at /usr/src/debug/kdelibs-4.8.2/kdeui/kernel/kapplication.cpp:311
#12 0x00007f541b39222c in QCoreApplication::notifyInternal (this=0x7fff882d2c30, receiver=0x4893d10, event=0x75ed650)
    at kernel/qcoreapplication.cpp:876
#13 0x00007f541b395aca in sendEvent (event=0x75ed650, receiver=0x4893d10) at kernel/qcoreapplication.h:231

#2  0x00007f541aba43df in QAbstractScrollAreaPrivate::layoutChildren (this=0x4c964a0) at widgets/qabstractscrollarea.cpp:473
473         scrollBarContainers[Qt::Vertical]->setVisible(needv);
#3  0x00007f541b3ab2b6 in QObject::event (this=0x4893d10, e=<optimized out>) at kernel/qobject.cpp:1204
1204                    mce->placeMetaCall(this);

#2  QMetaObject::activate (sender=0x4d77690, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff882d11d0)
    at kernel/qobject.cpp:3516
3516                    queued_activate(sender, signal_absolute_index, c, argv ? argv : empty_argv);
#3  0x00007f541ada1f0f in QAbstractSlider::rangeChanged (this=<optimized out>, _t1=0, _t2=16)
    at .moc/release-shared/moc_qabstractslider.cpp:222
222         QMetaObject::activate(this, &staticMetaObject, 4, _a);

#2  QMetaObject::activate (sender=0x4d776c0, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff882d08b0)
    at kernel/qobject.cpp:3516
3516                    queued_activate(sender, signal_absolute_index, c, argv ? argv : empty_argv);
#3  0x00007f541ada1f0f in QAbstractSlider::rangeChanged (this=<optimized out>, _t1=0, _t2=18)
    at .moc/release-shared/moc_qabstractslider.cpp:222
222         QMetaObject::activate(this, &staticMetaObject, 4, _a);

These backtraces (in QAbstractSlider::rangeChanged and in QAbstractScrollAreaPrivate::layoutChildren) interleave.