Version:           Version of the application: $Id: kded.cpp 1031638 2009-10-05 16:59:11Z lunakl $ (using KDE 4.3.4)
OS:                Linux
Installed from:    Debian testing/unstable Packages

At every login, kded4 crashes.

Network Manager has stopped working and I notice a bit of slowness sometimes.

The crash seems to have started after upgrading xserver-common from 1.6.5 to 1.7.4.

/var/log/messages show the following line:
kded4[17844]: segfault at 8 ip 00007f3257014c66 sp 00007fffae0ef830 error 4 in libQtCore.so.4.6.0[7f3256e77000+289000]

This is the backtrace:
Application that crashed: kded4
Version of the application: $Id: kded.cpp 1031638 2009-10-05 16:59:11Z lunakl $
KDE Version: 4.3.4 (KDE 4.3.4)
Qt Version: 4.6.0
Operating System: Linux 2.6.32-trunk-amd64 x86_64
Distribution: Debian GNU/Linux testing (squeeze)

What I was doing when the application crashed:
<In detail, tell us what you were doing  when the application crashed.>

 -- Backtrace:
Application: KDE Dæmon (kdeinit4), signal: Segmentation fault
The current source language is "auto; currently c".
[KCrash Handler]
#5  qVariantToHelper<QStringList> (this=0x0) at kernel/qvariant.cpp:2061
#6  QVariant::toStringList (this=0x0) at kernel/qvariant.cpp:2080
#7  0x00007f498e555ef0 in HalPower::brightnessControlsAvailable() () from /usr/lib/kde4/solid_hal_power.so
#8  0x00007f498eb898c8 in Solid::Control::PowerManager::brightnessControlsAvailable() () from /usr/lib/libsolidcontrol.so.4
#9  0x00007f498eb8ae81 in Solid::Control::PowerManager::setBrightness(float, QString const&) () from /usr/lib/libsolidcontrol.so.4
#10 0x00007f498edbce75 in PowerDevilDaemon::applyProfile() () from /usr/lib/kde4/kded_powerdevil.so
#11 0x00007f498edbf4b4 in PowerDevilDaemon::PowerDevilDaemon(QObject*, QList<QVariant> const&) () from /usr/lib/kde4/kded_powerdevil.so
#12 0x00007f498edc3bd7 in QObject* KPluginFactory::createInstance<PowerDevilDaemon, QObject>(QWidget*, QObject*, QList<QVariant> const&) () from /usr/lib/kde4/kded_powerdevil.so
#13 0x00007f49a02530fe in KPluginFactory::create (this=0x1e40b10, iface=0x7f49a02984c0 "KDEDModule", parentWidget=<value optimized out>, parent=0x1c9ed30, args=..., keyword=<value optimized out>)
    at ../../kdecore/util/kpluginfactory.cpp:191
#14 0x00007f4994b829e5 in KPluginFactory::create<KDEDModule> (this=0x1c9ed30, s=<value optimized out>, onDemand=<value optimized out>) at ../../kdecore/util/kpluginfactory.h:491
#15 Kded::loadModule (this=0x1c9ed30, s=<value optimized out>, onDemand=<value optimized out>) at ../../kded/kded.cpp:380
#16 0x00007f4994b84125 in Kded::initModules (this=0x1c9ed30) at ../../kded/kded.cpp:238
#17 0x00007f4994b860a8 in KDEDApplication::newInstance (this=<value optimized out>) at ../../kded/kded.cpp:860
#18 0x00007f499f212986 in KUniqueApplicationAdaptor::newInstance (this=0x1d56350, asn_id=<value optimized out>, args=...) at ../../kdeui/kernel/kuniqueapplication.cpp:459
#19 0x00007f499f212f76 in KUniqueApplicationAdaptor::qt_metacall (this=0x1d56350, _c=QMetaObject::InvokeMetaMethod, _id=-1600683264, _a=0x7fff007c0ea0) at ./kuniqueapplication_p.moc:75
#20 0x00007f499c57d344 in QDBusConnectionPrivate::deliverCall (this=0x1c97080, object=0x1d56350, msg=..., metaTypes=..., slotIdx=4) at qdbusintegrator.cpp:904
#21 0x00007f499c57e319 in QDBusConnectionPrivate::activateCall (this=0x1c97080, object=0x1d56350, flags=337, msg=...) at qdbusintegrator.cpp:809
#22 0x00007f499c57ebf8 in QDBusConnectionPrivate::activateObject (this=0x1c97080, node=..., msg=..., pathStartPos=<value optimized out>) at qdbusintegrator.cpp:1368
#23 0x00007f499c57ef38 in QDBusActivateObjectEvent::placeMetaCall (this=0x1d589f0) at qdbusintegrator.cpp:1481
#24 0x00007f49a066fd38 in QObject::event (this=0x7fff007c1e90, e=0x1d589f0) at kernel/qobject.cpp:1260
#25 0x00007f499e5006ba in QApplication::event (this=0x7fff007c1e90, e=0x1d589f0) at kernel/qapplication.cpp:2344
#26 0x00007f499e4fd08d in QApplicationPrivate::notify_helper (this=0x1c9fb40, receiver=0x7fff007c1e90, e=0x1d589f0) at kernel/qapplication.cpp:4242
#27 0x00007f499e5033bd in QApplication::notify (this=0x7fff007c1e90, receiver=0x7fff007c1e90, e=0x1d589f0) at kernel/qapplication.cpp:4125
#28 0x00007f499f20be06 in KApplication::notify (this=0x7fff007c1e90, receiver=0x7fff007c1e90, event=0x1d589f0) at ../../kdeui/kernel/kapplication.cpp:302
#29 0x00007f49a065fbdc in QCoreApplication::notifyInternal (this=0x7fff007c1e90, receiver=0x7fff007c1e90, event=0x1d589f0) at kernel/qcoreapplication.cpp:704
#30 0x00007f49a0660abc in QCoreApplication::sendEvent (receiver=0x0, event_type=0, data=0x1c1a3f0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#31 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x1c1a3f0) at kernel/qcoreapplication.cpp:1345
#32 0x00007f49a0689b23 in QCoreApplication::sendPostedEvents (s=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:220
#33 postEventSourceDispatch (s=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:276
#34 0x00007f499cfd3a7e in g_main_dispatch (context=0x1ca2520) at /build/buildd/glib2.0-2.23.1/glib/gmain.c:1960
#35 IA__g_main_context_dispatch (context=0x1ca2520) at /build/buildd/glib2.0-2.23.1/glib/gmain.c:2513
#36 0x00007f499cfd7438 in g_main_context_iterate (context=0x1ca2520, block=<value optimized out>, dispatch=<value optimized out>, self=<value optimized out>)
    at /build/buildd/glib2.0-2.23.1/glib/gmain.c:2591
#37 0x00007f499cfd7560 in IA__g_main_context_iteration (context=0x1ca2520, may_block=1) at /build/buildd/glib2.0-2.23.1/glib/gmain.c:2654
#38 0x00007f49a068968c in QEventDispatcherGlib::processEvents (this=0x1c1b970, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:407
#39 0x00007f499e5ad53f in QGuiEventDispatcherGlib::processEvents (this=0x0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#40 0x00007f49a065e4c2 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at kernel/qeventloop.cpp:149
#41 0x00007f49a065e894 in QEventLoop::exec (this=0x7fff007c1de0, flags=...) at kernel/qeventloop.cpp:201
#42 0x00007f49a0660d46 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#43 0x00007f4994b84c3b in kdemain (argc=<value optimized out>, argv=<value optimized out>) at ../../kded/kded.cpp:936
#44 0x0000000000406e9e in launch (argc=1, _name=<value optimized out>, args=<value optimized out>, cwd=<value optimized out>, envc=0, envs=<value optimized out>, reset_env=false, tty=0x0, 
    avoid_loops=false, startup_id_str=0x40a057 "0") at ../../kinit/kinit.cpp:677
#45 0x0000000000408a6a in main (argc=<value optimized out>, argv=<value optimized out>, envp=<value optimized out>) at ../../kinit/kinit.cpp:1740