Application: kscreenlocker (2.0)
KDE Platform Version: 4.4.2 (KDE 4.4.2)
Qt Version: 4.6.2
Operating System: Linux 2.6.32-24-generic x86_64
Distribution: Ubuntu 10.04.1 LTS

-- Information about the crash:
The screen lock quit unexpectedly. The computer was idle for more than 15 minutes and the screensaver was supposed to start along with a screen lock. However, the screen lock crashed upon starting.  Coincidently, the plasma-desktop process has been occupying 881M of physical memory (which seems a little bit too much than usual and might have been an overflow; also, at that point composite also quit with the message that it was too slow to continue). At the point of the crash Kopete, Amarok, Chrome, Dolphine, Skype, Yakuake were running along with a number of widgets (gmail, quickaccess, rss now, picture frame, folder view, and analog clock). The entire gui became rather sluggish as the total RAM occupied was 1.7 out of 1.9G at that point.

 -- Backtrace:
Application: KDE Screen Locker (kscreenlocker), signal: Segmentation fault
[KCrash Handler]
#5  QBasicAtomicInt::ref (this=0xeafc30, layoutUnit=...) at /usr/include/qt4/QtCore/qatomic_x86_64.h:121
#6  QString (this=0xeafc30, layoutUnit=...) at /usr/include/qt4/QtCore/qstring.h:715
#7  LayoutUnit::toPair (this=0xeafc30, layoutUnit=...) at ../../../kcontrol/kxkb/kxkbconfig.h:78
#8  KxkbWidget::setCurrentLayout (this=0xeafc30, layoutUnit=...) at ../../../kcontrol/kxkb/kxkbwidget.cpp:50
#9  0x00007fac21610c41 in KxkbCore::initTray (this=0xceeec0) at ../../../kcontrol/kxkb/kxkbcore.cpp:303
#10 0x00007fac21610de7 in KxkbCore::setWidget (this=0xceeec0, kxkbWidget=0xeafc30) at ../../../kcontrol/kxkb/kxkbcore.cpp:291
#11 0x00007fac21617ec1 in KxkbPart (this=0xcde900, parent=<value optimized out>, args=<value optimized out>) at ../../../kcontrol/kxkb/kxkb_part.cpp:53
#12 0x00007fac21618735 in KPluginFactory::createInstance<KxkbPart, QWidget> (parentWidget=<value optimized out>, parent=<value optimized out>, args=...) at /usr/include/KDE/../kpluginfactory.h:461
#13 0x00007fac2c3b896c in KPluginFactory::create (this=0xcf0690, iface=0x7fac2ceb82e0 "QWidget", parentWidget=<value optimized out>, parent=0x7fffcd5b8a70, args=..., keyword=<value optimized out>)
    at ../../kdecore/util/kpluginfactory.cpp:191
#14 0x000000000041abee in KPluginFactory::create<QWidget> (this=0x7fffcd5b8a70, parent=<value optimized out>, plugin=<value optimized out>, text=...) at /usr/include/KDE/../kpluginfactory.h:491
#15 PasswordDlg (this=0x7fffcd5b8a70, parent=<value optimized out>, plugin=<value optimized out>, text=...) at ../../../krunner/lock/lockdlg.cc:122
#16 0x0000000000416466 in LockProcess::checkPass (this=0x7fffcd5b9b00) at ../../../krunner/lock/lockprocess.cc:1126
#17 0x00000000004171b8 in LockProcess::x11Event (this=0x7fffcd5b9b00, event=0x7fffcd5b9740) at ../../../krunner/lock/lockprocess.cc:1309
#18 0x00007fac2e0e8d06 in KAppX11HackWidget::publicx11Event (this=<value optimized out>, _event=0x7fffcd5b9740) at ../../kdeui/kernel/kapplication.cpp:903
#19 KApplication::x11EventFilter (this=<value optimized out>, _event=0x7fffcd5b9740) at ../../kdeui/kernel/kapplication.cpp:953
#20 0x00007fac2c882641 in qt_x11EventFilter (ev=0x7fffcd5b9740) at kernel/qapplication_x11.cpp:399
#21 0x00007fac2c891191 in QApplication::x11ProcessEvent (this=<value optimized out>, event=0x7fffcd5b9740) at kernel/qapplication_x11.cpp:3231
#22 0x00007fac2c8bd882 in x11EventSourceDispatch (s=0xb83750, callback=<value optimized out>, user_data=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:146
#23 0x00007fac28b4f8c2 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#24 0x00007fac28b53748 in ?? () from /lib/libglib-2.0.so.0
#25 0x00007fac28b538fc in g_main_context_iteration () from /lib/libglib-2.0.so.0
#26 0x00007fac2bc49513 in QEventDispatcherGlib::processEvents (this=0xb68730, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:412
#27 0x00007fac2c8bd46e in QGuiEventDispatcherGlib::processEvents (this=0xeafc30, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:204
#28 0x00007fac2bc1e992 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#29 0x00007fac2bc1ed6c in QEventLoop::exec (this=0x7fffcd5b9a70, flags=) at kernel/qeventloop.cpp:201
#30 0x00007fac2bc22aab in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#31 0x000000000041e226 in main (argc=<value optimized out>, argv=<value optimized out>) at ../../../krunner/lock/main.cc:173

Reported using DrKonqi