Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.2.96 (KDE 4.2.96 (KDE 4.3 RC2))
Qt Version: 4.5.2
Operating System: Linux 2.6.30-10-generic x86_64
Distribution: Ubuntu karmic (development branch)

What I was doing when the application crashed:
sometimes plasma crashes if I launch apps, no metter I use menu, panel or desktop icon. it happens randomly, not always

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f37edf4d760 (LWP 3690))]

Thread 2 (Thread 0x7f37db198950 (LWP 3693)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:261
#1  0x00000031bbc5f49b in QWaitConditionPrivate::wait (this=<value optimized out>, mutex=<value optimized out>, time=<value optimized out>) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=<value optimized out>, mutex=<value optimized out>, time=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#3  0x00000031bd08271c in QHostInfoAgent::run (this=<value optimized out>) at kernel/qhostinfo.cpp:260
#4  0x00000031bbc5e3e5 in QThreadPrivate::start (arg=<value optimized out>) at thread/qthread_unix.cpp:188
#5  0x00000035f2e073ba in start_thread (arg=<value optimized out>) at pthread_create.c:297
#6  0x00000035f22e61bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f37edf4d760 (LWP 3690)):
[KCrash Handler]
#5  Tasks::itemTopMargin (this=0x53a3c30) at ../../../../plasma/applets/tasks/tasks.h:92
#6  AbstractTaskItem::basicPreferredSize (this=0x53a3c30) at ../../../../plasma/applets/tasks/abstracttaskitem.cpp:102
#7  0x00007f37ddc20045 in TaskItemLayout::maximumRows (this=0x1c5a5f0) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:185
#8  0x00007f37ddc289a7 in TaskGroupItem::optimumCapacity (this=0x1c5fdf0) at ../../../../plasma/applets/tasks/taskgroupitem.cpp:1224
#9  0x00007f37ddc1bb90 in Tasks::adjustGroupingStrategy (this=0x1b3efc0) at ../../../../plasma/applets/tasks/tasks.cpp:241
#10 0x00007f37ddc1bda8 in Tasks::constraintsEvent (this=0x1b3efc0, constraints=) at ../../../../plasma/applets/tasks/tasks.cpp:165
#11 0x00000035ae2aceb9 in Plasma::Applet::flushPendingConstraintsEvents (this=<value optimized out>) at ../../plasma/applet.cpp:1160
#12 0x00000035ae2ad645 in Plasma::Applet::timerEvent (this=<value optimized out>, event=<value optimized out>) at ../../plasma/applet.cpp:2104
#13 0x00000031bbd53dc3 in QObject::event (this=<value optimized out>, e=<value optimized out>) at kernel/qobject.cpp:1075
#14 0x00000031bdb724bb in QGraphicsWidget::event (this=<value optimized out>, event=<value optimized out>) at graphicsview/qgraphicswidget.cpp:1340
#15 0x00000031bd5a062c in QApplicationPrivate::notify_helper (this=<value optimized out>, receiver=<value optimized out>, e=<value optimized out>) at kernel/qapplication.cpp:4056
#16 0x00000031bd5a78fe in QApplication::notify (this=<value optimized out>, receiver=<value optimized out>, e=<value optimized out>) at kernel/qapplication.cpp:4021
#17 0x00000035aca233f6 in KApplication::notify (this=<value optimized out>, receiver=<value optimized out>, event=<value optimized out>) at ../../kdeui/kernel/kapplication.cpp:302
#18 0x00000031bbd44c6c in QCoreApplication::notifyInternal (this=<value optimized out>, receiver=<value optimized out>, event=<value optimized out>) at kernel/qcoreapplication.cpp:610
#19 0x00000031bbd6f912 in QCoreApplication::sendEvent (this=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#20 QTimerInfoList::activateTimers (this=<value optimized out>) at kernel/qeventdispatcher_unix.cpp:572
#21 0x00000031bbd6d2ad in timerSourceDispatch (source=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:165
#22 0x00000031bb03b9fe in g_main_dispatch (context=<value optimized out>) at /build/buildd/glib2.0-2.21.3/glib/gmain.c:1960
#23 IA__g_main_context_dispatch (context=<value optimized out>) at /build/buildd/glib2.0-2.21.3/glib/gmain.c:2513
#24 0x00000031bb03f3c8 in g_main_context_iterate (context=<value optimized out>, block=<value optimized out>, dispatch=<value optimized out>, self=<value optimized out>)
    at /build/buildd/glib2.0-2.21.3/glib/gmain.c:2591
#25 0x00000031bb03f4f0 in IA__g_main_context_iteration (context=<value optimized out>, may_block=<value optimized out>) at /build/buildd/glib2.0-2.21.3/glib/gmain.c:2654
#26 0x00000031bbd6d1f6 in QEventDispatcherGlib::processEvents (this=<value optimized out>, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#27 0x00000031bd634ace in QGuiEventDispatcherGlib::processEvents (this=<value optimized out>, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#28 0x00000031bbd43572 in QEventLoop::processEvents (this=<value optimized out>, flags=<value optimized out>) at kernel/qeventloop.cpp:149
#29 0x00000031bbd43944 in QEventLoop::exec (this=<value optimized out>, flags=<value optimized out>) at kernel/qeventloop.cpp:201
#30 0x00000031bbd45af9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#31 0x00007f37ed83974f in kdemain (argc=<value optimized out>, argv=<value optimized out>) at ../../../../plasma/shells/desktop/main.cpp:50
#32 0x0000000000406d88 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=0x40a2e1 "0") at ../../kinit/kinit.cpp:676
#33 0x0000000000407a80 in handle_launcher_request (sock=7, who=<value optimized out>) at ../../kinit/kinit.cpp:1168
#34 0x000000000040801f in handle_requests (waitForPid=<value optimized out>) at ../../kinit/kinit.cpp:1361
#35 0x0000000000408bd2 in main (argc=2, argv=<value optimized out>, envp=<value optimized out>) at ../../kinit/kinit.cpp:1788

Reported using DrKonqi