Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.1 (KDE 4.3.1)
Qt Version: 4.5.2
Operating System: Linux 2.6.28-15-generic x86_64
Distribution: Ubuntu 9.04

What I was doing when the application crashed:
When switching desktops with the appropriate hotkeys, the window bar first freezes (leaving the left-most section empty with window buttons starting in the middle of the bar) and then plasma crashes after a few seconds. The bug happens rather seldom and unreproducible.

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 0 (LWP 4670)]

Thread 2 (Thread 0x7f5cafed3950 (LWP 4673)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:261
#1  0x00007f5ccf753d19 in QWaitCondition::wait (this=0x1767020, mutex=0x1767018, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  0x00007f5cce5d981c in QHostInfoAgent::run (this=0x1767000) at kernel/qhostinfo.cpp:260
#3  0x00007f5ccf752d35 in QThreadPrivate::start (arg=0x1767000) at thread/qthread_unix.cpp:188
#4  0x00007f5ccb6473ba in start_thread (arg=<value optimized out>) at pthread_create.c:297
#5  0x00007f5ccc22bfcd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#6  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f5ccfd14750 (LWP 4670)):
[KCrash Handler]
#5  AbstractTaskItem::basicPreferredSize (this=0x16d9410) at /build/buildd/kdebase-workspace-4.3.1/plasma/applets/tasks/tasks.h:92
#6  0x00007f5cb259b3f6 in TaskItemLayout::preferredColumns (this=0x163fb70) at /build/buildd/kdebase-workspace-4.3.1/plasma/applets/tasks/taskitemlayout.cpp:206
#7  0x00007f5cb259bd4c in TaskItemLayout::gridLayoutSize (this=0x163fb70) at /build/buildd/kdebase-workspace-4.3.1/plasma/applets/tasks/taskitemlayout.cpp:222
#8  0x00007f5cb259bddb in TaskItemLayout::layoutItems (this=0x0) at /build/buildd/kdebase-workspace-4.3.1/plasma/applets/tasks/taskitemlayout.cpp:245
#9  0x00007f5cb259c994 in TaskItemLayout::insert (this=0x163fb70, index=7, item=0x2d0dea0) at /build/buildd/kdebase-workspace-4.3.1/plasma/applets/tasks/taskitemlayout.cpp:125
#10 0x00007f5cb259cb70 in TaskItemLayout::addTaskItem (this=0x163fb70, item=0x2d0dea0) at /build/buildd/kdebase-workspace-4.3.1/plasma/applets/tasks/taskitemlayout.cpp:82
#11 0x00007f5cb25a8618 in TaskGroupItem::itemAdded (this=0x163f200, groupableItem=0x2d98910) at /build/buildd/kdebase-workspace-4.3.1/plasma/applets/tasks/taskgroupitem.cpp:477
#12 0x00007f5cb25a8c0c in TaskGroupItem::qt_metacall (this=0x163f200, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffd7d4fe90)
    at /build/buildd/kdebase-workspace-4.3.1/obj-x86_64-linux-gnu/plasma/applets/tasks/taskgroupitem.moc:113
#13 0x00007f5ccf851ea2 in QMetaObject::activate (sender=0x163d950, from_signal_index=<value optimized out>, to_signal_index=21, argv=0x0) at kernel/qobject.cpp:3113
#14 0x00007f5cb236dccf in TaskManager::TaskGroup::itemAdded (this=0x0, _t1=0x2d98910) at /build/buildd/kdebase-workspace-4.3.1/obj-x86_64-linux-gnu/libs/taskmanager/taskgroup.moc:139
#15 0x00007f5cb236e82b in TaskManager::TaskGroup::add (this=0x163d950, item=0x2d98910) at /build/buildd/kdebase-workspace-4.3.1/libs/taskmanager/taskgroup.cpp:138
#16 0x00007f5cb235d5e3 in TaskManager::ProgramGroupingStrategy::handleItem (this=0x2cbd9f0, item=0x2d98910)
    at /build/buildd/kdebase-workspace-4.3.1/libs/taskmanager/strategies/programgroupingstrategy.cpp:154
#17 0x00007f5cb23570bd in TaskManager::GroupManagerPrivate::addTask (this=0x12ad480, task={d = 0x7fffd7d4fff0}) at /build/buildd/kdebase-workspace-4.3.1/libs/taskmanager/groupmanager.cpp:288
#18 0x00007f5cb2357df1 in TaskManager::GroupManagerPrivate::actuallyReloadTasks (this=0x12ad480) at /build/buildd/kdebase-workspace-4.3.1/libs/taskmanager/groupmanager.cpp:155
#19 0x00007f5cb2359262 in TaskManager::GroupManager::qt_metacall (this=0x134bcb0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffd7d50160)
    at /build/buildd/kdebase-workspace-4.3.1/obj-x86_64-linux-gnu/libs/taskmanager/groupmanager.moc:108
#20 0x00007f5ccf851ea2 in QMetaObject::activate (sender=0x12ad4e8, from_signal_index=<value optimized out>, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3113
#21 0x00007f5ccf84c263 in QObject::event (this=0x12ad4e8, e=0x7f5ccc282528) at kernel/qobject.cpp:1075
#22 0x00007f5ccce02f4d in QApplicationPrivate::notify_helper (this=0xfdb020, receiver=0x12ad4e8, e=0x7fffd7d50810) at kernel/qapplication.cpp:4056
#23 0x00007f5ccce0b18a in QApplication::notify (this=0xf9c1b0, receiver=0x12ad4e8, e=0x7fffd7d50810) at kernel/qapplication.cpp:4021
#24 0x00007f5ccdf15deb in KApplication::notify (this=0xf9c1b0, receiver=0x12ad4e8, event=0x7fffd7d50810) at /build/buildd/kde4libs-4.3.1/kdeui/kernel/kapplication.cpp:302
#25 0x00007f5ccf83c6ac in QCoreApplication::notifyInternal (this=0xf9c1b0, receiver=0x12ad4e8, event=0x7fffd7d50810) at kernel/qcoreapplication.cpp:610
#26 0x00007f5ccf869516 in QTimerInfoList::activateTimers (this=0xfde5c0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#27 0x00007f5ccf865b2d in timerSourceDispatch (source=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:165
#28 0x00007f5ccb89620a in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#29 0x00007f5ccb8998e0 in ?? () from /usr/lib/libglib-2.0.so.0
#30 0x00007f5ccb899a7c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#31 0x00007f5ccf865a8f in QEventDispatcherGlib::processEvents (this=0xfdab50, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#32 0x00007f5ccce9bbdf in QGuiEventDispatcherGlib::processEvents (this=0x0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#33 0x00007f5ccf83af42 in QEventLoop::processEvents (this=<value optimized out>, flags={i = -673904000}) at kernel/qeventloop.cpp:149
#34 0x00007f5ccf83b314 in QEventLoop::exec (this=0x7fffd7d50ac0, flags={i = -673903920}) at kernel/qeventloop.cpp:201
#35 0x00007f5ccf83d5e4 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#36 0x00007f5cc375f3eb in kdemain (argc=1, argv=0xf4e9b0) at /build/buildd/kdebase-workspace-4.3.1/plasma/shells/desktop/main.cpp:50
#37 0x0000000000407215 in launch (argc=1, _name=0xf8f3f8 "/usr/bin/plasma-desktop", args=<value optimized out>, cwd=0x0, envc=0, envs=0xf8f418 "", reset_env=false, tty=0x0, avoid_loops=false, 
    startup_id_str=0x40a3a1 "0") at /build/buildd/kde4libs-4.3.1/kinit/kinit.cpp:677
#38 0x0000000000407a38 in handle_launcher_request (sock=7, who=<value optimized out>) at /build/buildd/kde4libs-4.3.1/kinit/kinit.cpp:1169
#39 0x0000000000407fe5 in handle_requests (waitForPid=0) at /build/buildd/kde4libs-4.3.1/kinit/kinit.cpp:1362
#40 0x0000000000408b26 in main (argc=2, argv=0x7fffd7d51968, envp=0x7fffd7d51980) at /build/buildd/kde4libs-4.3.1/kinit/kinit.cpp:1793

This bug may be a duplicate of or related to bug 206677

Reported using DrKonqi