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 2.6.30-1-amd64 x86_64
Distribution: Debian GNU/Linux testing (squeeze)

What I was doing when the application crashed:
Usually I keep 2 konsole and 1 ksysguard in the last workspace, (I have 6 workspaces in total). If the tree windows in the same desktop, randomly changing between desktops eventually leads to a crash of plasma.

However if I move the ksysguard instance to workspace number 5 having only 1 there window there and leaving the 2 konsole open in the last workspace I can no longer reproduce the bug.

Putting the 3 applications back together in the same workspace, independently of the number of the desktop will return the crashing behavior.

 -- Backtrace:
Application: Plasma Workspace (plasma-desktop), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f1b3d8b37a0 (LWP 31421))]

Thread 2 (Thread 0x7f1b2a162950 (LWP 31423)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:261
#1  0x00007f1b464cd469 in QWaitConditionPrivate::wait (this=0x27216b0, mutex=0x27216a8, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=0x27216b0, mutex=0x27216a8, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f1b4349e024 in QHostInfoAgent::run (this=0x2721690) at kernel/qhostinfo.cpp:260
#4  0x00007f1b464cc475 in QThreadPrivate::start (arg=0x2721690) at thread/qthread_unix.cpp:188
#5  0x00007f1b410a5f9a in start_thread (arg=<value optimized out>) at pthread_create.c:300
#6  0x00007f1b4934856d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f1b3d8b37a0 (LWP 31421)):
[KCrash Handler]
#5  Tasks::itemTopMargin (this=0x2bedf70) at ../../../../plasma/applets/tasks/tasks.h:92
#6  AbstractTaskItem::basicPreferredSize (this=0x2bedf70) at ../../../../plasma/applets/tasks/abstracttaskitem.cpp:100
#7  0x00007f1b2c5fb366 in TaskItemLayout::preferredColumns (this=0x2714920) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:206
#8  0x00007f1b2c5fbcdc in TaskItemLayout::gridLayoutSize (this=0x2714920) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:222
#9  0x00007f1b2c5fbd6b in TaskItemLayout::layoutItems (this=0x200000001) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:245
#10 0x00007f1b2c5fc904 in TaskItemLayout::insert (this=0x2714920, index=3, item=0x2be46a0) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:125
#11 0x00007f1b2c5fcae8 in TaskItemLayout::addTaskItem (this=0x2714920, item=0x2be46a0) at ../../../../plasma/applets/tasks/taskitemlayout.cpp:82
#12 0x00007f1b2c608508 in TaskGroupItem::itemAdded (this=0x2713fa0, groupableItem=0x2be8690) at ../../../../plasma/applets/tasks/taskgroupitem.cpp:477
#13 0x00007f1b2c608af2 in TaskGroupItem::qt_metacall (this=0x2713fa0, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff4a4b09c0) at ./taskgroupitem.moc:113
#14 0x00007f1b465c7682 in QMetaObject::activate (sender=0x2705810, from_signal_index=<value optimized out>, to_signal_index=21, argv=0x0) at kernel/qobject.cpp:3112
#15 0x00007f1b2c84247f in TaskManager::TaskGroup::itemAdded (this=0x200000001, _t1=0x2be8690) at ./taskgroup.moc:139
#16 0x00007f1b2c842fab in TaskManager::TaskGroup::add (this=0x2705810, item=0x2be8690) at ../../../libs/taskmanager/taskgroup.cpp:138
#17 0x00007f1b2c83201f in TaskManager::ProgramGroupingStrategy::handleItem (this=0x2bf07d0, item=0x2be8690) at ../../../libs/taskmanager/strategies/programgroupingstrategy.cpp:154
#18 0x00007f1b2c82bb6d in TaskManager::GroupManagerPrivate::addTask (this=0x2703110, task=...) at ../../../libs/taskmanager/groupmanager.cpp:288
#19 0x00007f1b2c82c891 in TaskManager::GroupManagerPrivate::actuallyReloadTasks (this=0x2703110) at ../../../libs/taskmanager/groupmanager.cpp:155
#20 0x00007f1b2c82dcd2 in TaskManager::GroupManager::qt_metacall (this=0x21e0370, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff4a4b0c80) at ./groupmanager.moc:108
#21 0x00007f1b465c7682 in QMetaObject::activate (sender=0x2703178, from_signal_index=<value optimized out>, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3112
#22 0x00007f1b465c1bf3 in QObject::event (this=0x2703178, e=0x7f1b49396bc8) at kernel/qobject.cpp:1074
#23 0x00007f1b46cf480d in QApplicationPrivate::notify_helper (this=0x1f00020, receiver=0x2703178, e=0x7fff4a4b1330) at kernel/qapplication.cpp:4056
#24 0x00007f1b46cfc86a in QApplication::notify (this=0x1ee0d70, receiver=0x2703178, e=0x7fff4a4b1330) at kernel/qapplication.cpp:4021
#25 0x00007f1b47dd143b in KApplication::notify (this=0x1ee0d70, receiver=0x2703178, event=0x7fff4a4b1330) at ../../kdeui/kernel/kapplication.cpp:302
#26 0x00007f1b465b251c in QCoreApplication::notifyInternal (this=0x1ee0d70, receiver=0x2703178, event=0x7fff4a4b1330) at kernel/qcoreapplication.cpp:610
#27 0x00007f1b465de826 in QCoreApplication::sendEvent (this=0x1f03770) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#28 QTimerInfoList::activateTimers (this=0x1f03770) at kernel/qeventdispatcher_unix.cpp:572
#29 0x00007f1b465dac9d in timerSourceDispatch (source=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:165
#30 0x00007f1b412f386a in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#31 0x00007f1b412f6eb8 in ?? () from /usr/lib/libglib-2.0.so.0
#32 0x00007f1b412f706c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#33 0x00007f1b465dabff in QEventDispatcherGlib::processEvents (this=0x1ec76a0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#34 0x00007f1b46d8b64f in QGuiEventDispatcherGlib::processEvents (this=0x200000001, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#35 0x00007f1b465b0de2 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at kernel/qeventloop.cpp:149
#36 0x00007f1b465b11b4 in QEventLoop::exec (this=0x7fff4a4b15e0, flags=...) at kernel/qeventloop.cpp:201
#37 0x00007f1b465b3424 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#38 0x00007f1b4960a26b in kdemain (argc=1, argv=0x7fff4a4b18e8) at ../../../../plasma/shells/desktop/main.cpp:50
#39 0x00007f1b4929a5c6 in __libc_start_main (main=0x400710 <main>, argc=1, ubp_av=0x7fff4a4b18e8, init=0x400740 <__libc_csu_init>, fini=<value optimized out>, rtld_fini=<value optimized out>, 
    stack_end=0x7fff4a4b18d8) at libc-start.c:222
#40 0x0000000000400649 in _start () at ../sysdeps/x86_64/elf/start.S:113

This bug may be a duplicate of or related to bug 206496

Reported using DrKonqi