Application: plasma-desktop (0.4)
KDE Platform Version: 4.8.2 (4.8.2)
Qt Version: 4.8.1
Operating System: Linux 3.2.0-23-generic x86_64
Distribution: Ubuntu 12.04 LTS

-- Information about the crash:
- What I was doing when the application crashed:
I changed the preferences for the window list in my launch bar for the first time. The bar used to show all windows on all desktops, now I changed it to only display those on the active desktop.

- Unusual behavior I noticed:
I noticed that after having changed the preferences, the window buttons on the bar seemed to fully overlap others. This already happened before sometimes, after launching KDE, and may well be a different bug.

- Custom settings of the application:
Changed preferences of window bar from
  show all windows
to
  show windows on active desktop.

The crash does not seem to be reproducible.

-- Backtrace:
Application: Plasma-Desktop-Umgebung (plasma-desktop), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fd12ddd3780 (LWP 1751))]

Thread 5 (Thread 0x7fd1085f5700 (LWP 1752)):
#0  0x00007fd12d69bb03 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007fd121858ff6 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fd121859124 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fd12a879426 in QEventDispatcherGlib::processEvents (this=0x7fd1000008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#4  0x00007fd12a848c82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007fd12a848ed7 in QEventLoop::exec (this=0x7fd1085f4dd0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007fd12a747fa7 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#7  0x00007fd12a8289ff in QInotifyFileSystemWatcherEngine::run (this=0x22dc7a0) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007fd12a74afcb in QThreadPrivate::start (arg=0x22dc7a0) at thread/qthread_unix.cpp:298
#9  0x00007fd12215de9a in start_thread (arg=0x7fd1085f5700) at pthread_create.c:308
#10 0x00007fd12d6a74bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 4 (Thread 0x7fd10701b700 (LWP 1753)):
#0  0x00007fd12216105d in __pthread_mutex_unlock_usercnt (mutex=<optimized out>, decr=<optimized out>) at pthread_mutex_unlock.c:52
#1  __pthread_mutex_unlock (mutex=0x7fd0f8000a60) at pthread_mutex_unlock.c:290
#2  0x00007fd121894591 in g_mutex_unlock () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fd121858fa9 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007fd121859124 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fd12a879426 in QEventDispatcherGlib::processEvents (this=0x7fd0f80008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:426
#6  0x00007fd12a848c82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007fd12a848ed7 in QEventLoop::exec (this=0x7fd10701add0, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007fd12a747fa7 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:501
#9  0x00007fd12a8289ff in QInotifyFileSystemWatcherEngine::run (this=0x23f4ce0) at io/qfilesystemwatcher_inotify.cpp:248
#10 0x00007fd12a74afcb in QThreadPrivate::start (arg=0x23f4ce0) at thread/qthread_unix.cpp:298
#11 0x00007fd12215de9a in start_thread (arg=0x7fd10701b700) at pthread_create.c:308
#12 0x00007fd12d6a74bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#13 0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7fd0f7d1a700 (LWP 1756)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007fd12762d222 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007fd12762d259 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007fd12215de9a in start_thread (arg=0x7fd0f7d1a700) at pthread_create.c:308
#4  0x00007fd12d6a74bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#5  0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7fd0f4a79700 (LWP 1761)):
#0  0x00007fd12d69bb03 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007fd121858ff6 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fd12185945a in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fd0f55632c6 in ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
#4  0x00007fd12187a9a5 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007fd12215de9a in start_thread (arg=0x7fd0f4a79700) at pthread_create.c:308
#6  0x00007fd12d6a74bd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7fd12ddd3780 (LWP 1751)):
[KCrash Handler]
#6  QHashData::nextNode (node=0x3bf7ae0) at tools/qhash.cpp:294
#7  0x00007fd11152351c in operator++ (this=<synthetic pointer>) at /usr/include/qt4/QtCore/qhash.h:427
#8  TaskItemLayout::size (this=<optimized out>) at ../../../../../plasma/desktop/applets/tasks/taskitemlayout.cpp:166
#9  0x00007fd111524032 in TaskItemLayout::gridLayoutSize (this=0x34179c0) at ../../../../../plasma/desktop/applets/tasks/taskitemlayout.cpp:256
#10 0x00007fd1115240cd in TaskItemLayout::layoutItems (this=0x34179c0) at ../../../../../plasma/desktop/applets/tasks/taskitemlayout.cpp:281
#11 0x00007fd111524857 in TaskItemLayout::remove (this=0x34179c0, item=0x45620f0) at ../../../../../plasma/desktop/applets/tasks/taskitemlayout.cpp:153
#12 0x00007fd11152488d in qt_static_metacall (_a=<optimized out>, _o=<optimized out>, _c=<optimized out>, _id=<optimized out>) at ./taskitemlayout.moc:50
#13 TaskItemLayout::qt_static_metacall (_o=<optimized out>, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at ./taskitemlayout.moc:44
#14 0x00007fd12a85e281 in QMetaObject::activate (sender=0x45620f0, m=<optimized out>, local_signal_index=<optimized out>, argv=0x7fff4bfab480) at kernel/qobject.cpp:3547
#15 0x00007fd111529812 in AbstractTaskItem::destroyed (this=<optimized out>, _t1=0x45620f0) at ./abstracttaskitem.moc:169
#16 0x00007fd111529b84 in AbstractTaskItem::~AbstractTaskItem (this=0x45620f0, __in_chrg=<optimized out>) at ../../../../../plasma/desktop/applets/tasks/abstracttaskitem.cpp:155
#17 0x00007fd11151e1e5 in ~WindowTaskItem (this=0x45620f0, __in_chrg=<optimized out>) at ../../../../../plasma/desktop/applets/tasks/windowtaskitem.h:34
#18 WindowTaskItem::~WindowTaskItem (this=0x45620f0, __in_chrg=<optimized out>) at ../../../../../plasma/desktop/applets/tasks/windowtaskitem.h:34
#19 0x00007fd12a1bda46 in QGraphicsItem::~QGraphicsItem (this=0x3dd9de0, __in_chrg=<optimized out>) at graphicsview/qgraphicsitem.cpp:1493
#20 0x00007fd12a20d4e9 in ~QGraphicsObject (this=0x3dd9dd0, __in_chrg=<optimized out>) at ../../include/QtGui/../../src/gui/graphicsview/qgraphicsitem.h:547
#21 QGraphicsWidget::~QGraphicsWidget (this=0x3dd9dd0, __in_chrg=<optimized out>) at graphicsview/qgraphicswidget.cpp:232
#22 0x00007fd11152cdf9 in TaskGroupItem::~TaskGroupItem (this=0x3dd9dd0, __in_chrg=<optimized out>) at ../../../../../plasma/desktop/applets/tasks/taskgroupitem.cpp:87
#23 0x00007fd12a863478 in QObject::event (this=0x3dd9dd0, e=<optimized out>) at kernel/qobject.cpp:1176
#24 0x00007fd12a20964b in QGraphicsWidget::event (this=0x3dd9dd0, event=0x45bad90) at graphicsview/qgraphicswidget.cpp:1461
#25 0x00007fd129bcc894 in notify_helper (e=0x45bad90, receiver=0x3dd9dd0, this=0x18fc9a0) at kernel/qapplication.cpp:4559
#26 QApplicationPrivate::notify_helper (this=0x18fc9a0, receiver=0x3dd9dd0, e=0x45bad90) at kernel/qapplication.cpp:4531
#27 0x00007fd129bd1713 in QApplication::notify (this=0x18ef430, receiver=0x3dd9dd0, e=0x45bad90) at kernel/qapplication.cpp:4420
#28 0x00007fd12b526b46 in KApplication::notify (this=0x18ef430, receiver=0x3dd9dd0, event=0x45bad90) at ../../kdeui/kernel/kapplication.cpp:311
#29 0x00007fd12a849e9c in QCoreApplication::notifyInternal (this=0x18ef430, receiver=0x3dd9dd0, event=0x45bad90) at kernel/qcoreapplication.cpp:876
#30 0x00007fd12a84dc6a in sendEvent (event=0x45bad90, receiver=0x3dd9dd0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#31 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0x187e1f0) at kernel/qcoreapplication.cpp:1500
#32 0x00007fd12a878f93 in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#33 postEventSourceDispatch (s=<optimized out>) at kernel/qeventdispatcher_glib.cpp:279
#34 0x00007fd121858c9a in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#35 0x00007fd121859060 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#36 0x00007fd121859124 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#37 0x00007fd12a8793bf in QEventDispatcherGlib::processEvents (this=0x187fad0, flags=...) at kernel/qeventdispatcher_glib.cpp:424
#38 0x00007fd129c74d6e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#39 0x00007fd12a848c82 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#40 0x00007fd12a848ed7 in QEventLoop::exec (this=0x7fff4bfabf30, flags=...) at kernel/qeventloop.cpp:204
#41 0x00007fd12a84df67 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1148
#42 0x00007fd12d9b3a13 in kdemain (argc=1, argv=0x7fff4bfac318) at ../../../../plasma/desktop/shell/main.cpp:120
#43 0x00007fd12d5d676d in __libc_start_main (main=0x400640 <main(int, char**)>, argc=1, ubp_av=0x7fff4bfac318, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff4bfac308) at libc-start.c:226
#44 0x0000000000400671 in _start ()

Reported using DrKonqi