Application: plasma-desktop (0.4)
KDE Platform Version: 4.7.3 (4.7.3)
Qt Version: 4.7.4
Operating System: Linux 3.0.0-14-generic x86_64
Distribution: Ubuntu 11.10

-- Information about the crash:
I was task switching. Plasma crashes and reloads. 
This happens quite often and sometimes every other minute.. Overall average 10times a day. maybe even more.

The crash can be reproduced some of the time.

-- Backtrace:
Application: Plasma Desktop Shell (plasma-desktop), signal: Segmentation fault
[Current thread is 1 (Thread 0x7ffd81c547a0 (LWP 3699))]

Thread 4 (Thread 0x7ffd64dee700 (LWP 3701)):
#0  0x00007ffd81543773 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffd75acdf68 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007ffd75ace429 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffd7e734f3e in QEventDispatcherGlib::processEvents (this=0x290fba0, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:424
#4  0x00007ffd7e708cf2 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007ffd7e708ef7 in QEventLoop::exec (this=0x7ffd64deddb0, flags=...) at kernel/qeventloop.cpp:201
#6  0x00007ffd7e62027f in QThread::exec (this=<optimized out>) at thread/qthread.cpp:498
#7  0x00007ffd7e6ebcbf in QInotifyFileSystemWatcherEngine::run (this=0x290d030) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007ffd7e622d05 in QThreadPrivate::start (arg=0x290d030) at thread/qthread_unix.cpp:331
#9  0x00007ffd765daefc in start_thread (arg=0x7ffd64dee700) at pthread_create.c:304
#10 0x00007ffd8154f89d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7ffd5999f700 (LWP 3702)):
#0  0x00007ffd765de1fd in __pthread_mutex_unlock_usercnt (mutex=<optimized out>, decr=<optimized out>) at pthread_mutex_unlock.c:52
#1  __pthread_mutex_unlock (mutex=0x2abbbc8) at pthread_mutex_unlock.c:290
#2  0x00007ffd75accfe4 in g_main_context_prepare () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffd75acddfd in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007ffd75ace429 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007ffd7e734f3e in QEventDispatcherGlib::processEvents (this=0x2abb730, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:424
#6  0x00007ffd7e708cf2 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007ffd7e708ef7 in QEventLoop::exec (this=0x7ffd5999edb0, flags=...) at kernel/qeventloop.cpp:201
#8  0x00007ffd7e62027f in QThread::exec (this=<optimized out>) at thread/qthread.cpp:498
#9  0x00007ffd7e6ebcbf in QInotifyFileSystemWatcherEngine::run (this=0x2ab79d0) at io/qfilesystemwatcher_inotify.cpp:248
#10 0x00007ffd7e622d05 in QThreadPrivate::start (arg=0x2ab79d0) at thread/qthread_unix.cpp:331
#11 0x00007ffd765daefc in start_thread (arg=0x7ffd5999f700) at pthread_create.c:304
#12 0x00007ffd8154f89d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#13 0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7ffd537c6700 (LWP 3710)):
#0  0x00007ffd81543773 in __GI___poll (fds=<optimized out>, nfds=<optimized out>, timeout=<optimized out>) at ../sysdeps/unix/sysv/linux/poll.c:87
#1  0x00007ffd75acdf68 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007ffd75ace792 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007ffd542a4516 in ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
#4  0x00007ffd75af32b6 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007ffd765daefc in start_thread (arg=0x7ffd537c6700) at pthread_create.c:304
#6  0x00007ffd8154f89d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7ffd81c547a0 (LWP 3699)):
[KCrash Handler]
#6  isNull (this=0x4d0000) at /usr/include/qt4/QtCore/qsharedpointer_impl.h:568
#7  operator! (this=0x4d0000) at /usr/include/qt4/QtCore/qsharedpointer_impl.h:574
#8  TaskManager::TaskItem::task (this=0x35ab200) at ../../../libs/taskmanager/taskitem.cpp:113
#9  0x00007ffd68e34112 in WindowTaskItem::publishIconGeometry (this=0x3301010) at ../../../../../plasma/desktop/applets/tasks/windowtaskitem.cpp:120
#10 0x00007ffd68e42b7c in AbstractTaskItem::timerEvent (this=0x3301010, event=<optimized out>) at ../../../../../plasma/desktop/applets/tasks/abstracttaskitem.cpp:439
#11 0x00007ffd7e720789 in QObject::event (this=0x3301010, e=<optimized out>) at kernel/qobject.cpp:1181
#12 0x00007ffd7e0d889b in QGraphicsWidget::event (this=0x3301010, event=0x7fff0098ec20) at graphicsview/qgraphicswidget.cpp:1455
#13 0x00007ffd7daba424 in notify_helper (e=0x7fff0098ec20, receiver=0x3301010, this=0x201eb60) at kernel/qapplication.cpp:4486
#14 QApplicationPrivate::notify_helper (this=0x201eb60, receiver=0x3301010, e=0x7fff0098ec20) at kernel/qapplication.cpp:4458
#15 0x00007ffd7dabf291 in QApplication::notify (this=0x1fffa50, receiver=0x3301010, e=0x7fff0098ec20) at kernel/qapplication.cpp:4365
#16 0x00007ffd7f3b8126 in KApplication::notify (this=0x1fffa50, receiver=0x3301010, event=0x7fff0098ec20) at ../../kdeui/kernel/kapplication.cpp:311
#17 0x00007ffd7e709afc in QCoreApplication::notifyInternal (this=0x1fffa50, receiver=0x3301010, event=0x7fff0098ec20) at kernel/qcoreapplication.cpp:787
#18 0x00007ffd7e736d62 in sendEvent (event=0x7fff0098ec20, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#19 QTimerInfoList::activateTimers (this=0x20215d0) at kernel/qeventdispatcher_unix.cpp:603
#20 0x00007ffd7e734538 in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:184
#21 idleTimerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:231
#22 0x00007ffd75acda5d in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#23 0x00007ffd75ace258 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#24 0x00007ffd75ace429 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#25 0x00007ffd7e734ed6 in QEventDispatcherGlib::processEvents (this=0x1faff40, flags=<optimized out>) at kernel/qeventdispatcher_glib.cpp:422
#26 0x00007ffd7db6207e in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=<optimized out>) at kernel/qguieventdispatcher_glib.cpp:204
#27 0x00007ffd7e708cf2 in QEventLoop::processEvents (this=<optimized out>, flags=...) at kernel/qeventloop.cpp:149
#28 0x00007ffd7e708ef7 in QEventLoop::exec (this=0x7fff0098eeb0, flags=...) at kernel/qeventloop.cpp:201
#29 0x00007ffd7e70d789 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1064
#30 0x00007ffd8184e1a3 in kdemain (argc=1, argv=0x7fff0098f298) at ../../../../plasma/desktop/shell/main.cpp:120
#31 0x00007ffd8148f30d in __libc_start_main (main=0x400640 <main(int, char**)>, argc=1, ubp_av=0x7fff0098f298, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff0098f288) at libc-start.c:226
#32 0x0000000000400671 in _start ()

Possible duplicates by query: bug 290538, bug 290507, bug 290506, bug 290505, bug 290499.

Reported using DrKonqi