if i start KDE on Konsole, i have a lot of :
plasma-desktop(6803)/plasma TaskGroupItem::reload: invalid Item
plasma-desktop(6803)/plasma TaskGroupItem::reload: invalid Item
plasma-desktop(6803)/plasma TaskGroupItem::reload: invalid Item
plasma-desktop(6803)/plasma TaskGroupItem::reload: invalid Item

and then the crash

- Is this with an existant user account ? Have you tried with a clean account ?
- What are your taskbar settings ?

So far I haven't experienced this crash while running 4.4trunk...

Thanks

i am trying with a fresh user and with kde vanilla configuration

i put the output of the start of plasma-desktop on a file, and i have more than 330 000 times "plasma-desktop(6803)/plasma TaskGroupItem::reload: invalid Item"

in fact 8620364 times "plasma-desktop(6803)/plasma TaskGroupItem::reload: invalid Item"

i rebuilded KDE with latest trunk and this is still valid

I wonder what's wrong in your config/build as I never experienced such crash.
Could it be related to the type of windows you have when Plasma start? (some applications being restarted by sessionmanagement or may be some Mandriva specific app)
You could try to manually edit the plasmarc files and remove the taskbar to try to load Plasma without crashing and "playing" with it to help you determine the real cause... :-\

the taskbar is the culprit because the last time i had the time to remove  the taskbar when kde started ( before the bug ) and after  no crashes. I tried to add back the taskbar and it crashed immediatly

Have you tried adding the taskbar to different sized panels or even on desktop. What about loading plasmoidviewer with it ? - Will it crash on all the situations ?

to be sure this wasn't an extern issue,  i removed mandriva custom config files to use KDE defaults and it was the same but i have not tried with different sizes.

if really needed i can try

I'm just guessing as I'm not an expert in this things... but well.. let's wait for a Plasma dev.

SVN commit 1062470 by mart:

use a weak pointer and guard m_group everywhere
BUG:217392


 M  +48 -43    taskgroupitem.cpp  
 M  +1 -1      taskgroupitem.h  


WebSVN link: http://websvn.kde.org/?view=rev&revision=1062470

i just rebuilded and it still crash at start

the crash seems a little different : 

Thread 1 (Thread 0x7fc353926720 (LWP 27838)):
[KCrash Handler]
#5  QMimeData::setData (this=0xfffffffd, mimeType=@0x7fff4e8d8c10, data=@0x7fff4e8d8c20) at kernel/qmimedata.h:97
#6  0x00007fc331c4a3a5 in TaskManager::Task::addMimeData (this=<value optimized out>, mimeData=0xfffffffd) at /home/neoclust/Documents/KDE/kdebase/workspace/libs/taskmanager/task.cpp:837
#7  0x00007fc3317fcc6d in WindowTaskItem::updateTask (this=0x19ca420, changes=) at /home/neoclust/Documents/trunk/KDE/kdebase/workspace/plasma/desktop/applets/tasks/windowtaskitem.cpp:151
#8  0x00007fc3317fc3f1 in WindowTaskItem::setWindowTask (this=0x19ca420, taskItem=<value optimized out>)
    at /home/neoclust/Documents/trunk/KDE/kdebase/workspace/plasma/desktop/applets/tasks/windowtaskitem.cpp:286
#9  0x00007fc3317fc8cb in WindowTaskItem::setTask (this=0x19ca420, taskItem=0x19af510) at /home/neoclust/Documents/trunk/KDE/kdebase/workspace/plasma/desktop/applets/tasks/windowtaskitem.cpp:302
#10 0x00007fc33180f308 in TaskGroupItem::createAbstractItem (this=0x14efb90, groupableItem=0x19af510)
    at /home/neoclust/Documents/trunk/KDE/kdebase/workspace/plasma/desktop/applets/tasks/taskgroupitem.cpp:434
#11 0x00007fc33180f473 in TaskGroupItem::itemAdded (this=0x14efb90, groupableItem=0x19af510) at /home/neoclust/Documents/trunk/KDE/kdebase/workspace/plasma/desktop/applets/tasks/taskgroupitem.cpp:463
#12 0x00007fc33181014c in TaskGroupItem::qt_metacall (this=0x14efb90, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff4e8d9050)
    at /home/neoclust/Documents/trunk/KDE/kdebase/build/workspace/plasma/desktop/applets/tasks/taskgroupitem.moc:119
#13 0x00007fc34deb01b3 in QMetaObject::activate (sender=0x14eea30, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x186149e) at kernel/qobject.cpp:3286
#14 0x00007fc331c5282f in TaskManager::TaskGroup::itemAdded (this=0xfffffffd, _t1=0x19af510) at /home/neoclust/Documents/KDE/kdebase/workspace/build/libs/taskmanager/taskgroup.moc:151
#15 0x00007fc331c5410f in TaskManager::TaskGroup::add (this=0x14eea30, item=0x19af510) at /home/neoclust/Documents/KDE/kdebase/workspace/libs/taskmanager/taskgroup.cpp:138
#16 0x00007fc331c3d10e in TaskManager::GroupManagerPrivate::addTask (this=0x14e3b10, task=) at /home/neoclust/Documents/KDE/kdebase/workspace/libs/taskmanager/groupmanager.cpp:290
#17 0x00007fc331c3dd2e in TaskManager::GroupManager::qt_metacall (this=0x1362ab0, _c=<value optimized out>, _id=<value optimized out>, _a=0x7fff4e8d92f0)
    at /home/neoclust/Documents/KDE/kdebase/workspace/build/libs/taskmanager/groupmanager.moc:109
#18 0x00007fc34deb01b3 in QMetaObject::activate (sender=0x1358b10, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x186149e) at kernel/qobject.cpp:3286
#19 0x00007fc331c55f92 in TaskManager::TaskManager::taskAdded (this=0xfffffffd, _t1=<value optimized out>) at /home/neoclust/Documents/KDE/kdebase/workspace/build/libs/taskmanager/taskmanager.moc:161
#20 0x00007fc331c56f5b in TaskManager::TaskManager::windowAdded (this=0x1358b10, w=37748774) at /home/neoclust/Documents/KDE/kdebase/workspace/libs/taskmanager/taskmanager.cpp:262
#21 0x00007fc331c57567 in TaskManager::TaskManager::qt_metacall (this=0x1358b10, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fff4e8d95c0)
    at /home/neoclust/Documents/KDE/kdebase/workspace/build/libs/taskmanager/taskmanager.moc:115
#22 0x00007fc34deb01b3 in QMetaObject::activate (sender=0x1022510, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x186149e) at kernel/qobject.cpp:3286
#23 0x00007fc35106d6f2 in KWindowSystem::windowAdded (this=0xfffffffd, _t1=37748774) at /home/neoclust/Documents/trunk/KDE/kdelibs/build/kdeui/kwindowsystem.moc:126
#24 0x00007fc35106fa42 in KWindowSystemPrivate::addClient (this=0x1022af0, w=37748774) at /home/neoclust/Documents/trunk/KDE/kdelibs/kdeui/windowmanagement/kwindowsystem_x11.cpp:229
#25 0x00007fc35107c097 in NETRootInfo::update (this=0x1022b18, dirty_props=<value optimized out>) at /home/neoclust/Documents/trunk/KDE/kdelibs/kdeui/windowmanagement/netwm.cpp:2196
#26 0x00007fc35107d328 in NETRootInfo::event (this=0x1022b18, event=<value optimized out>, properties=0x7fff4e8d98f0, properties_size=5)
    at /home/neoclust/Documents/trunk/KDE/kdelibs/kdeui/windowmanagement/netwm.cpp:2068
#27 0x00007fc35106fd86 in KWindowSystemPrivate::x11Event (this=0x1022af0, ev=0x7fff4e8da0f0) at /home/neoclust/Documents/trunk/KDE/kdelibs/kdeui/windowmanagement/kwindowsystem_x11.cpp:136
#28 0x00007fc350f5a122 in KApplication::x11EventFilter (this=<value optimized out>, _event=0x7fff4e8da0f0) at /home/neoclust/Documents/trunk/KDE/kdelibs/kdeui/kernel/kapplication.cpp:959
#29 0x00007fc353534e43 in PlasmaApp::x11EventFilter (this=0xca1920, event=0x7fff4e8da0f0) at /home/neoclust/Documents/trunk/KDE/kdebase/workspace/plasma/desktop/shell/plasmaapp.cpp:539
#30 0x00007fc34e647d31 in qt_x11EventFilter (ev=0x7fff4e8da0f0) at kernel/qapplication_x11.cpp:399
#31 0x00007fc34e656861 in QApplication::x11ProcessEvent (this=<value optimized out>, event=0x7fff4e8da0f0) at kernel/qapplication_x11.cpp:3231
#32 0x00007fc34e681aa2 in x11EventSourceDispatch (s=0xcbc850, callback=<value optimized out>, user_data=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:146
#33 0x00007fc3483bf65e in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#34 0x00007fc3483c3028 in ?? () from /usr/lib64/libglib-2.0.so.0
#35 0x00007fc3483c3150 in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#36 0x00007fc34dec6a13 in QEventDispatcherGlib::processEvents (this=0xc88860, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:407
#37 0x00007fc34e68168e in QGuiEventDispatcherGlib::processEvents (this=0xfffffffd, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#38 0x00007fc34de9bd82 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#39 0x00007fc34de9c15c in QEventLoop::exec (this=0x7fff4e8da420, flags=) at kernel/qeventloop.cpp:201
#40 0x00007fc34de9fe9b in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#41 0x00007fc35352054a in kdemain (argc=<value optimized out>, argv=<value optimized out>) at /home/neoclust/Documents/trunk/KDE/kdebase/workspace/plasma/desktop/shell/main.cpp:112
#42 0x00007fc34d028afd in __libc_start_main () from /lib64/libc.so.6
#43 0x00000000004007a9 in _start () at ../sysdeps/x86_64/elf/start.S:113

SVN commit 1063320 by mart:

actually delete the tasks when the corresponding window closes.
this solves ghost entries as well as some memory wasting
BUG:217392


 M  +8 -6      groupmanager.cpp  
 M  +1 -1      groupmanager.h  
 M  +37 -38    taskitem.cpp  
 M  +1 -0      taskmanager.cpp  


WebSVN link: http://websvn.kde.org/?view=rev&revision=1063320

wrokng bug # in the commit

the last backtrace is a bit weird
i.e at line 151 of windowtaskitem.cpp Task::addMimeData is -not- called
this could mean the applet is still trying to use an old incompatible version of libtaskmanager

sorry, i reinstalled my mandriva and now all is OK, i think some of my previous manual kde compile were the culprit

*** Bug 321438 has been marked as a duplicate of this bug. ***