can you please activate the debug medias and install :


qt4-debug
kdelibs4-debug
kdebase4-runtimed-debug
kdebase4-workspace-debug

and please give the new crash log

Under XGuest user is OK. Maybe because of a lot widgets on desktop (around 10).

NEW CRASH LOG:

Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.3
Operating System: Linux 2.6.31.12-desktop-1mnb i686
Distribution: "Mandriva Linux 2010.0"

What I was doing when the application crashed:
<In detail, tell us what you were doing  when the application crashed.>

 -- Backtrace:
Application: Рабочее пространство Plasma (kdeinit4), signal: Aborted
[KCrash Handler]
#6  0xffffe424 in __kernel_vsyscall ()
#7  0xb5e8b611 in raise () from /lib/i686/libc.so.6
#8  0xb5e8cf62 in abort () from /lib/i686/libc.so.6
#9  0xb5ecc35b in ?? () from /lib/i686/libc.so.6
#10 0xb5ed1869 in ?? () from /lib/i686/libc.so.6
#11 0xb5ed10df in realloc () from /lib/i686/libc.so.6
#12 0xb75405f3 in qRealloc (ptr=0x5e8cb008, size=1073741824) at global/qmalloc.cpp:65
#13 0xb758dfee in QString::realloc (this=0x978ab90, alloc=536870902) at tools/qstring.cpp:1090
#14 0xb758e481 in QString::append (this=0x978ab90, ch={ucs = 8233}) at tools/qstring.cpp:1369
#15 0xb642ca85 in QTextDocumentPrivate::insertBlock (this=0x978ab48, blockSeparator=@0xbfe0521e, pos=268435506, blockFormat=1, charFormat=0, op=QTextUndoCommand::MoveCursor)
    at text/qtextdocument_p.cpp:388
#16 0xb642ceae in QTextDocumentPrivate::insertBlock (this=0x978ab48, pos=268435506, blockFormat=1, charFormat=0, op=QTextUndoCommand::MoveCursor) at text/qtextdocument_p.cpp:431
#17 0xb645451c in QTextCursorPrivate::insertBlock (this=0x96abaf8, format=@0xbfe05308, charFormat=@0xbfe05298) at text/qtextcursor.cpp:202
#18 0xb645a744 in QTextCursor::insertBlock (this=0xbfe05378, format=@0xbfe05308, _charFormat=@0xbfe052d8) at text/qtextcursor.cpp:1897
#19 0xb645a805 in QTextCursor::insertBlock (this=0xbfe05378, format=@0xbfe05308) at text/qtextcursor.cpp:1875
#20 0xb645a86d in QTextCursor::insertBlock (this=0xbfe05378) at text/qtextcursor.cpp:1860
#21 0xb13d234e in ?? () from /usr/lib/kde4/plasma_applet_fileWatcher.so
#22 0xb13d2d68 in ?? () from /usr/lib/kde4/plasma_applet_fileWatcher.so
#23 0xb13d3c67 in ?? () from /usr/lib/kde4/plasma_applet_fileWatcher.so
#24 0xb53dfef5 in Plasma::Corona::loadLayout (this=0x8ebb2c0, configName=@0xbfe05828) at /usr/src/debug/kdelibs-4.3.2/plasma/corona.cpp:377
#25 0xb53e0fb4 in Plasma::Corona::initializeLayout (this=0x8ebb2c0, configName=@0xbfe05828) at /usr/src/debug/kdelibs-4.3.2/plasma/corona.cpp:324
#26 0xb2daa7fb in PlasmaApp::corona (this=0x8daa680) at /usr/src/debug/kdebase-workspace-4.3.2/plasma/shells/desktop/plasmaapp.cpp:574
#27 0xb2daab20 in PlasmaApp::setupDesktop (this=0x8daa680) at /usr/src/debug/kdebase-workspace-4.3.2/plasma/shells/desktop/plasmaapp.cpp:252
#28 0xb2daad79 in PlasmaApp::qt_metacall (this=0x8daa680, _c=QMetaObject::InvokeMetaMethod, _id=30, _a=0xbfe059cc)
    at /usr/src/debug/kdebase-workspace-4.3.2/build/plasma/shells/desktop/plasmaapp.moc:115
#29 0xb7653144 in QMetaObject::activate (sender=0x8ea5b18, from_signal_index=4, to_signal_index=4, argv=0x0) at kernel/qobject.cpp:3112
#30 0xb7653e65 in QMetaObject::activate (sender=0x8ea5b18, m=0xb772e908, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3186
#31 0xb7658405 in QSingleShotTimer::timeout (this=0x8ea5b18) at .moc/release-shared/qtimer.moc:76
#32 0xb765853c in QSingleShotTimer::timerEvent (this=0x8ea5b18) at kernel/qtimer.cpp:298
#33 0xb764cdfb in QObject::event (this=0x8ea5b18, e=0xbfe05e40) at kernel/qobject.cpp:1074
#34 0xb61c268c in QApplicationPrivate::notify_helper (this=0x8db0408, receiver=0x8ea5b18, e=0xbfe05e40) at kernel/qapplication.cpp:4065
#35 0xb61ca0ce in QApplication::notify (this=0x8daa680, receiver=0x8ea5b18, e=0xbfe05e40) at kernel/qapplication.cpp:3605
#36 0xb6c239e1 in KApplication::notify (this=0x8daa680, receiver=0x8ea5b18, event=0xbfe05e40) at /usr/src/debug/kdelibs-4.3.2/kdeui/kernel/kapplication.cpp:302
#37 0xb763cc0e in QCoreApplication::notifyInternal (this=0x8daa680, receiver=0x8ea5b18, event=0xbfe05e40) at kernel/qcoreapplication.cpp:610
#38 0xb766b2c1 in QTimerInfoList::activateTimers (this=0x8db3034) at ../../src/corelib/kernel/qcoreapplication.h:213
#39 0xb7668bd2 in timerSourceDispatch (source=0x8db3000) at kernel/qeventdispatcher_glib.cpp:184
#40 0xb5db1b92 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#41 0xb5db5468 in ?? () from /usr/lib/libglib-2.0.so.0
#42 0xb5db558e in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#43 0xb76688f1 in QEventDispatcherGlib::processEvents (this=0x8dada60, flags={i = 36}) at kernel/qeventdispatcher_glib.cpp:406
#44 0xb62644ba in QGuiEventDispatcherGlib::processEvents (this=0x8dada60, flags={i = 36}) at kernel/qguieventdispatcher_glib.cpp:202
#45 0xb763b26d in QEventLoop::processEvents (this=0xbfe060c4, flags=) at kernel/qeventloop.cpp:149
#46 0xb763b6b9 in QEventLoop::exec (this=0xbfe060c4, flags={i = 0}) at kernel/qeventloop.cpp:201
#47 0xb763db50 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#48 0xb61c2504 in QApplication::exec () at kernel/qapplication.cpp:3525
#49 0xb2d8dbd9 in kdemain (argc=1, argv=0x8d19928) at /usr/src/debug/kdebase-workspace-4.3.2/plasma/shells/desktop/main.cpp:50
#50 0x0804da54 in launch (argc=148308200, _name=<value optimized out>, args=<value optimized out>, cwd=0x0, envc=0, envs=0x8d700e8 "", reset_env=false, tty=0x0, avoid_loops=false, 
    startup_id_str=0x8050e85 "0") at /usr/src/debug/kdelibs-4.3.2/kinit/kinit.cpp:677
#51 0x0804e717 in handle_launcher_request (sock=<value optimized out>, who=<value optimized out>) at /usr/src/debug/kdelibs-4.3.2/kinit/kinit.cpp:1169
#52 0x0804eb64 in handle_requests (waitForPid=<value optimized out>) at /usr/src/debug/kdelibs-4.3.2/kinit/kinit.cpp:1362
#53 0x0804f85f in main (argc=2, argv=0xbfe06914, envp=0xbfe06920) at /usr/src/debug/kdelibs-4.3.2/kinit/kinit.cpp:1793

- Are you monitoring a big file using the "File Watcher" widget ? 
I wonder if this could be related to bug 196207.
Regards

Yes, exactly, KFile widget which is wathcing /var/log/messages

- How big is "/var/log/messages" in your system ?
- Does Plasma crash when you restart it manually ?
Regards

Yes, it was really big. 160m.
Manual restart of Plasma didn't have any success.

If you can't still use Plasma, try this:
(Plasma is not started)
- Start Konsole
- Type "export QT_NO_GLIB=1" + Enter
- Type "export MALLOC_CHECK_=" + Enter
- Type "plasma-desktop" + Enter
- Check if it crashes or not
If it doesn't crash, then it is likely to be bug 196207. 
Regards

Waiting for feedback.

Closing for lack of feedback.