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 2.6.30.9-90.fc11.i586 i686

What I was doing when the application crashed:
Sometimes (not always) Plasma crash when I start Firefox from the Kickoff menu. Generally, I have previusly open only the Spotify-on-wine application and the aMSN. But other times, I have not any desktop application running, and plasma crash.
The firefox version is 3.5.3

 -- Backtrace:
Application: Plasma Workspace (plasma-desktop), signal: Segmentation fault
[Current thread is 1 (Thread 0xb77db7a0 (LWP 2709))]

Thread 4 (Thread 0xac681b70 (LWP 2713)):
#0  0x0083c422 in __kernel_vsyscall ()
#1  0x00dc3fa5 in pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S:122
#2  0x009ff337 in QWaitConditionPrivate::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:87
#3  QWaitCondition::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#4  0x07a574d2 in QHostInfoAgent::run (this=0x94df660) at kernel/qhostinfo.cpp:260
#5  0x009fe2f2 in QThreadPrivate::start (arg=0x94df660) at thread/qthread_unix.cpp:188
#6  0x00dbf935 in start_thread (arg=0xac681b70) at pthread_create.c:297
#7  0x00cf494e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

Thread 3 (Thread 0xa98fdb70 (LWP 2725)):
#0  0x00dc31e2 in __pthread_mutex_unlock_usercnt (mutex=<value optimized out>, mutex=<value optimized out>, decr=<value optimized out>) at pthread_mutex_unlock.c:52
#1  __pthread_mutex_unlock (mutex=<value optimized out>, mutex=<value optimized out>, decr=<value optimized out>) at pthread_mutex_unlock.c:289
#2  0x00158f76 in IA__g_main_context_check (context=0xabb01690, max_priority=2147483647, fds=0xa61338d0, n_fds=1) at gmain.c:2331
#3  0x0015972c in g_main_context_iterate (context=0xabb01690, block=<value optimized out>, dispatch=1, self=0xa61b7f98) at gmain.c:2452
#4  0x00159b13 in IA__g_main_context_iteration (context=0xabb01690, may_block=1) at gmain.c:2518
#5  0x00b19627 in QEventDispatcherGlib::processEvents (this=0xabb01680, flags={i = 36}) at kernel/qeventdispatcher_glib.cpp:329
#6  0x00aed0d9 in QEventLoop::processEvents (this=0xa98fd1f4, flags={i = 36}) at kernel/qeventloop.cpp:149
#7  0x00aed52a in QEventLoop::exec (this=0xa98fd1f4, flags={i = 0}) at kernel/qeventloop.cpp:201
#8  0x009faff3 in QThread::exec (this=0x9b68cb0) at thread/qthread.cpp:487
#9  0x01216cdc in ?? () from /usr/lib/kde4/plugins/marble/GpsdPositionProviderPlugin.so
#10 0x009fe2f2 in QThreadPrivate::start (arg=0x9b68cb0) at thread/qthread_unix.cpp:188
#11 0x00dbf935 in start_thread (arg=0xa98fdb70) at pthread_create.c:297
#12 0x00cf494e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

Thread 2 (Thread 0xabaffb70 (LWP 2824)):
#0  0x0083c422 in __kernel_vsyscall ()
#1  0x00dc42d2 in pthread_cond_timedwait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_timedwait.S:179
#2  0x009ff2bf in QWaitConditionPrivate::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:85
#3  QWaitCondition::wait (time=<value optimized out>, this=<value optimized out>) at thread/qwaitcondition_unix.cpp:159
#4  0x009f4926 in QThreadPoolThread::run (this=0xab6f500) at concurrent/qthreadpool.cpp:140
#5  0x009fe2f2 in QThreadPrivate::start (arg=0xab6f500) at thread/qthread_unix.cpp:188
#6  0x00dbf935 in start_thread (arg=0xabaffb70) at pthread_create.c:297
#7  0x00cf494e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:130

Thread 1 (Thread 0xb77db7a0 (LWP 2709)):
[KCrash Handler]
#6  0x0277a31a in QGraphicsLayoutItem::isLayout (this=0x960d330) at graphicsview/qgraphicslayoutitem.cpp:784
#7  0x0277916d in QGraphicsLayoutPrivate::activateRecursive (this=0x960d330, item=0xabf5e88) at graphicsview/qgraphicslayout_p.cpp:189
#8  0x0277916d in QGraphicsLayoutPrivate::activateRecursive (this=0x960d330, item=0x95022a8) at graphicsview/qgraphicslayout_p.cpp:189
#9  0x02778956 in QGraphicsLayout::activate (this=0x95022a8) at graphicsview/qgraphicslayout.cpp:258
#10 0x02778a2c in QGraphicsLayout::widgetEvent (this=0x95022a8, e=0x9e50ce8) at graphicsview/qgraphicslayout.cpp:366
#11 0x0277ebb6 in QGraphicsWidget::event (this=0x9613488, event=0x9e50ce8) at graphicsview/qgraphicswidget.cpp:1262
#12 0x02127974 in QApplicationPrivate::notify_helper (this=0x90ab258, receiver=0x9613488, e=0x9e50ce8) at kernel/qapplication.cpp:4056
#13 0x0212f0e9 in QApplication::notify (this=0x90a64c0, receiver=0x9613488, e=0x9e50ce8) at kernel/qapplication.cpp:3603
#14 0x02b7560a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#15 0x00aeeb0b in QCoreApplication::notifyInternal (this=0x90a64c0, receiver=0x9613488, event=0x9e50ce8) at kernel/qcoreapplication.cpp:610
#16 0x00aef732 in QCoreApplication::sendEvent (event=<value optimized out>, receiver=<value optimized out>) at kernel/qcoreapplication.h:213
#17 QCoreApplicationPrivate::sendPostedEvents (event=<value optimized out>, receiver=<value optimized out>) at kernel/qcoreapplication.cpp:1247
#18 0x00aef8ed in QCoreApplication::sendPostedEvents (receiver=0x0, event_type=0) at kernel/qcoreapplication.cpp:1140
#19 0x00b199bf in QCoreApplication::sendPostedEvents () at kernel/qcoreapplication.h:218
#20 postEventSourceDispatch () at kernel/qeventdispatcher_glib.cpp:210
#21 0x00156308 in g_main_dispatch (context=<value optimized out>) at gmain.c:1824
#22 IA__g_main_context_dispatch (context=<value optimized out>) at gmain.c:2377
#23 0x001599e0 in g_main_context_iterate (context=0x90ad290, block=<value optimized out>, dispatch=1, self=0x90aacd8) at gmain.c:2455
#24 0x00159b13 in IA__g_main_context_iteration (context=0x90ad290, may_block=1) at gmain.c:2518
#25 0x00b195ec in QEventDispatcherGlib::processEvents (this=0x90912c8, flags={i = 36}) at kernel/qeventdispatcher_glib.cpp:327
#26 0x021c6cb5 in QGuiEventDispatcherGlib::processEvents (this=0x90912c8, flags={i = 36}) at kernel/qguieventdispatcher_glib.cpp:202
#27 0x00aed0d9 in QEventLoop::processEvents (this=0xbfe99d34, flags={i = 36}) at kernel/qeventloop.cpp:149
#28 0x00aed52a in QEventLoop::exec (this=0xbfe99d34, flags={i = 0}) at kernel/qeventloop.cpp:201
#29 0x00aef9af in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#30 0x021277f7 in QApplication::exec () at kernel/qapplication.cpp:3525
#31 0x05db042d in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so
#32 0x080486fb in _start ()

Reported using DrKonqi