Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.62 (KDE 4.3.62 (KDE 4.4 >= 20090728))
Qt Version: 4.5.1
Operating System: Linux 2.6.28-1-amd64 x86_64
Distribution: Debian GNU/Linux testing (squeeze)

What I was doing when the application crashed:
Simply working and few times per day plasma-desktop crash. Good on it that stat again immediately. Please have a look.

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f1067fcb750 (LWP 5815))]

Thread 2 (Thread 0x7f104409b950 (LWP 5818)):
#0  0x00007f10678d2c09 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f1067b4d249 in QWaitConditionPrivate::wait (this=0x1cb3350, mutex=0x1cb3348, time=18446744073709551615) at /usr/src/kde4/qt-copy/src/corelib/thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=0x1cb3350, mutex=0x1cb3348, time=18446744073709551615) at /usr/src/kde4/qt-copy/src/corelib/thread/qwaitcondition_unix.cpp:159
#3  0x00007f10667815f4 in QHostInfoAgent::run (this=0x1cb3330) at /usr/src/kde4/qt-copy/src/network/kernel/qhostinfo.cpp:260
#4  0x00007f1067b4c4b9 in QThreadPrivate::start (arg=0x1cb3330) at /usr/src/kde4/qt-copy/src/corelib/thread/qthread_unix.cpp:189
#5  0x00007f10678cefaa in start_thread () from /lib/libpthread.so.0
#6  0x00007f106447d29d in clone () from /lib/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f1067fcb750 (LWP 5815)):
[KCrash Handler]
#5  0x00007f1044f81623 in WindowTaskItem::updateToolTip() () from /opt/kde4/lib/kde4/plasma_applet_tasks.so
#6  0x00007f1044f89154 in AbstractTaskItem::toolTipAboutToShow() () from /opt/kde4/lib/kde4/plasma_applet_tasks.so
#7  0x00007f1044f8a358 in AbstractTaskItem::qt_metacall(QMetaObject::Call, int, void**) () from /opt/kde4/lib/kde4/plasma_applet_tasks.so
#8  0x00007f1044f81515 in WindowTaskItem::qt_metacall(QMetaObject::Call, int, void**) () from /opt/kde4/lib/kde4/plasma_applet_tasks.so
#9  0x00007f1067c26f2c in QMetaMethod::invoke (this=0x7fff70110d60, object=0x1a8ba50, connectionType=Qt::DirectConnection, returnValue=..., val0=..., val1=..., val2=..., val3=..., val4=..., 
    val5=..., val6=..., val7=..., val8=..., val9=...) at /usr/src/kde4/qt-copy/src/corelib/kernel/qmetaobject.cpp:1522
#10 0x00007f1067c27634 in QMetaObject::invokeMethod (obj=0x1a8ba50, member=<value optimized out>, type=Qt::AutoConnection, ret=..., val0=..., val1=..., val2=..., val3=..., val4=..., val5=..., 
    val6=..., val7=..., val8=..., val9=...) at /usr/src/kde4/qt-copy/src/corelib/kernel/qmetaobject.cpp:1114
#11 0x00007f105a8370f8 in Plasma::ToolTipManagerPrivate::showToolTip() () from /opt/kde4/lib/libplasma.so.3
#12 0x00007f105a837659 in Plasma::ToolTipManager::qt_metacall(QMetaObject::Call, int, void**) () from /opt/kde4/lib/libplasma.so.3
#13 0x00007f1067c31b27 in QMetaObject::activate (sender=0x17dc590, from_signal_index=<value optimized out>, to_signal_index=4, argv=0x7fff70110890)
    at /usr/src/kde4/qt-copy/src/corelib/kernel/qobject.cpp:3117
#14 0x00007f1067c2e273 in QObject::event (this=0x17dc590, e=0x1cab110) at /usr/src/kde4/qt-copy/src/corelib/kernel/qobject.cpp:1082
#15 0x00007f106508302d in QApplicationPrivate::notify_helper (this=0x162bc50, receiver=0x17dc590, e=0x7fff70111700) at /usr/src/kde4/qt-copy/src/gui/kernel/qapplication.cpp:4057
#16 0x00007f106508b87a in QApplication::notify (this=0x1622ba0, receiver=0x17dc590, e=0x7fff70111700) at /usr/src/kde4/qt-copy/src/gui/kernel/qapplication.cpp:4022
#17 0x00007f10660ca98b in KApplication::notify(QObject*, QEvent*) () from /opt/kde4/lib/libkdeui.so.5
#18 0x00007f1067c1f95c in QCoreApplication::notifyInternal (this=0x1622ba0, receiver=0x17dc590, event=0x7fff70111700) at /usr/src/kde4/qt-copy/src/corelib/kernel/qcoreapplication.cpp:606
#19 0x00007f1067c47e36 in QCoreApplication::sendEvent (this=0x162fb50) at ../../include/QtCore/../../../../qt-copy/src/corelib/kernel/qcoreapplication.h:213
#20 QTimerInfoList::activateTimers (this=0x162fb50) at /usr/src/kde4/qt-copy/src/corelib/kernel/qeventdispatcher_unix.cpp:572
#21 0x00007f1067c4490d in timerSourceDispatch (source=<value optimized out>) at /usr/src/kde4/qt-copy/src/corelib/kernel/qeventdispatcher_glib.cpp:164
#22 0x00007f1063b0210a in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#23 0x00007f1063b05968 in ?? () from /usr/lib/libglib-2.0.so.0
#24 0x00007f1063b05b1c in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#25 0x00007f1067c4486f in QEventDispatcherGlib::processEvents (this=0x162b550, flags=<value optimized out>) at /usr/src/kde4/qt-copy/src/corelib/kernel/qeventdispatcher_glib.cpp:324
#26 0x00007f1065108bef in QGuiEventDispatcherGlib::processEvents (this=0x1b12690, flags=<value optimized out>) at /usr/src/kde4/qt-copy/src/gui/kernel/qguieventdispatcher_glib.cpp:202
#27 0x00007f1067c1e332 in QEventLoop::processEvents (this=<value optimized out>, flags=...) at /usr/src/kde4/qt-copy/src/corelib/kernel/qeventloop.cpp:149
#28 0x00007f1067c1e4c5 in QEventLoop::exec (this=0x7fff701119b0, flags=...) at /usr/src/kde4/qt-copy/src/corelib/kernel/qeventloop.cpp:196
#29 0x00007f1067c2053c in QCoreApplication::exec () at /usr/src/kde4/qt-copy/src/corelib/kernel/qcoreapplication.cpp:888
#30 0x00007f1056ddb84c in kdemain () from /opt/kde4/lib/libkdeinit4_plasma-desktop.so
#31 0x00000000004074b4 in launch(int, char const*, char const*, char const*, int, char const*, bool, char const*, bool, char const*) ()
#32 0x0000000000407c78 in handle_launcher_request(int, char const*) ()
#33 0x00000000004081fe in handle_requests(int) ()
#34 0x000000000040890b in main ()

Reported using DrKonqi