Application that crashed: plasma-desktop
Version of the application: 0.3
KDE Version: 4.3.2 (KDE 4.3.2)
Qt Version: 4.5.2
Operating System: Linux 2.6.31-17-generic x86_64
Distribution: Ubuntu 9.10

What I was doing when the application crashed:
I created a second panel on a second screen, and added a second system tray. Shortly after, Plasma crashed.

 -- Backtrace:
Application: Plasma Workspace (kdeinit4), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f609f5ca750 (LWP 5587))]

Thread 2 (Thread 0x7f607e548910 (LWP 5588)):
#0  0x00007f609bd805a9 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/libpthread.so.0
#1  0x00007f609f0064fb in QWaitConditionPrivate::wait (this=<value optimized out>, mutex=0x1502c28, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:87
#2  QWaitCondition::wait (this=<value optimized out>, mutex=0x1502c28, time=18446744073709551615) at thread/qwaitcondition_unix.cpp:159
#3  0x00007f609b43d78c in QHostInfoAgent::run (this=0x1502c10) at kernel/qhostinfo.cpp:260
#4  0x00007f609f005445 in QThreadPrivate::start (arg=0x1502c10) at thread/qthread_unix.cpp:188
#5  0x00007f609bd7ba04 in start_thread () from /lib/libpthread.so.0
#6  0x00007f609c95b80d in clone () from /lib/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f609f5ca750 (LWP 5587)):
[KCrash Handler]
#5  0x00007f609d61c484 in QGraphicsItem::isWidget (this=0x22bc2d0) at graphicsview/qgraphicsitem.cpp:1143
#6  0x00007f609d61eb89 in QGraphicsItem::isWindow (this=0x22bc2d0) at graphicsview/qgraphicsitem.cpp:1156
#7  0x00007f609d652269 in QGraphicsScene::event (this=0xfdc170, event=<value optimized out>) at graphicsview/qgraphicsscene.cpp:3850
#8  0x00007f609d09befc in QApplicationPrivate::notify_helper (this=0xf773a0, receiver=0xfdc170, e=0x7fff25ed8390) at kernel/qapplication.cpp:4056
#9  0x00007f609d0a31ce in QApplication::notify (this=0xf6e240, receiver=0xfdc170, e=0x7fff25ed8390) at kernel/qapplication.cpp:4021
#10 0x00007f609dcd2ab6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#11 0x00007f609f0ebc2c in QCoreApplication::notifyInternal (this=0xf6e240, receiver=0xfdc170, event=0x7fff25ed8390) at kernel/qcoreapplication.cpp:610
#12 0x00007f609d6639f6 in QCoreApplication::sendEvent (this=0x15a00c0, event=0x7fff25ed8390) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#13 QGraphicsView::viewportEvent (this=0x15a00c0, event=0x7fff25ed8390) at graphicsview/qgraphicsview.cpp:2880
#14 0x00007f609f0eaf47 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<value optimized out>, receiver=0x159f1d0, event=0x7fff25ed8390) at kernel/qcoreapplication.cpp:726
#15 0x00007f609d09becc in QApplicationPrivate::notify_helper (this=0xf773a0, receiver=0x159f1d0, e=0x7fff25ed8390) at kernel/qapplication.cpp:4052
#16 0x00007f609d0a31ce in QApplication::notify (this=0xf6e240, receiver=0x159f1d0, e=0x7fff25ed8390) at kernel/qapplication.cpp:4021
#17 0x00007f609dcd2ab6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#18 0x00007f609f0ebc2c in QCoreApplication::notifyInternal (this=0xf6e240, receiver=0x159f1d0, event=0x7fff25ed8390) at kernel/qcoreapplication.cpp:610
#19 0x00007f609d0eab6b in QCoreApplication::sendEvent (this=<value optimized out>, event=0x7fff25ed8390) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:213
#20 QWidget::event (this=<value optimized out>, event=0x7fff25ed8390) at kernel/qwidget.cpp:7797
#21 0x00007f609d4462a6 in QFrame::event (this=0x15a00c0, e=0x7fff25ed8390) at widgets/qframe.cpp:559
#22 0x00007f609d4d5bc9 in QAbstractScrollArea::event (this=0x15a00c0, e=0x7fff25ed8390) at widgets/qabstractscrollarea.cpp:918
#23 0x00007f609d09befc in QApplicationPrivate::notify_helper (this=0xf773a0, receiver=0x15a00c0, e=0x7fff25ed8390) at kernel/qapplication.cpp:4056
#24 0x00007f609d0a31ce in QApplication::notify (this=0xf6e240, receiver=0x15a00c0, e=0x7fff25ed8390) at kernel/qapplication.cpp:4021
#25 0x00007f609dcd2ab6 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#26 0x00007f609f0ebc2c in QCoreApplication::notifyInternal (this=0xf6e240, receiver=0x15a00c0, event=0x7fff25ed8390) at kernel/qcoreapplication.cpp:610
#27 0x00007f609d0a655b in QCoreApplication::sendSpontaneousEvent (act=<value optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:216
#28 QApplication::setActiveWindow (act=<value optimized out>) at kernel/qapplication.cpp:2414
#29 0x00007f609d107b9e in QApplication::x11ProcessEvent (this=<value optimized out>, event=0x7fff25ed9c70) at kernel/qapplication_x11.cpp:3469
#30 0x00007f609d130d0c in x11EventSourceDispatch (s=<value optimized out>, callback=<value optimized out>, user_data=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:146
#31 0x00007f609bfccbce in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#32 0x00007f609bfd0598 in ?? () from /lib/libglib-2.0.so.0
#33 0x00007f609bfd06c0 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#34 0x00007f609f1141a6 in QEventDispatcherGlib::processEvents (this=0xeeb040, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:327
#35 0x00007f609d1304be in QGuiEventDispatcherGlib::processEvents (this=0x22bc2d0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#36 0x00007f609f0ea532 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#37 0x00007f609f0ea904 in QEventLoop::exec (this=0x7fff25ed9fa0, flags=) at kernel/qeventloop.cpp:201
#38 0x00007f609f0ecab9 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:888
#39 0x00007f609346d4cf in kdemain () from /usr/lib/libkdeinit4_plasma-desktop.so
#40 0x0000000000406da8 in _start ()

Reported using DrKonqi