Application that crashed: ksysguard
Version of the application: 4.3.00 (KDE 4.3.0)
KDE Version: 4.3.00 (KDE 4.3.0)
Qt Version: 4.5.2
Operating System: Linux 2.6.30.5-43.fc11.i586 i686

What I was doing when the application crashed:
Launch System Monitor
Go to System Load tab
Right click Network History then click Properties
In Signal Plotter Settings, go to Scales Tab
Untick Automatic Range Detection
Set Minimum to 0, Maximum to anything (eg 15000)
Crash

The reason I was setting a static scale is because Network History was displaying a negative scale, from 0 to -500,000 MiB/s. This is during a large transfer of an entire hard drive via CIFS.

 -- Backtrace:
Application: System Monitor (ksysguard), signal: Segmentation fault
[KCrash Handler]
#6  0x04889bb9 in QWidget::setUpdatesEnabled(bool) () from /usr/lib/libkdeinit4_ksysguard.so
#7  0x0486cf20 in QWidget::setUpdatesEnabled(bool) () from /usr/lib/libkdeinit4_ksysguard.so
#8  0x0486df86 in QWidget::setUpdatesEnabled(bool) () from /usr/lib/libkdeinit4_ksysguard.so
#9  0x03201853 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#10 0x032024b2 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#11 0x0416dc47 in KDialog::okClicked() () from /usr/lib/libkdeui.so.5
#12 0x04170558 in KDialog::slotButtonClicked(int) () from /usr/lib/libkdeui.so.5
#13 0x04172a5c in KDialog::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libkdeui.so.5
#14 0x0423a97a in KPageDialog::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libkdeui.so.5
#15 0x0486fc3a in QWidget::setUpdatesEnabled(bool) () from /usr/lib/libkdeinit4_ksysguard.so
#16 0x03201853 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#17 0x032024b2 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/libQtCore.so.4
#18 0x03204443 in QSignalMapper::mapped(int) () from /usr/lib/libQtCore.so.4
#19 0x03204cdd in QSignalMapper::map(QObject*) () from /usr/lib/libQtCore.so.4
#20 0x03204ebe in QSignalMapper::map() () from /usr/lib/libQtCore.so.4
#21 0x032056fb in QSignalMapper::qt_metacall(QMetaObject::Call, int, void**) () from /usr/lib/libQtCore.so.4
#22 0x03201853 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/libQtCore.so.4
#23 0x03201cc8 in QMetaObject::activate(QObject*, QMetaObject const*, int, int, void**) () from /usr/lib/libQtCore.so.4
#24 0x03d08e41 in QAbstractButton::clicked(bool) () from /usr/lib/libQtGui.so.4
#25 0x03a31229 in ?? () from /usr/lib/libQtGui.so.4
#26 0x03a32e64 in ?? () from /usr/lib/libQtGui.so.4
#27 0x03a33101 in QAbstractButton::mouseReleaseEvent(QMouseEvent*) () from /usr/lib/libQtGui.so.4
#28 0x036d2b9a in QWidget::event(QEvent*) () from /usr/lib/libQtGui.so.4
#29 0x03a310ce in QAbstractButton::event(QEvent*) () from /usr/lib/libQtGui.so.4
#30 0x03adb4dd in QPushButton::event(QEvent*) () from /usr/lib/libQtGui.so.4
#31 0x0367d974 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#32 0x03685a9b in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#33 0x04209a7a in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#34 0x031ebb0b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#35 0x036849de in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&) () from /usr/lib/libQtGui.so.4
#36 0x036f3090 in ?? () from /usr/lib/libQtGui.so.4
#37 0x036f2523 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#38 0x0371d5d2 in ?? () from /usr/lib/libQtGui.so.4
#39 0x00c66cf8 in g_main_context_dispatch () from /lib/libglib-2.0.so.0
#40 0x00c6a370 in ?? () from /lib/libglib-2.0.so.0
#41 0x00c6a4a3 in g_main_context_iteration () from /lib/libglib-2.0.so.0
#42 0x032165ec in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#43 0x0371ccb5 in ?? () from /usr/lib/libQtGui.so.4
#44 0x031ea0d9 in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#45 0x031ea52a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#46 0x031ec9af in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#47 0x0367d7f7 in QApplication::exec() () from /usr/lib/libQtGui.so.4
#48 0x048ac1d7 in kdemain () from /usr/lib/libkdeinit4_ksysguard.so
#49 0x0804868b in _start ()

Reported using DrKonqi