Application: kwin (4.3.90 (KDE 4.3.90 (KDE 4.4 RC1)))
KDE Platform Version: 4.3.90 (KDE 4.3.90 (KDE 4.4 RC1))
Qt Version: 4.6.0
Operating System: Linux 2.6.32-ARCH x86_64
Distribution (Platform): Archlinux Packages

-- Information about the crash:
I switched plasma over to netbook mode on my AMD64 machine and KWin crashed. I've also experienced this on a x86 machine. 

I'm using archlinux kdemod packages of KDE4.4rc

 -- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
[KCrash Handler]
#5  KDecoration::widget (this=0x3324e80, check_workspace_pos=true, force=<value optimized out>)
    at /home/mikko/kdemod/testing/kdebase-workspace/src/kdebase-workspace-4.3.90/kwin/lib/kdecoration.h:1026
#6  KWin::Client::updateDecoration (this=0x3324e80, check_workspace_pos=true, force=<value optimized out>)
    at /home/mikko/kdemod/testing/kdebase-workspace/src/kdebase-workspace-4.3.90/kwin/client.cpp:370
#7  0x00007ff3be4647ff in KWin::Workspace::slotReconfigure (this=0x25d6190) at /home/mikko/kdemod/testing/kdebase-workspace/src/kdebase-workspace-4.3.90/kwin/workspace.cpp:1077
#8  0x00007ff3be4659e1 in KWin::Workspace::qt_metacall (this=0x25d6190, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7ffff35f0f00)
    at /home/mikko/kdemod/testing/kdebase-workspace/src/kdebase-workspace-4.3.90/kwin/workspace.moc:498
#9  0x00007ff3bb7a40a3 in QMetaObject::activate (sender=0x25d6490, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0xfffffff4) at kernel/qobject.cpp:3294
#10 0x00007ff3bb7a0d13 in QObject::event (this=0x25d6490, e=0x7ffff35f15c0) at kernel/qobject.cpp:1224
#11 0x00007ff3bbedb69c in QApplicationPrivate::notify_helper (this=0x237a700, receiver=0x25d6490, e=0x7ffff35f15c0) at kernel/qapplication.cpp:4242
#12 0x00007ff3bbee1cbd in QApplication::notify (this=0x7ffff35f1920, receiver=0x25d6490, e=0x7ffff35f15c0) at kernel/qapplication.cpp:4125
#13 0x00007ff3be01b206 in KApplication::notify (this=0x7ffff35f1920, receiver=0x25d6490, event=0x7ffff35f15c0)
    at /home/mikko/kdemod/testing/kdelibs/src/kdelibs-4.3.90/kdeui/kernel/kapplication.cpp:302
#14 0x00007ff3bb7913cc in QCoreApplication::notifyInternal (this=0x7ffff35f1920, receiver=0x25d6490, event=0x7ffff35f15c0) at kernel/qcoreapplication.cpp:704
#15 0x00007ff3bb7be122 in QCoreApplication::sendEvent (this=0x237e4b0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#16 QTimerInfoList::activateTimers (this=0x237e4b0) at kernel/qeventdispatcher_unix.cpp:603
#17 0x00007ff3bb7bac48 in timerSourceDispatch (source=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:184
#18 idleTimerSourceDispatch (source=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:231
#19 0x00000034d2e3926e in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#20 0x00000034d2e3cc28 in g_main_context_iterate () from /usr/lib/libglib-2.0.so.0
#21 0x00000034d2e3cd50 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#22 0x00007ff3bb7ba913 in QEventDispatcherGlib::processEvents (this=0x233aa30, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:407
#23 0x00007ff3bbf8877e in QGuiEventDispatcherGlib::processEvents (this=0x3324e80, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#24 0x00007ff3bb78fcf2 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#25 0x00007ff3bb7900cc in QEventLoop::exec (this=0x7ffff35f1860, flags=) at kernel/qeventloop.cpp:201
#26 0x00007ff3bb793e0b in QCoreApplication::exec () at kernel/qcoreapplication.cpp:981
#27 0x00007ff3be47f56e in kdemain (argc=<value optimized out>, argv=<value optimized out>) at /home/mikko/kdemod/testing/kdebase-workspace/src/kdebase-workspace-4.3.90/kwin/main.cpp:526
#28 0x00000034cfa1eb6d in __libc_start_main () from /lib/libc.so.6
#29 0x0000000000400629 in _start ()

Reported using DrKonqi