Application: kwin (4.5.1 (KDE 4.5.1))
KDE Platform Version: 4.5.1 (KDE 4.5.1)
Qt Version: 4.7.0
Operating System: Linux 2.6.35-27-generic x86_64
Distribution: Ubuntu 10.10

-- Information about the crash:
- What I was doing when the application crashed:
After selecting Meta+Mouse wheel to cycle grouped windows under System Settings/Window Behavior/Window Behavior/Window Actions, spinning the wheel (actually it's a touchpad configured to pretend to scroll when you slide on the side) with Meta (Windows) key crashed. Taskbar disappeared and reappeared.

-- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f7cd8310780 (LWP 2390))]

Thread 2 (Thread 0x7f7cb9309700 (LWP 2414)):
#0  0xffffffffff60017b in ?? ()
#1  0x00007f7cb9308ad0 in ?? ()
#2  0x00007fff767ff852 in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Thread 1 (Thread 0x7f7cd8310780 (LWP 2390)):
[KCrash Handler]
#6  size (this=0x0, c=0xd37ef0) at /usr/include/qt4/QtCore/qlist.h:94
#7  indexOf (this=0x0, c=0xd37ef0) at /usr/include/qt4/QtCore/qlist.h:829
#8  KWin::ClientGroup::indexOfClient (this=0x0, c=0xd37ef0) at ../../kwin/clientgroup.h:182
#9  0x00007f7cd7ec903c in KWin::Client::performMouseCommand (this=0xd37ef0, command=<value optimized out>, globalPos=..., handled=false) at ../../kwin/useractions.cpp:1091
#10 0x00007f7cd7ea5ee5 in KWin::Client::buttonPressEvent (this=0xd37ef0, w=36551873, button=4, state=64, x=740, y=499, x_root=802, y_root=499) at ../../kwin/events.cpp:1278
#11 0x00007f7cd7ea638c in KWin::Client::windowEvent (this=0xd37ef0, e=0x7fff7666a830) at ../../kwin/events.cpp:677
#12 0x00007f7cd7ea6b08 in KWin::Workspace::workspaceEvent (this=0x7ff120, e=0x7fff7666a830) at ../../kwin/events.cpp:307
#13 0x00007f7cd7e822a8 in KWin::Application::x11EventFilter (this=0x7fff7666aa70, e=0x7fff7666a830) at ../../kwin/main.cpp:363
#14 0x00007f7cd35fe751 in qt_x11EventFilter (ev=0x7fff7666a830) at kernel/qapplication_x11.cpp:408
#15 0x00007f7cd360e4f1 in QApplication::x11ProcessEvent (this=<value optimized out>, event=0x7fff7666a830) at kernel/qapplication_x11.cpp:3248
#16 0x00007f7cd363bb6f in QEventDispatcherX11::processEvents (this=<value optimized out>, flags=) at kernel/qeventdispatcher_x11.cpp:132
#17 0x00007f7cd443ca02 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#18 0x00007f7cd443cdec in QEventLoop::exec (this=0x7fff7666a9b0, flags=) at kernel/qeventloop.cpp:201
#19 0x00007f7cd4440ebb in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1009
#20 0x00007f7cd7e83f9d in kdemain (argc=<value optimized out>, argv=<value optimized out>) at ../../kwin/main.cpp:531
#21 0x00007f7cd7accd8e in __libc_start_main (main=<value optimized out>, argc=<value optimized out>, ubp_av=<value optimized out>, init=<value optimized out>, fini=<value optimized out>, rtld_fini=<value optimized out>, stack_end=0x7fff7666b078) at libc-start.c:226
#22 0x0000000000400669 in _start ()

Possible duplicates by query: bug 240765, bug 240464.

Reported using DrKonqi