Version:            (using KDE 4.2.1)
OS:                Linux
Installed from:    Unlisted Binary Package

Using the "present windows" desktop effect occasionally crashes KWin.

Application: KWin (kwin), signal SIGSEGV
0x00007ff064aee8a0 in __nanosleep_nocancel () from /lib/libc.so.6
Current language:  auto; currently c
[Current thread is 1 (Thread 0x7ff06514b760 (LWP 9232))]

Thread 1 (Thread 0x7ff06514b760 (LWP 9232)):
[KCrash Handler]
#5  0x0000000000000005 in ?? ()
#6  0x00007ff05ab883e3 in KWin::PresentWindowsEffect::setHighlightedWindow (this=0x173c0e0, w=0x16b5900) at ../../../kwin/effects/presentwindows.cpp:1270
#7  0x00007ff05ab933df in KWin::PresentWindowsEffect::rearrangeWindows (this=0x173c0e0) at ../../../kwin/effects/presentwindows.cpp:487
#8  0x00007ff05ab93f11 in KWin::PresentWindowsEffect::setActive (this=0x173c0e0, active=<value optimized out>, closingTab=<value optimized out>) at ../../../kwin/effects/presentwindows.cpp:1153
#9  0x00007ff05ab94835 in KWin::PresentWindowsEffect::borderActivated (this=0x173c0e0, border=KWin::ElectricTopLeft) at ../../../kwin/effects/presentwindows.h:99
#10 0x00007ff064e3d994 in KWin::EffectsHandlerImpl::borderActivated (this=<value optimized out>, border=KWin::ElectricTopLeft) at ../../kwin/effects.cpp:321
#11 0x00007ff064dcd65c in KWin::Workspace::checkElectricBorder (this=0x167b1b0, pos=@0x7fff6d27e9c0, now=44199187) at ../../kwin/workspace.cpp:2260
#12 0x00007ff064dcd75f in KWin::Workspace::electricBorderEvent (this=0x167b1b0, e=0x7fff6d27f360) at ../../kwin/workspace.cpp:2324
#13 0x00007ff064df083a in KWin::Workspace::workspaceEvent (this=0x167b1b0, e=0x7fff6d27f360) at ../../kwin/events.cpp:475
#14 0x00007ff064ddeaa8 in KWin::Application::x11EventFilter (this=0x7fff6d27f750, e=0x7fff6d27f360) at ../../kwin/main.cpp:359
#15 0x00007ff061b5796f in qt_x11EventFilter (ev=0x7fff6d27f360) at kernel/qapplication_x11.cpp:375
#16 0x00007ff061b6ad8f in QApplication::x11ProcessEvent (this=0x7fff6d27f750, event=0x7fff6d27f360) at kernel/qapplication_x11.cpp:3273
#17 0x00007ff061b93ee4 in x11EventSourceDispatch (s=0x15a1500, callback=0, user_data=0x0) at kernel/qguieventdispatcher_glib.cpp:146
#18 0x00007ff05e2f5f1a in IA__g_main_context_dispatch (context=0x15a0120) at /tmp/buildd/glib2.0-2.19.10/glib/gmain.c:1814
#19 0x00007ff05e2f95e0 in g_main_context_iterate (context=0x15a0120, block=1, dispatch=1, self=<value optimized out>) at /tmp/buildd/glib2.0-2.19.10/glib/gmain.c:2448
#20 0x00007ff05e2f977c in IA__g_main_context_iteration (context=0x15a0120, may_block=1) at /tmp/buildd/glib2.0-2.19.10/glib/gmain.c:2511
#21 0x00007ff0613e129f in QEventDispatcherGlib::processEvents (this=0x159a1d0, flags=<value optimized out>) at kernel/qeventdispatcher_glib.cpp:323
#22 0x00007ff061b9368f in QGuiEventDispatcherGlib::processEvents (this=0x1766cb0, flags=<value optimized out>) at kernel/qguieventdispatcher_glib.cpp:202
#23 0x00007ff0613b64f2 in QEventLoop::processEvents (this=<value optimized out>, flags={i = 1831335504}) at kernel/qeventloop.cpp:149
#24 0x00007ff0613b68bd in QEventLoop::exec (this=0x7fff6d27f690, flags={i = 1831335584}) at kernel/qeventloop.cpp:200
#25 0x00007ff0613b8b84 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:880
#26 0x00007ff064de231f in kdemain (argc=3, argv=0x7fff6d27fc28) at ../../kwin/main.cpp:519
#27 0x00007ff064a6e5a6 in __libc_start_main (main=0x4006f0 <main>, argc=3, ubp_av=0x7fff6d27fc28, init=0x400720 <__libc_csu_init>, fini=<value optimized out>, rtld_fini=<value optimized out>, 
    stack_end=0x7fff6d27fc18) at libc-start.c:222
#28 0x0000000000400629 in _start () at ../sysdeps/x86_64/elf/start.S:113


Installed from Debian experimental packages (Amd64).
Video card is a Radeon X1650 Pro w/ X.org "radeon" driver version 6.11.0