Application: kwin (4.5.1 (KDE 4.5.1))
KDE Platform Version: 4.5.1 (KDE 4.5.1) (Compiled from sources)
Qt Version: 4.7.0
Operating System: Linux 2.6.35-25-generic x86_64
Distribution: Ubuntu 10.10

-- Information about the crash:
- What I was doing when the application crashed:
I was taking the mouse pointer to the top of the screen to activate the top custom button (i mean the custom button area at the top-left, top, top right, right and so on, in the screen)  to change the desktop.  
- Unusual behavior I noticed:
My bottom panel is normally hidden. When i put the mouse on the bottom to show it, in the center of the screen appear something like i had opened a folder (a folder window) but i can see only the edge. Obviously, when the panel disappear because i change the mouse position, this fake window disappear too. This behaviour is not continuative. It is random. But if this fake window appears one time, it appears until i turn off the computer.
I don't know if this behavior is related to the error, but it is strange

-- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
[Current thread is 1 (Thread 0x7f06c84de780 (LWP 2198))]

Thread 2 (Thread 0x7f06aa3fa700 (LWP 2204)):
#0  0x00007f06c7d522c3 in select () at ../sysdeps/unix/syscall-template.S:82
#1  0x00007f06c462c76e in qt_safe_select (nfds=16, fdread=0x2a455c0, fdwrite=0x2a45858, fdexcept=0x2a45af0, orig_timeout=0x0) at kernel/qcore_unix.cpp:82
#2  0x00007f06c4631beb in QEventDispatcherUNIXPrivate::doSelect (this=0x2a45400, flags=<value optimized out>, timeout=<value optimized out>) at kernel/qeventdispatcher_unix.cpp:219
#3  0x00007f06c463281b in QEventDispatcherUNIX::processEvents (this=0x2a46a00, flags=) at kernel/qeventdispatcher_unix.cpp:919
#4  0x00007f06c4601a02 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#5  0x00007f06c4601dec in QEventLoop::exec (this=0x7f06aa3f9d90, flags=) at kernel/qeventloop.cpp:201
#6  0x00007f06c450c2fd in QThread::exec (this=<value optimized out>) at thread/qthread.cpp:490
#7  0x00007f06c45e15f8 in QInotifyFileSystemWatcherEngine::run (this=0x2a3d790) at io/qfilesystemwatcher_inotify.cpp:248
#8  0x00007f06c450f27e in QThreadPrivate::start (arg=0x2a3d790) at thread/qthread_unix.cpp:266
#9  0x00007f06c4284971 in start_thread (arg=<value optimized out>) at pthread_create.c:304
#10 0x00007f06c7d5992d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:112
#11 0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f06c84de780 (LWP 2198)):
[KCrash Handler]
#6  0x00007f06a91ac64a in KWin::DesktopGridEffect::finish (this=0x2b89650) at ../../../kwin/effects/desktopgrid/desktopgrid.cpp:1322
#7  0x00007f06a91af1b1 in KWin::DesktopGridEffect::prePaintScreen (this=0x2b89650, data=<value optimized out>, time=251) at ../../../kwin/effects/desktopgrid/desktopgrid.cpp:146
#8  0x00007f06c80c8b1b in KWin::EffectsHandlerImpl::prePaintScreen (this=0x27960a0, data=..., time=251) at ../../kwin/effects.cpp:158
#9  0x00007f06c80c8b1b in KWin::EffectsHandlerImpl::prePaintScreen (this=0x27960a0, data=..., time=251) at ../../kwin/effects.cpp:158
#10 0x00007f06c80c8b1b in KWin::EffectsHandlerImpl::prePaintScreen (this=0x27960a0, data=..., time=251) at ../../kwin/effects.cpp:158
#11 0x00007f06c80c8b1b in KWin::EffectsHandlerImpl::prePaintScreen (this=0x27960a0, data=..., time=251) at ../../kwin/effects.cpp:158
#12 0x00007f06a91c00a4 in KWin::LoginEffect::prePaintScreen (this=0x2ba8eb0, data=..., time=10) at ../../../kwin/effects/login/login.cpp:52
#13 0x00007f06c80c8b1b in KWin::EffectsHandlerImpl::prePaintScreen (this=0x27960a0, data=..., time=251) at ../../kwin/effects.cpp:158
#14 0x00007f06c80c8b1b in KWin::EffectsHandlerImpl::prePaintScreen (this=0x27960a0, data=..., time=251) at ../../kwin/effects.cpp:158
#15 0x00007f06c80b009a in KWin::Scene::paintScreen (this=0x26a29c0, mask=0x7fffcb11d42c, region=0x7fffcb11d550) at ../../kwin/scene.cpp:116
#16 0x00007f06c80b9001 in KWin::SceneXrender::paint (this=0x26a29c0, damage=<value optimized out>, toplevels=<value optimized out>) at ../../kwin/scene_xrender.cpp:278
#17 0x00007f06c80ab2a7 in KWin::Workspace::performCompositing (this=<value optimized out>) at ../../kwin/composite.cpp:454
#18 0x00007f06c802c7dd in KWin::Workspace::qt_metacall (this=0x2627e60, _c=QMetaObject::InvokeMetaMethod, _id=<value optimized out>, _a=0x7fffcb11d700) at ./workspace.moc:583
#19 0x00007f06c461ab27 in QMetaObject::activate (sender=0x2628328, m=<value optimized out>, local_signal_index=<value optimized out>, argv=0x2f3b470) at kernel/qobject.cpp:3280
#20 0x00007f06c46148f9 in QObject::event (this=0x2628328, e=0x30c4150) at kernel/qobject.cpp:1183
#21 0x00007f06c374cfdc in QApplicationPrivate::notify_helper (this=0x250edc0, receiver=0x2628328, e=0x7fffcb11de50) at kernel/qapplication.cpp:4396
#22 0x00007f06c3752aed in QApplication::notify (this=0x7fffcb11e240, receiver=0x2628328, e=0x7fffcb11de50) at kernel/qapplication.cpp:4277
#23 0x00007f06c7855156 in KApplication::notify (this=0x7fffcb11e240, receiver=0x2628328, event=0x7fffcb11de50) at ../../kdeui/kernel/kapplication.cpp:310
#24 0x00007f06c4602cdc in QCoreApplication::notifyInternal (this=0x7fffcb11e240, receiver=0x2628328, event=0x7fffcb11de50) at kernel/qcoreapplication.cpp:732
#25 0x00007f06c46326f2 in sendEvent (this=0x250f7d0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:215
#26 QTimerInfoList::activateTimers (this=0x250f7d0) at kernel/qeventdispatcher_unix.cpp:602
#27 0x00007f06c463282c in QEventDispatcherUNIX::processEvents (this=0x24eb6e0, flags=) at kernel/qeventdispatcher_unix.cpp:923
#28 0x00007f06c3800c2f in QEventDispatcherX11::processEvents (this=<value optimized out>, flags=) at kernel/qeventdispatcher_x11.cpp:152
#29 0x00007f06c4601a02 in QEventLoop::processEvents (this=<value optimized out>, flags=) at kernel/qeventloop.cpp:149
#30 0x00007f06c4601dec in QEventLoop::exec (this=0x7fffcb11e180, flags=) at kernel/qeventloop.cpp:201
#31 0x00007f06c4605ebb in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1009
#32 0x00007f06c8048f9d in kdemain (argc=<value optimized out>, argv=<value optimized out>) at ../../kwin/main.cpp:531
#33 0x00007f06c7c91d8e 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=0x7fffcb11e848) at libc-start.c:226
#34 0x0000000000400669 in _start ()

Possible duplicates by query: bug 263431, bug 262099, bug 259344, bug 259194, bug 255890.

Reported using DrKonqi