It seems to happen when there are no windows open, and when the "show window list when switching windows" option is activated.

*** Bug 124524 has been marked as a duplicate of this bug. ***

On my Fedora Core 4 box, since I upgraded KDE to 3.5.2
(kdebase-3.5.2-1.0.fc4.kde ), Kwin also crashes when I use the Alt-TAB
key to switch windows.  Below is the backtrace I got.  Here are my
window setting:

Desktop/Window behavior/Navigation

  Show window list while switching windows ON
  Traverse windows on all desktops         ON
  Desktop navigation wraps around          OFF
  Popup desktop name on desktop switch     OFF

Notice that Kwin doesn't crash if I disable "Show window list while
switching windows". So, as a workaround for now, I just disabled it.

Hope it will help.

David

(no debugging symbols found)
Using host libthread_db library "/lib/libthread_db.so.1".
(no debugging symbols found)
`shared object read from target memory' has disappeared; keeping its symbols.
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
[Thread debugging using libthread_db enabled]
[New Thread -1209107776 (LWP 3441)]
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
[KCrash handler]
#6  0x00406b52 in KWinInternal::Workspace::nextFocusChainClient ()
   from /usr/lib/libkdeinit_kwin.so
#7  0x00406d29 in KWinInternal::TabBox::nextPrev ()
   from /usr/lib/libkdeinit_kwin.so
#8  0x00406e86 in KWinInternal::Workspace::KDEWalkThroughWindows ()
   from /usr/lib/libkdeinit_kwin.so
#9  0x0041ad5b in KWinInternal::Workspace::tabBoxKeyPress ()
   from /usr/lib/libkdeinit_kwin.so
#10 0x0044bf50 in KWinInternal::Workspace::workspaceEvent ()
   from /usr/lib/libkdeinit_kwin.so
#11 0x0044c0cc in KWinInternal::Application::x11EventFilter ()
   from /usr/lib/libkdeinit_kwin.so
#12 0x04a54ca1 in qt_set_x11_event_filter ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#13 0x04a61803 in QApplication::x11ProcessEvent ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#14 0x04a764b8 in QEventLoop::processEvents ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#15 0x04ae61f2 in QEventLoop::enterLoop ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#16 0x04ae6116 in QEventLoop::exec () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#17 0x04acd559 in QApplication::exec () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#18 0x00448deb in kdemain () from /usr/lib/libkdeinit_kwin.so
#19 0x0084fd7f in __libc_start_main () from /lib/libc.so.6
#20 0x080483e1 in ?? ()

Same problem here with 3.5.2 and gentoo packages. Reverting back to kwin-3.5.1 solves this issue for me.

SVN commit 524823 by mueller:

a kwin that crashes is a bad kwin
BUG: 124511


 M  +4 -0      tabbox.cpp  


--- branches/KDE/3.5/kdebase/kwin/tabbox.cpp #524822:524823
@@ -1152,6 +1152,8 @@
 */
 Client* Workspace::nextFocusChainClient( Client* c ) const
     {
+    if ( !c )
+        return 0;
     int desktop = c->isOnAllDesktops() ? currentDesktop() : c->desktop();
     if ( focus_chain[desktop].isEmpty() )
         return 0;
@@ -1170,6 +1172,8 @@
 */
 Client* Workspace::previousFocusChainClient( Client* c ) const
     {
+    if ( !c )
+        return 0;
     int desktop = c->isOnAllDesktops() ? currentDesktop() : c->desktop();
     if ( focus_chain[desktop].isEmpty() )
         return 0;

After upgrading kwin with this patch, I get weird behaviour: alt+tab no longer causes crashes, but no longer is useless: when a window is minimized, it is not concidered by alt+tab as available (so e.g. 10 windows minimized->alt+tab gives "no windows" message).

>"no longer is useless"
sorry, I ment "no longer is useful"

For me this patch solves the crash, but the issue that only windows from the currently active desktop are shown although the option "Traverse windows on all desktops" is activated in kcontrol, still remains. Any suggestions?

I updated the patch accordingly.

*** Bug 124817 has been marked as a duplicate of this bug. ***

Dirk, I have the updated patch applied. But the issue persists. Not being  comfortable with the KDE code base, might be the change from

readNumEntry to readBoolEntry be the problem (with existing configuration data)?

*** Bug 124816 has been marked as a duplicate of this bug. ***

Applied the updated patch, too. But I'm still not able to browse through all windows. No change noticeable since the last patch...

*** Bug 124826 has been marked as a duplicate of this bug. ***

*** Bug 126209 has been marked as a duplicate of this bug. ***

*** Bug 126214 has been marked as a duplicate of this bug. ***

After upgrading to kdebase-3.5.2-0.2.fc5 (with yum) last weekend, I have the same problem (No windows form other Desktops and crash on double-alt-tab if only one window is shown)

*** Bug 126516 has been marked as a duplicate of this bug. ***

*** Bug 127278 has been marked as a duplicate of this bug. ***

*** Bug 127710 has been marked as a duplicate of this bug. ***

*** Bug 127748 has been marked as a duplicate of this bug. ***

*** Bug 128092 has been marked as a duplicate of this bug. ***

*** Bug 128927 has been marked as a duplicate of this bug. ***

*** Bug 131749 has been marked as a duplicate of this bug. ***

*** Bug 139934 has been marked as a duplicate of this bug. ***