Created attachment 75710 [details]
last crash trace

Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0xb76f87c0 (LWP 801))]

Thread 2 (Thread 0xb2bcdb40 (LWP 822)):
#0  0xb772e424 in __kernel_vsyscall ()
#1  0x4f6d412c in pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S:172
#2  0x493675dd in QTWTF::TCMalloc_PageHeap::scavengerThread (this=this@entry=0x49476280) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#3  0x49367610 in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=0x49476280) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#4  0x4f6d0adf in start_thread (arg=0xb2bcdb40) at pthread_create.c:309
#5  0x4784f42e in clone () at ../sysdeps/unix/sysv/linux/i386/clone.S:133

Thread 1 (Thread 0xb76f87c0 (LWP 801)):
[KCrash Handler]
#7  __cxxabiv1::__dynamic_cast (src_ptr=0x9f1c4d8, src_type=0x49d29720, dst_type=0x49d28c8c, src2dst=0) at ../../../../libstdc++-v3/libsupc++/dyncast.cc:61
#8  0x49c89488 in KWin::Toplevel::windowType (this=0x9f1c4d8, direct=false, supported_types=0) at /usr/src/debug/kde-workspace-4.9.3/kwin/toplevel.cpp:164
#9  0x49c25ca1 in isNormalWindow (this=<optimized out>) at /usr/src/debug/kde-workspace-4.9.3/kwin/toplevel.h:483
#10 KWin::Client::setShade (this=this@entry=0x9e2ac38, mode=<optimized out>, mode@entry=KWin::ShadeHover) at /usr/src/debug/kde-workspace-4.9.3/kwin/client.cpp:1137
#11 0x49c25ea9 in KWin::Client::shadeHover (this=this@entry=0x9e2ac38) at /usr/src/debug/kde-workspace-4.9.3/kwin/client.cpp:1161
#12 0x49c26217 in qt_static_metacall (_a=0xbfeb79bc, _id=29, _o=0x9e2ac38, _c=<optimized out>) at /usr/src/debug/kde-workspace-4.9.3/i686-redhat-linux-gnu/kwin/client.moc:251
#13 KWin::Client::qt_static_metacall (_o=0x9e2ac38, _c=QMetaObject::InvokeMetaMethod, _id=29, _a=0xbfeb79bc) at /usr/src/debug/kde-workspace-4.9.3/i686-redhat-linux-gnu/kwin/client.moc:216
#14 0x461681ce in QMetaObject::activate (sender=0x9e7cde0, m=0x462bca18, local_signal_index=0, argv=0x0) at kernel/qobject.cpp:3539
#15 0x461bb476 in QTimer::timeout (this=0x9e7cde0) at .moc/release-shared/moc_qtimer.cpp:147
#16 0x46170916 in QTimer::timerEvent (this=0x9e7cde0, e=0xbfeb7ef0) at kernel/qtimer.cpp:280
#17 0x4616750c in QObject::event (this=0x9e7cde0, e=0xbfeb7ef0) at kernel/qobject.cpp:1156
#18 0x46a6405c in QApplicationPrivate::notify_helper (this=0x97943a0, receiver=0x9e7cde0, e=0xbfeb7ef0) at kernel/qapplication.cpp:4562
#19 0x46a68b1f in QApplication::notify (this=0xbfeb7ef0, receiver=0x9e7cde0, e=0xbfeb7ef0) at kernel/qapplication.cpp:3944
#20 0x48d5cfe2 in KApplication::notify (this=0xbfeb82b8, receiver=0x9e7cde0, event=0xbfeb7ef0) at /usr/src/debug/kdelibs-4.9.3/kdeui/kernel/kapplication.cpp:311
#21 0x49c319a0 in notify (e=0xbfeb7ef0, o=0x9e7cde0, this=0xbfeb82b8) at /usr/src/debug/kde-workspace-4.9.3/kwin/main.cpp:371
#22 KWin::Application::notify (this=0xbfeb82b8, o=0x9e7cde0, e=0xbfeb7ef0) at /usr/src/debug/kde-workspace-4.9.3/kwin/main.cpp:367
#23 0x4615100e in QCoreApplication::notifyInternal (this=0xbfeb82b8, receiver=0x9e7cde0, event=0xbfeb7ef0) at kernel/qcoreapplication.cpp:946
#24 0x461864b0 in sendEvent (event=0xbfeb7ef0, receiver=<optimized out>) at kernel/qcoreapplication.h:231
#25 QTimerInfoList::activateTimers (this=0x9794b1c) at kernel/qeventdispatcher_unix.cpp:622
#26 0x46186535 in QEventDispatcherUNIX::activateTimers (this=0x9794b1c, this@entry=0x97507e0) at kernel/qeventdispatcher_unix.cpp:879
#27 0x461866b8 in QEventDispatcherUNIX::processEvents (this=0x97507e0, flags=...) at kernel/qeventdispatcher_unix.cpp:941
#28 0x46b17703 in QEventDispatcherX11::processEvents (this=0x97507e0, flags=...) at kernel/qeventdispatcher_x11.cpp:152
#29 0x4614faad in QEventLoop::processEvents (this=this@entry=0xbfeb8138, flags=...) at kernel/qeventloop.cpp:149
#30 0x4614fda9 in QEventLoop::exec (this=0xbfeb8138, flags=...) at kernel/qeventloop.cpp:204
#31 0x461552eb in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1218
#32 0x46a61ed5 in QApplication::exec () at kernel/qapplication.cpp:3823
#33 0x49c34340 in kdemain (argc=3, argv=0xbfeb83a4) at /usr/src/debug/kde-workspace-4.9.3/kwin/main.cpp:545
#34 0x0804876c in main (argc=3, argv=0xbfeb83a4) at /usr/src/debug/kde-workspace-4.9.3/i686-redhat-linux-gnu/kwin/kwin_dummy.cpp:3

if order.indexOf(this) + 1 >=  order.count() "shade_below" is not researched and might end up being a dangeling pointer.

Matches the onTop condition, don't you have any panels covering all windows?
(Not a complain, but to harden the theory)

(In reply to comment #3)
> if order.indexOf(this) + 1 >=  order.count() "shade_below" is not researched
> and might end up being a dangeling pointer.
> 
> Matches the onTop condition, don't you have any panels covering all windows?
> (Not a complain, but to harden the theory)

Errm, I have my main panel at the bottom of the screen and this set to autohide.

Created attachment 75718 [details]
Fix attempt

Fits.
Can you try the attached patch?

(In reply to comment #5)
> Created attachment 75718 [details]
> Fix attempt
> 
> Fits.
> Can you try the attached patch?

My main build box is down atm (dead psu) I'll see if I can get the fedora kde folk to do me scratch build for testing if not it'll most likely be two weeks before I can put this patch to the test ....

too late, i'll just push it and you can try rc1 then

ok I'll back port to 4.9.x when I get a chance

Git commit 89f8c4a1514fb76139207c9e18f8803dfa128d73 by Thomas Lübking.
Committed on 08/12/2012 at 14:52.
Pushed by luebking into branch 'master'.

invalidate old shade_below before searching a new

for the search could be implicitly skipped and we end up
with a dangeling pointer
FIXED-IN: 4.10

M  +2    -0    kwin/client.cpp

http://commits.kde.org/kde-workspace/89f8c4a1514fb76139207c9e18f8803dfa128d73