Unfortunately the backtrace is missing debug symbols. If possible please attach a new backtrace although I must say it looks very much like #315872.

(In reply to comment #1)
> Unfortunately the backtrace is missing debug symbols. If possible please
> attach a new backtrace although I must say it looks very much like #315872.
Could you help me understand, which packages I should rebuild with debug symbols?

given the backtrace I'd say kde-workspace should be enough.

Is this reproducible for you?

(In reply to comment #4)
> Is this reproducible for you?
Yes, as I see now, it is easy reproducible, if okular view presentation.pdf in fullscreen/presentation mode (Ctrl+Shift+P).

Very good. (Well, not so much for you ;-)

- How many screens do you have attached?
- as a gentoo user you probably won't have trouble compiling in some little debug out patch?

(In reply to comment #6)
> Very good. (Well, not so much for you ;-)
> - How many screens do you have attached?
One screen laptop, intel open source driver.
% xrandr 
Screen 0: minimum 320 x 200, current 1366 x 768, maximum 8192 x 8192
LVDS1 connected 1366x768+0+0 (normal left inverted right x axis y axis) 256mm x 144mm
   1366x768       60.0*+
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 disconnected (normal left inverted right x axis y axis)

> - as a gentoo user you probably won't have trouble compiling in some little
> debug out patch?
Yes, without any problems.

(In reply to comment #3)
> given the backtrace I'd say kde-workspace should be enough.
I'm a bit confused, because kwin and plasma-desktop already compiled with debug symbols. Actually I'm compiling *everything* with debug symbols (with splitdebug option).

(In reply to comment #7)
> Screen 0: minimum 320 x 200, current 1366 x 768, maximum 8192 x 8192
ok, dead end here.

> Yes, without any problems.
splendid. first let's locate the crash....


diff --git a/kwin/layers.cpp b/kwin/layers.cpp
index d01cba0..41bd4b7 100644
--- a/kwin/layers.cpp
+++ b/kwin/layers.cpp
@@ -512,10 +512,13 @@ ToplevelList Workspace::constrainedStackingOrder()
     QVector< QMap<Group*, Layer> > minimum_layer(numScreens());
     for (ToplevelList::ConstIterator it = unconstrained_stacking_order.constBegin(),
                                   end = unconstrained_stacking_order.constEnd(); it != end; ++it) {
+        qDebug() << *it;
         Layer l = (*it)->layer();
-
+        qDebug() << "Layer" << l;
         const int screen = (*it)->screen();
+        qDebug() << "Screen" << screen;
         Client *c = qobject_cast<Client*>(*it);
+        qDebug() << c;
         QMap< Group*, Layer >::iterator mLayer = minimum_layer[screen].find(c ? c->group() : NULL);
+        qDebug() << "===================";
         if (mLayer != minimum_layer[screen].end()) {
             // If a window is raised above some other window in the same window group


/-- snip -------------------------

This will talk a lot. Just run "kwin --replace&" from konsole and trigger the crash. The last lines will tell us whether really the object_cast segfaults and for what window/layer.

> (In reply to comment #3)
> > given the backtrace I'd say kde-workspace should be enough.
> I'm a bit confused, because kwin and plasma-desktop already compiled with
> debug symbols. Actually I'm compiling *everything* with debug symbols (with
> splitdebug option).

(In reply to comment #8)
> > Yes, without any problems.
> splendid. first let's locate the crash....
Looks like It doesn't crash after applying patch, I'm going sleep and continue experiments tomorrow.

Created attachment 78979 [details]
New crash information added by DrKonqi

kwin (4.10.2) on KDE Platform 4.10.2 using Qt 4.8.4

I reproduced crash with kwin-4.10.2 and patch applyed,
but output in konsole wasn't stopped...

btw, looks like new backtrace is a bit different now.

-- Backtrace (Reduced):
#6  0x00007f0aa34000bb in operator<<(QDebug, QObject const*) () from /usr/lib64/qt4/libQtCore.so.4
#7  0x00007f0aa816e51d in KWin::Workspace::constrainedStackingOrder() () from /usr/lib64/libkdeinit4_kwin.so
#8  0x00007f0aa816f4a3 in KWin::Workspace::updateStackingOrder(bool) () from /usr/lib64/libkdeinit4_kwin.so
#9  0x00007f0aa816f630 in KWin::Workspace::blockStackingUpdates(bool) () from /usr/lib64/libkdeinit4_kwin.so
#10 0x00007f0aa8163fcb in KWin::Client::releaseWindow(bool) () from /usr/lib64/libkdeinit4_kwin.so

So, I reproduced crash once more, and output is attached (see below):
% kwin --replace --fg --nocrashhandler
....
KWin::Client(0x1fbf580) 
Layer 2 
Screen 0 
KWin::Client(0x1fbf580) 
=================== 
KWin::Client(0x22c6dc0) 
Layer 2 
Screen 0 
KWin::Client(0x22c6dc0) 
=================== 
KWin::Client(0x1fc7ff0) 
Layer 2 
Screen 0 
KWin::Client(0x1fc7ff0) 
=================== 
%

If that's the complete (finishing) output and the next thing is a crash, this means
qDebug() << *it;
crashes, ie. there's likely a dangeling pointer in the unconstrained stacking order.

(In reply to comment #12)
> If that's the complete (finishing) output and the next thing is a crash,
> this means
Yes, its complete(finished) output.

To add more info, I found that crash happened more often when I'm pressing alt-tab, when okular in backgrounds updates presentation, which is showed in fullscreen/presentation mode.

bug status still: NEEDSINFO, BACKTRACE, which info I could provide to help you?

qdbus org.kde.kwin /KWin supportInformation

% qdbus org.kde.kwin /KWin supportInformation
KWin Support Information:
The following information should be used when requesting support on e.g. http://forum.kde.org.
It provides information about the currently running instance, which options are used,
what OpenGL driver and which effects are running.
Please post the information provided underneath this introductory text to a paste bin service
like http://paste.kde.org instead of pasting into support threads.

==========================

Version
=======
KWin version: 4.10.2
KDE SC version (runtime): 4.10.2
KDE SC version (compile): 4.10.2
Qt Version: 4.8.4

Options
=======
focusPolicy: 0
nextFocusPrefersMouse: false
clickRaise: true
autoRaise: false
autoRaiseInterval: 0
delayFocusInterval: 0
shadeHover: false
shadeHoverInterval: 250
separateScreenFocus: false
activeMouseScreen: false
placement: 4
focusPolicyIsReasonable: true
borderSnapZone: 10
windowSnapZone: 10
centerSnapZone: 0
snapOnlyWhenOverlapping: false
showDesktopIsMinimizeAll: false
rollOverDesktops: true
focusStealingPreventionLevel: 1
legacyFullscreenSupport: false
operationTitlebarDblClick: 
commandActiveTitlebar1: 0
commandActiveTitlebar2: 30
commandActiveTitlebar3: 2
commandInactiveTitlebar1: 4
commandInactiveTitlebar2: 30
commandInactiveTitlebar3: 2
commandWindow1: 7
commandWindow2: 8
commandWindow3: 8
commandWindowWheel: 31
commandAll1: 10
commandAll2: 3
commandAll3: 14
keyCmdAllModKey: 16777251
showGeometryTip: false
condensedTitle: false
electricBorders: false
electricBorderDelay: 150
electricBorderCooldown: 350
electricBorderPushbackPixels: 1
electricBorderMaximize: true
electricBorderTiling: true
electricBorderCornerRatio: 0.25
borderlessMaximizedWindows: false
killPingTimeout: 5000
hideUtilityWindowsForInactive: true
inactiveTabsSkipTaskbar: false
autogroupSimilarWindows: false
autogroupInForeground: true
compositingMode: 1
useCompositing: false
compositingInitialized: false
hiddenPreviews: 1
unredirectFullscreen: false
glSmoothScale: 2
glVSync: true
colorCorrected: false
xrenderSmoothScale: false
maxFpsInterval: 17
refreshRate: 0
vBlankTime: 6144
glDirect: true
glStrictBinding: true
glStrictBindingFollowsDriver: true
glLegacy: false

Screens
=======
Multi-Head: no
Number of Screens: 1
Screen 0 Geometry: 0,0,1366x768

Compositing
===========
Qt Graphics System: native
Compositing is not active

Are you usually not using compositing? (esp. not when this happens)

(In reply to comment #17)
> Are you usually not using compositing? (esp. not when this happens)
Yes, I don't using it. Should I try to reproduce bug with compositing enabled?

i bet you can't...

*** Bug 319206 has been marked as a duplicate of this bug. ***

*** Bug 315872 has been marked as a duplicate of this bug. ***

*** Bug 319766 has been marked as a duplicate of this bug. ***

Last dupe reporter neither uses compositing.
Self-reminder: it's probably about the handling of Deleted windows in this case, polluting the stacking order with their -here- short-term existence.

No idea atm how precisely, though.

*** Bug 320349 has been marked as a duplicate of this bug. ***

@Maksim

can you in deleted.cpp ~line 354 turn
- del->unrefWindow();
+ del->unrefWindow(true);

and see what happens?

Thanks a lot and sorry for the delay.

errr ... sorry, not "deleted.cpp" but "client.cpp" - i'll attach you a patch in doubt.

Added review for a patch candidate.

(In reply to comment #27)
> Added review for a patch candidate.
Works for me now! Could not reproduce crash anymore...

Git commit d418aa421c93407ba3018cebb15496200843840e by Thomas Lübking.
Committed on 31/05/2013 at 19:15.
Pushed by luebking into branch 'master'.

always defer delete of Deleted to next event cycle
FIXED-IN: 4.11
REVIEW: 110756

M  +6    -7    kwin/deleted.cpp
M  +1    -1    kwin/deleted.h
M  +1    -1    kwin/effects.cpp

http://commits.kde.org/kde-workspace/d418aa421c93407ba3018cebb15496200843840e

*** Bug 321445 has been marked as a duplicate of this bug. ***

*** Bug 326376 has been marked as a duplicate of this bug. ***

*** Bug 326416 has been marked as a duplicate of this bug. ***

*** Bug 330965 has been marked as a duplicate of this bug. ***

no, deferring Deleted deletions does not do it. :-(

FTR - late reports both include invocation of tabbox!

*** Bug 333381 has been marked as a duplicate of this bug. ***

Answering here the question from bug 333381:

"were you using compositing and a closing effect ("fade") at that time?"

No, i don't use compositing

*** Bug 333384 has been marked as a duplicate of this bug. ***

Better backtrace from duplicate:

Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fbe937c7800 (LWP 2852))]

Thread 3 (Thread 0x7fbe74a05700 (LWP 27175)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007fbe921aaffb in QTWTF::TCMalloc_PageHeap::scavengerThread
(this=0x7fbe924a8f00 <QTWTF::pageheap_memory>) at
../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#2  0x00007fbe921ab039 in QTWTF::TCMalloc_PageHeap::runScavengerThread
(context=<optimized out>) at
../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#3  0x00007fbe8ad50182 in start_thread (arg=0x7fbe74a05700) at
pthread_create.c:312
#4  0x00007fbe92fbc30d in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7fbdee982700 (LWP 27176)):
#0  0x00007fbe92fb3c33 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007fbe8d3a52c7 in qt_safe_select (nfds=13, fdread=0x7fbe70000ac8,
fdwrite=0x7fbe70000d60, fdexcept=0x7fbe70000ff8, orig_timeout=0x0) at
kernel/qcore_unix.cpp:79
#2  0x00007fbe8d3aa824 in QEventDispatcherUNIXPrivate::doSelect
(this=this@entry=0x7fbe70000910, flags=..., timeout=0x0) at
kernel/qeventdispatcher_unix.cpp:223
#3  0x00007fbe8d3aac92 in QEventDispatcherUNIX::processEvents
(this=0x7fbe700008f0, flags=...) at kernel/qeventdispatcher_unix.cpp:936
#4  0x00007fbe8d3790af in QEventLoop::processEvents
(this=this@entry=0x7fbdee981da0, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007fbe8d3793a5 in QEventLoop::exec (this=this@entry=0x7fbdee981da0,
flags=...) at kernel/qeventloop.cpp:204
#6  0x00007fbe8d275c5f in QThread::exec (this=this@entry=0x187a060) at
thread/qthread.cpp:537
#7  0x00007fbe8d35a823 in QInotifyFileSystemWatcherEngine::run (this=0x187a060)
at io/qfilesystemwatcher_inotify.cpp:265
#8  0x00007fbe8d27832f in QThreadPrivate::start (arg=0x187a060) at
thread/qthread_unix.cpp:349
#9  0x00007fbe8ad50182 in start_thread (arg=0x7fbdee982700) at
pthread_create.c:312
#10 0x00007fbe92fbc30d in clone () at
../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7fbe937c7800 (LWP 2852)):
[KCrash Handler]
#6  0x00000000018463e0 in ?? ()
#7  0x00007fbe932fe1ad in KWin::Workspace::constrainedStackingOrder
(this=this@entry=0x17d9e50) at ../../kwin/layers.cpp:509
#8  0x00007fbe932fe780 in KWin::Workspace::updateStackingOrder
(this=this@entry=0x17d9e50, propagate_new_clients=<optimized out>) at
../../kwin/layers.cpp:117
#9  0x00007fbe932feb1d in updateStackingOrder (propagate_new_clients=<optimized
out>, this=0x17d9e50) at ../../kwin/layers.cpp:609
#10 KWin::Workspace::blockStackingUpdates (this=this@entry=0x17d9e50,
block=block@entry=false) at ../../kwin/layers.cpp:616
#11 0x00007fbe932ee7eb in ~StackingUpdatesBlocker (this=<synthetic pointer>,
__in_chrg=<optimized out>) at ../../kwin/workspace.h:565
#12 KWin::Client::destroyClient (this=this@entry=0x199e8a0) at
../../kwin/client.cpp:355
#13 0x00007fbe93309e71 in KWin::Client::unmapNotifyEvent (this=0x199e8a0,
e=<optimized out>) at ../../kwin/events.cpp:597
#14 0x00007fbe9330bfeb in KWin::Client::windowEvent (this=0x199e8a0,
e=e@entry=0x7fffc5325a90) at ../../kwin/events.cpp:451
#15 0x00007fbe9330d62f in KWin::Workspace::workspaceEvent (this=0x17d9e50,
e=e@entry=0x7fffc5325a90) at ../../kwin/events.cpp:164
#16 0x00007fbe93301970 in KWin::Application::x11EventFilter
(this=0x7fffc5325e80, e=0x7fffc5325a90) at ../../kwin/main.cpp:422
#17 0x00007fbe8c77c5dc in qt_x11EventFilter (ev=0x7fffc5325a90) at
kernel/qapplication_x11.cpp:442
#18 0x00007fbe8c78ce40 in QApplication::x11ProcessEvent (this=0x7fffc5325e80,
event=event@entry=0x7fffc5325a90) at kernel/qapplication_x11.cpp:3461
#19 0x00007fbe8c7b6470 in QEventDispatcherX11::processEvents (this=0x1602af0,
flags=...) at kernel/qeventdispatcher_x11.cpp:132
#20 0x00007fbe8d3790af in QEventLoop::processEvents
(this=this@entry=0x7fffc5325cf0, flags=...) at kernel/qeventloop.cpp:149
#21 0x00007fbe8d3793a5 in QEventLoop::exec (this=this@entry=0x7fffc5325cf0,
flags=...) at kernel/qeventloop.cpp:204
#22 0x00007fbe8d37eb79 in QCoreApplication::exec () at
kernel/qcoreapplication.cpp:1225
#23 0x00007fbe8c71237c in QApplication::exec () at kernel/qapplication.cpp:3828
#24 0x00007fbe93302856 in kdemain (argc=3, argv=0x7fffc5325fc8) at
../../kwin/main.cpp:597
#25 0x00007fbe92ee2ec5 in __libc_start_main (main=0x4006d0 <main(int, char**)>,
argc=3, argv=0x7fffc5325fc8, init=<optimized out>, fini=<optimized out>,
rtld_fini=<optimized out>, stack_end=0x7fffc5325fb8) at libc-start.c:287
#26 0x00000000004006fe in _start ()

Created attachment 86091 [details]
Patch for 4.11 to skip creation of Deleted window w/o compositing

I believe that this is around replacing Cient's by Deleted's in the stacking order.
Since the Deleted windows are not required at all when not compositing, the attached patch simply skips their creation - so if you're not using compositing, hit this bug more often then never and can compile the patch, it would be great to know on whether
a) the patch causes regressions
b) the patch prevents the bug for you

Does not apply here

kdeunstable@xps:~/kde-workspace:KDE/4.11$ patch -p1 <attachment.cgi\?id\=86091 
patching file kwin/client.cpp
Hunk #1 succeeded at 308 (offset 1 line).
Hunk #2 succeeded at 349 (offset 1 line).
patching file kwin/deleted.cpp
patching file kwin/unmanaged.cpp
patching file kwin/workspace.cpp                                                                                                                                                                                                                                               
Hunk #1 FAILED at 644.                                                                                                                                                                                                                                                         
1 out of 1 hunk FAILED -- saving rejects to file kwin/workspace.cpp.rej                                                                                                                                                                                                        
patching file kwin/workspace.h                                                                                                                                                                                                                                                 
Hunk #1 succeeded at 259 (offset -1 lines).

Created attachment 86100 [details]
Patch for VANILLA 4.11 to skip creation of Deleted window w/o compositing

Sorry (i've really too many local commits)

won't help - i just encountered the bug.

alt+tabbing while a progress dialog exited, no compositing.
i've no visual tabbox, so that's not related, but changing the stack order while a (managed) window gets removed will be the only cause.

*** Bug 333663 has been marked as a duplicate of this bug. ***

Created attachment 89629 [details]
New crash information added by DrKonqi

kwin (4.11.12) on KDE Platform 4.14.2 using Qt 4.8.6

- What I was doing when the application crashed:

i used CVLC to play a ogg theora video from konsole and tried to use alt+tab to switch to my desktop and suddenly KWin crashed ... 
I use Gallium 0.4 on my RV770 (no software llvm) with oibafs ppa ... 
OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD RV770
OpenGL core profile version string: 3.3 (Core Profile) Mesa 10.4.0-devel (git-920f875 2014-11-17 utopic-oibaf-ppa)
OpenGL core profile shading language version string: 3.30

-- Backtrace (Reduced):
#7  0x00007fd69e3f53f5 in KWin::Workspace::constrainedStackingOrder (this=this@entry=0x1253810) at ../../kwin/layers.cpp:509
#8  0x00007fd69e3f5a12 in KWin::Workspace::updateStackingOrder (this=this@entry=0x1253810, propagate_new_clients=<optimized out>) at ../../kwin/layers.cpp:117
#9  0x00007fd69e3f5dfd in updateStackingOrder (propagate_new_clients=<optimized out>, this=0x1253810) at ../../kwin/layers.cpp:609
#10 KWin::Workspace::blockStackingUpdates (this=this@entry=0x1253810, block=block@entry=false) at ../../kwin/layers.cpp:616
#11 0x00007fd69e3e4f3a in ~StackingUpdatesBlocker (this=<synthetic pointer>, __in_chrg=<optimized out>) at ../../kwin/workspace.h:565

Today's crash while Alt+tabbing

Qt: 4.8.6
KDE Development Platform: 4.14.8
KWin: 4.11.19


Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f62beafa7c0 (LWP 24601))]

Thread 2 (Thread 0x7f62a3e56700 (LWP 27757)):
#0  pthread_cond_wait () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f62bd7a520a in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0x7f62bdaa8f00 <QTWTF::pageheap_memory>) at .../qt-everywhere-opensource-src-4.8.6/src/3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#2  0x00007f62bd7a5239 in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=<optimized out>) at .../qt-everywhere-opensource-src-4.8.6/src/3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#3  0x00007f62b8ce9304 in start_thread (arg=0x7f62a3e56700) at pthread_create.c:333
#4  0x00007f62be6acc2d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f62beafa7c0 (LWP 24601)):
[KCrash Handler]
#6  0x00007f62be959c38 in main_arena () from /lib64/libc.so.6
#7  0x00007f62be29e32d in constrainedStackingOrder (this=0xbf6d20) at .../kwin-4.11.19/kwin/layers.cpp:509
#8  KWin::Workspace::updateStackingOrder(bool) [clone .part.50] [clone .lto_priv.1497] (this=0xbf6d20, propagate_new_clients=<optimized out>) at .../kwin-4.11.19/kwin/layers.cpp:117
#9  0x00007f62be29ef1d in updateStackingOrder () at .../kwin-4.11.19/kwin/layers.cpp:609
#10 KWin::Workspace::blockStackingUpdates(bool) (this=<optimized out>, block=<optimized out>) at .../kwin-4.11.19/kwin/layers.cpp:616
#11 0x00007f62be2bc8fb in __base_dtor () at .../kwin-4.11.19/kwin/workspace.h:565
#12 KWin::Client::releaseWindow (this=this@entry=0x13ff780, on_shutdown=on_shutdown@entry=false) at .../kwin-4.11.19/kwin/client.cpp:266
#13 0x00007f62be329034 in unmapNotifyEvent (e=0x7ffd2679dfb0, this=0x13ff780) at .../kwin-4.11.19/kwin/events.cpp:595
#14 windowEvent (this=0x13ff780, e=e@entry=0x7ffd2679dfb0) at .../kwin-4.11.19/kwin/events.cpp:451
#15 0x00007f62be329c08 in KWin::Workspace::workspaceEvent(_XEvent*) [clone .part.83] [clone .constprop.315] (this=0xbf6d20, e=e@entry=0x7ffd2679dfb0) at .../kwin-4.11.19/kwin/events.cpp:164
#16 0x00007f62be29dbeb in workspaceEvent (e=0x7ffd2679dfb0, this=<optimized out>) at .../kwin-4.11.19/kwin/events.cpp:83
#17 x11EventFilter (this=0x7ffd2679e350, e=0x7ffd2679dfb0) at .../kwin-4.11.19/kwin/main.cpp:422
#18 0x00007f62b852cbfe in qt_x11EventFilter(_XEvent*) [clone .lto_priv.4171] (ev=0x7ffd2679dfb0) at /mnt/tmp/tmp/portage/dev-qt/qtgui-4.8.6-r4/work/qt-everywhere-opensource-src-4.8.6/src/gui/kernel/qapplication_x11.cpp:436
#19 0x00007f62b854fa36 in QApplication::x11ProcessEvent (this=0x7f62b8ce1b08 <qt_x11Data>, event=event@entry=0x7ffd2679dfb0) at /mnt/tmp/tmp/portage/dev-qt/qtgui-4.8.6-r4/work/qt-everywhere-opensource-src-4.8.6/src/gui/kernel/qapplication_x11.cpp:3354
#20 0x00007f62b855328f in QEventDispatcherX11::processEvents (this=0xb1f300, flags=...) at /mnt/tmp/tmp/portage/dev-qt/qtgui-4.8.6-r4/work/qt-everywhere-opensource-src-4.8.6/src/gui/kernel/qeventdispatcher_x11.cpp:132
#21 0x00007f62b9083041 in QEventLoop::processEvents (this=this@entry=0x7ffd2679e200, flags=...) at .../qt-everywhere-opensource-src-4.8.6/src/corelib/kernel/qeventloop.cpp:149
#22 0x00007f62b9083355 in QEventLoop::exec (this=this@entry=0x7ffd2679e200, flags=...) at .../qt-everywhere-opensource-src-4.8.6/src/corelib/kernel/qeventloop.cpp:204
#23 0x00007f62b9088c99 in QCoreApplication::exec () at .../qt-everywhere-opensource-src-4.8.6/src/corelib/kernel/qcoreapplication.cpp:1225

*** Bug 356616 has been marked as a duplicate of this bug. ***

*** Bug 360135 has been marked as a duplicate of this bug. ***

- What I was doing when the application crashed:

Sending a mail via Seamonkey, a popup window with "sending..." progress bar was present. While that window was present, I hit Alt-Tab a few times. Roughly at the same time as the progress bar window was closed by Seamonkey, (I was still in the Alt-Tab overview screen), Kwin crashed

Created attachment 99095 [details]
Crash log by DrKonqi

Created attachment 100443 [details]
KWin support information for KWin 5.7

This happened to me when using alt+tab, with no compositing, when a notification appeared and disappeared while using alt+tab (I was highlighted in WeeChat which uses notify-send to tell me).

KWin Support Information: attached

Backtrace of the crash I experienced:

Application: KWin (kwin_x11), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f7740287800 (LWP 3518))]

Thread 7 (Thread 0x7f76866fe700 (LWP 3655)):
#0  0x00007f773dafcaa9 in QEventDispatcherUNIXPrivate::doSelect (this=0x7f76800008c0, flags=..., timeout=0x0) at kernel/qeventdispatcher_unix.cpp:186
#1  0x00007f773dafdb9d in QEventDispatcherUNIX::processEvents (this=0x7f76800c20b0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#2  0x00007f773daaf001 in QEventLoop::processEvents (flags=..., this=<optimized out>) at kernel/qeventloop.cpp:128
#3  QEventLoop::exec (this=0x7f76866fddd0, flags=...) at kernel/qeventloop.cpp:204
#4  0x00007f773d9045e9 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:500
#5  0x00007f77384babf6 in QQmlThreadPrivate::run (this=0x16d7210) at qml/ftw/qqmlthread.cpp:141
#6  0x00007f773d907d24 in QThreadPrivate::start (arg=0x16d7210) at thread/qthread_unix.cpp:341
#7  0x00007f773fe09434 in start_thread (arg=0x7f76866fe700) at pthread_create.c:333
#8  0x00007f773fb508fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 6 (Thread 0x7f7707fff700 (LWP 3603)):
#0  pthread_cond_wait () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f773ccfaeaa in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0x7f773cddd820 <QTWTF::pageheap_memory>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#2  0x00007f773ccfae26 in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=0x7f773cdeb8f4 <QTWTF::pageheap_memory+57556>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#3  0x00007f773fe09434 in start_thread (arg=0x7f7707fff700) at pthread_create.c:333
#4  0x00007f773fb508fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 5 (Thread 0x7f770d979700 (LWP 3582)):
#0  pthread_cond_wait () at ../sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f7713242bb3 in cnd_wait (mtx=0xec83f0, cond=<optimized out>) at /var/tmp/portage/media-libs/mesa-11.1.0/work/mesa-11.1.0/include/c11/threads_posix.h:159
#2  pipe_semaphore_wait (sema=0xec83f0) at /var/tmp/portage/media-libs/mesa-11.1.0/work/mesa-11.1.0/src/gallium/auxiliary/os/os_thread.h:259
#3  radeon_drm_cs_emit_ioctl (param=param@entry=0xec80a0) at /var/tmp/portage/media-libs/mesa-11.1.0/work/mesa-11.1.0/src/gallium/winsys/radeon/drm/radeon_drm_winsys.c:653
#4  0x00007f7713242307 in impl_thrd_routine (p=<optimized out>) at /var/tmp/portage/media-libs/mesa-11.1.0/work/mesa-11.1.0/include/c11/threads_posix.h:87
#5  0x00007f773fe09434 in start_thread (arg=0x7f770d979700) at pthread_create.c:333
#6  0x00007f773fb508fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 4 (Thread 0x7f7720d5f700 (LWP 3568)):
#0  0x00007f773dafcaac in QEventDispatcherUNIXPrivate::doSelect (this=0x7f77180008e0, flags=..., timeout=0x0) at kernel/qeventdispatcher_unix.cpp:186
#1  0x00007f773dafdb9d in QEventDispatcherUNIX::processEvents (this=0x7f77180008c0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#2  0x00007f773daaf001 in QEventLoop::processEvents (flags=..., this=<optimized out>) at kernel/qeventloop.cpp:128
#3  QEventLoop::exec (this=0x7f7720d5edd0, flags=...) at kernel/qeventloop.cpp:204
#4  0x00007f773d9045e9 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:500
#5  0x00007f77384babf6 in QQmlThreadPrivate::run (this=0xda2cd0) at qml/ftw/qqmlthread.cpp:141
#6  0x00007f773d907d24 in QThreadPrivate::start (arg=0xda2cd0) at thread/qthread_unix.cpp:341
#7  0x00007f773fe09434 in start_thread (arg=0x7f7720d5f700) at pthread_create.c:333
#8  0x00007f773fb508fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7f7722e56700 (LWP 3562)):
#0  0x00007f773fb49503 in select () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f773dafbf74 in qt_safe_select (nfds=8, fdread=0x7f771c000a78, fdwrite=0x7f771c000d08, fdexcept=0x7f771c000f98, orig_timeout=<optimized out>) at kernel/qcore_unix.cpp:75
#2  0x00007f773dafcb0b in QEventDispatcherUNIXPrivate::doSelect (this=0x7f771c0008e0, flags=..., timeout=0x0) at kernel/qeventdispatcher_unix.cpp:192
#3  0x00007f773dafdb9d in QEventDispatcherUNIX::processEvents (this=0x7f771c0008c0, flags=...) at kernel/qeventdispatcher_unix.cpp:607
#4  0x00007f773daaf001 in QEventLoop::processEvents (flags=..., this=<optimized out>) at kernel/qeventloop.cpp:128
#5  QEventLoop::exec (this=0x7f7722e55dc0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f773d9045e9 in QThread::exec (this=<optimized out>) at thread/qthread.cpp:500
#7  0x00007f7740396430 in QDBusConnectionManager::run (this=0x7f77403f8260 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:189
#8  0x00007f773d907d24 in QThreadPrivate::start (arg=0x7f77403f8260 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:341
#9  0x00007f773fe09434 in start_thread (arg=0x7f7722e56700) at pthread_create.c:333
#10 0x00007f773fb508fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f772928d700 (LWP 3557)):
#0  0x00007f773fb477fd in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f773ecfaac2 in poll (__timeout=-1, __nfds=1, __fds=0x7f772928ccd0) at /usr/include/bits/poll2.h:46
#2  _xcb_conn_wait (c=c@entry=0xc00420, cond=cond@entry=0xc00460, vector=vector@entry=0x0, count=count@entry=0x0) at /var/tmp/portage/x11-libs/libxcb-1.11.1/work/libxcb-1.11.1/src/xcb_conn.c:459
#3  0x00007f773ecfc72f in xcb_wait_for_event (c=0xc00420) at /var/tmp/portage/x11-libs/libxcb-1.11.1/work/libxcb-1.11.1/src/xcb_in.c:693
#4  0x00007f7729d3e935 in QXcbEventReader::run (this=0xc13470) at qxcbconnection.cpp:1325
#5  0x00007f773d907d24 in QThreadPrivate::start (arg=0xc13470) at thread/qthread_unix.cpp:341
#6  0x00007f773fe09434 in start_thread (arg=0x7f772928d700) at pthread_create.c:333
#7  0x00007f773fb508fd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f7740287800 (LWP 3518)):
[KCrash Handler]
#6  0x0000000000000000 in ?? ()
#7  0x00007f773f6ba054 in KWin::Workspace::constrainedStackingOrder (this=<optimized out>) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/layers.cpp:514
#8  0x00007f773f6b9dc6 in KWin::Workspace::updateStackingOrder (this=0xce3920, propagate_new_clients=true) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/layers.cpp:120
#9  0x00007f773f6bcd99 in KWin::Workspace::blockStackingUpdates (this=0x33fa010, block=<optimized out>) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/layers.cpp:622
#10 0x00007f773f67afb9 in KWin::StackingUpdatesBlocker::~StackingUpdatesBlocker (this=<optimized out>) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/workspace.h:634
#11 KWin::Client::releaseWindow (this=0x33fa010, on_shutdown=<optimized out>) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/client.cpp:271
#12 0x00007f773f6cb787 in KWin::Client::unmapNotifyEvent (this=0x33fa010, e=<optimized out>) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/events.cpp:813
#13 0x00007f773f6cb228 in KWin::Client::windowEvent (this=0x33fa010, e=0x7f7724001880) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/events.cpp:655
#14 0x00007f773f6c9655 in KWin::Workspace::workspaceEvent (this=0xce3920, e=0x7f7724001880) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/events.cpp:343
#15 0x00007f773f6bffc7 in KWin::XcbEventFilter::nativeEventFilter (this=0x33fa010, eventType=..., message=0x7f7724001880, result=0xe) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/main.cpp:402
#16 0x00007f773daae1c3 in QAbstractEventDispatcher::filterNativeEvent (this=<optimized out>, eventType=..., message=0x7f7724001880, result=0x7ffe33ba72e0) at kernel/qabstracteventdispatcher.cpp:460
#17 0x00007f7729d3d1bd in QXcbConnection::handleXcbEvent (this=0xbfec30, event=0x7f7724001880) at qxcbconnection.cpp:1091
#18 0x00007f7729d3f570 in QXcbConnection::processXcbEvents (this=0xbfec30) at qxcbconnection.cpp:1723
#19 0x00007f773dada36f in QObject::event (this=0xbfec30, e=<optimized out>) at kernel/qobject.cpp:1256
#20 0x00007f7729d3ff88 in QXcbConnection::event (this=0x33fa010, e=0x7f7724001750) at qxcbconnection.cpp:2339
#21 0x00007f773e349792 in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0xbfec30, e=0x7f7724001750) at kernel/qapplication.cpp:3804
#22 0x00007f773e34b5c2 in QApplication::notify (this=<optimized out>, receiver=0xbfec30, e=0x7f7724001750) at kernel/qapplication.cpp:3163
#23 0x00007f7740025fe6 in KWin::ApplicationX11::notify (this=0x7ffe33ba7b30, o=0xbfec30, e=0x7f7724001750) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/main_x11.cpp:276
#24 0x00007f773dab273b in QCoreApplication::notifyInternal2 (receiver=0xbfec30, event=0x7f7724001750) at kernel/qcoreapplication.cpp:1015
#25 0x00007f773dab32f8 in QCoreApplication::sendEvent (receiver=0xbfec30, event=0x7f7724001750) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:225
#26 QCoreApplicationPrivate::sendPostedEvents (receiver=0x0, event_type=0, data=0xbe8290) at kernel/qcoreapplication.cpp:1650
#27 0x00007f773dafdaf8 in QEventDispatcherUNIX::processEvents (this=0xc4f7d0, flags=...) at kernel/qeventdispatcher_unix.cpp:579
#28 0x00007f7729daceba in QUnixEventDispatcherQPA::processEvents (this=0x33fa010, flags=...) at eventdispatchers/qunixeventdispatcher.cpp:62
#29 0x00007f773daaf001 in QEventLoop::processEvents (flags=..., this=<optimized out>) at kernel/qeventloop.cpp:128
#30 QEventLoop::exec (this=0x7ffe33ba7a40, flags=...) at kernel/qeventloop.cpp:204
#31 0x00007f773dab2d63 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1285
#32 0x00007f7740026b54 in kdemain (argc=<optimized out>, argv=<optimized out>) at /var/tmp/portage/kde-plasma/kwin-5.7.1/work/kwin-5.7.1/main_x11.cpp:466
#33 0x00007f773fa89790 in __libc_start_main (main=0x4008e0 <main(int, char**)>, argc=1, argv=0x7ffe33ba7cc8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffe33ba7cb8) at ../csu/libc-start.c:289
#34 0x00000000004007f9 in _start ()

*** Bug 350814 has been marked as a duplicate of this bug. ***

*** Bug 369318 has been marked as a duplicate of this bug. ***

*** Bug 404632 has been marked as a duplicate of this bug. ***

We haven't gotten dupes within past 3-4 years and there were some refactorings affecting constraining the stacking order, let's mark it as WORKSFORME.