Version: 4:4.0.68+svn794641-1 Debian experimental (using Devel)
Installed from: Compiled sources
I am not sure how to reproduce this, but sometimes alt tabbing using the "Cover switch" plugin causes kwin to crash. I attached a backtrace.
Created attachment 24341 [details]
I have never seen a crash with this effect...
When looking at the backtrace I saw one thing that struck me: do you have the zoom effect enabled when the crash appeared?
I just checked and yes, zoom was enabled.
>I just checked and yes, zoom was enabled.
It was a guess and I think I guessed wrong.
As you post in your initial comment it will become difficult to track this crash. I looked at the mentioned code and I have a very good guess.
for( int i=0; i < rightWindowCount; i++ )
EffectWindow* window = rightWindows->at( i );
x = window->x();
The crash appears when accessing the window pointer. rightWindowCount is a previous stored "rightWindows->count()". So in case that one window disappears during window switching rightWindowCount > rightWindows->count() in the for loop leading to a null pointer.
Do you think that this is possible in your situation? A window disappearing during switching? I know kopete to be such a candidate. If yes I would prepare a patch with some null pointer checks.
I do remember I was opening and closing some programs at the moment the crash happened, so what you are saying sounds very probable.
SVN commit 802111 by graesslin:
Adding some checks for Null-pointers. This should prevent from very unlikely crashes when a window closes during the animation.
M +10 -0 coverswitch.cpp
WebSVN link: http://websvn.kde.org/?view=rev&revision=802111