Bug#495483: Another instance of the DoSwapInterval segfault

[Hugo Herbelin <hugo.herbelin@inria.fr>]

Hi,

After further browsing the code, it seems that the problem was in fact
that the function swapInterval called by DoSwapInterval was not
initialised. The faulty function is __glXMesaScreenProbe in
glglxcore.c which initialises all __GLXscreen fields but the
swapInterval field. It seems to me that __glXMesaScreenProbe should at
minima set swapInterval to NULL.

Indeed, after recompilation with the patch below, the gnome
screensaver does not crash any longer. I would guess this will address
also the following bug reports:

https://bugs.launchpad.net/bugs/115609
http://bugs.debian.org/500887

Regards,

Hugo Herbelin


*** GL/glx/glxglcore.c.orig     2009-01-07 13:42:17.000000000 +0100
--- GL/glx/glxglcore.c  2009-01-07 13:43:25.000000000 +0100
***************
*** 390,395 ****
--- 390,396 ----
      screen->base.destroy        = __glXMesaScreenDestroy;
      screen->base.createContext  = __glXMesaScreenCreateContext;
      screen->base.createDrawable = __glXMesaScreenCreateDrawable;
+     screen->base.swapInterval   = NULL;
      screen->base.pScreen       = pScreen;
  
      /*