[PATCH] dix: Clear any existing selections before initializing privates

[Adam Jackson]

On Mon, 2013-12-30 at 09:15 -0600, Andrew Eikum wrote:
> If there is a selection left over from a previous execution of the
> main loop, and that selection has privates allocated for it, the X
> server will crash. This is because dixResetPrivates() resets the
> privates refcounts to zero without accounting for the reference held
> by the selection object. When the selection is then deleted in
> InitSelections() after the call to dixResetPrivates(), the refcount
> for its privates type goes negative and bad things happen.
> 
> To fix this, we should delete any existing selections before calling
> dixResetPrivates(). This will properly release the selection's
> privates and avoid the crash.
> 
> A more thorough description of the problem and a test case to
> reproduce the crash is available at a previous mail:
>   "Negative Selection devPrivates refcount?"
>   By Andrew Eikum to xorg-devel on 10 Dec 2013
>   http://lists.freedesktop.org/archives/xorg-devel/2013-December/039492.html

Reviewed-by: Adam Jackson <ajax at redhat.com>

- ajax