Re: [PATCH v2] slab: Add POISON_POINTER_DELTA to ZERO_SIZE_PTR
From: Christoph Lameter
Date: Fri Nov 18 2016 - 12:47:10 EST
On Thu, 17 Nov 2016, Michael Ellerman wrote:
> Currently ZERO_OR_NULL_PTR() uses a trick of doing a single check that
> x <= ZERO_SIZE_PTR, and ignoring the fact that it also matches 1-15.
Well yes that was done so we do not add too many branches all over the
> That no longer really works once we add the poison delta, so split it
> into two checks. Assign x to a temporary to avoid evaluating it
> twice (suggested by Kees Cook).
And now you are doing just that.