Re: [PATCH v7 1/3] mm: Shuffle initial free memory to improve memory-side-cache utilization

[Kees Cook]

On Thu, Jan 10, 2019 at 1:29 PM Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
> Note that higher order merging is not a current concern since the
> implementation is already randomizing on MAX_ORDER sized pages. Since
> memory side caches are so large there's no worry about a 4MB
> randomization boundary.
>
> However, for the (unproven) security use case where folks want to
> experiment with randomizing on smaller granularity, they should be
> wary of this (/me nudges Kees).

Yup. And I think this is well noted in the Kconfig help already. I
view this as slightly more fine grain randomization than we get from
just effectively the base address randomization that
CONFIG_RANDOMIZE_MEMORY performs.

I remain a fan of this series. :)

-- 
Kees Cook