Re: [PATCH] kasan: fix mention for KASAN_HW_TAGS

[Marco Elver]

On Mon, 19 Jun 2023 at 12:15, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
> On Mon, 19 Jun 2023 at 12:12, Chanho Min <chanho.min@xxxxxxx> wrote:
> >
> > This patch removes description of the KASAN_HW_TAGS's memory consumption.
> > KASAN_HW_TAGS does not set 1/32nd shadow memory.
>
> The hardware still allocates/uses shadow in MTE.
> Though, it may be 1/16-th, not sure.

I think the point is that it depends on the hardware implementation of
MTE. There are a range of possibilities, but enabling KASAN_HW_TAGS
doesn't consume any extra memory for tags itself if the hardware has
to enable MTE and provision tag space via firmware to begin with.

> > Signed-off-by: Chanho Min <chanho.min@xxxxxxx>

I think you just have to be a bit clearer in the commit description,
just briefly mentioning how/where the tag space is allocated in
hardware that do support MTE. Then removing this line is probably
fair, if KASAN_HW_TAGS isn't the direct reason for tag memory being
allocated.