Re: [PATCH RFC 0/8] kasan: hardware tag-based mode for production use on arm64

[Dmitry Vyukov]

On Mon, Oct 19, 2020 at 2:23 PM Marco Elver <elver@xxxxxxxxxx> wrote:
>
> On Wed, 14 Oct 2020 at 22:44, Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote:
> [...]
> > A question to KASAN maintainers: what would be the best way to support the
> > "off" mode? I see two potential approaches: add a check into each kasan
> > callback (easier to implement, but we still call kasan callbacks, even
> > though they immediately return), or add inline header wrappers that do the
> > same.
>
> This is tricky, because we don't know how bad the performance will be
> if we keep them as calls. We'd have to understand the performance
> impact of keeping them as calls, and if the performance impact is
> acceptable or not.
>
> Without understanding the performance impact, the only viable option I
> see is to add __always_inline kasan_foo() wrappers, which use the
> static branch to guard calls to __kasan_foo().

This sounds reasonable to me.