Re: [PATCH mm v4 28/39] kasan, page_alloc: allow skipping unpoisoning for HW_TAGS

Marco Elver
2021-12-21T12:19:58Z

On Tue, 21 Dec 2021 at 13:14, Marco Elver <elver@google.com> wrote:
>
> On Mon, Dec 20, 2021 at 11:02PM +0100, andrey.konovalov@linux.dev wrote:
> [...]
> > +static inline bool should_skip_kasan_unpoison(gfp_t flags, bool init_tags)
> > +{
> > + /* Don't skip if a software KASAN mode is enabled. */
> > + if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
> > + IS_ENABLED(CONFIG_KASAN_SW_TAGS))
> > + return false;
> > +
> > + /* Skip, if hardware tag-based KASAN is not enabled. */
> > + if (!kasan_hw_tags_enabled())
> > + return true;
>
> Same question here: why is IS_ENABLED(CONFIG_KASAN_{GENERIC,SW_TAGS})
> check required if kasan_hw_tags_enabled() is always false if one of
> those is configured?

Hmm, I pattern-matched too quickly. In this case there's probably no
way around it because the return value is different, so not exactly
like the should_skip_init().