Re: [PATCH v2 32/33] s390: Implement the architecture-specific kmsan functions

[Alexander Potapenko]

> +static inline void *arch_kmsan_get_meta_or_null(void *addr, bool is_origin)
> +{
> +       if (addr >= (void *)&S390_lowcore &&
> +           addr < (void *)(&S390_lowcore + 1)) {
> +               /*
> +                * Different lowcores accessed via S390_lowcore are described
> +                * by the same struct page. Resolve the prefix manually in
> +                * order to get a distinct struct page.
> +                */
> +               addr += (void *)lowcore_ptr[raw_smp_processor_id()] -
> +                       (void *)&S390_lowcore;
> +               return kmsan_get_metadata(addr, is_origin);
> +       }
> +       return NULL;
> +}

Is there a possibility for infinite recursion here? E.g. can
`lowcore_ptr[raw_smp_processor_id()]` point somewhere in between
`(void *)&S390_lowcore` and `(void *)(&S390_lowcore + 1))`?