Re: [PATCH] ARM: kasan: Only map modules if CONFIG_KASAN_VMALLOC=n

[Linus Walleij]

On Sat, Aug 27, 2022 at 11:32 PM Alexander A Sverdlin
<alexander.sverdlin@xxxxxxxxx> wrote:

> -       create_mapping((void *)MODULES_VADDR, (void *)(PKMAP_BASE + PMD_SIZE));
> +       if (!IS_ENABLED(CONFIG_KASAN_VMALLOC) && IS_ENABLED(CONFIG_MODULES))
> +               create_mapping((void *)MODULES_VADDR, (void *)(MODULES_END));

So the way I understand it is that modules are first and foremost loaded into
the area MODULES_VADDR .. MODULES_END, and then after that is out,
they get loaded into VMALLOC. See arch/arm/kernel/module.c, module_alloc().

If you do this, how are the addresses between MODULES_VADDR..MODULES_END
shadowed when using CONFIG_KASAN_VMALLOC?

> +       create_mapping((void *)PKMAP_BASE, (void *)(PKMAP_BASE + PMD_SIZE));

(Splitting this in two steps if probably good in any case.)

Pls keep me on CC for Kasan ARM patches, thanks! (Maybe I should add some
MAINTAINERS blurb.)

Yours,
Linus Walleij