Re: [PATCH] LoongArch: Add kernel address sanitizer support

[Qing Zhang]

On 2023/3/30 上午10:55, Andrey Konovalov wrote:
> On Thu, Mar 30, 2023 at 4:06 AM Qing Zhang <zhangqing@xxxxxxxxxxx> wrote:
> > > But I don't think you need this check here at all: addr_has_metadata
> > > already checks that shadow exists.
> > On LongArch, there's a lot of holes between different segments, so kasan
> > shadow area is some different type of memory that we concatenate, we
> > can't use if (unlikely((void *)addr <
> > kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) to determine the
> > validity, and in arch/loongarch/include/asm/kasan.h I construct invalid
> > NULL.
>
> I get that, but you already added a special case for
> __HAVE_ARCH_SHADOW_MAP to addr_has_metadata, so you can just call it?
ok, all the changes are going to be in v2.

Thanks,
-Qing
> > This is because in pagetable_init on loongarch/mips, we populate pmd/pud
> > with invalid_pmd_table/invalid_pud_table,
>
> I see. Please add this into the patch description for v2.
>
> > So pmd_init/pud_init(p) is required, perhaps we define them as __weak in
> > mm/kasan/init.c, like mm/sparse-vmemmap.c.
>
> Yes, this makes sense to do, so that KASAN doesn't depend on
> definitions from sparse-vmemmap.c.
>
> Thank you!