Re: [PATCH v3 3/3] kasan: add memory corruption identification support for hardware tag-based mode

[Kuan-Ying Lee]

On Tue, 2021-06-22 at 16:54 +0300, Andrey Konovalov wrote:
> On Sun, Jun 20, 2021 at 2:48 PM Kuan-Ying Lee
> <Kuan-Ying.Lee@xxxxxxxxxxxx> wrote:
> > 
> > Add memory corruption identification support for hardware tag-based
> > mode. We store one old free pointer tag and free backtrace.
> 
> Please explain why only one.
> 

Got it. I will rewrite this commit message in v4.

> > Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@xxxxxxxxxxxx>
> > Suggested-by: Marco Elver <elver@xxxxxxxxxx>
> > Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
> > Cc: Alexander Potapenko <glider@xxxxxxxxxx>
> > Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
> > Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > ---
> >  lib/Kconfig.kasan | 2 +-
> >  mm/kasan/kasan.h  | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
> > index 6f5d48832139..2cc25792bc2f 100644
> > --- a/lib/Kconfig.kasan
> > +++ b/lib/Kconfig.kasan
> > @@ -157,7 +157,7 @@ config KASAN_STACK
> > 
> >  config KASAN_TAGS_IDENTIFY
> >         bool "Enable memory corruption identification"
> > -       depends on KASAN_SW_TAGS
> > +       depends on KASAN_SW_TAGS || KASAN_HW_TAGS
> >         help
> >           This option enables best-effort identification of bug
> > type
> >           (use-after-free or out-of-bounds) at the cost of
> > increased
> > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> > index b0fc9a1eb7e3..d6f982b8a84e 100644
> > --- a/mm/kasan/kasan.h
> > +++ b/mm/kasan/kasan.h
> > @@ -153,7 +153,7 @@ struct kasan_track {
> >         depot_stack_handle_t stack;
> >  };
> > 
> > -#ifdef CONFIG_KASAN_TAGS_IDENTIFY
> > +#if defined(CONFIG_KASAN_TAGS_IDENTIFY) &&
> > defined(CONFIG_KASAN_SW_TAGS)
> >  #define KASAN_NR_FREE_STACKS 5
> >  #else
> >  #define KASAN_NR_FREE_STACKS 1
> > --
> > 2.18.0
> > 
> 
> Other than that:
> 
> Reviewed-by: Andrey Konovalov <andreyknvl@xxxxxxxxx>