[PATCH v2 2/2] kasan, slub: reset tag when printing address

[kuan.ying lee]

On Wed, 2021-08-04 at 10:41 +0200, Marco Elver wrote:
> On Wed, 4 Aug 2021 at 10:23, Kuan-Ying Lee <
> Kuan-Ying.Lee at mediatek.com> wrote:
> > 
> > The address still includes the tags when it is printed.
> > With hardware tag-based kasan enabled, we will get a
> > false positive KASAN issue when we access metadata.
> > 
> > Reset the tag before we access the metadata.
> > 
> > Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing
> > metadata")
> > Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee at mediatek.com>
> > Suggested-by: Marco Elver <elver at google.com>
> 
> Note, in this case Suggested-by is inappropriate, because I did not
> suggest the change in any way (you already had it in v1). I just
> commented on the fact that it's missing a Fixes so stable can pick it
> up and some clarification.
> 
> Reviewed-by: Marco Elver <elver at google.com>

Got it.
I will remove it on v3.
Thanks.

> 
> > ---
> >  mm/slub.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/mm/slub.c b/mm/slub.c
> > index b6c5205252eb..f77d8cd79ef7 100644
> > --- a/mm/slub.c
> > +++ b/mm/slub.c
> > @@ -576,8 +576,8 @@ static void print_section(char *level, char
> > *text, u8 *addr,
> >                           unsigned int length)
> >  {
> >         metadata_access_enable();
> > -       print_hex_dump(level, kasan_reset_tag(text),
> > DUMP_PREFIX_ADDRESS,
> > -                       16, 1, addr, length, 1);
> > +       print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
> > +                       16, 1, kasan_reset_tag((void *)addr),
> > length, 1);
> >         metadata_access_disable();
> >  }
> > 
> > --
> > 2.18.0