diff mbox series

[2/2] kasan, mm: reset tag for hex dump address

Message ID 20210727040021.21371-3-Kuan-Ying.Lee@mediatek.com (mailing list archive)
State New
Headers show
Series kasan, mm: reset tag when access metadata | expand

Commit Message

Kuan-Ying Lee July 27, 2021, 4 a.m. UTC
Text is a string. We need to move this kasan_reset_tag()
to address but text.

Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
---
 mm/slub.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Marco Elver July 27, 2021, 7:20 a.m. UTC | #1
On Tue, 27 Jul 2021 at 06:00, Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com> wrote:
>
> Text is a string. We need to move this kasan_reset_tag()
> to address but text.
>
> Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>

This patch also makes sense (I think), thanks for sending. But it's
unclear what the problem is. The fact that when the address is printed
it still includes the tag? Or a false positive?
It'd be good to clarify in the commit message.

Here I'd also use a more descriptive patch title, something like
"kasan, slub: reset tag when printing address".

Also, I think this patch requires a:

  Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing metadata")

So that stable kernels can pick this up if appropriate.

> ---
>  mm/slub.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 6dad2b6fda6f..d20674f839ba 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
>
> --
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Kuan-Ying Lee July 27, 2021, 8:54 a.m. UTC | #2
On Tue, 2021-07-27 at 09:20 +0200, Marco Elver wrote:
> On Tue, 27 Jul 2021 at 06:00, Kuan-Ying Lee <
> Kuan-Ying.Lee@mediatek.com> wrote:
> > 
> > Text is a string. We need to move this kasan_reset_tag()
> > to address but text.
> > 
> > Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
> 
> This patch also makes sense (I think), thanks for sending. But it's
> unclear what the problem is. The fact that when the address is
> printed
> it still includes the tag? Or a false positive?
> It'd be good to clarify in the commit message.

Yes, printed address includes the tag, so when we access the
metadata, we will encounter tag mismatch with HW tag-based kasan
enabled.

> 
> Here I'd also use a more descriptive patch title, something like
> "kasan, slub: reset tag when printing address".
> 
> Also, I think this patch requires a:
> 
>   Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing
> metadata")
> 
> So that stable kernels can pick this up if appropriate.

Thank you, Marco.
I will refine commit message in the v2.

> 
> > ---
> >  mm/slub.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/mm/slub.c b/mm/slub.c
> > index 6dad2b6fda6f..d20674f839ba 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
> > 
> > --
> > You received this message because you are subscribed to the Google
> > Groups "kasan-dev" group.
> > To unsubscribe from this group and stop receiving emails from it,
> > send an email to kasan-dev+unsubscribe@googlegroups.com.
> > To view this discussion on the web visit 
> > https://urldefense.com/v3/__https://groups.google.com/d/msgid/kasan-dev/20210727040021.21371-3-Kuan-Ying.Lee*40mediatek.com__;JQ!!CTRNKA9wMg0ARbw!13XOuYbzPQrBvIDMNbrT7vm8RGc56Oqr402PDfQRDmHrrBsujrZUr7O9q24JeDJ_3NlWSQ$
> >  .
diff mbox series

Patch

diff --git a/mm/slub.c b/mm/slub.c
index 6dad2b6fda6f..d20674f839ba 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();
 }