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From:   Marco Elver <elver@google.com>
Date:   Tue, 3 Mar 2020 21:21:05 +0100
Message-ID: <CANpmjNOaZ7PBiQh9r06ZuvsbtyYpKjGCt+0hXTVabOJD18OXEA@mail.gmail.com>
Subject: Re: [PATCH -next 2/2] Revert "mm/kmemleak: annotate various data
 races obj->ptr"
To:     Qian Cai <cai@lca.pw>
Cc:     Andrew Morton <akpm@linux-foundation.org>, catalin.marinas@arm.com,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Tue, 3 Mar 2020 at 20:28, Qian Cai <cai@lca.pw> wrote:
>
> This reverts commit a03184297d546c6531cdd40878f1f50732d3bac9.
>
> Signed-off-by: Qian Cai <cai@lca.pw>

Acked-by: Marco Elver <elver@google.com>

Thank you!

> ---
>  mm/kmemleak.c | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/mm/kmemleak.c b/mm/kmemleak.c
> index 788dc5509539..e362dc3d2028 100644
> --- a/mm/kmemleak.c
> +++ b/mm/kmemleak.c
> @@ -1169,12 +1169,7 @@ static bool update_checksum(struct kmemleak_object *object)
>         u32 old_csum = object->checksum;
>
>         kasan_disable_current();
> -       /*
> -        * crc32() will dereference object->pointer. If an unstable value was
> -        * returned due to a data race, it will be corrected in the next scan.
> -        */
> -       object->checksum = data_race(crc32(0, (void *)object->pointer,
> -                                          object->size));
> +       object->checksum = crc32(0, (void *)object->pointer, object->size);
>         kasan_enable_current();
>
>         return object->checksum != old_csum;
> @@ -1248,7 +1243,7 @@ static void scan_block(void *_start, void *_end,
>                         break;
>
>                 kasan_disable_current();
> -               pointer = data_race(*ptr);
> +               pointer = *ptr;
>                 kasan_enable_current();
>
>                 untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer);
> --
> 1.8.3.1
>