linux-kernel - Re: [PATCH -next 1/2] mm: disable KCSAN for kmemleak

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Date:   Tue, 3 Mar 2020 21:20:40 +0100
From:   Marco Elver <elver@...gle.com>
To:     Qian Cai <cai@....pw>
Cc:     Andrew Morton <akpm@...ux-foundation.org>, catalin.marinas@....com,
        Linux Memory Management List <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH -next 1/2] mm: disable KCSAN for kmemleak

On Tue, 3 Mar 2020 at 20:28, Qian Cai <cai@....pw> wrote:
>
> Kmemleak could scan task stacks while plain writes happens to those
> stack variables which could results in data races. For example, in
> sys_rt_sigaction and do_sigaction(), it could have plain writes in
> a 32-byte size. Since the kmemleak does not care about the actual values
> of a non-pointer and all do_sigaction() call sites only copy to stack
> variables, just disable KCSAN for kmemleak to avoid annotating anything
> outside Kmemleak just because Kmemleak scans everything.
>
> Suggested-by: Marco Elver <elver@...gle.com>
> Signed-off-by: Qian Cai <cai@....pw>

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

Thank you!

> ---
>  mm/Makefile | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/mm/Makefile b/mm/Makefile
> index 946754cc66b6..6e263045f0c2 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -14,6 +14,7 @@ KCSAN_SANITIZE_slab_common.o := n
>  KCSAN_SANITIZE_slab.o := n
>  KCSAN_SANITIZE_slub.o := n
>  KCSAN_SANITIZE_page_alloc.o := n
> +KCSAN_SANITIZE_kmemleak.o := n
>
>  # These files are disabled because they produce non-interesting and/or
>  # flaky coverage that is not a function of syscall inputs. E.g. slab is out of
> --
> 1.8.3.1
>