linux-kernel - Re: [PATCH RFC v2 08/21] kasan: remove __kasan_unpoison

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Message-ID: <CACT4Y+Zqg475fdxWp_ARvb0APS=zKdLmzRW_0m4ZcoH6rADrzA@mail.gmail.com>
Date:   Wed, 28 Oct 2020 11:57:53 +0100
From:   Dmitry Vyukov <dvyukov@...gle.com>
To:     Andrey Konovalov <andreyknvl@...gle.com>
Cc:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        Alexander Potapenko <glider@...gle.com>,
        Marco Elver <elver@...gle.com>,
        Evgenii Stepanov <eugenis@...gle.com>,
        Kostya Serebryany <kcc@...gle.com>,
        Peter Collingbourne <pcc@...gle.com>,
        Serban Constantinescu <serbanc@...gle.com>,
        Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Elena Petrova <lenaptr@...gle.com>,
        Branislav Rankov <Branislav.Rankov@....com>,
        Kevin Brodsky <kevin.brodsky@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        kasan-dev <kasan-dev@...glegroups.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux-MM <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RFC v2 08/21] kasan: remove __kasan_unpoison_stack

On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <andreyknvl@...gle.com> wrote:
>
> There's no need for __kasan_unpoison_stack() helper, as it's only
> currently used in a single place. Removing it also removes undeed
> arithmetic.
>
> No functional changes.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>
> Link: https://linux-review.googlesource.com/id/Ie5ba549d445292fe629b4a96735e4034957bcc50

Reviewed-by: Dmitry Vyukov <dvyukov@...gle.com>

> ---
>  mm/kasan/common.c | 12 +++---------
>  1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index a3e67d49b893..9008fc6b0810 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -59,18 +59,12 @@ void kasan_disable_current(void)
>  #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
>
>  #if CONFIG_KASAN_STACK
> -static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
> -{
> -       void *base = task_stack_page(task);
> -       size_t size = sp - base;
> -
> -       kasan_unpoison_memory(base, size);
> -}
> -
>  /* Unpoison the entire stack for a task. */
>  void kasan_unpoison_task_stack(struct task_struct *task)
>  {
> -       __kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE);
> +       void *base = task_stack_page(task);
> +
> +       kasan_unpoison_memory(base, THREAD_SIZE);
>  }
>
>  /* Unpoison the stack for the current task beyond a watermark sp value. */
> --
> 2.29.0.rc1.297.gfa9743e501-goog
>