linux-kernel - Re: [PATCH] include/linux/kasan.h: Notice about 0 for kasan_[dis/en]able

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Message-ID: <CAG_fn=W5Ai_cqhzyi=EBEyhhQtvoQtOsuyfBfRihf=fuKh2Xqw@mail.gmail.com>
Date:	Mon, 2 May 2016 12:49:25 +0200
From:	Alexander Potapenko <glider@...gle.com>
To:	chengang@...ndsoft.com.cn
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Andrey Ryabinin <aryabinin@...tuozzo.com>,
	Dmitriy Vyukov <dvyukov@...gle.com>,
	kasan-dev <kasan-dev@...glegroups.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux Memory Management List <linux-mm@...ck.org>,
	Chen Gang <gang.chen.5i5j@...il.com>
Subject: Re: [PATCH] include/linux/kasan.h: Notice about 0 for kasan_[dis/en]able_current()

On Mon, May 2, 2016 at 7:35 AM,  <chengang@...ndsoft.com.cn> wrote:
> From: Chen Gang <chengang@...ndsoft.com.cn>
>
> According to their comments and the kasan_depth's initialization, if
> kasan_depth is zero, it means disable. So kasan_depth need consider
> about the 0 overflow.
>
> Also remove useless comments for dummy kasan_slab_free().
>
> Signed-off-by: Chen Gang <gang.chen.5i5j@...il.com>
> ---
>  include/linux/kasan.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index 645c280..37fab04 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -32,13 +32,15 @@ static inline void *kasan_mem_to_shadow(const void *addr)
>  /* Enable reporting bugs after kasan_disable_current() */
>  static inline void kasan_enable_current(void)
>  {
> -       current->kasan_depth++;
> +       if (current->kasan_depth + 1)
> +               current->kasan_depth++;
>  }
>
>  /* Disable reporting bugs for current task */
>  static inline void kasan_disable_current(void)
>  {
> -       current->kasan_depth--;
> +       if (current->kasan_depth)
> +               current->kasan_depth--;
>  }
>
>  void kasan_unpoison_shadow(const void *address, size_t size);
> @@ -113,8 +115,6 @@ static inline void kasan_krealloc(const void *object, size_t new_size,
>
>  static inline void kasan_slab_alloc(struct kmem_cache *s, void *object,
>                                    gfp_t flags) {}
> -/* kasan_slab_free() returns true if the object has been put into quarantine.
> - */
>  static inline bool kasan_slab_free(struct kmem_cache *s, void *object)
>  {
>         return false;
> --
> 1.9.3
>

Acked-by: Alexander Potapenko <glider@...gle.com>

-- 
Alexander Potapenko
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