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From: Dan Streetman <ddstreet@ieee.org>
Date: Wed, 10 Jun 2015 16:59:53 -0400
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Subject: Re: [RFC][PATCH 4/5] mm/zpool: allow NULL `zpool' pointer in zpool_destroy_pool()
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Minchan Kim <minchan@kernel.org>, Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, Michal Hocko <mhocko@suse.cz>,
        David Rientjes <rientjes@google.com>, Linux-MM <linux-mm@kvack.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
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On Tue, Jun 9, 2015 at 8:04 AM, Sergey Senozhatsky
<sergey.senozhatsky@gmail.com> wrote:
> zpool_destroy_pool() does not tolerate a NULL zpool pointer
> argument and performs a NULL-pointer dereference. Although
> there is only one zpool_destroy_pool() user (as of 4.1),
> still update it to be coherent with the corresponding
> destroy() functions of the remainig pool-allocators (slab,
> mempool, etc.), which now allow NULL pool-pointers.
>
> For consistency, tweak zpool_destroy_pool() and NULL-check the
> pointer there.
>
> Proposed by Andrew Morton.
>
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Reported-by: Andrew Morton <akpm@linux-foundation.org>
> LKML-reference: https://lkml.org/lkml/2015/6/8/583

Acked-by: Dan Streetman <ddstreet@ieee.org>

> ---
>  mm/zpool.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/mm/zpool.c b/mm/zpool.c
> index bacdab6..2f59b90 100644
> --- a/mm/zpool.c
> +++ b/mm/zpool.c
> @@ -202,6 +202,9 @@ struct zpool *zpool_create_pool(char *type, char *name, gfp_t gfp,
>   */
>  void zpool_destroy_pool(struct zpool *zpool)
>  {
> +       if (unlikely(!zpool))
> +               return;
> +
>         pr_info("destroying pool type %s\n", zpool->type);
>
>         spin_lock(&pools_lock);
> --
> 2.4.3.368.g7974889
>
> --
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