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Date:   Sat, 6 Jun 2020 10:24:50 +0200 (CEST)
From:   Julia Lawall <julia.lawall@inria.fr>
To:     Denis Efremov <efremov@linux.com>
cc:     Joe Perches <joe@perches.com>, cocci@systeme.lip6.fr,
        linux-kernel@vger.kernel.org
Subject: Re: [Cocci] [PATCH 1/2] Coccinelle: extend memdup_user transformation
 with GFP_USER
In-Reply-To: <20200530205348.5812-2-efremov@linux.com>
Message-ID: <alpine.DEB.2.21.2006061024100.2578@hadrien>
References: <20200530205348.5812-1-efremov@linux.com> <20200530205348.5812-2-efremov@linux.com>
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On Sat, 30 May 2020, Denis Efremov wrote:

> Match GFP_USER allocations with memdup_user.cocci rule.
> Commit 6c2c97a24f09 ("memdup_user(): switch to GFP_USER") switched
> memdup_user() from GFP_KERNEL to GFP_USER. In most cases it is still
> a good idea to use memdup_user() for GFP_KERNEL allocations. The
> motivation behind altering memdup_user() to GFP_USER is here:
> https://lkml.org/lkml/2018/1/6/333

Should the rule somehow document the cases in which memdup_user should now
not be used?

julia


>
> Signed-off-by: Denis Efremov <efremov@linux.com>
> ---
>  scripts/coccinelle/api/memdup_user.cocci | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/coccinelle/api/memdup_user.cocci b/scripts/coccinelle/api/memdup_user.cocci
> index c809ab10bbce..49f487e6a5c8 100644
> --- a/scripts/coccinelle/api/memdup_user.cocci
> +++ b/scripts/coccinelle/api/memdup_user.cocci
> @@ -20,7 +20,7 @@ expression from,to,size;
>  identifier l1,l2;
>  @@
>
> --  to = \(kmalloc\|kzalloc\)(size,GFP_KERNEL);
> +-  to = \(kmalloc\|kzalloc\)(size,\(GFP_KERNEL\|GFP_USER\));
>  +  to = memdup_user(from,size);
>     if (
>  -      to==NULL
> @@ -43,7 +43,7 @@ position p;
>  statement S1,S2;
>  @@
>
> -*  to = \(kmalloc@p\|kzalloc@p\)(size,GFP_KERNEL);
> +*  to = \(kmalloc@p\|kzalloc@p\)(size,\(GFP_KERNEL\|GFP_USER\));
>     if (to==NULL || ...) S1
>     if (copy_from_user(to, from, size) != 0)
>     S2
> --
> 2.26.2
>
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