Re: [Nouveau] [PATCH][next] nouveau/svm: Use kvcalloc() instead of kvzalloc()

From: Karol Herbst <kherbst@redhat.com>
To: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Ben Skeggs <bskeggs@redhat.com>, David Airlie <airlied@linux.ie>,
	 Daniel Vetter <daniel@ffwll.ch>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	 nouveau <nouveau@lists.freedesktop.org>,
	LKML <linux-kernel@vger.kernel.org>,
	 linux-hardening@vger.kernel.org
Subject: Re: [Nouveau] [PATCH][next] nouveau/svm: Use kvcalloc() instead of kvzalloc()
Date: Wed, 29 Sep 2021 05:28:47 +0200	[thread overview]
Message-ID: <CACO55tsD98dNzw8fP=CiKLsdbnn2Vg78+wTRM90kutHtv1RZ5A@mail.gmail.com> (raw)
In-Reply-To: <20210928222513.GA294575@embeddedor>

Lack of documentation inside Linux here is a bit annoying, but do I
understand it correctly, that the main (and probably only) difference
is that kvcalloc checks whether the multiplication overflows and
returns NULL in this case?

On Wed, Sep 29, 2021 at 12:21 AM Gustavo A. R. Silva
<gustavoars@kernel.org> wrote:
>
> Use 2-factor argument form kvcalloc() instead of kvzalloc().
>
> Link: https://github.com/KSPP/linux/issues/162
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> ---
>  drivers/gpu/drm/nouveau/nouveau_svm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c
> index b0c3422cb01f..1a896a24288a 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_svm.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_svm.c
> @@ -992,7 +992,7 @@ nouveau_svm_fault_buffer_ctor(struct nouveau_svm *svm, s32 oclass, int id)
>         if (ret)
>                 return ret;
>
> -       buffer->fault = kvzalloc(sizeof(*buffer->fault) * buffer->entries, GFP_KERNEL);
> +       buffer->fault = kvcalloc(sizeof(*buffer->fault), buffer->entries, GFP_KERNEL);
>         if (!buffer->fault)
>                 return -ENOMEM;
>
> --
> 2.27.0
>