Re: [PATCH] drm/amdkfd: Check for null pointer after calling kmemdup

From: Felix Kuehling <felix.kuehling@amd.com>
To: Jiasheng Jiang <jiasheng@iscas.ac.cn>,
	alexander.deucher@amd.com, christian.koenig@amd.com,
	airlied@linux.ie, daniel@ffwll.ch
Cc: dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drm/amdkfd: Check for null pointer after calling kmemdup
Date: Wed, 5 Jan 2022 10:56:51 -0500	[thread overview]
Message-ID: <3a1a14b9-3bde-ed44-ea43-42845f4b568f@amd.com> (raw)
In-Reply-To: <20220105090943.2434040-1-jiasheng@iscas.ac.cn>

Am 2022-01-05 um 4:09 a.m. schrieb Jiasheng Jiang:
> As the possible failure of the allocation, kmemdup() may return NULL
> pointer.
> Therefore, it should be better to check the 'props2' in order to prevent
> the dereference of NULL pointer.
>
> Fixes: 3a87177eb141 ("drm/amdkfd: Add topology support for dGPUs")
> Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>

Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>


> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_crat.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> index c60e82697385..d15380c65c6d 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c
> @@ -410,6 +410,9 @@ static int kfd_parse_subtype_iolink(struct crat_subtype_iolink *iolink,
>  			return -ENODEV;
>  		/* same everything but the other direction */
>  		props2 = kmemdup(props, sizeof(*props2), GFP_KERNEL);
> +		if (!props2)
> +			return -ENOMEM;
> +
>  		props2->node_from = id_to;
>  		props2->node_to = id_from;
>  		props2->kobj = NULL;