Subject: 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
References: <20220105090943.2434040-1-jiasheng@iscas.ac.cn>
 <3a1a14b9-3bde-ed44-ea43-42845f4b568f@amd.com>
Organization: AMD Inc.
Message-ID: <0c34571c-6330-9258-a6cb-6886b170e8cb@amd.com>
Date:   Mon, 10 Jan 2022 16:23:30 -0500
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On 2022-01-05 10:56 a.m., Felix Kuehling wrote:
> 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>
I applied the patch to amd-staging-drm-next.

Regards,
   Felix


>
>> ---
>>   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;