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SubjectRe: [PATCH] media: rcar-vin: fix a potential NULL pointer dereference
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On 3/9/19 12:02 PM, Niklas Söderlund wrote:
> Hi Kangjie,
>
> Thanks for your patch.
>
> On 2019-03-09 01:05:27 -0600, Kangjie Lu wrote:
>> In case of_match_node cannot find a match, the fix returns
>> -EINVAL to avoid NULL pointer dereference.
>>
>> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
>> ---
>> drivers/media/platform/rcar-vin/rcar-core.c | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
>> index f0719ce24b97..a058e2023ca8 100644
>> --- a/drivers/media/platform/rcar-vin/rcar-core.c
>> +++ b/drivers/media/platform/rcar-vin/rcar-core.c
>> @@ -266,6 +266,8 @@ static int rvin_group_init(struct rvin_group *group, struct rvin_dev *vin)
>>
>> match = of_match_node(vin->dev->driver->of_match_table,
>> vin->dev->of_node);
>> + if (unlikely(!match))
>> + return -EINVAL;
>
> I don't think this is needed. The driver depends on selects OF and if we
> get this far we it is because we had a match already. The reason to call
> of_match_node() here is simply to retrieve which of the possible
> compatible strings was matched.
>
> Am I missing something? What scenario do you see where this can fail?

And even if it can fail, then please drop the 'unlikely'.

Regards,

Hans

>
>>
>> strscpy(mdev->driver_name, KBUILD_MODNAME, sizeof(mdev->driver_name));
>> strscpy(mdev->model, match->compatible, sizeof(mdev->model));
>> --
>> 2.17.1
>>
>

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