[PATCH] net: ethernet: mediatek: add NULL check on of_match_device() return value

Gustavo A. R. Silva
2017-07-07T20:08:31Z

Hi Andrew,

Quoting Andrew Lunn <andrew@lunn.ch>:

> On Fri, Jul 07, 2017 at 02:11:35AM -0500, Gustavo A. R. Silva wrote:
>> Check return value from call to of_match_device()
>> in order to prevent a NULL pointer dereference.
>>
>> In case of NULL print error message and return -ENODEV
>>
>> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
>> ---
>> drivers/net/ethernet/mediatek/mtk_eth_soc.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>> b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>> index adaaafc..6a77dea 100644
>> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
>> @@ -2408,6 +2408,11 @@ static int mtk_probe(struct platform_device *pdev)
>> int i;
>>
>> match = of_match_device(of_mtk_match, &pdev->dev);
>> + if (!match) {
>> + dev_err(&pdev->dev, "failed to match device\n");
>> + return -ENODEV;
>> + }
>> +
>> soc = (struct mtk_soc_data *)match->data;
>
> Hi Gustavo
>
> I think you are fixing the wrong thing. The soc variable is unused. Also,
>
> const struct of_device_id of_mtk_match[] = {
> { .compatible = "mediatek,mt2701-eth" },
> {},
> };
>
> So match->data is NULL. This code is all pointless and should be
> removed, rather than try to avoid a NULL pointer dereference which can
> not actually happen.
>

You are right. Thank you for pointing it out. I'll remove that code
and send a new patch shortly.

Thanks!
--
Gustavo A. R. Silva