Re: [PATCH] mdio_bus: Fix PTR_ERR applied after initialization to constant

[Michal Simek]

Hi David,

On 19. 11. 19 13:58, Harini Katakam wrote:
> On Mon, Nov 11, 2019 at 12:53 PM YueHaibing <yuehaibing@xxxxxxxxxx> wrote:
>>
>> Fix coccinelle warning:
>>
>> ./drivers/net/phy/mdio_bus.c:67:5-12: ERROR: PTR_ERR applied after initialization to constant on line 62
>> ./drivers/net/phy/mdio_bus.c:68:5-12: ERROR: PTR_ERR applied after initialization to constant on line 62
>>
>> Fix this by using IS_ERR before PTR_ERR
>>
>> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
>> Fixes: 71dd6c0dff51 ("net: phy: add support for reset-controller")
>> Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
>> ---
>>  drivers/net/phy/mdio_bus.c | 11 ++++++-----
>>  1 file changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
>> index 2e29ab8..3587656 100644
>> --- a/drivers/net/phy/mdio_bus.c
>> +++ b/drivers/net/phy/mdio_bus.c
>> @@ -64,11 +64,12 @@ static int mdiobus_register_reset(struct mdio_device *mdiodev)
>>         if (mdiodev->dev.of_node)
>>                 reset = devm_reset_control_get_exclusive(&mdiodev->dev,
>>                                                          "phy");
>> -       if (PTR_ERR(reset) == -ENOENT ||
>> -           PTR_ERR(reset) == -ENOTSUPP)
>> -               reset = NULL;
>> -       else if (IS_ERR(reset))
>> -               return PTR_ERR(reset);
>> +       if (IS_ERR(reset)) {
>> +               if (PTR_ERR(reset) == -ENOENT || PTR_ERR(reset) == -ENOSYS)
>> +                       reset = NULL;
>> +               else
>> +                       return PTR_ERR(reset);
>> +       }
>>
>>         mdiodev->reset_ctrl = reset;
>>
> 
> Adding Michal Simek to add some test comments.

This patch is causing access to bad area on Microblaze with axi ethernet
driver.

The issue is that origin patch was checking ENOTSUPP and new one is
using ENOSYS which completely changed kernel behavior.
And this is even not described in commit message.
I will send a patch to fix it and would be good to get it to v5.4.

Thanks,
Michal