Subject: Re: [PATCH] pxa168_eth: fix mdiobus_scan() error check

From: Sergei Shtylyov <[email-masked]>
Date: Sun, 1 May 2016 23:30:06 +0300

On 05/01/2016 11:25 PM, Sergei Shtylyov wrote:

>>> Since mdiobus_scan() returns either an error code or NULL on error, the
>>> driver should check  for both,  not only for NULL, otherwise a crash is
>>> imminent...
>>>
>>> Reported-by: Arnd Bergmann <[email-masked]>
>>> Signed-off-by: Sergei Shtylyov <[email-masked]>
>>>
>>> ---
>>> The patch is against DaveM's 'net.git' repo.
>>>
>>>   drivers/net/ethernet/marvell/pxa168_eth.c |    2 ++
>>>   1 file changed, 2 insertions(+)
>>>
>>> Index: net/drivers/net/ethernet/marvell/pxa168_eth.c
>>> ===================================================================
>>> --- net.orig/drivers/net/ethernet/marvell/pxa168_eth.c
>>> +++ net/drivers/net/ethernet/marvell/pxa168_eth.c
>>> @@ -979,6 +979,8 @@ static int pxa168_init_phy(struct net_de
>>>           return 0;
>>>
>>>       pep->phy = mdiobus_scan(pep->smi_bus, pep->phy_addr);
>>> +    if (IS_ERR(pep->phy))
>>> +        return PTR_ERR(pep->phy);
>>>       if (!pep->phy)
>>>           return -ENODEV;
>>
>> Should not this check be removed too and
>
>     That's my next move -- for now I'm fixing the existing bug in this driver
> only.

    In fact, it can't be removed yet as mdiobus_scan() may return NULL on 
other error path. There's certainly a space for improvements yet...
[...]

MBR, Sergei