netdev - Re: [PATCH net v2 1/3] net: phy: Fix PHY module checks

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Message-ID: <34e621b5-9fb7-aad5-126f-291b52af30be@gmail.com>
Date:   Wed, 8 Feb 2017 09:46:27 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     maowenan <maowenan@...wei.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Cc:     "davem@...emloft.net" <davem@...emloft.net>,
        "andrew@...n.ch" <andrew@...n.ch>,
        "rmk+kernel@...linux.org.uk" <rmk+kernel@...linux.org.uk>
Subject: Re: [PATCH net v2 1/3] net: phy: Fix PHY module checks

On 02/07/2017 11:57 PM, maowenan wrote:
> 
> 
>> -----Original Message-----
>> From: Florian Fainelli [mailto:f.fainelli@...il.com]
>> Sent: Wednesday, February 08, 2017 3:38 PM
>> To: netdev@...r.kernel.org
>> Cc: davem@...emloft.net; andrew@...n.ch; rmk+kernel@...linux.org.uk;
>> maowenan; Florian Fainelli
>> Subject: [PATCH net v2 1/3] net: phy: Fix PHY module checks
>>
>> The Generic PHY drivers gets assigned after we checked that the current PHY
>> driver is NULL, so we need to check a few things before we can safely
>> derference d->driver. Update phy_attach_direct() and phy_detach() accordingly
>> to be resilient to these cases.
>>
>> Even though the Generic PHY driver defaults to phy_probe() which can hardly
>> fail at the moment, let's fix the label so we don't call phy_detach() on a network
>> device we have not attached yet.
>>
>> Fixes: cafe8df8b9bc ("net: phy: Fix lack of reference count on PHY driver")
>> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
>> ---
>>  drivers/net/phy/phy_device.c | 8 +++++---
>>  1 file changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index
>> 0d8f4d3847f6..bde240bf8d7b 100644
>> --- a/drivers/net/phy/phy_device.c
>> +++ b/drivers/net/phy/phy_device.c
>> @@ -920,7 +920,7 @@ int phy_attach_direct(struct net_device *dev, struct
>> phy_device *phydev,
>>  		return -EIO;
>>  	}
>>
>> -	if (!try_module_get(d->driver->owner)) {
>> +	if (d->driver && !try_module_get(d->driver->owner)) {
>>  		dev_err(&dev->dev, "failed to get the device driver module\n");
>>  		return -EIO;
> 
> Hi Florian,
>   Here "return -EIO" will miss decreasing bus->owner reference count.

Good catch thanks!

-- 
Florian