Re: [PATCH v2 4/6] phy: core: Fix an OF node refcount leakage in _of_phy_get()

[Zijun Hu]

On 2024/10/29 21:47, Johan Hovold wrote:
> On Thu, Oct 24, 2024 at 10:39:29PM +0800, Zijun Hu wrote:
>> From: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
>>
>> It will leak refcount of OF node @args.np for _of_phy_get() not to
>> decrease refcount increased by previous of_parse_phandle_with_args()
>> when returns due to of_device_is_compatible() error.
>>
>> Fix by adding of_node_put() before the error return.
>>
>> Fixes: b7563e2796f8 ("phy: work around 'phys' references to usb-nop-xceiv devices")
>> Cc: stable@xxxxxxxxxxxxxxx
>> Signed-off-by: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
>> ---
>>  drivers/phy/phy-core.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
>> index 52ca590a58b9..967878b78797 100644
>> --- a/drivers/phy/phy-core.c
>> +++ b/drivers/phy/phy-core.c
>> @@ -629,8 +629,11 @@ static struct phy *_of_phy_get(struct device_node *np, int index)
>>  		return ERR_PTR(-ENODEV);
>>  
>>  	/* This phy type handled by the usb-phy subsystem for now */
>> -	if (of_device_is_compatible(args.np, "usb-nop-xceiv"))
>> +	if (of_device_is_compatible(args.np, "usb-nop-xceiv")) {
>> +		/* Put refcount above of_parse_phandle_with_args() got */
> 
> No need for a comment as this is already handled in the later paths.
> 

will remove it within v3

>> +		of_node_put(args.np);
> 
> For that reason you should probably initialise ret and add a new label
> out_put_node that you jump to here instead.
> 

will try  to do it within v3.

>>  		return ERR_PTR(-ENODEV);
>> +	}
>>  
>>  	mutex_lock(&phy_provider_mutex);
>>  	phy_provider = of_phy_provider_lookup(args.np);
> 
> Johan