Re: [PATCH v2 1/6] phy: core: Fix that API devm_phy_put() fails to release the phy

[Zijun Hu]

On 2024/10/29 21:40, Johan Hovold wrote:
> On Thu, Oct 24, 2024 at 10:39:26PM +0800, Zijun Hu wrote:
>> From: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
>>
>> For devm_phy_put(), its comment says it needs to invoke phy_put() to
>> release the phy, but it does not invoke the function actually since
>> devres_destroy() will not call devm_phy_release() at all which will
>> call the function, and the missing phy_put() call will cause:
> 
> Please split the above up in at least two sentences to make it easier to
> parse. Split it after devm_phy_release() and rephrase the latter part
> (e.g. by dropping "at all which will call the function").
>  

thank you for code review.
will take your suggestions and send v2 (^^).

>> - The phy fails to be released.
>> - devm_phy_put() can not fully undo what API devm_phy_get() does.
>> - Leak refcount of both the module and device for below typical usage:
>>
>>   devm_phy_get(); // or its variant
>>   ...
>>   err = do_something();
>>   if (err)
>>       goto err_out;
>>   ...
>>   err_out:
>>   devm_phy_put();
>>
>>   The file(s) affected by this issue are shown below since they have such
>>   typical usage.
>>   drivers/pci/controller/cadence/pcie-cadence.c
>>   drivers/net/ethernet/ti/am65-cpsw-nuss.c
>>
>> Fixed by using devres_release() instead of devres_destroy() within the API
>>
>> Fixes: ff764963479a ("drivers: phy: add generic PHY framework")
>> Cc: stable@xxxxxxxxxxxxxxx
>> Cc: Lorenzo Pieralisi <lpieralisi@xxxxxxxxxx>
>> Cc: "Krzysztof Wilczyński" <kw@xxxxxxxxx>
>> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
>> Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
>> Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
>> Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
>> Signed-off-by: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
> 
> Diff itself looks good. Nice find.
> 
> Johan