Re: [PATCH v1] usb: typec: Fix arg check for usb_power_delivery_unregister_capabilities

[Dmitry Baryshkov]

On Thu, Sep 19, 2024 at 12:58:12AM GMT, Amit Sunil Dhamne wrote:
> usb_power_delivery_register_capabilities() returns ERR_PTR in case of
> failure. usb_power_delivery_unregister_capabilities() we only check
> argument ("cap") for NULL. A more robust check would be checking for
> ERR_PTR as well.

No. The calling drivers are not supposed to pass ERR_PTR to
usb_power_delivery_unregister_capabilities(). If you check the TCPM and
UCSI driver code, they check return value of the register function
before saving it internally.

> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 662a60102c12 ("usb: typec: Separate USB Power Delivery from USB Type-C")
> Signed-off-by: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
> Reviewed-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
> ---
>  drivers/usb/typec/pd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/pd.c b/drivers/usb/typec/pd.c
> index d78c04a421bc..761fe4dddf1b 100644
> --- a/drivers/usb/typec/pd.c
> +++ b/drivers/usb/typec/pd.c
> @@ -519,7 +519,7 @@ EXPORT_SYMBOL_GPL(usb_power_delivery_register_capabilities);
>   */
>  void usb_power_delivery_unregister_capabilities(struct usb_power_delivery_capabilities *cap)
>  {
> -	if (!cap)
> +	if (IS_ERR_OR_NULL(cap))
>  		return;
>  
>  	device_for_each_child(&cap->dev, NULL, remove_pdo);
> 
> base-commit: 68d4209158f43a558c5553ea95ab0c8975eab18c
> -- 
> 2.46.0.792.g87dc391469-goog
> 

-- 
With best wishes
Dmitry