linux-kernel - Re: [PATCH] usb: typec: ucsi: glink: fix child node release in probe function

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Date: Mon, 17 Jun 2024 17:41:32 +0300
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Javier Carrasco <javier.carrasco.cruz@...il.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: Re: [PATCH] usb: typec: ucsi: glink: fix child node release in probe
 function

On Thu, Jun 13, 2024 at 02:14:48PM +0200, Javier Carrasco wrote:
> The device_for_each_child_node() macro requires explicit calls to
> fwnode_handle_put() in all early exits of the loop if the child node is
> not required outside. Otherwise, the child node's refcount is not
> decremented and the resource is not released.
> 
> The current implementation of pmic_glink_ucsi_probe() makes use of the
> device_for_each_child_node(), but does not release the child node on
> early returns. Add the missing calls to fwnode_handle_put().
> 
> Cc: stable@...r.kernel.org
> Fixes: c6165ed2f425 ("usb: ucsi: glink: use the connector orientation GPIO to provide switch events")
> Signed-off-by: Javier Carrasco <javier.carrasco.cruz@...il.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> ---
> This case would be a great opportunity for the recently introduced
> device_for_each_child_node_scoped(), but given that it has not been
> released yet, the traditional approach has been used to account for
> stable kernels (bug introduced with v6.7). A second patch to clean
> this up with that macro is ready to be sent once this fix is applied,
> so this kind of problem does not arise if more early returns are added.
> 
> This issue has been found while analyzing the code and not tested with
> hardware, only compiled and checked with static analysis tools. Any
> tests with real hardware are always welcome.
> ---
>  drivers/usb/typec/ucsi/ucsi_glink.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c
> index f7546bb488c3..41375e0f9280 100644
> --- a/drivers/usb/typec/ucsi/ucsi_glink.c
> +++ b/drivers/usb/typec/ucsi/ucsi_glink.c
> @@ -372,6 +372,7 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
>  		ret = fwnode_property_read_u32(fwnode, "reg", &port);
>  		if (ret < 0) {
>  			dev_err(dev, "missing reg property of %pOFn\n", fwnode);
> +			fwnode_handle_put(fwnode);
>  			return ret;
>  		}
>  
> @@ -386,9 +387,11 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev,
>  		if (!desc)
>  			continue;
>  
> -		if (IS_ERR(desc))
> +		if (IS_ERR(desc)) {
> +			fwnode_handle_put(fwnode);
>  			return dev_err_probe(dev, PTR_ERR(desc),
>  					     "unable to acquire orientation gpio\n");
> +		}
>  		ucsi->port_orientation[port] = desc;
>  	}
>  
> 
> ---
> base-commit: 83a7eefedc9b56fe7bfeff13b6c7356688ffa670
> change-id: 20240613-ucsi-glink-release-node-9fc09d81e138
> 
> Best regards,
> -- 
> Javier Carrasco <javier.carrasco.cruz@...il.com>

-- 
heikki