Re: [PATCH v2] usb: roles: fix of node refcount leak in usb_role_switch_is_parent()

["Chunfeng Yun (云春峰)" <Chunfeng.Yun@mediatek.com>]

On Sat, 2022-11-19 at 17:15 +0800, Yang Yingliang wrote:
> I got the following report while doing device(mt6370-tcpc) load
> test with CONFIG_OF_UNITTEST and CONFIG_OF_DYNAMIC enabled:
> 
>   OF: ERROR: memory leak, expected refcount 1 instead of 2,
>   of_node_get()/of_node_put() unbalanced - destroy cset entry:
>   attach overlay node /i2c/pmic@34
> 
> The 'parent' returned by fwnode_get_parent() with refcount
> incremented.
> it needs be put after using.
> 
> Fixes: 6fadd72943b8 ("usb: roles: get usb-role-switch from parent")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
> v1 -> v2:
>   Add description to how is the report generated.
> ---
>  drivers/usb/roles/class.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> index dfaed7eee94f..289950e5fcfb 100644
> --- a/drivers/usb/roles/class.c
> +++ b/drivers/usb/roles/class.c
> @@ -106,10 +106,14 @@ usb_role_switch_is_parent(struct fwnode_handle
> *fwnode)
>  	struct fwnode_handle *parent = fwnode_get_parent(fwnode);
>  	struct device *dev;
>  
> -	if (!parent || !fwnode_property_present(parent, "usb-role-
> switch"))
> +	if (!parent || !fwnode_property_present(parent, "usb-role-
> switch")) {
> +		if (parent)
> +			fwnode_handle_put(parent);
>  		return NULL;
> +	}
>  
>  	dev = class_find_device_by_fwnode(role_class, parent);
> +	fwnode_handle_put(parent);
>  	return dev ? to_role_switch(dev) : ERR_PTR(-EPROBE_DEFER);
>  }
>  
+ Heikki