Re: [PATCH 2/3] thermal: of: Fix OF node leak in thermal_of_zone_register()

[Chen-Yu Tsai <wenst@chromium.org>]

On Wed, Aug 14, 2024 at 09:58:22PM +0200, Krzysztof Kozlowski wrote:
> thermal_of_zone_register() calls of_thermal_zone_find() which will
> iterate over OF nodes with for_each_available_child_of_node() to find
> matching thermal zone node.  When it finds such, it exits the loop and
> returns the node.  Prematurely ending for_each_available_child_of_node()
> loops requires dropping OF node reference, thus success of
> of_thermal_zone_find() means that caller must drop the reference.
> 
> Fixes: 3fd6d6e2b4e8 ("thermal/of: Rework the thermal device tree initialization")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>

> ---
>  drivers/thermal/thermal_of.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c
> index 30f8d6e70484..b08a9b64718d 100644
> --- a/drivers/thermal/thermal_of.c
> +++ b/drivers/thermal/thermal_of.c
> @@ -491,7 +491,8 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
>  	trips = thermal_of_trips_init(np, &ntrips);
>  	if (IS_ERR(trips)) {
>  		pr_err("Failed to find trip points for %pOFn id=%d\n", sensor, id);
> -		return ERR_CAST(trips);
> +		ret = PTR_ERR(trips);
> +		goto out_of_node_put;
>  	}
>  
>  	ret = thermal_of_monitor_init(np, &delay, &pdelay);
> @@ -519,6 +520,7 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
>  		goto out_kfree_trips;
>  	}
>  
> +	of_node_put(np);
>  	kfree(trips);
>  
>  	ret = thermal_zone_device_enable(tz);
> @@ -533,6 +535,8 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
>  
>  out_kfree_trips:
>  	kfree(trips);
> +out_of_node_put:
> +	of_node_put(np);
>  
>  	return ERR_PTR(ret);
>  }
> -- 
> 2.43.0
>