Re: [PATCH v3] thermal/drivers/rcar: fix error checking in probe()

[Niklas Söderlund]

Hi Dan,

Thanks for your work.

On 2026-06-26 13:38:22 +0300, Dan Carpenter wrote:
> This code accidentally calls thermal_zone_device_enable() before checking
> whether thermal_zone_device_register_with_trips() failed.  Move the call
> until later to avoid an error pointer dereference of "priv->zone".
> 
> The driver works differently depending on if we are using OF thermal or
> not.  We use thermal_add_hwmon_sysfs() if we are using OF thermal and
> call thermal_zone_device_enable() if not.  We can share same error check
> for if either of these fail.
> 
> Moving the thermal_zone_device_enable() call is a bit cleaner as well.
> The original code used a three step process to cleanup:
> 1. Call thermal_zone_device_unregister() to cleanup.
> 2. Set priv->zone to an error pointer to preserve the error code.
> 3. Set priv->zone to NULL to avoid a second call to
>    thermal_zone_device_unregister() in the rcar_thermal_remove()
>    function.
> 
> Now we can just do a direct goto error_unregister and rcar_thermal_remove()
> handles the cleanup properly.
> 
> Fixes: bbcf90c0646a ("thermal: Explicitly enable non-changing thermal zone devices")
> Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>

> ---
> v2: Use the correct fixes tag and re-write the check in a cleaner way.
> v3: Share the same error checking as a further cleanup.  The
>     thermal_add_hwmon_sysfs() and thermal_zone_device_enable() functions
>     really do serve the same purpose even though their names are
>     different.
> 
>  drivers/thermal/renesas/rcar_thermal.c | 15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/thermal/renesas/rcar_thermal.c b/drivers/thermal/renesas/rcar_thermal.c
> index 6e5dcac5d47a..fd686da9252e 100644
> --- a/drivers/thermal/renesas/rcar_thermal.c
> +++ b/drivers/thermal/renesas/rcar_thermal.c
> @@ -492,12 +492,6 @@ static int rcar_thermal_probe(struct platform_device *pdev)
>  				"rcar_thermal", trips, ARRAY_SIZE(trips), priv,
>  						&rcar_thermal_zone_ops, NULL, 0,
>  						idle);
> -
> -			ret = thermal_zone_device_enable(priv->zone);
> -			if (ret) {
> -				thermal_zone_device_unregister(priv->zone);
> -				priv->zone = ERR_PTR(ret);
> -			}
>  		}
>  		if (IS_ERR(priv->zone)) {
>  			dev_err(dev, "can't register thermal zone\n");
> @@ -506,11 +500,12 @@ static int rcar_thermal_probe(struct platform_device *pdev)
>  			goto error_unregister;
>  		}
>  
> -		if (chip->use_of_thermal) {
> +		if (chip->use_of_thermal)
>  			ret = thermal_add_hwmon_sysfs(priv->zone);
> -			if (ret)
> -				goto error_unregister;
> -		}
> +		else
> +			ret = thermal_zone_device_enable(priv->zone);
> +		if (ret)
> +			goto error_unregister;
>  
>  		rcar_thermal_irq_enable(priv);
>  
> -- 
> 2.53.0
> 

-- 
Kind Regards,
Niklas Söderlund