Re: [PATCH v2] thermal/drivers/rcar: fix error checking in probe()

[Geert Uytterhoeven]

Hi Dan,

On Wed, 24 Jun 2026 at 15:03, Dan Carpenter <error27@xxxxxxxxx> 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.
>
> 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>
> ---
> v2: Use the correct fixes tag and re-write the check in a cleaner way.

Thanks for the update!

Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

> --- a/drivers/thermal/renesas/rcar_thermal.c
> +++ b/drivers/thermal/renesas/rcar_thermal.c

> @@ -510,6 +504,10 @@ static int rcar_thermal_probe(struct platform_device *pdev)
>                         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;

This error path is the same in the other branch, so it could be shared
after the if/else block.

>                 }
>
>                 rcar_thermal_irq_enable(priv);


Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds