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

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

[Dan Carpenter]

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@gmail.com>
---
v2: Use the correct fixes tag and re-write the check in a cleaner way.

 drivers/thermal/renesas/rcar_thermal.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/thermal/renesas/rcar_thermal.c b/drivers/thermal/renesas/rcar_thermal.c
index 6e5dcac5d47a..f8865b03ed23 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");
@@ -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;
 		}
 
 		rcar_thermal_irq_enable(priv);
-- 
2.53.0

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@gmail.com> 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@gmail.com>
> ---
> 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@glider.be>

> --- 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@linux-m68k.org

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

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

[Dan Carpenter]

On Wed, Jun 24, 2026 at 03:12:47PM +0200, Geert Uytterhoeven wrote:
> Hi Dan,
> 
> On Wed, 24 Jun 2026 at 15:03, Dan Carpenter <error27@gmail.com> 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@gmail.com>
> > ---
> > 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@glider.be>
> 
> > --- 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.
> 

Even better.  :)  v3 coming up.

regards,
dan carpenter