[PATCH master 1/2] regulator: handle regulator_get_voltage(NULL) gracefully

[Sascha Hauer]

On Mon, Jul 18, 2022 at 01:48:23PM +0200, Ahmad Fatoum wrote:
> Unlike recent versions of Linux, barebox represents the dummy regulator
> as a NULL pointer and regulator API is supposed to anticipate operation
> on a NULL pointer. When regulator_get_voltage was ported from Linux,
> this was not taken into consideration, which leads to
> regulator_get_voltage(NULL) crashing with a NULL pointer dereference.
> 
> Fix this by returning -EINVAL for dummy regulators. This aligns us with
> how Linux would behave in this situation.
> 
> Fixes: 6ee83ce08b24 ("regulator: add regulator_get_voltage() to API")
> Reported-by: Johannes Zink <j.zink at pengutronix.de>
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
>  drivers/regulator/core.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)

Applied, thanks

Sascha

> 
> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
> index 1fb344656f38..472b26f3a0ac 100644
> --- a/drivers/regulator/core.c
> +++ b/drivers/regulator/core.c
> @@ -574,9 +574,14 @@ EXPORT_SYMBOL_GPL(regulator_bulk_free);
>  
>  int regulator_get_voltage(struct regulator *regulator)
>  {
> -	struct regulator_dev *rdev = regulator->ri->rdev;
> +	struct regulator_dev *rdev;
>  	int sel, ret;
>  
> +	if (!regulator)
> +		return -EINVAL;
> +
> +	rdev = regulator->ri->rdev;
> +
>  	if (rdev->desc->ops->get_voltage_sel) {
>  		sel = rdev->desc->ops->get_voltage_sel(rdev);
>  		if (sel < 0)
> -- 
> 2.30.2
> 
> 
> 

-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |