[1/3] gpio: of: Fix of_gpiochip_add() error path

If the call to of_gpiochip_scan_gpios() in of_gpiochip_add() fails, no
error handling is performed.  This lead to the need of callers to call
of_gpiochip_remove() on failure, which causes "BAD of_node_put() on ..."
if the failure happened before the call to of_node_get().

Fix this by adding proper error handling.

Note that calling gpiochip_remove_pin_ranges() multiple times causes no
harm: subsequent calls are a no-op.

Fixes: dfbd379ba9b7431e ("gpio: of: Return error if gpio hog configuration failed")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/gpio/gpiolib-of.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

On 3/28/2019 6:43 PM, Geert Uytterhoeven wrote:
> If the call to of_gpiochip_scan_gpios() in of_gpiochip_add() fails, no
> error handling is performed.  This lead to the need of callers to call
> of_gpiochip_remove() on failure, which causes "BAD of_node_put() on ..."
> if the failure happened before the call to of_node_get().
>
> Fix this by adding proper error handling.
>
> Note that calling gpiochip_remove_pin_ranges() multiple times causes no
> harm: subsequent calls are a no-op.
>
> Fixes: dfbd379ba9b7431e ("gpio: of: Return error if gpio hog configuration failed")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>


Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>

-Mukesh

> ---
>   drivers/gpio/gpiolib-of.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
> index 8b9c3ab70f6eade4..257be7bac032a855 100644
> --- a/drivers/gpio/gpiolib-of.c
> +++ b/drivers/gpio/gpiolib-of.c
> @@ -717,7 +717,13 @@ int of_gpiochip_add(struct gpio_chip *chip)
>   
>   	of_node_get(chip->of_node);
>   
> -	return of_gpiochip_scan_gpios(chip);
> +	status = of_gpiochip_scan_gpios(chip);
> +	if (status) {
> +		of_node_put(chip->of_node);
> +		gpiochip_remove_pin_ranges(chip);
> +	}
> +
> +	return status;
>   }
>   
>   void of_gpiochip_remove(struct gpio_chip *chip)

On Thu, Mar 28, 2019 at 2:13 PM Geert Uytterhoeven
<geert+renesas@glider.be> wrote:

> If the call to of_gpiochip_scan_gpios() in of_gpiochip_add() fails, no
> error handling is performed.  This lead to the need of callers to call
> of_gpiochip_remove() on failure, which causes "BAD of_node_put() on ..."
> if the failure happened before the call to of_node_get().
>
> Fix this by adding proper error handling.
>
> Note that calling gpiochip_remove_pin_ranges() multiple times causes no
> harm: subsequent calls are a no-op.
>
> Fixes: dfbd379ba9b7431e ("gpio: of: Return error if gpio hog configuration failed")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Patch applied.

Yours,
Linus Walleij