[PATCH] iio: adc: gyroadc: fix leak of device node iterator

[PATCH] iio: adc: gyroadc: fix leak of device node iterator

[Tobias Jordan]

Add missing of_node_put calls for the error paths of the
for_each_child_of_node loop in rcar_gyroadc_parse_subdevs.

Thought about adding an "goto err_of_node_put" instead, but as the error
paths are quite divergent, I'm not sure if that wouldn't complicate
things.

Fixes: 059c53b32329 ("iio: adc: Add Renesas GyroADC driver")
Signed-off-by: Tobias Jordan <kernel@cdqe.de>
---
 drivers/iio/adc/rcar-gyroadc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/iio/adc/rcar-gyroadc.c b/drivers/iio/adc/rcar-gyroadc.c
index dcaefc108ff6..3746b0276b80 100644
--- a/drivers/iio/adc/rcar-gyroadc.c
+++ b/drivers/iio/adc/rcar-gyroadc.c
@@ -357,6 +357,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_3);
 			break;
 		default:
+			of_node_put(child);
 			return -EINVAL;
 		}
 
@@ -374,6 +375,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 				dev_err(dev,
 					"Failed to get child reg property of ADC \"%pOFn\".\n",
 					child);
+				of_node_put(child);
 				return ret;
 			}
 
@@ -382,6 +384,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 				dev_err(dev,
 					"Only %i channels supported with %pOFn, but reg = <%i>.\n",
 					num_channels, child, reg);
+				of_node_put(child);
 				return -EINVAL;
 			}
 		}
@@ -391,6 +394,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 			dev_err(dev,
 				"Channel %i uses different ADC mode than the rest.\n",
 				reg);
+			of_node_put(child);
 			return -EINVAL;
 		}
 
@@ -401,6 +405,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 		if (IS_ERR(vref)) {
 			dev_dbg(dev, "Channel %i 'vref' supply not connected.\n",
 				reg);
+			of_node_put(child);
 			return PTR_ERR(vref);
 		}
 
-- 
2.20.1

Re: [PATCH] iio: adc: gyroadc: fix leak of device node iterator

[Jonathan Cameron]

On Sat, 26 Sep 2020 12:45:15 +0200
Tobias Jordan <kernel@cdqe.de> wrote:

> Add missing of_node_put calls for the error paths of the
> for_each_child_of_node loop in rcar_gyroadc_parse_subdevs.
> 
> Thought about adding an "goto err_of_node_put" instead, but as the error
> paths are quite divergent, I'm not sure if that wouldn't complicate
> things.
> 
> Fixes: 059c53b32329 ("iio: adc: Add Renesas GyroADC driver")
> Signed-off-by: Tobias Jordan <kernel@cdqe.de>
Looks to me like there is one more route out of the
for_each_child_of_node() that this doesn't cover.

		if (childmode == RCAR_GYROADC_MODE_SELECT_1_MB88101A)
			break;

If you agree, could you add an of_put_node() to that as well.
It's not an error path, but it does break out early.
Probably also want to modify the description of the patch a tiny
bit to match with that changing being in there as well.

Thanks,

Jonathan

> ---
>  drivers/iio/adc/rcar-gyroadc.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/iio/adc/rcar-gyroadc.c b/drivers/iio/adc/rcar-gyroadc.c
> index dcaefc108ff6..3746b0276b80 100644
> --- a/drivers/iio/adc/rcar-gyroadc.c
> +++ b/drivers/iio/adc/rcar-gyroadc.c
> @@ -357,6 +357,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
>  			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_3);
>  			break;
>  		default:
> +			of_node_put(child);
>  			return -EINVAL;
>  		}
>  
> @@ -374,6 +375,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
>  				dev_err(dev,
>  					"Failed to get child reg property of ADC \"%pOFn\".\n",
>  					child);
> +				of_node_put(child);
>  				return ret;
>  			}
>  
> @@ -382,6 +384,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
>  				dev_err(dev,
>  					"Only %i channels supported with %pOFn, but reg = <%i>.\n",
>  					num_channels, child, reg);
> +				of_node_put(child);
>  				return -EINVAL;
>  			}
>  		}
> @@ -391,6 +394,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
>  			dev_err(dev,
>  				"Channel %i uses different ADC mode than the rest.\n",
>  				reg);
> +			of_node_put(child);
>  			return -EINVAL;
>  		}
>  
> @@ -401,6 +405,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
>  		if (IS_ERR(vref)) {
>  			dev_dbg(dev, "Channel %i 'vref' supply not connected.\n",
>  				reg);
> +			of_node_put(child);
>  			return PTR_ERR(vref);
>  		}
>