[PATCH v2] iio: adc: gyroadc: fix leak of device node iterator

[PATCH v2] iio: adc: gyroadc: fix leak of device node iterator

[Tobias Jordan]

Add missing of_node_put calls when exiting the for_each_child_of_node
loop in rcar_gyroadc_parse_subdevs early.

Also add goto-exception handling for the error paths in that loop.

Fixes: 059c53b32329 ("iio: adc: Add Renesas GyroADC driver")
Signed-off-by: Tobias Jordan <kernel@cdqe.de>
---
v2:
- added an of_node_put to the non-error "break" at the end
- used gotos for the error cases, doesn't look as bad as I thought

 drivers/iio/adc/rcar-gyroadc.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/adc/rcar-gyroadc.c b/drivers/iio/adc/rcar-gyroadc.c
index dcaefc108ff6..9f38cf3c7dc2 100644
--- a/drivers/iio/adc/rcar-gyroadc.c
+++ b/drivers/iio/adc/rcar-gyroadc.c
@@ -357,7 +357,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_3);
 			break;
 		default:
-			return -EINVAL;
+			goto err_e_inval;
 		}
 
 		/*
@@ -374,7 +374,7 @@ 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);
-				return ret;
+				goto err_of_node_put;
 			}
 
 			/* Channel number is too high. */
@@ -382,7 +382,7 @@ 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);
-				return -EINVAL;
+				goto err_e_inval;
 			}
 		}
 
@@ -391,7 +391,7 @@ 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);
-			return -EINVAL;
+			goto err_e_inval;
 		}
 
 		/* Channel is valid, grab the regulator. */
@@ -401,7 +401,8 @@ 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);
-			return PTR_ERR(vref);
+			ret = PTR_ERR(vref);
+			goto err_of_node_put;
 		}
 
 		priv->vref[reg] = vref;
@@ -425,8 +426,10 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 		 * attached to the GyroADC at a time, so if we found it,
 		 * we can stop parsing here.
 		 */
-		if (childmode == RCAR_GYROADC_MODE_SELECT_1_MB88101A)
+		if (childmode == RCAR_GYROADC_MODE_SELECT_1_MB88101A) {
+			of_node_put(child);
 			break;
+		}
 	}
 
 	if (first) {
@@ -435,6 +438,12 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
 	}
 
 	return 0;
+
+err_e_inval:
+	ret = -EINVAL;
+err_of_node_put:
+	of_node_put(child);
+	return ret;
 }
 
 static void rcar_gyroadc_deinit_supplies(struct iio_dev *indio_dev)
-- 
2.20.1

Re: [PATCH v2] iio: adc: gyroadc: fix leak of device node iterator

[Jonathan Cameron]

On Sat, 26 Sep 2020 18:19:46 +0200
Tobias Jordan <kernel@cdqe.de> wrote:

> Add missing of_node_put calls when exiting the for_each_child_of_node
> loop in rcar_gyroadc_parse_subdevs early.
> 
> Also add goto-exception handling for the error paths in that loop.
> 
> Fixes: 059c53b32329 ("iio: adc: Add Renesas GyroADC driver")
> Signed-off-by: Tobias Jordan <kernel@cdqe.de>
> ---
> v2:
> - added an of_node_put to the non-error "break" at the end
> - used gotos for the error cases, doesn't look as bad as I thought
Was marginal, so I'll go with it.

Applied to the fixes-togreg branch of iio.git and marked for stable.
> 
>  drivers/iio/adc/rcar-gyroadc.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/adc/rcar-gyroadc.c b/drivers/iio/adc/rcar-gyroadc.c
> index dcaefc108ff6..9f38cf3c7dc2 100644
> --- a/drivers/iio/adc/rcar-gyroadc.c
> +++ b/drivers/iio/adc/rcar-gyroadc.c
> @@ -357,7 +357,7 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
>  			num_channels = ARRAY_SIZE(rcar_gyroadc_iio_channels_3);
>  			break;
>  		default:
> -			return -EINVAL;
> +			goto err_e_inval;
>  		}
>  
>  		/*
> @@ -374,7 +374,7 @@ 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);
> -				return ret;
> +				goto err_of_node_put;
>  			}
>  
>  			/* Channel number is too high. */
> @@ -382,7 +382,7 @@ 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);
> -				return -EINVAL;
> +				goto err_e_inval;
>  			}
>  		}
>  
> @@ -391,7 +391,7 @@ 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);
> -			return -EINVAL;
> +			goto err_e_inval;
>  		}
>  
>  		/* Channel is valid, grab the regulator. */
> @@ -401,7 +401,8 @@ 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);
> -			return PTR_ERR(vref);
> +			ret = PTR_ERR(vref);
> +			goto err_of_node_put;
>  		}
>  
>  		priv->vref[reg] = vref;
> @@ -425,8 +426,10 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
>  		 * attached to the GyroADC at a time, so if we found it,
>  		 * we can stop parsing here.
>  		 */
> -		if (childmode == RCAR_GYROADC_MODE_SELECT_1_MB88101A)
> +		if (childmode == RCAR_GYROADC_MODE_SELECT_1_MB88101A) {
> +			of_node_put(child);
>  			break;
> +		}
>  	}
>  
>  	if (first) {
> @@ -435,6 +438,12 @@ static int rcar_gyroadc_parse_subdevs(struct iio_dev *indio_dev)
>  	}
>  
>  	return 0;
> +
> +err_e_inval:
> +	ret = -EINVAL;
> +err_of_node_put:
> +	of_node_put(child);
> +	return ret;
>  }
>  
>  static void rcar_gyroadc_deinit_supplies(struct iio_dev *indio_dev)