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

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Date:   Sat, 26 Sep 2020 17:23:58 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Tobias Jordan <kernel@...e.de>
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        Marek Vasut <marek.vasut@...il.com>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>
Subject: Re: [PATCH v2] iio: adc: gyroadc: fix leak of device node iterator

On Sat, 26 Sep 2020 18:19:46 +0200
Tobias Jordan <kernel@...e.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@...e.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)