[PATCH] iio: adc: meson-saradc: fix calibration buffer leak on error

[Rosen Penev]

On Sat, Apr 25, 2026 at 9:07 AM Felix Gu <ustc.gu at gmail.com> wrote:
>
> meson_sar_adc_temp_sensor_init() allocates a buffer with
> nvmem_cell_read(), but the old code leaked it if
> syscon_regmap_lookup_by_phandle() failed.
>
> Switch buf to __free(kfree) so all return paths release it.
>
> Fixes: d6f2eac64403 ("iio: adc: meson: no devm for nvmem_cell_get")
> Signed-off-by: Felix Gu <ustc.gu at gmail.com>
> ---
>  drivers/iio/adc/meson_saradc.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
> index 23991a3612bd..9708ddcc4919 100644
> --- a/drivers/iio/adc/meson_saradc.c
> +++ b/drivers/iio/adc/meson_saradc.c
> @@ -786,7 +786,7 @@ static int meson_sar_adc_clk_init(struct iio_dev *indio_dev,
>  static int meson_sar_adc_temp_sensor_init(struct iio_dev *indio_dev)
>  {
>         struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> -       u8 *buf, trimming_bits, trimming_mask, upper_adc_val;
> +       u8 trimming_bits, trimming_mask, upper_adc_val;
>         struct device *dev = indio_dev->dev.parent;
>         struct nvmem_cell *temperature_calib;
>         size_t read_len;
> @@ -807,14 +807,12 @@ static int meson_sar_adc_temp_sensor_init(struct iio_dev *indio_dev)
>         }
>
>         read_len = MESON_SAR_ADC_EFUSE_BYTES;
> -       buf = nvmem_cell_read(temperature_calib, &read_len);
> +       u8 *buf __free(kfree) = nvmem_cell_read(temperature_calib, &read_len);
>         nvmem_cell_put(temperature_calib);
>         if (IS_ERR(buf))
>                 return dev_err_probe(dev, PTR_ERR(buf), "failed to read temperature_calib cell\n");
> -       if (read_len != MESON_SAR_ADC_EFUSE_BYTES) {
> -               kfree(buf);
I don't like this. Just add the missing kfree.
> +       if (read_len != MESON_SAR_ADC_EFUSE_BYTES)
>                 return dev_err_probe(dev, -EINVAL, "invalid read size of temperature_calib cell\n");
> -       }
>
>         priv->tsc_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "amlogic,hhi-sysctrl");
>         if (IS_ERR(priv->tsc_regmap))
> @@ -835,8 +833,6 @@ static int meson_sar_adc_temp_sensor_init(struct iio_dev *indio_dev)
>         priv->temperature_sensor_adc_val |= upper_adc_val << BITS_PER_BYTE;
>         priv->temperature_sensor_adc_val >>= trimming_bits;
>
> -       kfree(buf);
> -
>         return 0;
>  }
>
>
> ---
> base-commit: 7080e32d3f09d8688c4a87d81bdcc71f7f606b16
> change-id: 20260425-meson_saradc-54abc52d9b31
>
> Best regards,
> --
> Felix Gu <ustc.gu at gmail.com>
>