Hi Yizhuo,
thank you for this patch
On Sun, Sep 29, 2019 at 6:48 PM Yizhuo <yzhai003@xxxxxxx> wrote:
>
> Several functions in this file are trying to use regmap_read() to
> initialize the specific variable, however, if regmap_read() fails,
> the variable could be uninitialized but used directly, which is
> potentially unsafe. The return value of regmap_read() should be
> checked and handled.
the meson_saradc driver is using a MMIO regmap so read failures are
unlikely (unless there's a bug in the code somewhere)
did you find these issues with some static code analysis tool or did
you experience a real world problem?
> Signed-off-by: Yizhuo <yzhai003@xxxxxxx>
> ---
> drivers/iio/adc/meson_saradc.c | 30 ++++++++++++++++++++++++------
> 1 file changed, 24 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/adc/meson_saradc.c b/drivers/iio/adc/meson_saradc.c
> index 7b28d045d271..4b6c2983ef39 100644
> --- a/drivers/iio/adc/meson_saradc.c
> +++ b/drivers/iio/adc/meson_saradc.c
> @@ -323,6 +323,7 @@ static int meson_sar_adc_wait_busy_clear(struct iio_dev *indio_dev)
> {
> struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> int regval, timeout = 10000;
> + int ret;
why not add "ret" to the variables in the line above?
so this could be shortened to (which is also consistent with the
coding style in meson_saradc):
int ret, regval, timeout = 10000;
> @@ -506,7 +514,10 @@ static int meson_sar_adc_lock(struct iio_dev *indio_dev)
> */
> do {
> udelay(1);
> - regmap_read(priv->regmap, MESON_SAR_ADC_DELAY, &val);
> + ret = regmap_read(priv->regmap,
> + MESON_SAR_ADC_DELAY, &val);
> + if (ret)
> + return ret;
this is a big problem because we're returning with &indio_dev->mlock held
see the "timeout < 0" block below
> @@ -771,7 +782,7 @@ static int meson_sar_adc_init(struct iio_dev *indio_dev)
> {
> struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> int regval, i, ret;
> -
> + int ret;
this removes an empty line between the variable declarations and the
first code (comment)
also "ret" is already defined in the line before
(I haven't compile-tested this myself yet but I'm surprised that this
doesn't give an error or at least a warning)
> @@ -1013,8 +1027,12 @@ static irqreturn_t meson_sar_adc_irq(int irq, void *data)
> struct meson_sar_adc_priv *priv = iio_priv(indio_dev);
> unsigned int cnt, threshold;
> u32 regval;
> + int ret;
> +
> + ret = regmap_read(priv->regmap, MESON_SAR_ADC_REG0, ®val);
> + if (ret)
> + return ret;
this function doesn't return "int" but irqreturn_t
the only allowed values are: [0]
Martin
[0] https://elixir.bootlin.com/linux/v5.3/source/include/linux/irqreturn.h#L11
