Am Dienstag, dem 22.02.2022 um 10:42 +0800 schrieb haibo.chen@xxxxxxx:
> From: Haibo Chen <haibo.chen@xxxxxxx>
>
> The original logic to get mma8452_data is wrong, the *dev point to
> the device belong to iio_dev. we can't use this dev to find the
> correct i2c_client. The original logic happen to work because it
> finally use dev->driver_data to get iio_dev. Here use the API
> to_i2c_client() is wrong and make reader confuse. To correct the
> logic, it should be like this
>
> struct mma8452_data *data = iio_priv(dev_get_drvdata(dev));
>
> But after commit 8b7651f25962 ("iio: iio_device_alloc(): Remove
> unnecessary self drvdata"), the upper logic also can't work.
> When try to show the avialable scale in userspace, will meet kernel
> dump, kernel handle NULL pointer dereference.
>
> So use dev_to_iio_dev() to correct the logic.
>
> Fixes: c3cdd6e48e35 ("iio: mma8452: refactor for seperating chip
> specific data")
> Cc: <Stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx>
Reviewed-by: Martin Kepplinger <martink@xxxxxxxxx>
thank you for this fix!
> ---
> drivers/iio/accel/mma8452.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/accel/mma8452.c
> b/drivers/iio/accel/mma8452.c
> index 64b82b4503ad..0016bb947c10 100644
> --- a/drivers/iio/accel/mma8452.c
> +++ b/drivers/iio/accel/mma8452.c
> @@ -379,8 +379,8 @@ static ssize_t mma8452_show_scale_avail(struct
> device *dev,
> struct device_attribute
> *attr,
> char *buf)
> {
> - struct mma8452_data *data = iio_priv(i2c_get_clientdata(
> - to_i2c_client(dev)));
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct mma8452_data *data = iio_priv(indio_dev);
>
> return mma8452_show_int_plus_micros(buf, data->chip_info-
> >mma_scales,
> ARRAY_SIZE(data->chip_info->mma_scales));
