> From: Marek Vasut <marex@xxxxxxx>
> Sent: Monday, March 28, 2022 9:53 PM
> To: linux-iio@xxxxxxxxxxxxxxx
> Cc: Marek Vasut <marex@xxxxxxx>; Andy Shevchenko
> <andy@xxxxxxxxxx>; Daniel Baluta <daniel.baluta@xxxxxxx>;
> Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> Subject: [PATCH v3] iio: core: Print error in case sample bits do not fit
> storage bits
>
> [External]
>
> Add runtime check to verify whether storagebits are at least as big
> as shifted realbits. This should help spot broken drivers which may
> set realbits + shift above storagebits.
>
> Signed-off-by: Marek Vasut <marex@xxxxxxx>
> Cc: Andy Shevchenko <andy@xxxxxxxxxx>
> Cc: Daniel Baluta <daniel.baluta@xxxxxxx>
> Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> ---
> V2: Use dev_err() instead as WARN_ON() may panic() the kernel on
> existing machines
> V3: Abort probe and return -EINVAL in case this condition is triggered
> ---
Reviewed-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
> drivers/iio/industrialio-buffer.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-
> buffer.c
> index b078eb2f3c9de..75a1c57b49102 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -1629,6 +1629,19 @@ static int
> __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
> if (channels[i].scan_index < 0)
> continue;
>
> + /* Verify that sample bits fit into storage */
> + if (channels[i].scan_type.storagebits <
> + channels[i].scan_type.realbits +
> + channels[i].scan_type.shift) {
> + dev_err(&indio_dev->dev,
> + "Channel %d storagebits (%d) <
> shifted realbits (%d + %d)\n",
> + i,
> channels[i].scan_type.storagebits,
> + channels[i].scan_type.realbits,
> + channels[i].scan_type.shift);
> + ret = -EINVAL;
> + goto error_cleanup_dynamic;
> + }
> +
> ret = iio_buffer_add_channel_sysfs(indio_dev,
> buffer,
> &channels[i]);
> if (ret < 0)
> --
> 2.35.1
