On Wed, 22 Jul 2020 16:50:37 +0100
Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
>
> iio_push_to_buffers_with_timestamp assumes 8 byte alignment which
> is not guaranteed by an array of smaller elements.
>
> Note that whilst in this particular case the alignment forcing
> of the ts element is not strictly necessary it acts as good
> documentation. Doing this where not necessary should cut
> down on the number of cut and paste introduced errors elsewhere.
>
> Reported-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Applied to the fixes-togreg branch of iio.git and marked for stable.
Thanks,
Jonathan
> ---
> drivers/iio/accel/kxsd9.c | 16 +++++++++++-----
> 1 file changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/iio/accel/kxsd9.c b/drivers/iio/accel/kxsd9.c
> index 66b2e4cf24cf..0e18b92e2099 100644
> --- a/drivers/iio/accel/kxsd9.c
> +++ b/drivers/iio/accel/kxsd9.c
> @@ -209,14 +209,20 @@ static irqreturn_t kxsd9_trigger_handler(int irq, void *p)
> const struct iio_poll_func *pf = p;
> struct iio_dev *indio_dev = pf->indio_dev;
> struct kxsd9_state *st = iio_priv(indio_dev);
> + /*
> + * Ensure correct positioning and alignment of timestamp.
> + * No need to zero initialize as all elements written.
> + */
> + struct {
> + __be16 chan[4];
> + s64 ts __aligned(8);
> + } hw_values;
> int ret;
> - /* 4 * 16bit values AND timestamp */
> - __be16 hw_values[8];
>
> ret = regmap_bulk_read(st->map,
> KXSD9_REG_X,
> - &hw_values,
> - 8);
> + hw_values.chan,
> + sizeof(hw_values.chan));
> if (ret) {
> dev_err(st->dev,
> "error reading data\n");
> @@ -224,7 +230,7 @@ static irqreturn_t kxsd9_trigger_handler(int irq, void *p)
> }
>
> iio_push_to_buffers_with_timestamp(indio_dev,
> - hw_values,
> + &hw_values,
> iio_get_time_ns(indio_dev));
> iio_trigger_notify_done(indio_dev->trig);
>
