Re: [PATCH] iio: imu: st_lsm6dsx: fix possible lockup during FIFO read

[Lorenzo Bianconi]

I guess you missed v2 here. Moreover, can you please proper Fixes tag?

Reply-To: 
In-Reply-To: <20250310132508.24660-2-s.seva@xxxxxxxxx>

> Prevent st_lsm6dsx_read_fifo and st_lsm6dsx_read_tagged_fifo functions
> from falling in an infinite loop in case pattern_len is equal to zero and
> the device FIFO is not empty.
> 
> Signed-off-by: Silvano Seva <s.seva@xxxxxxxxx>
> ---
>  drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> index 0a7cd8c1aa33..39a7e15ae9ae 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c
> @@ -392,9 +392,14 @@ int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
>  	if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK))
>  		return 0;
>  
> +	if (!pattern_len)
> +		pattern_len = ST_LSM6DSX_SAMPLE_SIZE;
> +
>  	fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
>  		   ST_LSM6DSX_CHAN_SIZE;
>  	fifo_len = (fifo_len / pattern_len) * pattern_len;
> +	if (!fifo_len)
> +		return 0;

this is not needed, please drop it.

Regards,
Lorenzo

>  
>  	acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
>  	gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]);
> @@ -623,6 +628,9 @@ int st_lsm6dsx_read_tagged_fifo(struct st_lsm6dsx_hw *hw)
>  	if (!fifo_len)
>  		return 0;
>  
> +	if (!pattern_len)
> +		pattern_len = ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
> +
>  	for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
>  		err = st_lsm6dsx_read_block(hw,
>  					    ST_LSM6DSX_REG_FIFO_OUT_TAG_ADDR,
> -- 
> 2.48.1
>

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