Re: [PATCH RFC] iio: irsd200: fix -Warray-bounds bug in irsd200_trigger_handler

["Gustavo A. R. Silva" <gustavoars@kernel.org>]

On Tue, Aug 08, 2023 at 04:37:19PM +0800, GONG, Ruiqi wrote:
> From: "GONG, Ruiqi" <gongruiqi1@huawei.com>
> 
> When compiling with gcc 13 with -Warray-bounds enabled:
> 
> In file included from drivers/iio/proximity/irsd200.c:15:
> In function ‘iio_push_to_buffers_with_timestamp’,
>     inlined from ‘irsd200_trigger_handler’ at drivers/iio/proximity/irsd200.c:770:2:
> ./include/linux/iio/buffer.h:42:46: error: array subscript ‘int64_t {aka long long int}[0]’
> is partly outside array bounds of ‘s16[1]’ {aka ‘short int[1]’} [-Werror=array-bounds=]
>    42 |                 ((int64_t *)data)[ts_offset] = timestamp;
>       |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
> drivers/iio/proximity/irsd200.c: In function ‘irsd200_trigger_handler’:
> drivers/iio/proximity/irsd200.c:763:13: note: object ‘buf’ of size 2
>   763 |         s16 buf = 0;
>       |             ^~~
> 
> The problem seems to be that irsd200_trigger_handler() is taking a s16
> variable as an int64_t buffer. Fix it by extending the buffer to 64 bits.

Thanks for working on this!

> 
> Link: https://github.com/KSPP/linux/issues/331
> Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>

Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>

--
Gustavo

> ---
> 
> RFC: It's a preliminary patch since I'm not familiar with this hardware.
> Further comments/reviews are needed about whether this fix is correct,
> or we should use iio_push_to_buffers() instead of the *_with_timestamp()
> version.
> 
>  drivers/iio/proximity/irsd200.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/proximity/irsd200.c b/drivers/iio/proximity/irsd200.c
> index 5bd791b46d98..34c479881bdf 100644
> --- a/drivers/iio/proximity/irsd200.c
> +++ b/drivers/iio/proximity/irsd200.c
> @@ -759,10 +759,10 @@ static irqreturn_t irsd200_trigger_handler(int irq, void *pollf)
>  {
>  	struct iio_dev *indio_dev = ((struct iio_poll_func *)pollf)->indio_dev;
>  	struct irsd200_data *data = iio_priv(indio_dev);
> -	s16 buf = 0;
> +	int64_t buf = 0;
>  	int ret;
>  
> -	ret = irsd200_read_data(data, &buf);
> +	ret = irsd200_read_data(data, (s16 *)&buf);
>  	if (ret)
>  		goto end;
>  
> -- 
> 2.41.0
>