Re: [PATCH] media: omap3isp: fix out-of-range warning

Laurent Pinchart
2021-11-24T22:27:02Z

Hi Arnd,

Thank you for the patch.

On Wed, Nov 24, 2021 at 08:24:15PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> clang points out that the 8-bit height/width values never exceed
> the range of that type when building with 'make W=1 LLVM=1':
>
> drivers/media/platform/omap3isp/isph3a_af.c:173:6: error: result of comparison of constant 256 with expression of type '__u8' (aka 'unsigned char') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
> if (IS_OUT_OF_BOUNDS(paxel_cfg->height, OMAP3ISP_AF_PAXEL_HEIGHT_MIN,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/media/platform/omap3isp/isph3a_af.c:24:33: note: expanded from macro 'IS_OUT_OF_BOUNDS'
> (((value) < (min)) || ((value) > (max)))
> ~~~~~~~ ^ ~~~~~
> drivers/media/platform/omap3isp/isph3a_af.c:179:6: error: result of comparison of constant 256 with expression of type '__u8' (aka 'unsigned char') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
> if (IS_OUT_OF_BOUNDS(paxel_cfg->width, OMAP3ISP_AF_PAXEL_WIDTH_MIN,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/media/platform/omap3isp/isph3a_af.c:24:33: note: expanded from macro 'IS_OUT_OF_BOUNDS'
> (((value) < (min)) || ((value) > (max)))
> ~~~~~~~ ^ ~~~~~
>
> Add a cast to 32-bit to avoid the warning. Checking just the lower bounds
> would be sufficient as well, but it seems more consistent to use
> the IS_OUT_OF_BOUNDS() check for all members.

Mauro has submitted a fix that handles the cast in the
IS_OUT_OF_BOUNDS() macro, see
https://lore.kernel.org/all/b70f819b11e024649f113be1158f34b24914a1ed.1637573097.git.mchehab+huawei@kernel.org/.

> Fixes: 68e342b3068c ("[media] omap3isp: Statistics")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> drivers/media/platform/omap3isp/isph3a_af.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/platform/omap3isp/isph3a_af.c b/drivers/media/platform/omap3isp/isph3a_af.c
> index a65cfdfa9637..c544d9c812b0 100644
> --- a/drivers/media/platform/omap3isp/isph3a_af.c
> +++ b/drivers/media/platform/omap3isp/isph3a_af.c
> @@ -170,13 +170,13 @@ static int h3a_af_validate_params(struct ispstat *af, void *new_conf)
> OMAP3ISP_AF_PAXEL_VERTICAL_COUNT_MAX))
> return -EINVAL;
>
> - if (IS_OUT_OF_BOUNDS(paxel_cfg->height, OMAP3ISP_AF_PAXEL_HEIGHT_MIN,
> + if (IS_OUT_OF_BOUNDS((u32)paxel_cfg->height, OMAP3ISP_AF_PAXEL_HEIGHT_MIN,
> OMAP3ISP_AF_PAXEL_HEIGHT_MAX) ||
> paxel_cfg->height % 2)
> return -EINVAL;
>
> /* Check width */
> - if (IS_OUT_OF_BOUNDS(paxel_cfg->width, OMAP3ISP_AF_PAXEL_WIDTH_MIN,
> + if (IS_OUT_OF_BOUNDS((u32)paxel_cfg->width, OMAP3ISP_AF_PAXEL_WIDTH_MIN,
> OMAP3ISP_AF_PAXEL_WIDTH_MAX) ||
> paxel_cfg->width % 2)
> return -EINVAL;

--
Regards,

Laurent Pinchart