On Fri, 2024-10-18 at 07:53 +0200, Mauro Carvalho Chehab wrote:
> fepriv->auto_sub_step is unsigned. Setting it to -1 is just a
> trick to avoid calling continue, as reported by Coverity.
>
> It relies to have this code just afterwards:
>
> if (!ready) fepriv->auto_sub_step++;
>
> Simplify the code by simply setting it to zero and use
> continue to return to the while loop.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Oh wow, back to the big-bang-commit ^^'
So is this a bug or not? It seems to me that the uint underflows to
UINT_MAX, and then wrapps around to 0 again through the ++..
I take the liberty of ++CCing Kees, since I heard him talk a lot about
overflowing on Plumbers.
If it's not a bug, I would not use "Fixes". If it is a bug, it should
be backported to stable, agreed?
Plus, is there a report-link somewhere by Coverty that could be linked
with "Closes: "?
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
Anyways, this in my eyes does what it's intended to do:
Reviewed-by: Philipp Stanner <pstanner@xxxxxxxxxx>
> ---
> drivers/media/dvb-core/dvb_frontend.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/media/dvb-core/dvb_frontend.c
> b/drivers/media/dvb-core/dvb_frontend.c
> index d48f48fda87c..c9283100332a 100644
> --- a/drivers/media/dvb-core/dvb_frontend.c
> +++ b/drivers/media/dvb-core/dvb_frontend.c
> @@ -443,8 +443,8 @@ static int dvb_frontend_swzigzag_autotune(struct
> dvb_frontend *fe, int check_wra
>
> default:
> fepriv->auto_step++;
> - fepriv->auto_sub_step = -1; /* it'll be
> incremented to 0 in a moment */
> - break;
> + fepriv->auto_sub_step = 0;
> + continue;
> }
>
> if (!ready) fepriv->auto_sub_step++;
