Re: [PATCH 00/35] media: Fix coccinelle warning/errors

Ricardo Ribalda
2024-04-17T16:19:53Z

Hi Laurent

On Wed, 17 Apr 2024 at 17:51, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> On Tue, Apr 16, 2024 at 11:47:17AM +0300, Dan Carpenter wrote:
> > In my opinion, it's better to just ignore old warnings.
>
> I agree. Whatever checkers we enable, whatever code we test, there will
> always be false positives. A CI system needs to be able to ignore those
> false positives and only warn about new issues.

We already have support for that:
https://gitlab.freedesktop.org/linux-media/media-ci/-/tree/main/testdata/static?ref_type=heads

But it would be great if those lists were as small as possible:

- If we have a lot of warnings, two error messages can be combined and
will scape the filters
eg:
print(AAAA);
print(BBBB);
> AABBBAAB

- The filters might hide new errors if they are too broad

Most of the patches in this series are simple and make a nicer code:
Eg the non return minmax() ,
Other patches show real integer overflows.

Now that the patches are ready, let's bite the bullet and try to
reduce our technical debt.

Regards!
>
> > When code is new the warnings are going to be mostly correct. The
> > original author is there and knows what the code does. Someone has
> > the hardware ready to test any changes. High value, low burden.
> >
> > When the code is old only the false positives are left. No one is
> > testing the code. It's low value, high burden.
> >
> > Plus it puts static checker authors in a difficult place because now
> > people have to work around our mistakes. It creates animosity.
> >
> > Now we have to hold ourselves to a much higher standard for false
> > positives. It sounds like I'm complaining and lazy, right? But Oleg
> > Drokin has told me previously that I spend too much time trying to
> > silence false positives instead of working on new code. He's has a
> > point which is that actually we have limited amount of time and we have
> > to make choices about what's the most useful thing we can do.
> >
> > So what I do and what the zero day bot does is we look at warnings one
> > time and we re-review old warnings whenever a file is changed.
> >
> > Kernel developers are very good at addressing static checker warnings
> > and fixing the real issues... People sometimes ask me to create a
> > database of warnings which I have reviewed but the answer is that
> > anything old can be ignored. As I write this, I've had a thought that
> > instead of a database of false positives maybe we should record a
> > database of real bugs to ensure that the fixes for anything real is
> > applied.
>
> --
> Regards,
>
> Laurent Pinchart

--
Ricardo Ribalda