Re: [PATCH v3 00/11] Introduce Simple atomic counters

Dan Carpenter
2020-11-10T18:50:33Z

On Fri, Oct 16, 2020 at 03:51:25PM -0700, Kees Cook wrote:
> On Fri, Oct 16, 2020 at 12:53:13PM +0200, Peter Zijlstra wrote:
> > That's like saying: "I'm too lazy to track what I've looked at already".
> > You're basically proposing to graffiti "Kees was here -- 16/10/2020" all
> > over the kernel. Just so you can see where you still need to go.
> >
> > It says the code was (assuming your audit was correct) good at that
> > date, but has no guarantees for any moment after that.
>
> That kind of bit-rot marking is exactly what I would like to avoid: just
> putting a comment in is pointless. Making the expectations of the usage
> become _enforced_ is the goal. And having it enforced by the _compiler_
> is key. Just adding a meaningless attribute that a static checker
> will notice some time and hope people fix them doesn't scale either
> (just look at how many sparse warnings there are).

Most Sparse warnings are false positives. People do actually fix the
ones which matter.

I think this patchset could be useful. I'm working on a refcounting
check for Smatch. I want to warn about when we forget to drop a
reference on an error path. Right now I just assume that anything with
"error", "drop" or "->stats->" in the name is just a counter.

regards,
dan carpenter