Re: KCSAN: data-race in __alloc_file / __alloc_file

[Linus Torvalds]

On Fri, Nov 8, 2019 at 11:48 AM Marco Elver <elver@xxxxxxxxxx> wrote:
>
> It's not explicitly aware of initialization or release. We rely on
> compiler instrumentation for all memory accesses; KCSAN then sets up
> "watchpoints" for sampled memory accesses, delaying execution, and
> checking if a concurrent access is observed.

Ok.

> This same approach could be used to ignore "idempotent writes" where
> we would otherwise report a data race; i.e. if there was a concurrent
> write, but the data value did not change, do not report the race. I'm
> happy to add this feature if this should always be ignored.

Hmm. I don't think it's valid in general, but it might be useful
enough in practice, at least as an option to lower the false
positives.

               Linus