Re: [PATCH v6] taskstats: fix data-race

[Dmitry Vyukov]

On Thu, Oct 24, 2019 at 3:43 PM Andrea Parri <parri.andrea@xxxxxxxxx> wrote:
>
> > But why? I think kernel contains lots of such cases and it seems to be
> > officially documented by the LKMM:
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/memory-model/Documentation/explanation.txt
> > address dependencies and ppo
>
> Well, that same documentation also alerts about some of the pitfalls
> developers can incur while relying on dependencies.  I'm sure you're
> more than aware of some of the debate surrounding these issues.

I thought that LKMM is finally supposed to stop all these
centi-threads around subtle details of ordering. And not we finally
have it. And it says that using address-dependencies is legal. And you
are one of the authors. And now you are arguing here that we better
not use it :) Can we have some black/white yes/no for code correctness
reflected in LKMM please :) If we are banning address dependencies,
don't we need to fix all of rcu uses?