Re: [PATCH v3] tty: tty_io: remove hung_up_tty_fops

From: Paul E. McKenney
Date: Wed May 01 2024 - 15:02:36 EST


On Wed, May 01, 2024 at 11:56:26AM -0700, Linus Torvalds wrote:
> On Wed, 1 May 2024 at 11:46, Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
> >
> > In short, I for one do greatly value KCSAN's help. Along with that of
> > a great many other tools, none of which are perfect, but all of which
> > are helpful.
>
> It's not that I don't value what KCSAN does, but I really think this
> is a KCSAN issue.
>
> I absolutely *detest* these crazy "randomly add data race annotations".
>
> Could we instead annotate particular structure fields? I don't want to
> mark things actually "volatile", because that then causes the compiler
> to generate absolutely horrendous code. But some KCSAN equivalent of
> "this field has data races, and we don't care" kind of annotation
> would be lovely..

That would give the poor sleep-deprived innocent bystander some way
to figure out which fields were shared, so that does sound like a good
improvement!

I would naively expect that KCSAN's ability to handle volatile fields
would make this doable, but there is much that I do not know about
KCSAN internals. So I must defer to Marco on this one.

Thanx, Paul