Re: Fixed buffers have out-dated content

Linus Torvalds
2021-01-16T23:06:28Z

On Sat, Jan 16, 2021 at 2:12 PM Jens Axboe <axboe@kernel.dk> wrote:
>
> Linus, I'm looking into the above report, all of it should still be
> intact in the quoted section. Figured it would not hurt to loop you in,
> in case this is a generic problem and since Martin identified that
> reverting the above changes on the mm side makes it go away. Maybe
> there's already some discussion elsewhere about it that I'm not privy
> to.

Ok, that commit clearly ended up more painful that it should have been.

The problem is that with it, if we revert it, then we'd have to also
revert a308c71bf1e6 ("mm/gup: Remove enfornced COW mechanism"). which
depends on it.

And that fixed its own set of problems.

Darn.

I'll go think about this.

Martin, since you can apparently trigger the problem easily, hopefully
you're willing to try a couple of patches?

Linus