Re: [PATCH] mm/userfaultfd: fix memory corruption due to writeprotect

From: Linus Torvalds
Date: Mon Dec 21 2020 - 18:35:43 EST


On Mon, Dec 21, 2020 at 3:12 PM Yu Zhao <yuzhao@xxxxxxxxxx> wrote:
>
> I can't say I disagree with you but the man has made the call and I
> think we should just move on.

"The man" can always be convinced by numbers.

So if somebody comes up with an alternate patch, and explains it, and
shows that it is better - go for it.

I just think that if mprotect() can take the mmap lock for writing,
then userfaultfd sure as hell can. What odd load does people have
where userfaultfd is more important than mprotect?

So as far as the man is concerned, I think "just fix userfaultfd" is
simply the default obvious operation.

Not necessarily a final endpoint.

Linus