Re: mmap denywrite mess (Was: [GIT PULL] overlayfs fixes for 5.14-rc6)

From: Linus Torvalds
Date: Wed Aug 11 2021 - 12:20:44 EST

On Wed, Aug 11, 2021 at 4:45 AM David Hildenbrand <david@xxxxxxxxxx> wrote:
> I proposed a while ago to get rid of VM_DENYWRITE completely:
> I haven't looked how much it still applies to current upstream, but
> maybe that might help cleaning up that code.

I like it.

I agree that we could - and probably should - just do it this way.

We don't expose MAP_DENYWRITE to user space any more - and the old
legacy library loading code certainly isn't worth it - and so
effectively the only way to set it is with execve().

And yes, it gets rid of all the silly games with the per-mapping flags.