Re: [PATCH 2/7] mm/hugetlb: Fix hugetlb_follow_page_mask() on permission checks

[David Hildenbrand]

On 14.06.23 17:46, Peter Xu wrote:
> On Wed, Jun 14, 2023 at 05:31:36PM +0200, David Hildenbrand wrote:
> > On 13.06.23 23:53, Peter Xu wrote:
> > > It seems hugetlb_follow_page_mask() was missing permission checks.  For
> > > example, one follow_page() can get the hugetlb page with FOLL_WRITE even if
> > > the page is read-only.
> >
> > I'm curious if there even is a follow_page() user that operates on hugetlb
> > ...
> >
> > s390x secure storage does not apply to hugetlb IIRC.
>
> You're the expert, so I'll rely on you. :)

Hehe, there is a comment in gmap_destroy_page(), above one of the 
follow_page() users:

	/*
	 * Huge pages should not be able to become secure
	 */
	if (is_vm_hugetlb_page(vma))
		goto out;


--
Cheers,

David / dhildenb