On Thu, Jan 12, 2023 at 1:02 PM Peter Xu <peterx@xxxxxxxxxx> wrote:
>
> On Thu, Jan 05, 2023 at 10:18:17AM +0000, James Houghton wrote:
> > @@ -6731,22 +6746,22 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
> > * and skip the same_page loop below.
> > */
> > if (!pages && !vmas && !pfn_offset &&
> > - (vaddr + huge_page_size(h) < vma->vm_end) &&
> > - (remainder >= pages_per_huge_page(h))) {
> > - vaddr += huge_page_size(h);
> > - remainder -= pages_per_huge_page(h);
> > - i += pages_per_huge_page(h);
> > + (vaddr + pages_per_hpte < vma->vm_end) &&
> > + (remainder >= pages_per_hpte)) {
> > + vaddr += pages_per_hpte;
>
> This silently breaks hugetlb GUP.. should be
>
> vaddr += hugetlb_pte_size(&hpte);
>
> It caused misterious MISSING events when I'm playing with this tree, and
> I'm surprised it rooted here. So far the most time consuming one. :)
Thanks Peter!! And the `vaddr + pages_per_hpte < vma->vm_end` should
be `vaddr + hugetlb_pte_size(&hpte) < vma->vm_end` too.
