[merged mm-stable] mm-hugetlb-make-hugetlb_follow_page_mask-safe-to-pmd-unshare.patch removed from -mm tree

[merged mm-stable] mm-hugetlb-make-hugetlb_follow_page_mask-safe-to-pmd-unshare.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm/hugetlb: make hugetlb_follow_page_mask() safe to pmd unshare
has been removed from the -mm tree.  Its filename was
     mm-hugetlb-make-hugetlb_follow_page_mask-safe-to-pmd-unshare.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Peter Xu <peterx@redhat.com>
Subject: mm/hugetlb: make hugetlb_follow_page_mask() safe to pmd unshare
Date: Fri, 16 Dec 2022 10:52:19 -0500

Since hugetlb_follow_page_mask() walks the pgtable, it needs the vma lock
to make sure the pgtable page will not be freed concurrently.

Link: https://lkml.kernel.org/r/20221216155219.2043714-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/mm/hugetlb.c~mm-hugetlb-make-hugetlb_follow_page_mask-safe-to-pmd-unshare
+++ a/mm/hugetlb.c
@@ -6396,9 +6396,10 @@ struct page *hugetlb_follow_page_mask(st
 	if (WARN_ON_ONCE(flags & FOLL_PIN))
 		return NULL;
 
+	hugetlb_vma_lock_read(vma);
 	pte = huge_pte_offset(mm, haddr, huge_page_size(h));
 	if (!pte)
-		return NULL;
+		goto out_unlock;
 
 	ptl = huge_pte_lock(h, mm, pte);
 	entry = huge_ptep_get(pte);
@@ -6421,6 +6422,8 @@ struct page *hugetlb_follow_page_mask(st
 	}
 out:
 	spin_unlock(ptl);
+out_unlock:
+	hugetlb_vma_unlock_read(vma);
 	return page;
 }
 
_

Patches currently in -mm which might be from peterx@redhat.com are

selftests-vm-remove-__use_gnu-in-hugetlb-madvisec.patch