+ mm-migrate-fix-read-only-page-got-writable-when-recover-pte-fix.patch added to mm-hotfixes-unstable branch

+ mm-migrate-fix-read-only-page-got-writable-when-recover-pte-fix.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Date: Thu, 1 Dec 2022 10:19:22 -0500
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-migrate-fix-read-only-page-got-writable-when-recover-pte-fix.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-migrate-fix-read-only-page-got-writable-when-recover-pte-fix.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Peter Xu <peterx@redhat.com>
Date: Thu, 1 Dec 2022 10:19:22 -0500
Subject: mm-migrate-fix-read-only-page-got-writable-when-recover-pte-fix

enhance comment

Link: https://lkml.kernel.org/r/Y4jIHureiOd8XjDX@x1n
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Ives van Hoorne <ives@codesandbox.io>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/migrate.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/mm/migrate.c~mm-migrate-fix-read-only-page-got-writable-when-recover-pte-fix
+++ a/mm/migrate.c
@@ -214,7 +214,14 @@ static bool remove_migration_pte(struct
 		if (is_writable_migration_entry(entry))
 			pte = maybe_mkwrite(pte, vma);
 		else
-			/* NOTE: mk_pte can have write bit set */
+			/*
+			 * NOTE: mk_pte() can have write bit set per memory
+			 * type (e.g. shmem), or pte_mkdirty() per archs
+			 * (e.g., sparc64).  If this is a read migration
+			 * entry, we need to make sure when we recover the
+			 * pte from migration entry to present entry the
+			 * write bit is cleared.
+			 */
 			pte = pte_wrprotect(pte);
 
 		if (pte_swp_uffd_wp(*pvmw.pte)) {
_

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

mm-migrate-fix-read-only-page-got-writable-when-recover-pte.patch
mm-migrate-fix-read-only-page-got-writable-when-recover-pte-fix.patch
mm-hugetlb-let-vma_offset_start-to-return-start.patch
mm-hugetlb-dont-wait-for-migration-entry-during-follow-page.patch
mm-hugetlb-document-huge_pte_offset-usage.patch
mm-hugetlb-move-swap-entry-handling-into-vma-lock-when-faulted.patch
mm-hugetlb-make-userfaultfd_huge_must_wait-safe-to-pmd-unshare.patch
mm-hugetlb-make-hugetlb_follow_page_mask-safe-to-pmd-unshare.patch
mm-hugetlb-make-follow_hugetlb_page-safe-to-pmd-unshare.patch
mm-hugetlb-make-walk_hugetlb_range-safe-to-pmd-unshare.patch
mm-hugetlb-make-page_vma_mapped_walk-safe-to-pmd-unshare.patch
mm-hugetlb-introduce-hugetlb_walk.patch
mm-hugetlb-introduce-hugetlb_walk-fix.patch
mm-hugetlb-introduce-hugetlb_walk-fix-2.patch