[merged mm-stable] mm-rmap-use-huge_ptep_get-in-try_to_migrate_one.patch removed from -mm tree

The quilt patch titled
     Subject: mm/rmap: use huge_ptep_get() in try_to_migrate_one()
has been removed from the -mm tree.  Its filename was
     mm-rmap-use-huge_ptep_get-in-try_to_migrate_one.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: Dev Jain <[email protected]>
Subject: mm/rmap: use huge_ptep_get() in try_to_migrate_one()
Date: Fri, 3 Jul 2026 11:41:56 +0000

try_to_migrate_one() is used by folio migration to replace a present
mapping with a migration entry. For hugetlb folios, page_vma_mapped_walk()
returns the pte pointer to the hugetlb folio in pvmw.pte, but the code
reads the huge pte entry with ptep_get().

On arches which provide their own huge_ptep_get() to dereference a huge
pte pointer, accessing via ptep_get() would cause pte_pfn(), pte_present()
etc to misbehave.

It is not clear whether this has a trivially visible effect to userspace.

Use huge_ptep_get() to dereference a huge pte pointer.

Commit a98a2f0c8ce1 copied the bug from try_to_unmap_one into
try_to_migrate_one.

[[email protected]: coding-style cleanups]
Link: https://lore.kernel.org/[email protected]
Fixes: a98a2f0c8ce1 ("mm/rmap: split migration into its own function")
Signed-off-by: Dev Jain <[email protected]>
Acked-by: Muchun Song <[email protected]>
Acked-by: David Hildenbrand (Arm) <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Byungchul Park <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Gregory Price <[email protected]>
Cc: Harry Yoo <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Josh Poimboeuf <[email protected]>
Cc: Joshua Hahn <[email protected]>
Cc: Jun'ichi "Nick" Nomura <[email protected]>
Cc: Kiryl Shutsemau <[email protected]>
Cc: Lance Yang <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Matthew Brost <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Pedro Falcato <[email protected]>
Cc: Rakie Kim <[email protected]>
Cc: Ralph Campbell <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Zi Yan <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 mm/rmap.c |   15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

--- a/mm/rmap.c~mm-rmap-use-huge_ptep_get-in-try_to_migrate_one
+++ a/mm/rmap.c
@@ -2500,14 +2500,18 @@ static bool try_to_migrate_one(struct fo
 		/* Unexpected PMD-mapped THP? */
 		VM_BUG_ON_FOLIO(!pvmw.pte, folio);
 
-		/*
-		 * Handle PFN swap PTEs, such as device-exclusive ones, that
-		 * actually map pages.
-		 */
-		pteval = ptep_get(pvmw.pte);
+		address = pvmw.address;
+		if (folio_test_hugetlb(folio))
+			pteval = huge_ptep_get(mm, address, pvmw.pte);
+		else
+			pteval = ptep_get(pvmw.pte);
 		if (likely(pte_present(pteval))) {
 			pfn = pte_pfn(pteval);
 		} else {
+			/*
+			 * Handle PFN swap PTEs, such as device-exclusive ones,
+			 * that actually map pages.
+			 */
 			const softleaf_t entry = softleaf_from_pte(pteval);
 
 			pfn = softleaf_to_pfn(entry);
@@ -2515,7 +2519,6 @@ static bool try_to_migrate_one(struct fo
 		}
 
 		subpage = folio_page(folio, pfn - folio_pfn(folio));
-		address = pvmw.address;
 		anon_exclusive = folio_test_anon(folio) &&
 				 PageAnonExclusive(subpage);
 
_

Patches currently in -mm which might be from [email protected] are

mm-rmap-convert-page-folio-for-hwpoison-checks.patch
mm-rmap-add-try_to_unmap_poisoned_hugetlb_one.patch
mm-rmap-refactor-some-code-around-lazyfree-folio-unmapping.patch
mm-rmap-refactor-anon-folio-unmap-in-try_to_unmap_one.patch
mm-rmap-add-anon-folio-unmap-dispatcher.patch
mm-memory-move-pte_install_uffd_wp_if_needed-into-memoryc.patch
mm-memory-batch-set-uffd-wp-markers-during-zapping.patch
mm-rmap-batch-unmap-file-folios-belonging-to-uffd-wp-vmas.patch