[merged mm-stable] mm-migrate_device-move-softleaf_to_folio-inside-device-private-branch.patch removed from -mm tree

The quilt patch titled
     Subject: mm/migrate_device: move softleaf_to_folio() inside device-private branch
has been removed from the -mm tree.  Its filename was
     mm-migrate_device-move-softleaf_to_folio-inside-device-private-branch.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: Usama Arif <[email protected]>
Subject: mm/migrate_device: move softleaf_to_folio() inside device-private branch
Date: Mon, 6 Jul 2026 04:42:07 -0700

migrate_vma_collect_pmd() calls softleaf_to_folio() on a non-present PMD
before checking the entry's type.  softleaf_to_folio() converts the
entry's offset to a PFN, which is only meaningful for migration or
device-private entries.

A PMD swap entry's offset is a swap offset, not a PFN, so the lookup would
either return a bogus folio pointer or trip pfn_to_page validation on a
debug kernel.  In the non-device-private path the returned folio is then
unused (the OR short-circuits to migrate_vma_collect_skip()), but the
lookup itself is already unsafe.

Move the softleaf_to_folio() call inside the device-private branch where
the folio is actually needed, mirroring the equivalent
change_non_present_huge_pmd() fix.

Link: https://lore.kernel.org/[email protected]
Signed-off-by: Usama Arif <[email protected]>
Reviewed-by: Zi Yan <[email protected]>
Acked-by: David Hildenbrand (Arm) <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: Baolin Wang <[email protected]>
Cc: Baoquan He <[email protected]>
Cc: Barry Song <[email protected]>
Cc: Chris Li <[email protected]>
Cc: Dev Jain <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Kairui Song <[email protected]>
Cc: Kemeng Shi <[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 Wilcox (Oracle) <[email protected]>
Cc: Nhat Pham <[email protected]>
Cc: Nico Pache <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 mm/migrate_device.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

--- a/mm/migrate_device.c~mm-migrate_device-move-softleaf_to_folio-inside-device-private-branch
+++ a/mm/migrate_device.c
@@ -166,11 +166,14 @@ static int migrate_vma_collect_huge_pmd(
 	} else if (!pmd_present(*pmdp)) {
 		const softleaf_t entry = softleaf_from_pmd(*pmdp);
 
-		folio = softleaf_to_folio(entry);
-
 		if (!softleaf_is_device_private(entry) ||
-			!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_PRIVATE) ||
-			(folio->pgmap->owner != migrate->pgmap_owner)) {
+		    !(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_PRIVATE)) {
+			spin_unlock(ptl);
+			return migrate_vma_collect_skip(start, end, walk);
+		}
+
+		folio = softleaf_to_folio(entry);
+		if (folio->pgmap->owner != migrate->pgmap_owner) {
 			spin_unlock(ptl);
 			return migrate_vma_collect_skip(start, end, walk);
 		}
_

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

mm-mempolicy-skip-non-present-pmds-when-queueing-folios.patch
mm-madvise-skip-device-private-pmds-in-cold-and-pageout-walks.patch
mm-huge_memory-skip-device-private-pmds-in-madvise_free_huge_pmd.patch
mm-vmstat-mm-memcontrol-add-_monotonic-vmstat-readers.patch
mm-vmscan-reduce-lru_lock-contention-via-vmstat-derived-scan-balance-cost.patch