Merge tag 'mm-hotfixes-stable-2025-05-10-14-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mmHEADmaster

Pull misc hotfixes from Andrew Morton:
 "22 hotfixes. 13 are cc:stable and the remainder address post-6.14
  issues or aren't considered necessary for -stable kernels.

  About half are for MM. Five OCFS2 fixes and a few MAINTAINERS updates"

* tag 'mm-hotfixes-stable-2025-05-10-14-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
  mm: fix folio_pte_batch() on XEN PV
  nilfs2: fix deadlock warnings caused by lock dependency in init_nilfs()
  mm/hugetlb: copy the CMA flag when demoting
  mm, swap: fix false warning for large allocation with !THP_SWAP
  selftests/mm: fix a build failure on powerpc
  selftests/mm: fix build break when compiling pkey_util.c
  mm: vmalloc: support more granular vrealloc() sizing
  tools/testing/selftests: fix guard region test tmpfs assumption
  ocfs2: stop quota recovery before disabling quotas
  ocfs2: implement handshaking with ocfs2 recovery thread
  ocfs2: switch osb->disable_recovery to enum
  mailmap: map Uwe's BayLibre addresses to a single one
  MAINTAINERS: add mm THP section
  mm/userfaultfd: fix uninitialized output field for -EAGAIN race
  selftests/mm: compaction_test: support platform with huge mount of memory
  MAINTAINERS: add core mm section
  ocfs2: fix panic in failed foilio allocation
  mm/huge_memory: fix dereferencing invalid pmd migration entry
  MAINTAINERS: add reverse mapping section
  x86: disable image size check for test builds
  ...

1 files changed, 8 insertions, 3 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2a47682d1ab7..47d76d03ce30 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3075,6 +3075,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address,
 			   pmd_t *pmd, bool freeze, struct folio *folio)
 {
+	bool pmd_migration = is_pmd_migration_entry(*pmd);
+
 	VM_WARN_ON_ONCE(folio && !folio_test_pmd_mappable(folio));
 	VM_WARN_ON_ONCE(!IS_ALIGNED(address, HPAGE_PMD_SIZE));
 	VM_WARN_ON_ONCE(folio && !folio_test_locked(folio));
@@ -3085,9 +3087,12 @@ void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address,
 	 * require a folio to check the PMD against. Otherwise, there
 	 * is a risk of replacing the wrong folio.
 	 */
-	if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) ||
-	    is_pmd_migration_entry(*pmd)) {
-		if (folio && folio != pmd_folio(*pmd))
+	if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || pmd_migration) {
+		/*
+		 * Do not apply pmd_folio() to a migration entry; and folio lock
+		 * guarantees that it must be of the wrong folio anyway.
+		 */
+		if (folio && (pmd_migration || folio != pmd_folio(*pmd)))
 			return;
 		__split_huge_pmd_locked(vma, pmd, address, freeze);
 	}