[PATCH v3 0/6] Fix incorrect access of hugetlb pte entries

[Dev Jain]

There are various places which use ptep_get() to get the pte entry
corresponding to a hugetlb folio. Some arches (like s390) have special
handling to compute the pteval, so they provide huge_ptep_get(). Use this
helper consistently.

Additionally, some code paths may provide huge_ptep_get with an unaligned
address. This is a problem on arm64 (I checked other arches and it looks
fine for them), which is fixed in patch 1. The fix is made to be
backport-friendly: the cleaner fix would be to perhaps pass the hstate
to huge_ptep_get() - that is wider churn and we can do that later.

---
v2->v3:
 - Place comment at appropriate place in patches 2 and 3
 - Modify indentation in patch 2, patch 6

v1->v2:
 - Add patch 1
 - Mention s390 in cover letter

Dev Jain (6):
  arm64: make huge_ptep_get handled unaligned addresses
  mm/rmap: use huge_ptep_get() in try_to_unmap_one()
  mm/rmap: use huge_ptep_get() in try_to_migrate_one()
  mm/migrate: use huge_ptep_get() in remove_migration_pte()
  mm/page_vma_mapped: use huge_ptep_get() for hugetlb
  mm/mprotect: use huge_ptep_get() for hugetlb

 arch/arm64/mm/hugetlbpage.c |  2 +-
 include/linux/hugetlb.h     |  2 ++
 mm/migrate.c                |  6 +++++-
 mm/mprotect.c               | 12 +++++++++---
 mm/page_vma_mapped.c        |  8 +++++++-
 mm/rmap.c                   | 32 ++++++++++++++++++++------------
 6 files changed, 44 insertions(+), 18 deletions(-)

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2.43.0