[PATCH 6.18.y v4 0/9] mm: backport sticky VMA flags and soft-dirty fix

[Ahmed Elaidy <elaidya225@gmail.com>]

This series backports the sticky VMA flags infrastructure and the
VM_SOFTDIRTY-on-merge fix to linux-6.18.y.

Motivation: CRIU incremental dump/restore can hit a missing-parent-pagemap
failure when VM_SOFTDIRTY is lost during VMA merge operations.

Patch 8 is the target fix:
  mm: propagate VM_SOFTDIRTY on merge

The preceding patches provide required dependencies on 6.18.y and are included
to preserve upstream behavior, as requested by maintainers for stable backports.

Changes since v3:
  - Reverted to sending the full 9-patch series as requested by Greg KH and Lorenzo.
  - Updated Lorenzo's email to ljs@kernel.org across all patches.
  - Added Cc: stable@vger.kernel.org # 6.18.x to all patches.
  - Added Fixes tag for soft-dirty merging in Patch 8.

Lorenzo Stoakes (9):
  mm: introduce VM_MAYBE_GUARD and make visible in /proc/$pid/smaps
  mm: add atomic VMA flags and set VM_MAYBE_GUARD as such
  mm: update vma_modify_flags() to handle residual flags, document
  mm: implement sticky VMA flags
  mm: introduce copy-on-fork VMAs and make VM_MAYBE_GUARD one
  mm: set the VM_MAYBE_GUARD flag on guard region install
  tools/testing/vma: add VMA sticky userland tests
  mm: propagate VM_SOFTDIRTY on merge
  testing/selftests/mm: add soft-dirty merge self-test

 Documentation/filesystems/proc.rst      |   5 +-
 fs/proc/task_mmu.c                      |   1 +
 include/linux/mm.h                      | 100 +++++++++++++++++
 include/trace/events/mmflags.h          |   1 +
 mm/khugepaged.c                         |  71 +++++++-----
 mm/madvise.c                            |  24 +++--
 mm/memory.c                             |  14 +--
 mm/mlock.c                              |   2 +-
 mm/mprotect.c                           |   2 +-
 mm/mseal.c                              |   7 +-
 mm/vma.c                                |  81 +++++++-------
 mm/vma.h                                | 138 +++++++++++++++++-------
 tools/testing/selftests/mm/soft-dirty.c | 127 +++++++++++++++++++++-
 tools/testing/vma/vma.c                 |  92 ++++++++++++++--
 tools/testing/vma/vma_internal.h        |  49 +++++++++
 15 files changed, 579 insertions(+), 135 deletions(-)

-- 
2.54.0