[PATCH 6.18.y v1 0/9] mm: backport sticky VMA flags and soft-dirty fix

[PATCH 6.18.y v1 0/9] mm: backport sticky VMA flags and soft-dirty fix

[Ahmed Elaidy]

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.

Backport notes:
  - Non-trivial context conflicts were resolved in:
    - mm/mseal.c
    - mm/vma.c
  - Conflict resolution keeps upstream semantics; no intentional behavior
    changes beyond context adaptation for 6.18.y.

Cc: stable@vger.kernel.org



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(-)

-- 
2.53.0

[PATCH 6.18.y v1 0/9] mm: backport sticky VMA flags and soft-dirty fix

[Ahmed Elaidy]

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.

Backport notes:
  - Non-trivial context conflicts were resolved in:
    - mm/mseal.c
    - mm/vma.c
  - Conflict resolution keeps upstream semantics; no intentional behavior
    changes beyond context adaptation for 6.18.y.

Cc: stable@vger.kernel.org



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(-)

-- 
2.53.0

Re: [PATCH 6.18.y v1 0/9] mm: backport sticky VMA flags and soft-dirty fix

[Andrei Vagin]

On Fri, Apr 24, 2026 at 2:13 PM Ahmed Elaidy <elaidya225@gmail.com> wrote:
>
> 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

Have you tried fixing only the VM_SOFTDIRTY propagation issue without porting
the entire series?

I think this fix will be small, reducing the chance of breaking something else.

Thanks,
Andrei