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

[Lorenzo Stoakes <ljs@kernel.org>]

On Fri, May 15, 2026 at 03:42:10PM +0300, Ahmed Elaidy wrote:
> This series backports the sticky VMA flags infrastructure and the
> VM_SOFTDIRTY-on-merge fix to linux-6.18.y.

Thanks again for doing this Ahmed! :)

Cheers, Lorenzo

>
> 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
>