# Re: \[PATCH 31/39\] mm/uffd: use predicates for userfaultfd checks

- From: sashiko-bot@kernel.org
- Date: 2026-09-08 20:45:34 
- List: linux-trace-kernel
- Page: https://ratatoskr.run/linux-trace-kernel/2026/09/17533730
- Thread: https://ratatoskr.run/linux-trace-kernel/2026/09/17533522/t.md

```text
> Rather than directly checking VMA flags, use the newly introduced
> vma_is_kernel_owned() and vma_is_persistent() helpers in userfaultfd when
> assessing VMA suitability for userfaultfd and UFFDIO_MOVE.
> 
> Update vma_move_compatible() so it's expressed in terms of VMA
> characteristics rather than arbitrary flags.
> 
> Additionally, update the use of the deprecated VMA flag API when checking
> VMA_SHADOW_STACK_BIT.
> 
> A VMA_IO_BIT check is no longer required but that is fine as a hard
> invariant has been established that only kernel-owned mappings may set
> VMA_IO_BIT so the check is now redundant.
> 
> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260908-b4-mmap-prepare-vma-flag-sanify-v1-0-dacf19cce22b@kernel.org?part=31

```