Re: [PATCH v2] mm/khugepaged: clear MMF_VM_HUGEPAGE on mm_slot_alloc() failure

[Baolin Wang]

On 5/6/26 9:21 AM, Ye Liu wrote:
> From: Ye Liu <liuye@xxxxxxxxxx>
>
> __khugepaged_enter() sets MMF_VM_HUGEPAGE before allocating the
> corresponding mm_slot.  If mm_slot_alloc() fails, the function
> returns with the flag set but without inserting the mm into the
> khugepaged tracking structures.
>
> This leaves the mm in an inconsistent state: it is marked as
> registered (MMF_VM_HUGEPAGE set), but will never be scanned by
> khugepaged.  Future attempts to register the mm are skipped since
> khugepaged_enter_vma() checks the flag and returns early.
>
> Fix this by clearing MMF_VM_HUGEPAGE when mm_slot_alloc() fails,
> restoring the ability to retry registration later.
>
> Fixes: 16618670276a ("mm: khugepaged: avoid pointless allocation for struct mm_slot")
> Signed-off-by: Ye Liu <liuye@xxxxxxxxxx>
> ---

Good catch. Feel free to add:
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>