Re: [PATCH v2] mm/migrate_device: Cleanup up PMD Checks and warnings

[Sunny Patel]

On Sun, 19 Apr 2026 23:17:43 +0530 Sunny Patel <nueralspacetech@xxxxxxxxx> wrote:

> Remove the odd VM_WARN_ON_FOLIO(!folio, folio) usage and replace it
> with a simpler VM_WARN_ON_ONCE(!folio) check.
>
> Drop the redundant VM_WARN_ON_ONCE(!pmd_none(*pmdp) &&
> !is_huge_zero_pmd(*pmdp)).
>
> Refactor the PMD checks, making the control flow
> clearer and avoiding duplicate condition checks.

AI review might have found a bug in the surrounding code:
        https://sashiko.dev/#/patchset/20260419174747.10701-1-nueralspacetech@xxxxxxxxx

NOTE: Ignore the previous message was sent on different 
Subject Header by mistake.

After looking into the AI comment found two potential leak.

1. The goto should be unlock_abort instead of abort to ensure 
the spinlock is released.

2. The pgtable allocation at the top of the function
is indeed not freed on the unlock_abort path. Will add a
pte_free(vma->vm_mm, pgtable). 

Since this patch is more of Cleanup on PMD checks and
Warnings Is it ok if I send different patch to address
this potential leak issues or need it in this revision
itself?

Thanks,
Sunny Patel