Re: [PATCH mm-new v2 2/3] mm/khugepaged: use VM_WARN_ON_FOLIO instead of VM_BUG_ON_FOLIO for non-anon folios

[Dev Jain]

On 06/10/25 8:13 pm, Lance Yang wrote:
> From: Lance Yang <lance.yang@xxxxxxxxx>
>
> As Zi pointed out, we should avoid crashing the kernel for conditions
> that can be handled gracefully. Encountering a non-anonymous folio in an
> anonymous VMA is a bug, but a warning is sufficient.
>
> This patch changes the VM_BUG_ON_FOLIO(!folio_test_anon(folio)) to a
> VM_WARN_ON_FOLIO() in both __collapse_huge_page_isolate() and
> hpage_collapse_scan_pmd(), and then aborts the scan with SCAN_PAGE_ANON.
>
> Making more of the scanning logic common between hpage_collapse_scan_pmd()
> and __collapse_huge_page_isolate(), as suggested by Dev.
>
> Suggested-by: Dev Jain <dev.jain@xxxxxxx>
> Suggested-by: Zi Yan <ziy@xxxxxxxxxx>
> Signed-off-by: Lance Yang <lance.yang@xxxxxxxxx>
> ---
>   

Reviewed-by: Dev Jain <dev.jain@xxxxxxx>