[PATCH 2/5] mm: rmap: add a ZONE_DEVICE folio warning in folio_referenced()

[Rik van Riel]

On Tue, 2026-02-24 at 09:56 +0800, Baolin Wang wrote:
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index bff8f222004e..be785dfc9336 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1065,6 +1065,7 @@ int folio_referenced(struct folio *folio, int
> is_locked,
>  		.invalid_vma = invalid_folio_referenced_vma,
>  	};
>  
> +	VM_WARN_ON_FOLIO(folio_is_zone_device(folio), folio);
>  	*vm_flags = 0;
>  	if (!pra.mapcount)
>  		return 0;

Should be a VM_WARN_ON_ONCE_FOLIO so we do not cause
a softlockup if we try to print information about a
million ZONE_DEVICE pages?

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