Re: [PATCH v1 10/36] mm: sanity-check maximum folio size in folio_set_order()

* David Hildenbrand <[email protected]> [250827 18:05]:
> Let's sanity-check in folio_set_order() whether we would be trying to
> create a folio with an order that would make it exceed MAX_FOLIO_ORDER.
> 
> This will enable the check whenever a folio/compound page is initialized
> through prepare_compound_head() / prepare_compound_page().
> 
> Reviewed-by: Zi Yan <[email protected]>
> Signed-off-by: David Hildenbrand <[email protected]>

Reviewed-by: Liam R. Howlett <[email protected]>

> ---
>  mm/internal.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/internal.h b/mm/internal.h
> index 45da9ff5694f6..9b0129531d004 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -755,6 +755,7 @@ static inline void folio_set_order(struct folio *folio, unsigned int order)
>  {
>  	if (WARN_ON_ONCE(!order || !folio_test_large(folio)))
>  		return;
> +	VM_WARN_ON_ONCE(order > MAX_FOLIO_ORDER);
>  
>  	folio->_flags_1 = (folio->_flags_1 & ~0xffUL) | order;
>  #ifdef NR_PAGES_IN_LARGE_FOLIO
> -- 
> 2.50.1
> 
>