Re: [PATCH v5 4/6] mm/huge_memory: convert VM_BUG* to VM_WARN* in __folio_split.

[David Hildenbrand]

On 18.07.25 20:37, Zi Yan wrote:
> These VM_BUG* can be handled gracefully without crashing kernel.
>
> Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> ---
>   mm/huge_memory.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index d36f7bdaeb38..d98283164eda 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -3601,8 +3601,8 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
>   	pgoff_t end;
>   	bool is_hzp;
>   
> -	VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
> -	VM_BUG_ON_FOLIO(!folio_test_large(folio), folio);
> +	VM_WARN_ON_ONCE_FOLIO(!folio_test_locked(folio), folio);
> +	VM_WARN_ON_ONCE_FOLIO(!folio_test_large(folio), folio);
>   
>   	if (folio != page_folio(split_at) || folio != page_folio(lock_at))
>   		return -EINVAL;
> @@ -3766,7 +3766,11 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
>   		}
>   
>   		if (folio_test_swapcache(folio)) {
> -			VM_BUG_ON(mapping);
> +			if (mapping) {
> +				VM_WARN_ON_ONCE_FOLIO(mapping, folio);
> +				ret = -EINVAL;
> +				goto fail;
> +			}
>   
>   			swap_cache = swap_address_space(folio->swap);
>   			xa_lock(&swap_cache->i_pages);


Acked-by: David Hildenbrand <david@xxxxxxxxxx>

--
Cheers,

David / dhildenb