Re: [PATCH v3 01/16] mm/rmap: fix missing swap_free() in try_to_unmap() after arch_unmap_one() failed

[Vlastimil Babka]

On 3/29/22 18:04, David Hildenbrand wrote:
> In case arch_unmap_one() fails, we already did a swap_duplicate(). let's
> undo that properly via swap_free().
> 
> Fixes: ca827d55ebaa ("mm, swap: Add infrastructure for saving page metadata on swap")
> Reviewed-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx>
> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
>  mm/rmap.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 5cb970d51f0a..07f59bc6ffc1 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1637,6 +1637,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
>  				break;
>  			}
>  			if (arch_unmap_one(mm, vma, address, pteval) < 0) {
> +				swap_free(entry);
>  				set_pte_at(mm, address, pvmw.pte, pteval);
>  				ret = false;
>  				page_vma_mapped_walk_done(&pvmw);