Re: [PATCH STABLE v6.1.y] mm/migrate: set swap entry values of THP tail pages properly.

David Hildenbrand
2024-03-05T16:22:17Z

On 05.03.24 17:13, Zi Yan wrote:
> From: Zi Yan <ziy@nvidia.com>
>
> The tail pages in a THP can have swap entry information stored in their
> private field. When migrating to a new page, all tail pages of the new
> page need to update ->private to avoid future data corruption.
>
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> ---
> mm/migrate.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/mm/migrate.c b/mm/migrate.c
> index c93dd6a31c31..c5968021fde0 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -423,8 +423,12 @@ int folio_migrate_mapping(struct address_space *mapping,
> if (folio_test_swapbacked(folio)) {
> __folio_set_swapbacked(newfolio);
> if (folio_test_swapcache(folio)) {
> + int i;
> +
> folio_set_swapcache(newfolio);
> - newfolio->private = folio_get_private(folio);
> + for (i = 0; i < nr; i++)
> + set_page_private(folio_page(newfolio, i),
> + page_private(folio_page(folio, i)));
> }
> entries = nr;
> } else {

Hopefully Charan can run the reproducer against this.

Acked-by: David Hildenbrand <david@redhat.com>

--
Cheers,

David / dhildenb