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

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