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

Zi Yan
2024-03-05T16:13:17Z

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 {
--
2.43.0