From: Zi Yan <ziy@xxxxxxxxxx>
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.
Corresponding swapcache entries need to be updated as well.
e71769ae5260 ("mm: enable thp migration for shmem thp") fixed it already.
Fixes: 616b8371539a ("mm: thp: enable thp migration in generic path")
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
mm/migrate.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index c7d5566623ad..c37af50f312d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -424,8 +424,12 @@ int migrate_page_move_mapping(struct address_space *mapping,
if (PageSwapBacked(page)) {
__SetPageSwapBacked(newpage);
if (PageSwapCache(page)) {
+ int i;
+
SetPageSwapCache(newpage);
- set_page_private(newpage, page_private(page));
+ for (i = 0; i < (1 << compound_order(page)); i++)
+ set_page_private(newpage + i,
+ page_private(page + i));
}
} else {
VM_BUG_ON_PAGE(PageSwapCache(page), page);
--
2.43.0
