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.
Closes: https://lore.kernel.org/linux-mm/1707814102-22682-1-git-send-email-quic_charante@xxxxxxxxxxx/
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 034b0662fd3b..9cfd53eaeb4e 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -441,8 +441,12 @@ 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
