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.
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_char... Fixes: 616b8371539a ("mm: thp: enable thp migration in generic path") 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 fcb7eb6a6eca..c0a8f3c9e256 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -447,8 +447,12 @@ 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);