1 files changed, 1 insertions, 0 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index ea9da3bed3e9..886ea0d5a136 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -824,6 +824,7 @@ int __set_page_dirty_nobuffers(struct page *page)
                 mapping2 = page_mapping(page);
                 if (mapping2) { /* Race with truncate? */
                         BUG_ON(mapping2 != mapping);
+                        WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
                         if (mapping_cap_account_dirty(mapping)) {
                                 __inc_zone_page_state(page, NR_FILE_DIRTY);
                                 task_io_account_write(PAGE_CACHE_SIZE);