1 files changed, 9 insertions, 1 deletions

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 55930cbed3fd..2c5fe4f7a0c6 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1399,7 +1399,15 @@ static void collapse_shmem(struct mm_struct *mm,
                  */
                 VM_BUG_ON_PAGE(!PageLocked(page), page);
                 VM_BUG_ON_PAGE(!PageUptodate(page), page);
-                VM_BUG_ON_PAGE(PageTransCompound(page), page);
+
+                /*
+                 * If file was truncated then extended, or hole-punched, before
+                 * we locked the first page, then a THP might be there already.
+                 */
+                if (PageTransCompound(page)) {
+                        result = SCAN_PAGE_COMPOUND;
+                        goto out_unlock;
+                }
 
                 if (page_mapping(page) != mapping) {
                         result = SCAN_TRUNCATED;