1 files changed, 9 insertions, 1 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 45bf0e5775f7..d27a73737f1a 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1401,7 +1401,15 @@ 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;