diff --git a/mm/memory.c b/mm/memory.c
index f594bb6..3922ffc 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1848,10 +1848,21 @@
 	 * not dirty accountable.
 	 */
 	if (PageAnon(old_page)) {
-		if (trylock_page(old_page)) {
-			reuse = can_share_swap_page(old_page);
-			unlock_page(old_page);
+		if (!trylock_page(old_page)) {
+			page_cache_get(old_page);
+			pte_unmap_unlock(page_table, ptl);
+			lock_page(old_page);
+			page_table = pte_offset_map_lock(mm, pmd, address,
+							 &ptl);
+			if (!pte_same(*page_table, orig_pte)) {
+				unlock_page(old_page);
+				page_cache_release(old_page);
+				goto unlock;
+			}
+			page_cache_release(old_page);
 		}
+		reuse = can_share_swap_page(old_page);
+		unlock_page(old_page);
 	} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
 					(VM_WRITE|VM_SHARED))) {
 		/*