diff --git a/mm/ksm.c b/mm/ksm.c
index dd9ed0bdb9f6..fd8843e4a8c5 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2366,6 +2366,23 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite
 		 */
 		if (!is_page_sharing_candidate(stable_node))
 			max_page_sharing_bypass = true;
+	} else {
+		remove_rmap_item_from_tree(rmap_item);
+
+		/*
+		 * If the hash value of the page has changed from the last time
+		 * we calculated it, this page is changing frequently: therefore we
+		 * don't want to insert it in the unstable tree, and we don't want
+		 * to waste our time searching for something identical to it there.
+		 */
+		checksum = calc_checksum(page);
+		if (rmap_item->oldchecksum != checksum) {
+			rmap_item->oldchecksum = checksum;
+			return;
+		}
+
+		if (!try_to_merge_with_zero_page(rmap_item, page))
+			return;
 	}
 
 	/* We first start with searching the page inside the stable tree */
@@ -2396,21 +2413,6 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite
 		return;
 	}
 
-	/*
-	 * If the hash value of the page has changed from the last time
-	 * we calculated it, this page is changing frequently: therefore we
-	 * don't want to insert it in the unstable tree, and we don't want
-	 * to waste our time searching for something identical to it there.
-	 */
-	checksum = calc_checksum(page);
-	if (rmap_item->oldchecksum != checksum) {
-		rmap_item->oldchecksum = checksum;
-		return;
-	}
-
-	if (!try_to_merge_with_zero_page(rmap_item, page))
-		return;
-
 	tree_rmap_item =
 		unstable_tree_search_insert(rmap_item, page, &tree_page);
 	if (tree_rmap_item) {