--- jsr166/src/jdk8/java/util/HashMap.java	2017/09/26 16:52:48	1.2
+++ jsr166/src/jdk8/java/util/HashMap.java	2017/09/26 16:58:06	1.3
@@ -2038,8 +2038,11 @@ public class HashMap<K,V> extends Abstra
                 return;
             if (root.parent != null)
                 root = root.root();
-            if (root == null || root.right == null ||
-                (rl = root.left) == null || rl.left == null) {
+            if (root == null
+                || (movable
+                    && (root.right == null
+                        || (rl = root.left) == null
+                        || rl.left == null))) {
                 tab[index] = first.untreeify(map);  // too small
                 return;
             }