diff --git a/src/main/java/org/apache/commons/pool3/impl/GenericObjectPool.java b/src/main/java/org/apache/commons/pool3/impl/GenericObjectPool.java
index 96b3c96b8..dcf2c83e1 100644
--- a/src/main/java/org/apache/commons/pool3/impl/GenericObjectPool.java
+++ b/src/main/java/org/apache/commons/pool3/impl/GenericObjectPool.java
@@ -1092,16 +1092,19 @@ public void returnObject(final T obj) {
             }
         } else {
 
-            synchronized (p) {
-                if(p.getState() != PooledObjectState.INVALID) {
-                    if (getLifo()) {
-                        idleObjects.addFirst(p);
-                    } else {
-                        idleObjects.addLast(p);
-                    }
-                }
+            if (!p.deallocate()) {
+                throw new IllegalStateException(
+                    "Object has already been returned to this pool or is invalid");
             }
 
+            if (getLifo()) {
+                idleObjects.addFirst(p);
+            } else {
+                idleObjects.addLast(p);
+            }
+
+
+
             if (isClosed()) {
                 // Pool closed while object was being added to idle objects.
                 // Make sure the returned object is destroyed rather than left