Release param memory only when actually allocated

src/ufo-lamino-bp-task.c

@@ -348,7 +348,11 @@ ufo_lamino_bp_task_finalize (GObject *object)
 {
     UfoLaminoBpTaskPrivate *priv = UFO_LAMINO_BP_TASK_GET_PRIVATE (object);
 
-    UFO_RESOURCES_CHECK_CLERR (clReleaseMemObject (priv->param_mem));
+    if (priv->param_mem) {
+        UFO_RESOURCES_CHECK_CLERR (clReleaseMemObject (priv->param_mem));
+        priv->param_mem = NULL;
+    }
+
     G_OBJECT_CLASS (ufo_lamino_bp_task_parent_class)->finalize (object);
 }