diff --git a/libxml2-2.9.9/parser.c b/libxml2-2.9.9/parser.c
index 5813a664..d12d9e8c 100644
--- a/libxml2-2.9.9/parser.c
+++ b/libxml2-2.9.9/parser.c
@@ -13898,6 +13898,7 @@ xmlParseBalancedChunkMemoryRecover(xmlDocPtr doc, xmlSAXHandlerPtr sax,
     xmlFreeParserCtxt(ctxt);
     newDoc->intSubset = NULL;
     newDoc->extSubset = NULL;
+    if(doc != NULL)
     newDoc->oldNs = NULL;
     xmlFreeDoc(newDoc);