Index: xmlreader.c
===================================================================
--- xmlreader.c	(revision 3787)
+++ xmlreader.c	(working copy)
@@ -4500,7 +4500,7 @@ xmlTextReaderStandalone(xmlTextReaderPtr
 /* helper to build a xmlMalloc'ed string from a format and va_list */
 static char *
 xmlTextReaderBuildMessage(const char *msg, va_list ap) {
-    int size;
+    int size, prev_size = -1;
     int chars;
     char *larger;
     char *str;
@@ -4513,10 +4513,17 @@ xmlTextReaderBuildMessage(const char *ms
 
     size = 150;
 
-    while (1) {
+    while (size < 64000) {
+        va_start(ap, msg);
         chars = vsnprintf(str, size, msg, ap);
-        if ((chars > -1) && (chars < size))
-            break;
+	va_end(ap);
+        if ((chars > -1) && (chars < size)) {
+	    if (prev_size == chars) {
+		break;
+	    } else {
+	        prev_size = chars;
+	    }
+	}
         if (chars > -1)
             size += chars + 1;
         else