[xml] xmllint segfault in recurring reference of xs:extension

["taihei goi" <taihei sis saison co jp>]

Hi.
I'm using libxml2.6.8 on redhat7.3.
I got a segfault when I used xmllint with --schema option.
so I report here.

The schema file is:
<?xml version="1.0" encoding="utf-8" ?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema";
targetNamespace="test" xmlns:t="test">
<xs:complexType name="comp1">
  <xs:complexContent>
   <xs:extension base="t:comp1">
   </xs:extension>
  </xs:complexContent>
 </xs:complexType>
</xs:schema>

This schema contains recurring reference.
But I didn't get segfault similar xs:restriction schema file.
And this didn't occur on any other schema component that uses recurring
reference as far as I test.
(memberTypes on xs:union,itemType on xs:list,base on xs:restriction,
ref on xs:element,xs:group,xs:attributeGroup)

Thanks
Taihei