The malformed HTML was generated after switch to XSLTPROC
from SGML tools. The reference title

  <refentrytitle><phrase id="API-struct-x">struct x</phrase></refentrytitle>

is converted into two recursive <a> tags

  <a href="re02.html"><span><a id="API-struct-x"></a>struct x</span></a>

There is more possible solutions for this problem.
One can be found at

  http://darkk.livejournal.com/

The proposed solution is based on suggestion provided by Jiri Kosek.
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>