[xwiki-users] Lucene re-index problem

After upgrading to XWiki 3.5 (from 2.6) I noticed that the Lucene search index was not working properly. On advice I got in the #xwiki IRC chat, I shut down the server (Tomcat), deleted the Lucene index directory, and restarted the server. Only about 300 of the thousands of pages were indexed at that point. I tried re-indexing using the Admin->Search page, but every time I do that the Admin->Search page gets 'stuck' (won't render). I saw no errors in the catalina.out log file, and I configured WEB-INF/classes/logback.xml to enable some more logging to a separate file... still nothing very informative. Any ideas what I can do to troubleshoot this? I'm guessing there's some page in my wiki database that is causing the re-index process to get stuck. Thanks in advance, - Josh