You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@tomcat.apache.org by bu...@apache.org on 2011/03/08 04:46:03 UTC

DO NOT REPLY [Bug 50885] New: JspServletWrapper can call destroy() on a JSP page that is still in service()

https://issues.apache.org/bugzilla/show_bug.cgi?id=50885

           Summary: JspServletWrapper can call destroy() on a JSP page
                    that is still in service()
           Product: Tomcat 7
           Version: trunk
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: minor
          Priority: P2
         Component: Jasper
        AssignedTo: dev@tomcat.apache.org
        ReportedBy: knst.kolinko@gmail.com


I noticed this while reviewing r1078409 which was a fix inspired by this
discussion,

"atomicity violation in the JspServletWrapper class" @dev list
http://tomcat.markmail.org/thread/htekwb5aq4urrf76


The Ch.2.3.4 of Servlet 3.0 says that before destroy() method of a servlet is
called all the threads must finish service() (or some timeout to pass).

What I do not like is that

1) JspServletWrapper.getServlet() calls JspServletWrapper.destroy() while there
is no guarantee that the servlet is not still in service.

2) we are able to call service() on a servlet after its destroy() has been
called.

This issue existed before r1078409, but now "2)" is slightly more noticeable,
because we remember the value returned by getServlet() in a local variable.
Reverting r1078409 is no good, because it just adds a risk of accessing an
instance of servlet before it is properly initialized (because reading of
theServlet field were not protected by a sync), but does not solve this issue.


I think this is hard to observe, though, because

1) The servlet is not just any servlet, but a JSP page.

The jspDestroy() method in a JSP page is usually a NOOP.

The _jspDestroy() method though does some work (see
Generator.generateDestroy()): releases tag handler pools.

2) The reloading occurs only when running with development=true in JspServlet
configuration.

Those running with development=false are unaffected.

--------------------------------------
There are also calls to JspServletWrapper.destroy() from JSP unloading feature
(new in TC7). I wonder whether those play fine.

-- 
Configure bugmail: https://issues.apache.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@tomcat.apache.org
For additional commands, e-mail: dev-help@tomcat.apache.org

DO NOT REPLY [Bug 50885] JspServletWrapper can call destroy() on a JSP page that is still in service()

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=50885

--- Comment #1 from Mark Thomas <ma...@apache.org> 2011-03-14 10:52:38 EDT ---
I'm leaning towards marking this as WONTFIX. No user has reported an error and
I can't see a way to fix this that wouldn't cause bigger problems.

If there were an error it would be in development mode only. From a spec
compliance point of view, Tomcat is spec compliant - it just uses a really,
really short time out ;)

For the unloading use case, no issue should occur with an appropriately sized
and configured cache.

-- 
Configure bugmail: https://issues.apache.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@tomcat.apache.org
For additional commands, e-mail: dev-help@tomcat.apache.org

DO NOT REPLY [Bug 50885] JspServletWrapper can call destroy() on a JSP page that is still in service()

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=50885

Mark Thomas <ma...@apache.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |WONTFIX

--- Comment #2 from Mark Thomas <ma...@apache.org> 2011-03-30 07:10:57 EDT ---
AS per my previous comment.

-- 
Configure bugmail: https://issues.apache.org/bugzilla/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@tomcat.apache.org
For additional commands, e-mail: dev-help@tomcat.apache.org