some question about before filter in rails 2.02

Hi guys,   Following is a simple before filter under rails 2.02

  users_controller.rb

class UsersController < ApplicationController

  skip_before_filter :authorize, :only => [:login]

  ## CRUD actions #####

  def login     if request.post?       session[:user] = nil       u = User.find_by_email params[:user][:email]       unless u && u.password_equal?(params[:user][:password])         session[:user] = u         uri = session[:original_uri]         session[:original_uri] = nil         redirect_to(uri || {:action => :index})       else         flash[:notice] = "the user name and email doesn't match!"       end     end   end

end

application_controller.rb

class ApplicationController < ActionController::Base   helper :all # include all helpers, all the time

  # See ActionController::RequestForgeryProtection for details   # Uncomment the :secret if you're not using the cookie session store   protect_from_forgery # :secret => '4477fc7de98463482e367d7b0d4279eb'

  before_filter :authorize

  protected

  def authorize     p "step to authorize"     unless session[:user]       flash[:notice] = "please login first..."       session[:original_uri] = request.request_uri       redirect_to(:controller => "users", :action => "login")     end   end end

when I get the url http://localhost:3000/users, it always do loop in "authorize" action and "step to authorize" appears several times and I got the error

"Redirect Loop   Firefox has detected that the server is redirecting the request for this address in a way that will never complete. The browser has stopped trying to retrieve the requested item. The site is redirecting the request in a way that will never complete.     * Have you disabled or blocked cookies required by this site?     * NOTE: If accepting the site's cookies does not resolve the problem, it is likely a server configuration issue and not your computer."

  what's up? It seems it should work well, can anybody point this problem?   I am under ubuntu 8.04 LTS, thanks.