--- timeout.rb.orig	2011-01-17 17:55:30.070125000 +0100
+++ timeout.rb	2011-01-17 18:35:28.976375000 +0100
@@ -21,7 +21,7 @@
 #
 # Copyright:: (C) 2000  Network Applied Communication Laboratory, Inc.
 # Copyright:: (C) 2000  Information-technology Promotion Agency, Japan
-
+require 'thread'
 module Timeout
   # Raised by Timeout#timeout when the block times out.
   class Error < RuntimeError
@@ -45,14 +45,19 @@
     exception = klass || Class.new(ExitException)
     begin
       x = Thread.current
-      y = Thread.start {
-        begin
-          sleep sec
-        rescue => e
-          x.raise e
-        else
-          x.raise exception, "execution expired" if x.alive?
-        end
+      m = Mutex.new
+      m.synchronize {
+        y = Thread.start {
+          m.synchronize {} # ensure variable y is pointing to the thread
+                           # before y starts the timer
+          begin
+            sleep sec
+          rescue => e
+            x.raise e
+          else
+            x.raise exception, "execution expired" if x.alive?
+          end
+        }
       }
       return yield(sec)
     rescue exception => e