--- httpd-2.2.11.orig/modules/proxy/mod_proxy.c	2008-11-11 21:01:59.000000000 +0100
+++ httpd-2.2.11.orig/modules/proxy/mod_proxy.c	2009-04-17 16:40:22.000000000 +0200
@@ -1024,6 +1024,14 @@ 
         /* Try again if the worker is unusable and the service is
          * unavailable.
          */
+        if (balancer) {
+            /* Since the unusable worker was returned by the pre_request
+             * handler, run the post_request handler to clean up (e.g.
+             * decrement the "busy" counter) before trying to find a new
+             * worker.
+             */
+            proxy_run_post_request(worker, balancer, r, conf);
+        }
     } while (!PROXY_WORKER_IS_USABLE(worker) &&
              max_attempts > attempts++);