From 77aa9827fe93f1361d23833ab371cde5192d8c6f Mon Sep 17 00:00:00 2001
From: VilhoRaatikka <vilho.raatikka@skysql.com>
Date: Fri, 14 Nov 2014 13:06:35 +0200
Subject: [PATCH] Fix candidate to bug #615,
 http://bugs.skysql.com/show_bug.cgi?id=615

---
 server/modules/protocol/mysql_backend.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/server/modules/protocol/mysql_backend.c b/server/modules/protocol/mysql_backend.c
index 33b114649..aae579d09 100644
--- a/server/modules/protocol/mysql_backend.c
+++ b/server/modules/protocol/mysql_backend.c
@@ -539,10 +539,13 @@ static int gw_read_backend_event(DCB *dcb) {
 				goto return_rc;
 			}
                 }
-                /*<
-                 * If dcb->session->client is freed already it may be NULL.
+                /**
+                 * Check that session is operable, and that client DCB is 
+		 * still listening the socket for replies.
                  */
-                if (dcb->session->client != NULL)
+		if (dcb->session->state == SESSION_STATE_ROUTER_READY &&
+			dcb->session->client != NULL && 
+			dcb->session->client->state == DCB_STATE_POLLING)
                 {
                         client_protocol = SESSION_PROTOCOL(dcb->session,
                                                            MySQLProtocol);
@@ -571,6 +574,10 @@ static int gw_read_backend_event(DCB *dcb) {
 				rc = 1;
 			}
 		}
+		else /*< session is closing; replying to client isn't possible */
+		{
+			gwbuf_free(read_buffer);
+		}
         }
         
 return_rc: