diff --git a/server/core/session.c b/server/core/session.c
index f48e6872d..cb72ea0bd 100644
--- a/server/core/session.c
+++ b/server/core/session.c
@@ -31,12 +31,16 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
+#include <errno.h>
 #include <session.h>
 #include <service.h>
 #include <router.h>
 #include <dcb.h>
 #include <spinlock.h>
 #include <atomic.h>
+#include <skygw_utils.h>
+#include <log_manager.h>
+
 
 static SPINLOCK	session_spin = SPINLOCK_INIT;
 static SESSION	*allSessions = NULL;
@@ -55,18 +59,40 @@ static SESSION	*allSessions = NULL;
 SESSION *
 session_alloc(SERVICE *service, DCB *client)
 {
-SESSION 	*session;
+        SESSION 	*session;
 
-	if ((session = (SESSION *)malloc(sizeof(SESSION))) == NULL)
+        session = (SESSION *)calloc(1, sizeof(SESSION));
+        
+        if (session == NULL) {
+                int eno = errno;
+                errno = 0;
+                skygw_log_write_flush(
+                        LOGFILE_ERROR,
+                        "%lu [session_alloc] Allocating memory for session "
+                        "object failed. Errno %d, %s.",
+                        pthread_self(),
+                        eno,
+                        strerror(eno));
 		return NULL;
+        }
+        session->ses_chk_top = CHK_NUM_SESSION;
+        session->ses_chk_tail = CHK_NUM_SESSION;
         spinlock_init(&session->ses_lock);
-	session->service = service;
+        /**
+         * Prevent backend threads from accessing before session is completely
+         * initialized.
+         */
+        spinlock_acquire(&session->ses_lock);
+        session->service = service;
 	session->client = client;
 	memset(&session->stats, 0, sizeof(SESSION_STATS));
 	session->stats.connect = time(0);
 	session->state = SESSION_STATE_ALLOC;
+        /**
+         * If client has data pointer to authentication info, set it to session.
+         */
+        session->data = client->data;
 	client->session = session;
-
 	/*
 	 * Only create a router session if we are not the listening 
 	 * DCB. Creating a router session may create a connection to a
@@ -75,17 +101,22 @@ SESSION 	*session;
 	 */
 	if (client->state != DCB_STATE_LISTENING)
 	{
-		session->router_session = service->router->newSession(service->router_instance, session);
+		session->router_session =
+                    service->router->newSession(service->router_instance, session);
 	}
-
 	spinlock_acquire(&session_spin);
 	session->next = allSessions;
 	allSessions = session;
 	spinlock_release(&session_spin);
 
+        /** This indicates that session is ready to be shared with backend DCBs. */
+        session->state = SESSION_STATE_READY;
+        /** Release session lock */
+        spinlock_release(&session->ses_lock);
+        
 	atomic_add(&service->stats.n_sessions, 1);
 	atomic_add(&service->stats.n_current, 1);
-
+        CHK_SESSION(session);
 	return session;
 }
 
@@ -98,8 +129,9 @@ void
 session_free(SESSION *session)
 {
 SESSION *ptr;
-
+        CHK_SESSION(session);
 	/* First of all remove from the linked list */
+         
 	spinlock_acquire(&session_spin);
 	if (allSessions == session)
 	{
@@ -117,7 +149,6 @@ SESSION *ptr;
 	}
 	spinlock_release(&session_spin);
 	atomic_add(&session->service->stats.n_current, -1);
-
 	/* Clean up session and free the memory */
 	free(session);
 }
diff --git a/server/include/session.h b/server/include/session.h
index c91b837bd..e0de9a303 100644
--- a/server/include/session.h
+++ b/server/include/session.h
@@ -35,6 +35,7 @@
 #include <time.h>
 #include <atomic.h>
 #include <spinlock.h>
+#include <skygw_utils.h>
 
 struct dcb;
 struct service;
@@ -46,6 +47,21 @@ typedef struct {
 	time_t		connect;	/**< Time when the session was started */
 } SESSION_STATS;
 
+
+#if 0
+#define SESSION_STATE_ALLOC		0	/**< The session has been allocated */
+#define SESSION_STATE_READY		1	/**< The session is ready to route queries */
+#define SESSION_STATE_LISTENER		2	/**< The session is a running listener */
+#define SESSION_STATE_LISTENER_STOPPED	3	/**< The session listener is stopped */
+#else
+typedef enum {
+    SESSION_STATE_ALLOC,
+    SESSION_STATE_READY,
+    SESSION_STATE_LISTENER,
+    SESSION_STATE_LISTENER_STOPPED
+} session_state_t;
+#endif
+
 /**
  * The session status block
  *
@@ -54,8 +70,9 @@ typedef struct {
  * and originating service together for the client session.
  */
 typedef struct session {
+        skygw_chk_t     ses_chk_top;
         SPINLOCK        ses_lock;
-	int 		state;		/**< Current descriptor state */
+	session_state_t state;		/**< Current descriptor state */
 	struct dcb	*client;	/**< The client connection */
 	struct dcb	*backends;	/**< The set of backend servers */
 	void 		*data;		/**< The session data */
@@ -63,13 +80,9 @@ typedef struct session {
 	SESSION_STATS	stats;		/**< Session statistics */
 	struct service	*service;	/**< The service this session is using */
 	struct session	*next;		/**< Linked list of all sessions */
+        skygw_chk_t     ses_chk_tail;
 } SESSION;
 
-#define SESSION_STATE_ALLOC		0	/**< The session has been allocated */
-#define SESSION_STATE_READY		1	/**< The session is ready to route queries */
-#define SESSION_STATE_LISTENER		2	/**< The session is a running listener */
-#define SESSION_STATE_LISTENER_STOPPED	3	/**< The session listener is stopped */
-
 #define SESSION_PROTOCOL(x, type)	DCB_PROTOCOL((x)->client, type)
 
 extern SESSION	*session_alloc(struct service *, struct dcb *);