diff --git a/server/core/Makefile b/server/core/Makefile
index 3f862a475..bd29fbae8 100644
--- a/server/core/Makefile
+++ b/server/core/Makefile
@@ -41,7 +41,7 @@ UTILSPATH := $(ROOT_PATH)/utils
 
 CC=cc
 
-CFLAGS=-c -I/usr/include -I../include -I../inih \
+CFLAGS=-c -I/usr/include -I../include -I../modules/include -I../inih \
 	$(MYSQL_HEADERS) \
 	-I$(LOGPATH) -I$(UTILSPATH) \
 	-Wall -g
@@ -59,7 +59,7 @@ SRCS= atomic.c buffer.c spinlock.c gateway.c \
 	monitor.c adminusers.c secrets.c
 
 HDRS= ../include/atomic.h ../include/buffer.h ../include/dcb.h \
-	../include/gw.h ../include/mysql_protocol.h \
+	../include/gw.h ../modules/include/mysql_client_server_protocol.h \
 	../include/session.h ../include/spinlock.h ../include/thread.h \
 	../include/modules.h ../include/poll.h ../include/config.h \
 	../include/users.h ../include/hashtable.h ../include/gwbitmask.h \
diff --git a/server/core/dbusers.c b/server/core/dbusers.c
index 4847c4c8b..41dda5a92 100644
--- a/server/core/dbusers.c
+++ b/server/core/dbusers.c
@@ -42,6 +42,7 @@
 #include <skygw_utils.h>
 #include <log_manager.h>
 #include <secrets.h>
+#include <mysql_client_server_protocol.h>
 
 #define USERS_QUERY_NO_ROOT " AND user NOT IN ('root')"
 #define LOAD_MYSQL_USERS_QUERY "SELECT user, host, password, concat(user,host,password) AS userdata FROM mysql.user WHERE user IS NOT NULL AND user <> ''"
diff --git a/server/core/dcb.c b/server/core/dcb.c
index f2e5e183a..c499e067b 100644
--- a/server/core/dcb.c
+++ b/server/core/dcb.c
@@ -68,6 +68,7 @@
 #include <atomic.h>
 #include <skygw_utils.h>
 #include <log_manager.h>
+#include <hashtable.h>
 
 extern int lm_enabled_logfiles_bitmask;
 
diff --git a/server/core/poll.c b/server/core/poll.c
index f1c65ebea..0b23a6b05 100644
--- a/server/core/poll.c
+++ b/server/core/poll.c
@@ -27,6 +27,7 @@
 #include <gwbitmask.h>
 #include <skygw_utils.h>
 #include <log_manager.h>
+#include <gw.h>
 
 extern int lm_enabled_logfiles_bitmask;
 
diff --git a/server/core/secrets.c b/server/core/secrets.c
index a11b0276d..c4d1822f5 100644
--- a/server/core/secrets.c
+++ b/server/core/secrets.c
@@ -21,6 +21,7 @@
 #include <skygw_utils.h>
 #include <log_manager.h>
 #include <ctype.h>
+#include <mysql_client_server_protocol.h>
 
 extern int lm_enabled_logfiles_bitmask;
 /**
diff --git a/server/core/service.c b/server/core/service.c
index 79522513c..efc441173 100644
--- a/server/core/service.c
+++ b/server/core/service.c
@@ -702,7 +702,7 @@ SERVICE	*ptr;
  * @param dcb		DCB to print data to
  * @param service	The service to print
  */
-dprintService(DCB *dcb, SERVICE *service)
+void dprintService(DCB *dcb, SERVICE *service)
 {
 SERVER	*server = service->databases;
 
diff --git a/server/modules/monitor/mysql_mon.c b/server/modules/monitor/mysql_mon.c
index 4cf7e6938..554f3810f 100644
--- a/server/modules/monitor/mysql_mon.c
+++ b/server/modules/monitor/mysql_mon.c
@@ -128,7 +128,7 @@ MYSQL_MONITOR *handle;
             handle->defaultPasswd = NULL;
             spinlock_init(&handle->lock);
         }
-        handle->tid = thread_start(monitorMain, handle);
+        handle->tid = (THREAD)thread_start(monitorMain, handle);
         return handle;
 }
 
@@ -143,7 +143,7 @@ stopMonitor(void *arg)
 MYSQL_MONITOR	*handle = (MYSQL_MONITOR *)arg;
 
         handle->shutdown = 1;
-        thread_wait(handle->tid);
+        thread_wait((void *)handle->tid);
 }
 
 /**
diff --git a/server/modules/protocol/mysql_backend.c b/server/modules/protocol/mysql_backend.c
index 2ba8402b8..e4b461dad 100644
--- a/server/modules/protocol/mysql_backend.c
+++ b/server/modules/protocol/mysql_backend.c
@@ -283,6 +283,11 @@ static int gw_read_backend_event(DCB *dcb) {
                         }
 
                         if (backend_protocol->state == MYSQL_AUTH_FAILED) {
+                                /** 
+                                 * protocol state won't change anymore, 
+                                 * lock can be freed 
+                                 */
+                                spinlock_release(&dcb->authlock);
                                 spinlock_acquire(&dcb->delayqlock);
                                 /*<
                                  * vraa : errorHandle
@@ -351,7 +356,7 @@ static int gw_read_backend_event(DCB *dcb) {
                                 /* close router_session */
                                 router->closeSession(router_instance, rsession);
                                 rc = 1;
-                                goto return_with_lock;
+                                goto return_rc;
                         }
                         else
                         {