diff -Naur /tmp/mosquitto-1.6.4/lib/connect.c ./lib/connect.c
--- /tmp/mosquitto-1.6.4/lib/connect.c	2019-08-01 12:50:01.000000000 -0700
+++ ./lib/connect.c	2019-08-07 23:00:43.993719811 -0700
@@ -272,7 +272,7 @@
 	mosq->state = mosq_cs_disconnecting;
 	pthread_mutex_unlock(&mosq->state_mutex);
 
-	if(mosq->sock == INVALID_SOCKET) return MOSQ_ERR_NO_CONN;
+	// if(mosq->sock == INVALID_SOCKET) return MOSQ_ERR_NO_CONN;
 	return send__disconnect(mosq, reason_code, outgoing_properties);
 }
 
diff -Naur /tmp/mosquitto-1.6.4/lib/handle_ping.c ./lib/handle_ping.c
--- /tmp/mosquitto-1.6.4/lib/handle_ping.c	2019-08-01 12:50:01.000000000 -0700
+++ ./lib/handle_ping.c	2019-08-07 23:08:46.798702752 -0700
@@ -55,9 +55,12 @@
 {
 	assert(mosq);
 
+	pthread_mutex_lock(&mosq->state_mutex);
 	if(mosq->state != mosq_cs_connected){
+            pthread_mutex_unlock(&mosq->state_mutex);
 		return MOSQ_ERR_PROTOCOL;
 	}
+	pthread_mutex_unlock(&mosq->state_mutex);
 
 	mosq->ping_t = 0; /* No longer waiting for a PINGRESP. */
 #ifdef WITH_BROKER
diff -Naur /tmp/mosquitto-1.6.4/lib/handle_pubackcomp.c ./lib/handle_pubackcomp.c
--- /tmp/mosquitto-1.6.4/lib/handle_pubackcomp.c	2019-08-01 12:50:01.000000000 -0700
+++ ./lib/handle_pubackcomp.c	2019-08-07 23:02:44.792973223 -0700
@@ -50,9 +50,12 @@
 
 	assert(mosq);
 
+	pthread_mutex_lock(&mosq->state_mutex);
 	if(mosq->state != mosq_cs_connected){
+            pthread_mutex_unlock(&mosq->state_mutex);
 		return MOSQ_ERR_PROTOCOL;
 	}
+	pthread_mutex_unlock(&mosq->state_mutex);
 
 	pthread_mutex_lock(&mosq->msgs_out.mutex);
 	util__increment_send_quota(mosq);
diff -Naur /tmp/mosquitto-1.6.4/lib/handle_publish.c ./lib/handle_publish.c
--- /tmp/mosquitto-1.6.4/lib/handle_publish.c	2019-08-01 12:50:01.000000000 -0700
+++ ./lib/handle_publish.c	2019-08-08 12:31:11.687790234 -0700
@@ -43,9 +43,12 @@
 
 	assert(mosq);
 
+	pthread_mutex_lock(&mosq->state_mutex);
 	if(mosq->state != mosq_cs_connected){
+            pthread_mutex_unlock(&mosq->state_mutex);
 		return MOSQ_ERR_PROTOCOL;
 	}
+	pthread_mutex_unlock(&mosq->state_mutex);
 
 	message = mosquitto__calloc(1, sizeof(struct mosquitto_message_all));
 	if(!message) return MOSQ_ERR_NOMEM;
diff -Naur /tmp/mosquitto-1.6.4/lib/handle_suback.c ./lib/handle_suback.c
--- /tmp/mosquitto-1.6.4/lib/handle_suback.c	2019-08-01 12:50:01.000000000 -0700
+++ ./lib/handle_suback.c	2019-08-07 23:04:21.152373047 -0700
@@ -43,9 +43,12 @@
 
 	assert(mosq);
 
+	pthread_mutex_lock(&mosq->state_mutex);
 	if(mosq->state != mosq_cs_connected){
+            pthread_mutex_unlock(&mosq->state_mutex);
 		return MOSQ_ERR_PROTOCOL;
 	}
+	pthread_mutex_unlock(&mosq->state_mutex);
 
 #ifdef WITH_BROKER
 	log__printf(NULL, MOSQ_LOG_DEBUG, "Received SUBACK from %s", mosq->id);
diff -Naur /tmp/mosquitto-1.6.4/lib/packet_mosq.c ./lib/packet_mosq.c
--- /tmp/mosquitto-1.6.4/lib/packet_mosq.c	2019-08-01 12:50:01.000000000 -0700
+++ ./lib/packet_mosq.c	2019-08-08 12:34:57.486324078 -0700
@@ -174,11 +174,12 @@
 #endif
 	}
 
-	if(mosq->in_callback == false && mosq->threaded == mosq_ts_none){
+        if(mosq->threaded == mosq_ts_none){
+            if(mosq->in_callback == false){
 		return packet__write(mosq);
-	}else{
-		return MOSQ_ERR_SUCCESS;
-	}
+            }
+        }
+        return MOSQ_ERR_SUCCESS;
 #endif
 }
 
@@ -217,14 +218,17 @@
 	}
 	pthread_mutex_unlock(&mosq->out_packet_mutex);
 
+	pthread_mutex_lock(&mosq->state_mutex);
 #if defined(WITH_TLS) && !defined(WITH_BROKER)
 	if((mosq->state == mosq_cs_connect_pending) || mosq->want_connect){
 #else
 	if(mosq->state == mosq_cs_connect_pending){
 #endif
+                pthread_mutex_unlock(&mosq->state_mutex);
 		pthread_mutex_unlock(&mosq->current_out_packet_mutex);
 		return MOSQ_ERR_SUCCESS;
 	}
+	pthread_mutex_unlock(&mosq->state_mutex);
 
 	while(mosq->current_out_packet){
 		packet = mosq->current_out_packet;
@@ -319,9 +323,12 @@
 	if(mosq->sock == INVALID_SOCKET){
 		return MOSQ_ERR_NO_CONN;
 	}
+        pthread_mutex_lock(&mosq->state_mutex);
 	if(mosq->state == mosq_cs_connect_pending){
+            pthread_mutex_unlock(&mosq->state_mutex);
 		return MOSQ_ERR_SUCCESS;
 	}
+            pthread_mutex_unlock(&mosq->state_mutex);
 
 	/* This gets called if pselect() indicates that there is network data
 	 * available - ie. at least one byte.  What we do depends on what data we
diff -Naur /tmp/mosquitto-1.6.4/lib/util_mosq.c ./lib/util_mosq.c
--- /tmp/mosquitto-1.6.4/lib/util_mosq.c	2019-08-01 12:50:01.000000000 -0700
+++ ./lib/util_mosq.c	2019-08-08 12:41:19.283074648 -0700
@@ -88,7 +88,9 @@
 	if(mosq->keepalive && mosq->sock != INVALID_SOCKET &&
 			(now >= next_msg_out || now - last_msg_in >= mosq->keepalive)){
 
+                pthread_mutex_lock(&mosq->state_mutex);
 		if(mosq->state == mosq_cs_connected && mosq->ping_t == 0){
+                        pthread_mutex_unlock(&mosq->state_mutex);
 			send__pingreq(mosq);
 			/* Reset last msg times to give the server time to send a pingresp */
 			pthread_mutex_lock(&mosq->msgtime_mutex);