diff --git a/log.c b/log.c
index 7a0f1e1..407efdd 100644
--- a/log.c
+++ b/log.c
@@ -163,6 +163,10 @@ void puts_log_xmlmsg(int severity, char *msg, int msgtype)
 	char buf[1024];
 	char *description, *separator;
 
+	if (msg == NULL) {
+		return;
+	}
+
 	pthread_mutex_lock(&mutex_log);
 
 	if (severity > log_severity) {
diff --git a/ubus_utils.c b/ubus_utils.c
index c21576c..41f8346 100644
--- a/ubus_utils.c
+++ b/ubus_utils.c
@@ -397,16 +397,33 @@ int icwmp_ubus_invoke(const char *obj, const char *method, struct blob_attr *msg
 {
 	uint32_t id;
 	int rc = 0;
+	int retry = 0;
 
 	struct ubus_context *ubus_ctx = NULL;
 
 	ubus_ctx = ubus_connect(NULL);
+	while (ubus_ctx == NULL && retry < 5) {
+		retry ++;
+		CWMP_LOG(DEBUG, "Failed to connect ubus retry after 1 sec");
+		sleep(1);
+		ubus_ctx = ubus_connect(NULL);
+	}
+
 	if (ubus_ctx == NULL) {
-		CWMP_LOG(ERROR, "Failed to connect with ubus");
+		CWMP_LOG(ERROR, "Failed to connect with ubus err: %d", errno);
 		return -1;
 	}
 
-	if (!ubus_lookup_id(ubus_ctx, obj, &id)) {
+	retry = 0;
+	rc = ubus_lookup_id(ubus_ctx, obj, &id);
+	while (rc != 0 && retry < 5) {
+		retry ++;
+		CWMP_LOG(DEBUG, "Failed to ubus lookup %s, retry after 1 sec", obj);
+		sleep(1);
+		rc = ubus_lookup_id(ubus_ctx, obj, &id);
+	}
+
+	if (!rc) {
 		rc = ubus_invoke(ubus_ctx, id, method, msg, icwmp_callback, callback_arg, 60000);
 	} else {
 		CWMP_LOG(ERROR, "Failed to ubus lookup %s", obj);
diff --git a/xml.c b/xml.c
index 084a239..3d5e223 100644
--- a/xml.c
+++ b/xml.c
@@ -140,9 +140,19 @@ int xml_send_message(struct cwmp *cwmp, struct session *session, struct rpc *rpc
 	mxml_node_t *b;
 	int compression = global_int_param_read(&cwmp->conf.compression);
 
+	if (session == NULL) {
+		CWMP_LOG(ERROR, "Received session is NULL");
+		return -1;
+	}
+
 	if (session->tree_out) {
 		unsigned char *zmsg_out;
 		msg_out = mxmlSaveAllocString(session->tree_out, whitespace_cb);
+		if (msg_out == NULL) {
+			CWMP_LOG(ERROR, "Received tree_out is empty");
+			return -1;
+		}
+
 		CWMP_LOG_XML_MSG(DEBUG, msg_out, XML_MSG_OUT);
 		if (compression != COMP_NONE) {
 			if (zlib_compress(msg_out, &zmsg_out, &msg_out_len, compression)) {