Index: uspace/srv/net/dhcp/transport.c
===================================================================
--- uspace/srv/net/dhcp/transport.c	(revision 5c65e613de52e725ff215514fe39a8d1428767d2)
+++ uspace/srv/net/dhcp/transport.c	(revision 566da7f8b9ae23f19ca44e238d25be2b62d26752)
@@ -172,5 +172,5 @@
 	dhcp_transport_t *dt = (dhcp_transport_t *)arg;
 	void *msg;
-	size_t size;
+	size_t size = (size_t) -1;
 	int rc;
 
@@ -179,4 +179,6 @@
 		if (rc != EOK)
 			break;
+
+		assert(size != (size_t) -1);
 
 		dt->recv_cb(dt->cb_arg, msg, size);
Index: uspace/srv/net/dnsrsrv/dns_msg.c
===================================================================
--- uspace/srv/net/dnsrsrv/dns_msg.c	(revision 5c65e613de52e725ff215514fe39a8d1428767d2)
+++ uspace/srv/net/dnsrsrv/dns_msg.c	(revision 566da7f8b9ae23f19ca44e238d25be2b62d26752)
@@ -487,5 +487,5 @@
 	size_t size;
 	dns_header_t hdr;
-	size_t q_size;
+	size_t q_size = 0;
 	size_t di;
 	int rc;
@@ -515,4 +515,6 @@
 			return rc;
 
+		assert(q_size > 0);
+
 		size += q_size;
 	}
@@ -532,4 +534,6 @@
 			return rc;
 		}
+
+		assert(q_size > 0);
 
 		di += q_size;
Index: uspace/srv/net/dnsrsrv/transport.c
===================================================================
--- uspace/srv/net/dnsrsrv/transport.c	(revision 5c65e613de52e725ff215514fe39a8d1428767d2)
+++ uspace/srv/net/dnsrsrv/transport.c	(revision 566da7f8b9ae23f19ca44e238d25be2b62d26752)
@@ -286,5 +286,5 @@
 static int transport_recv_fibril(void *arg)
 {
-	dns_message_t *resp;
+	dns_message_t *resp = NULL;
 	trans_req_t *treq;
 	int rc;
@@ -294,4 +294,6 @@
 		if (rc != EOK)
 			continue;
+
+		assert(resp != NULL);
 
 		fibril_mutex_lock(&treq_lock);