diff --git a/sys/net/gnrc/conn/udp/gnrc_conn_udp.c b/sys/net/gnrc/conn/udp/gnrc_conn_udp.c
index 0aa9212173..1ef54791db 100644
--- a/sys/net/gnrc/conn/udp/gnrc_conn_udp.c
+++ b/sys/net/gnrc/conn/udp/gnrc_conn_udp.c
@@ -56,6 +56,7 @@ void conn_udp_close(conn_udp_t *conn)
     assert(conn->l4_type == GNRC_NETTYPE_UDP);
     if (conn->netreg_entry.pid != KERNEL_PID_UNDEF) {
         gnrc_netreg_unregister(GNRC_NETTYPE_UDP, &conn->netreg_entry);
+        conn->netreg_entry.pid = KERNEL_PID_UNDEF;
     }
 }
 
diff --git a/sys/posix/sockets/posix_sockets.c b/sys/posix/sockets/posix_sockets.c
index d507ad9726..a0837051fc 100644
--- a/sys/posix/sockets/posix_sockets.c
+++ b/sys/posix/sockets/posix_sockets.c
@@ -255,6 +255,7 @@ static int socket_close(int socket)
                         res = -1;
                         break;
                 }
+                break;
             default:
                 res = -1;
                 break;