Update sal_socket.c

components/net/sal_socket/src/sal_socket.c

@@ -489,8 +489,7 @@ int sal_shutdown(int socket, int how)
     if (sock->ops->shutdown((int) sock->user_data, how) == 0)
     {
         rt_free(sock);
-        sock =  RT_NULL;
-        
+        socket_table.sockets[socket] = RT_NULL;
         return 0;
     }