Update ethernetif.c
if LWIP_NETIF_HOSTNAME enable, the length is 'sizeof(struct netif)+ LWIP_HOSTNAME_LEN',
not only  equal to  'sizeof(struct netif)'.
@@ -503,7 +503,11 @@ rt_err_t eth_device_init_with_flag(struct eth_device *dev, const char *name, rt_
rt_kprintf("malloc netif failed\n");
return -RT_ERROR;
}
+#if LWIP_NETIF_HOSTNAME
+ rt_memset(netif, 0, sizeof(struct netif)+ LWIP_HOSTNAME_LEN);
+#else
rt_memset(netif, 0, sizeof(struct netif));
+#endif
/* set netif */
dev->netif = netif;
