Uninitialized netif->name Causes Incorrect Debug Logs in LwIP Example with NETIF_DEBUG Enabled

[bricle]

Caution

Describe the set-up

• custom board.
• STM32CubeIDE with least version of CubeF4 packege.

Describe the bug
There is a bug in the LwIP example provided in the STM32CubeF4 software package. In the lwip.c file, the MX_LWIP_Init function calls

netif_add(&gnetif, &ipaddr, &netmask, &gw, NULL, &ethernetif_init, &ethernet_input).

Within netif_add, the netif_set_addr function is invoked, which subsequently calls netif_do_set_netmask. During the execution of netif_do_set_netmask, the following debug statement is executed (when NETIF_DEBUG is enabled):

LWIP_DEBUGF(NETIF_DEBUG | LWIP_DBG_TRACE | LWIP_DBG_STATE, ("netif: netmask of interface %c%c set to %"U16_F".%"U16_F".%"U16_F".%"U16_F"\n",
    netif->name[0], netif->name[1],
    ip4_addr1_16(netif_ip4_netmask(netif)),
    ip4_addr2_16(netif_ip4_netmask(netif)),
    ip4_addr3_16(netif_ip4_netmask(netif)),
    ip4_addr4_16(netif_ip4_netmask(netif))));

However, at this point, netif->name[0] and netif->name[1] have not yet been initialized, as their initialization happens later in the ethernetif_init function.

err_t ethernetif_init(struct netif *netif)
{
  LWIP_ASSERT("netif != NULL", (netif != NULL));

#if LWIP_NETIF_HOSTNAME
  /* Initialize interface hostname */
  netif->hostname = "lwip";
#endif /* LWIP_NETIF_HOSTNAME */

  /*
   * Initialize the snmp variables and counters inside the struct netif.
   * The last argument should be replaced with your link speed, in units
   * of bits per second.
   */
  // MIB2_INIT_NETIF(netif, snmp_ifType_ethernet_csmacd, LINK_SPEED_OF_YOUR_NETIF_IN_BPS);

  netif->name[0] = IFNAME0;
  netif->name[1] = IFNAME1;
...
}

You can see, netif_set_addr is called before init function.

#if LWIP_IPV4
  netif_set_addr(netif, ipaddr, netmask, gw);
#endif /* LWIP_IPV4 */

  /* call user specified initialization function for netif */
  if (init(netif) != ERR_OK) {
    return NULL;
  }

As a result, the debug output for netif->name produces incorrect or undefined values.

How To Reproduce

1. Application behavior: The application uses the default LwIP example generated by STM32CubeMX or provided in the CubeF4 software package.
2. Suspected modules: LwIP middleware and netif implementation.
3. Use case:

• Enable the NETIF_DEBUG option in lwipopts.h.
• Run the LwIP example on the provided board.
• Observe the debug logs where netif->name is used before it is initialized.

4. Reproduction steps:

• Generate a project with LwIP middleware enabled using STM32CubeMX.
• Ensure NETIF_DEBUG is enabled.
• Build and run the project.
• Monitor the logs .

Additional context
Proposed Fix:
The issue can be resolved by ensuring that netif->name is initialized before calling netif_add.

Screenshots

[ASEHSTM]

Hello @bricle
Thank you for your report. All our LwIP examples function correctly, even with the call to netif_set_addr before the initialization of netif->name. Could you please provide more details on why this caused an issue for you?

With Regards,