Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/admiyo-os-amperecomputing-com/mctp-pcc-Implement-MCTP-over-PCC-Transport/20250827-124953
base:   net-next/main
patch link:    https://lore.kernel.org/r/20250827044810.152775-2-admiyo%40os.amperecomputing.com
patch subject: [PATCH net-next v25 1/1] mctp pcc: Implement MCTP over PCC Transport
config: i386-randconfig-015-20250829 (https://download.01.org/0day-ci/archive/20250829/202508291628.CPVGma07-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250829/202508291628.CPVGma07-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot [off-list ref]
| Closes: https://lore.kernel.org/oe-kbuild-all/202508291628.CPVGma07-lkp@intel.com/ (local)

All errors (new ones prefixed by >>):

   ld: drivers/net/mctp/mctp-pcc.o: in function `mctp_pcc_tx':

quoted

drivers/net/mctp/mctp-pcc.c:153: undefined reference to `mbox_send_message'

vim +153 drivers/net/mctp/mctp-pcc.c

   130	
   131	static netdev_tx_t mctp_pcc_tx(struct sk_buff *skb, struct net_device *ndev)
   132	{
   133		struct mctp_pcc_ndev *mpnd = netdev_priv(ndev);
   134		struct pcc_header *pcc_header;
   135		int len = skb->len;
   136		int rc;
   137	
   138		rc = skb_cow_head(skb, sizeof(*pcc_header));
   139		if (rc) {
   140			dev_dstats_tx_dropped(ndev);
   141			kfree_skb(skb);
   142			return NETDEV_TX_OK;
   143		}
   144	
   145		pcc_header = skb_push(skb, sizeof(*pcc_header));
   146		pcc_header->signature = PCC_SIGNATURE | mpnd->outbox.index;
   147		pcc_header->flags = PCC_CMD_COMPLETION_NOTIFY;
   148		memcpy(&pcc_header->command, MCTP_SIGNATURE, MCTP_SIGNATURE_LENGTH);
   149		pcc_header->length = len + MCTP_SIGNATURE_LENGTH;
   150	
   151		skb_queue_head(&mpnd->outbox.packets, skb);
   152	
 > 153		rc = mbox_send_message(mpnd->outbox.chan->mchan, skb->data);
   154	
   155		if (rc < 0) {
   156			skb_unlink(skb, &mpnd->outbox.packets);
   157			return NETDEV_TX_BUSY;
   158		}
   159	
   160		dev_dstats_tx_add(ndev, len);
   161		return NETDEV_TX_OK;
   162	}
   163	

-- 
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https://github.com/intel/lkp-tests/wiki