Update: it turns out that the ETH input (receiver) is triggered (via mailboxes), but the mailbox content is 0x0. So, instead to assign the address of the received ETH, TCP/IP frame - the pointer becomes zero and the LwIP stack closes the TCP/IP socket.
BTW: closing this seems to result also in disabling the ETH MAC in general (for all further traffic).
The piece of code where it starts failing is in file 'sys_arch.c', in function 'sys_arch_mbox_fetch':
else
{
event = osMessageGet (*mbox, osWaitForever);
*msg = (void *)event.value.v;
return (osKernelSysTick() - starttime);
}
The event.value.v is 0x0 and it results in file 'api_lib.c', function 'netconn_recv_data', code:
/* If we are closed, we indicate that we no longer wish to use the socket */
if (buf == NULL) {
API_EVENT(conn, NETCONN_EVT_RCVMINUS, 0);
if (conn->pcb.ip == NULL) {
/* race condition: RST during recv */
return conn->last_err == ERR_OK ? ERR_RST : conn->last_err;
}
/* RX side is closed, so deallocate the recvmbox */
netconn_close_shutdown(conn, NETCONN_SHUT_RD);
/* Don' store ERR_CLSD as conn->err since we are only half-closed */
return ERR_CLSD;
to close the TCP/IP socket. Unfortunately, all is dead afterwards, we cannot create anymore any other or new network connection. The RTOS is still alive but for network the FW has to be restarted.
Why does this happen? - no clue. It does not look like a memory corruption (destroyed memories), it looks more like a unknown ETH frame, e.g. an empty ETH frame or an issue with the STM32H7 MAC filter (forwarding a corrupted or un-handled packet to LwIP).
