Ethernet close connection and restart MCU

Hi,

I have STM32F767 - Nucleo kit. I implement FreeRTOS, lwIP. And I create this connect.

struct tcp_pcb *server_pcb;
 
struct server_struct
{
	uint8_t state; 			/* current connection state */
	uint8_t retries;
	struct tcp_pcb *pcb; 	/* pointer on the current tcp_pcb */
	struct pbuf *p; 		/* pointer on the received/to be transmitted pbuf */
};
 
struct server_struct *ss;
 
enum server_states
{
	ES_NONE = 0,
	ES_ACCEPTED,
	ES_RECEIVED,
	ES_CLOSING
};
 
static void tcp_server_send(struct tcp_pcb *tpcb, struct server_struct *es)
{
	struct pbuf *ptr;
	err_t wr_err = ERR_OK;
	while ((wr_err == ERR_OK) && (es->p != NULL) && (es->p->len <= tcp_sndbuf(tpcb)))
	{
		ptr = es->p;
		wr_err = tcp_write(tpcb, ptr->payload, ptr->len, 1);
		if (wr_err == ERR_OK)
		{
			uint16_t plen;
			uint8_t freed;
			plen = ptr->len;
			es->p = ptr->next;
			if(es->p != NULL)
			{
				pbuf_ref(es->p);
			}
			do
			{
				freed = pbuf_free(ptr);
			}
			while(freed == 0);
			tcp_recved(tpcb, plen);
		}
		else if(wr_err == ERR_MEM)
		{
			es->p = ptr;
		}
		else
		{
			//other problem
		}
	}
}
 
static void tcp_server_connection_close(struct tcp_pcb *tpcb, struct server_struct *es)
{
	// remove all callbacks
	tcp_arg(tpcb, NULL);
	tcp_sent(tpcb, NULL);
	tcp_recv(tpcb, NULL);
	tcp_err(tpcb, NULL);
	tcp_poll(tpcb, NULL, 1);
	if (es != NULL)
	{
		mem_free(es);
	}
	tcp_close(tpcb);
}
 
static void tcp_server_error(void *arg, err_t err)
{
	//-TODO-
}
 
static err_t tcp_server_poll(void *arg, struct tcp_pcb *tpcb)
{
	err_t ret_err;
	struct server_struct *es;
	es = (struct server_struct *)arg;
 
	if (es != NULL)
	{
		if (es->p != NULL)
		{
		}
		else
		{
			if(es->state == ES_CLOSING)
		 {
				tcp_server_connection_close(tpcb, es);
		 }
		}
		ret_err = ERR_OK;
	}
	else
	{
		tcp_abort(tpcb);
		ret_err = ERR_ABRT;
	}
	return ret_err;
}
 
static err_t tcp_server_sent(void *arg, struct tcp_pcb *tpcb, uint16_t len)
{
	struct server_struct *es;
	LWIP_UNUSED_ARG(len);
	es = (struct server_struct *)arg;
	es->retries = 0;
	if(es->p != NULL)
	{
		tcp_server_send(tpcb, es);
	}
	else
	{
		if(es->state == ES_CLOSING)
		{
			tcp_server_connection_close(tpcb, es);
		}
	}
	return ERR_OK;
}
 
static err_t tcp_server_recv(void *arg, struct tcp_pcb *tpcb, struct pbuf *p, err_t err)
{
	char str1[100];
	struct server_struct *es;
	err_t ret_err;
	LWIP_ASSERT("arg != NULL",arg != NULL);
	es = (struct server_struct *)arg;
 
	if (p == NULL)
	{
		es->state = ES_CLOSING;
		if(es->p == NULL)
		{
			tcp_recved(tpcb, p->tot_len);
		}
		else
		{
			//acknowledge received packet
			tcp_sent(tpcb, tcp_server_sent);
			//send remaining data
			tcp_server_send(tpcb, es);
		}
		ret_err = ERR_OK;
	}
	else if(err != ERR_OK)
	{
		if (p != NULL)
		{
			es->p = NULL;
			pbuf_free(p);
		}
		ret_err = err;
	}
	else if(es->state == ES_ACCEPTED)
	{
		tcp_recved(tpcb, p->tot_len);
		strncpy(str1,p->payload,p->len);
		str1[p->len] = '\0';
/* -- Send data to Serial PORT */
		PrintSerial(str1);
		ret_err = ERR_OK;
	}
	else if (es->state == ES_RECEIVED)
	{
		if(es->p == NULL)
		{
			ret_err = ERR_OK;
		}
		else
		{
			struct pbuf *ptr;
			ptr = es->p;
			pbuf_chain(ptr,p);
		}
		ret_err = ERR_OK;
	}
	else if(es->state == ES_CLOSING)
	{
		tcp_recved(tpcb, p->tot_len);
		es->p = NULL;
		pbuf_free(p);
		ret_err = ERR_OK;
	}
	else
	{
		tcp_recved(tpcb, p->tot_len);
		es->p = NULL;
		pbuf_free(p);
		ret_err = ERR_OK;
	}
	return ret_err;
}
 
static err_t tcp_server_accept(void *arg, struct tcp_pcb *newpcb, err_t err)
{
	err_t ret_err;
	struct server_struct *es;
	LWIP_UNUSED_ARG(arg);
	LWIP_UNUSED_ARG(err);
	tcp_setprio(newpcb, TCP_PRIO_MIN);
	es = (struct server_struct *)mem_malloc(sizeof(struct server_struct));
	ss = (struct server_struct *)mem_malloc(sizeof(struct server_struct));
	if (es != NULL)
	{
		es->state = ES_ACCEPTED;
		es->pcb = newpcb;
	 ss->pcb = newpcb;
	 es->retries = 0;
	 es->p = NULL;
	 tcp_arg(newpcb, es);
	 tcp_recv(newpcb, tcp_server_recv);
	 tcp_err(newpcb, tcp_server_error);
	 tcp_sent(newpcb, tcp_server_sent);
	 tcp_poll(newpcb, tcp_server_poll, 1);
	 ret_err = ERR_OK;
	}
	else
	{
		tcp_server_connection_close(newpcb, es);
		ret_err = ERR_MEM;
	}
	return ret_err;
}
 
 
void Hello(void *pvParameters)
{
	ip_addr_t ipaddr;
	IP4_ADDR(&ipaddr, 192, 168, 11, 208);
 
	server_pcb = tcp_new();
	if (server_pcb != NULL)
	{
		err_t err;
		err = tcp_bind(server_pcb, IP_ADDR_ANY, 502);
		if (err == ERR_OK)
		{
			server_pcb = tcp_listen(server_pcb);
			tcp_accept(server_pcb, tcp_server_accept);
		}
		else
		{
			memp_free(MEMP_TCP_PCB, server_pcb);
		}
	}
 
 	while(1)
 	{
 		vTaskDelay(100);
 	}
}
 

In main function I create a task:

xTaskCreate( Hello, "Hello", 4096, ( void * ) NULL, 2, NULL );

And program works (when I send anything over TCP i see it in serial output). Problem is when I try disconnect. MCU is restart.

Any idea, what is wrong?

I always get this massage:

HardFault Exception 

Here is output:

• >>>> HardFault Exception <<<<

• Fault registers:
• SCB->HFSR = 0x40000000
•  DEBUGEVT = 0
•  FORCED  = 1
•  VECTTBL  = 0
• SCB->CFSR = 0x00010000
•  IACCVIOL = 0
•  DACCVIOL = 0
•  MUNSTKERR = 0
•  MSTKERR  = 0
•  MLSPERR  = 0
•  MMARVALID = 0
•  IBUSERR  = 0
•  PRECISE E = 0
•  IMPRECISE = 0
•  UNSTKERR = 0
•  STKERR  = 0
•  LSPERR  = 0
•  BFARVALID = 0
•  UNDEFINSTR= 1
•  INVSTATE = 0
•  INVPC   = 0
•  NOCP   = 0
•  UNALIGNED = 0
•  DIVBYZERO = 0
• SCB->DFSR = 0x00000000
• SCB->MMFAR = 0x00000000
• SCB->BFAR = 0x00000000
• SCB->AFSR = 0x00000000
• SCB->ABFSR = 0x00000000

• Exception stack frame:
• R0  0x20045c98
• R1  0x20068d8c
• R2  0x00000003
• R3  0x00009a90
• R12  0x20068a54
• LR  0x08007e87
• PC  0x0800fd5c
• xPSR 0x61000000

•  >>> forcing SYSTEM RESET