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Tool/software: Code Composer Studio
Hello!
I work on project where custom board based on TM4C129K MCU is connecting to external device via TCP/IP. The traffic is rather big - device sends me data at up to 125kb/sec, but controlling traffic from my board to device is not big.
Rarely (about once per couple of days) I got hard fault inside tcp_output() function:
if (TCP_TCPLEN(seg) > 0) {
seg->next = NULL;
/* unacked list is empty? */
if (pcb->unacked == NULL) {
pcb->unacked = seg;
useg = seg;
/* unacked list is not empty? */
} else {
/* In the case of fast retransmit, the packet should not go to the tail
* of the unacked queue, but rather somewhere before it. We need to check for
* this case. -STJ Jul 27, 2004 */
if (TCP_SEQ_LT(ntohl(seg->tcphdr->seqno), ntohl(useg->tcphdr->seqno))) {
/* add segment to before tail of unacked list, keeping the list sorted */
struct tcp_seg **cur_seg = &(pcb->unacked);
while (*cur_seg &&
TCP_SEQ_LT(ntohl((*cur_seg)->tcphdr->seqno), ntohl(seg->tcphdr->seqno))) {
cur_seg = &((*cur_seg)->next );
}
seg->next = (*cur_seg);
(*cur_seg) = seg;
} else {
/* add segment to tail of unacked list */
useg->next = seg;
useg = useg->next; // <---- HERE!
}
}
/* do not queue empty segments on the unacked list */
} else {
tcp_seg_free(seg);
}
seg = pcb->unsent;
in the line
useg = useg->next;
and useg here is ether 0 of corrupt.
Asked on lwip support forum, but they said the version of lwip is old and is a port by TI, so I should ask TI engineers.
Currently device is stopped in debug state right after hard fault, so I can browse any variables or memory.
The heap state at time of fault is ok, as I embedded heap checking in hard fault ISR.
Hi Oleg,
Can you check your stack size? Is it possible that you have a stack overflow? Here is an app note that will help you diagnose hard faults.
Another thing to check is the below options in the lwipopts.h file. In the TivaWare ethernet examples (e.g. enet_io, enet_lwip) the below memory and tcp options are used. I don't know what your configurations are. You might want to try with larger MEM_SIZE, MEMP_NUM_PBUF and MEMP_NUM_TCP_PCB to see if they make any differences.
Since you said the problem will only occur after many days, I will close the thread for now and you can update this post again if you have new findings.
//***************************************************************************** // // ---------- Memory options ---------- // //***************************************************************************** //#define MEM_LIBC_MALLOC 0 #define MEM_ALIGNMENT 4 #define MEM_SIZE (64 * 1024) //#define MEMP_OVERFLOW_CHECK 0 //#define MEMP_SANITY_CHECK 0 //#define MEM_USE_POOLS 0 //#define MEMP_USE_CUSTOM_POOLS 0 //***************************************************************************** // // ---------- Internal Memory Pool Sizes ---------- // //***************************************************************************** #define MEMP_NUM_PBUF 48 // Default 16 //#define MEMP_NUM_RAW_PCB 4 //#define MEMP_NUM_UDP_PCB 4 #define MEMP_NUM_TCP_PCB 16 // Default 5 //#define MEMP_NUM_TCP_PCB_LISTEN 8 //#define MEMP_NUM_TCP_SEG 16 //#define MEMP_NUM_REASSDATA 5 //#define MEMP_NUM_ARP_QUEUE 30 //#define MEMP_NUM_IGMP_GROUP 8 #define MEMP_NUM_SYS_TIMEOUT 8 //#define MEMP_NUM_NETBUF 2 //#define MEMP_NUM_NETCONN 4 //#define MEMP_NUM_TCPIP_MSG_API 8 //#define MEMP_NUM_TCPIP_MSG_INPKT 8 #define PBUF_POOL_SIZE 48 // Default 16
