6 days, 22 hours ago.

TCPSocket client.close() causes hardware fault.

Yesterday I received the MBED OS 5.10.1 available newsletter, in that newsletter it is said that an issue regarding client.accept() returning a NULL pointer was solved in the current MBED OS release.

I had some problems a few weeks ago regarding this so naturally I had to try ... You'll find the code I've written below.

EthernetInterface iface;
//TCPServer server;
TCPSocket server;
TCPSocket *client;
SocketAddress clientAddress;

int main (void)
    pc.printf("\n\nServer IP Address is %s\n", iface.get_ip_address());;

    while (true) {
         pc.printf("Server bound and listening\n");
        // server.accept(&client, &clientAddress);
        client = server.accept();

        char    buffer[1024];
        int     n = client->recvfrom(&clientAddress, buffer, sizeof(buffer));

        pc.printf("Connection succeeded!\nClient local stack address: 0x%08X\nClient's IP address: %s:%d\n\n", client, 
                     clientAddress.get_ip_address(), clientAddress.get_port());
        pc.printf("Received %u bytes from remote host\n", n);  //print received message to terminal
        buffer[n] = NULL;
        pc.printf("Received message from Client :'%s'\n", buffer);

        pc.printf("Sending echo to client\n");
        client->send(buffer, n);


The software implements a simple TCPSocket echo server and produces the output below.

Server IP Address is
Server bound and listening
Connection succeeded!
Client local stack address: 0x100032C0
Client's IP address:

Received 10 bytes from remote host
Received message from Client :'Hallo MBED'
Sending echo to client

++ MbedOS Fault Handler ++

FaultType: HardFault

R0   : 000063A1
R1   : 100029C8
R2   : 10001474
R3   : 00000001
R4   : 00000002
R5   : 000063A1
R6   : 00000000
R7   : 00000000
R8   : 100025A8
R9   : 0000C91E
R10  : 00000000
R11  : 00000000
R12  : 10000B68
SP   : 10007FB0
LR   : 00012C73
PC   : 0000FE78
xPSR : 21001C0B
PSP  : 10001470
MSP  : 10007F90
CPUID: 412FC230
HFSR : 40000000
MMFSR: 00000000
BFSR : 00000004
UFSR : 00000000
DFSR : 0000000A
AFSR : 00000000
Mode : Handler
Priv : Privileged
Stack: MSP

-- MbedOS Fault Handler --

++ MbedOS Error Info ++
Error Status: 0x80FF013D Code: 317 Module: 255
Error Message: Fault exception
Location: 0xD859
Error Value: 0xFE78
Current Thread: Id: 0x100029C8 Entry: 0xDACB StackSize: 0x1000 StackMem: 0x100019C8 SP: 0x10007F48
For more info, visit:
-- MbedOS Error Info --

My TCP client application received the echo ... so the line that generated the MBedOS Error must certainly be client->close(). Am I doing something wrong?

Kind regards,


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