Re: Memory corruption (?) I don't understand

[BERTRAND Joël]

BERTRAND Joël a écrit :
> Trampas Stern a écrit :
>> Does the code run if you comment out 'lora_send("coucou", 7);
> 
>       Yes. To be honnest, if I comment out LDL_MAC_otaa(&mac), it runs.
> 
>> Does it still crash with simple main() { _delay_ms(1000);
>> stty_print("hello");}
>>
>> That is start removing code until it works, when you find the line in
>> main that causes a crash, go into that function and start removing code
>> until it works.  Slowly you will find the problem. 
> 
>       I have tried (and I continue...) but I'm not sure that this bug is in
> LoRaWAN library. Indeed, LDL_MAC_otaa(&mac) shows my bug but, sometimes,
> just with a debug trace in main(), LDL_MAC_otaa(&mac) doesn't crash.

        In lorawan/ldl_mac.c, you have :


enum ldl_mac_status LDL_MAC_otaa(struct ldl_mac *self)
{
...
            fillJoinBuffer(self, U16(self->devNonce));

            self->devNonce++;

            arg.dev_nonce_updated.nextDevNonce = self->devNonce;

            self->handler(self->app, LDL_MAC_DEV_NONCE_UPDATED, &arg);

            self->tx.power = 0;

            self->op = LDL_OP_JOINING;
...
}


        If I comment out :

        self->handler(self->app, LDL_MAC_DEV_NONCE_UPDATED, &arg);

        Firmware doesn't crash. This pointer is a pointer to app_handler() in
./lorawan.c.

        Now, I suppose that this pointer is modified. Thus, I have add a debug
trace :

enum ldl_mac_status LDL_MAC_otaa(struct ldl_mac *self)
{
    enum ldl_mac_status retval;
    union ldl_mac_response_arg arg;
...
unsigned char t[80];
snprintf(t, 80, "self->handler=%p\r\n", self->handler);
stty_print(t);
            self->handler(self->app, LDL_MAC_DEV_NONCE_UPDATED, &arg);

            self->tx.power = 0;

            self->op = LDL_OP_JOINING;
...
}

and with this simple debug trace, it doesn't crash anymore !...