peripheral-and-central-uart-sample-crash

RE: peripheral-and-central-uart-sample-crash

Øivind — Tue, 19 Apr 2022 06:29:44 GMT

Hi again,

We now have a pull request up with a fix for the double free issue in these samples.

https://github.com/nrfconnect/sdk-nrf/pull/7190

Thank you for your patience.

RE: peripheral-and-central-uart-sample-crash

TF mulder — Fri, 08 Apr 2022 09:53:09 GMT

Ah Ok i see, thanks

it is becoming more clear now

RE: peripheral-and-central-uart-sample-crash

Øivind — Fri, 08 Apr 2022 08:34:30 GMT

Hi,

Great to see that you are trying to figure out what the issue is, but I unfortunately have to inform you that both those buffers already have an associated k_free().

The buffers allocated in central_uart's ble_data_received() and in peripheral_uart's bt_receive_cb() are later passed to k_free in the UART_TX_DONE case of uart_cb().

If you are seeing improvements from your changes, you should double check that uart_cb is getting the UART_TX_DONE event and freeing the buffer properly.

RE: peripheral-and-central-uart-sample-crash

TF mulder — Thu, 07 Apr 2022 15:09:14 GMT

Hi Øivind,

I have now only removed the k_free(), to prevent the crash, at the beginning.

After further working with the Central_uart AND the Peripheral_uart.. after some communication running it reveals an other-crash on both sides.

I found a memory leakage situation in the central AND in the peripheral...

->in the central_uart: in ble_data_received() there is a

struct uart_data_t *tx = k_malloc(sizeof(*tx));

but there is no k_free(tx) ;

->in the periferal_uart in bt_recive_cb() there is a

struct uart_data_t *tx = k_malloc(sizeof(*tx));

but there is no k_free(tx) ;

After i added these k_free()'s i had a continiously running communication...

-----

Do i now have earned a free nrf5340_DK board ?? :-), or several nrf52840-dongles.. ?? :-)

Best Regards,

Theo

RE: peripheral-and-central-uart-sample-crash

TF mulder — Wed, 06 Apr 2022 12:27:26 GMT

Ok Thanks Øivind, Looking forward to the update

Best Regards,

Theo

RE: peripheral-and-central-uart-sample-crash

Øivind — Wed, 06 Apr 2022 09:37:04 GMT

Hi,

As I said in the ticket you linked, we are working on a fix and I will update you when I have more to share.

probably not THE sollution, but when i empty (remove the code) of the routine:

static void ble_data_sent(struct bt_nus_client *nus, uint8_t err,

const uint8_t *const data, uint16_t len)

the the crash is gone, and the send data i see on the peripheral.

...but, probably i have now a missing feature ????

Removing the k_sem_give() in that callback would not be good, but it looks like it would mostly slow the sample down and produce a lot of warnings.

Removing the rest of the code, along with the k_free() would cause a memory leak and the sample would crash after enough messages were sent.