nrf_ble_lesc_request_handler() hangs with CC310 and more than 5 connections

[Bruno Randolf]

Hello,

I noticed that nrf_ble_lesc_request_handler() hangs when I have NRF_CRYPTO_BACKEND_CC310_ENABLED and use a NRF_SDH_BLE_TOTAL_LINK_COUNT bigger than 5. Using the Oberon crypto backend or a link count <= 5 this problem does not exist.

I have reduced the link count so it's not an urgent issue for me, but I wanted to report the bug.

[Vidar Berg]

Hello,

Thanks for reporting. I have not seen this issue before.

Some follow up questions if you have time:

1. Does the program hang inside the cryptocell runtime library? If it does, could you post the assembly view, CPU register content, and call stack here?

2. Do you use the interrupt variant of the library?

3. Do you have a bare metal application or an RTOS application?

Thanks,

Vidar

[Bruno Randolf]

Hello and thank you for your reply!

1. I will try to answer later.

2. I don't use the interrupt variant.

3. I don't use an RTOS, nrf_ble_lesc_request_handler() is called from the main loop.

[Vidar Berg]

Hello,

Any chance you could try to use the interrupt variant instead? The non-interrupt version is usually only used in RTOS applications, and I'm not sure how safe it is to use with our regular interrupt driven examples. I suspect there may be some problems if the API is used from multiple interrupt contexts.

[Bruno Randolf]

Sorry, I was wrong. I used the interrupt variant (external/nrf_cc310/lib/cortex-m4/hard-float/libnrf_cc310_0.9.12.a)

[Bruno Randolf]

Hm, i just tried with examples/ble_peripheral/ble_app_hrs and there the problem does not happen. Must be something with the rest of my application. As CC310 is not so attractive for LESC anyways (see my other question https://devzone.nordicsemi.com/f/nordic-q-a/84251/is-it-worth-to-use-cc310-hw-crypto-for-lesc) i don't want to spend more time debugging this. Thank you for your support!

[Vidar Berg]

Thanks for the update. Just let me know if you want to revisit this as at a later point. I agree that cc310 might not be worth it in this case where it's only used for pairing.