MPU Fault with NCS Zephyr on nrf52840s

RE: MPU Fault with NCS Zephyr on nrf52840s

Håkon Alseth — Thu, 06 Jul 2023 09:46:28 GMT

Hi,

Faults tend to move when changing the firmware, as the timing also changes when introducing changes, so this is to be expected.

Feel free to share information related to any new faults that occurs.

Could you try to look at the thread stack usage and see if any of your threads are "close to the limit" at any point? This can give an indication on which thread could be the culprit.

https://docs.zephyrproject.org/latest/services/debugging/thread-analyzer.html

Kind regards,

Håkon

RE: MPU Fault with NCS Zephyr on nrf52840s

scath — Thu, 06 Jul 2023 06:54:22 GMT

Hi,

We recently changed settings related to TLS connections, and this seems to have changed the nature of the problem.

I no longer get MPU Faults pointing to sched.c. Instead, the issue now appears to emanate from libc-hooks.c and uart_nrfx_uart.c. This new issue is regular: it repeats at roughly the same interval as the new issue, but the offending line has been consistently the same over multiple tests.

I'm thinking that the original issue can be put on hold while I investigate the new issue.

I'm wondering if I should create a new ticket?

With thanks,

S.

RE: MPU Fault with NCS Zephyr on nrf52840s

Håkon Alseth — Thu, 29 Jun 2023 12:27:08 GMT

Hi,

Q1: Is the assert message still similar? addr2line points to a memset() call?

Q2: Have you tried to see where the RAM mapped registers (ie. those with 0x2000xxxx) point to? This is unfortunately a manual operation by looking into the build-folder/zephyr/zephyr.map file

Q3: Could you set this configuration?

CONFIG_RESET_ON_FATAL_ERROR=n

This will ensure that you do not reset when a fault occurs, so that you can connect the debugger and see the callstack (in addition to the assert output). Please share this, to see if there's anything there to help us backtrack where this occurs.

Kind regards,

Håkon

RE: MPU Fault with NCS Zephyr on nrf52840s

scath — Wed, 28 Jun 2023 16:19:55 GMT

Hi Hakon,

This hasn't helped - I still get the same error at the same rate (roughly once per hour).

RE: MPU Fault with NCS Zephyr on nrf52840s

Håkon Alseth — Tue, 27 Jun 2023 08:49:06 GMT

Hi,

[quote user="scath"]Apologies for the late reply.
[/quote]

No worries.

[quote user="scath"]Have doubled the available memory and begun testing. [/quote]

Let me know if the issue still occurs

Kind regards,

Håkon

RE: MPU Fault with NCS Zephyr on nrf52840s

scath — Mon, 26 Jun 2023 15:20:56 GMT

Apologies for the late reply.

Have doubled the available memory and begun testing. Will report back asap.

Thanks!

RE: MPU Fault with NCS Zephyr on nrf52840s

Håkon Alseth — Wed, 21 Jun 2023 11:31:26 GMT

Hi,

Looks like the current thread is out of memory. Have you tried increasing CONFIG_MAIN_STACK_SIZE to see if this helps the scenario?

Kind regards,

Håkon