MPU Fault in Bluetooth: HCI Power Control

[vasilje]

OS:Ubuntu

Board: nrf52840DK

SDK: NRF Connect SDK (master branch)

After building provided example: Bluetooth: HCI Power Control and flashing the board, in serial monitor I get the following errors:

[00:00:00.000,091] <err> os: ***** MPU FAULT *****
[00:00:00.000,091] <err> os:   Data Access Violation
[00:00:00.000,122] <err> os:   MMFAR Address: 0x20004e80
[00:00:00.000,122] <err> os: r0/a1:  0x20004e38  r1/a2:  0x00000000  r2/a3:  0x00000220
[00:00:00.000,122] <err> os: r3/a4:  0x20004e80 r12/ip:  0xe000ed90 r14/lr:  0x0001c993
[00:00:00.000,122] <err> os:  xpsr:  0x81000000
[00:00:00.000,122] <err> os: Faulting instruction address (r15/pc): 0x0001e976
[00:00:00.000,122] <err> os: >>> ZEPHYR FATAL ERROR 0: CPU exception on CPU 0
[00:00:00.000,152] <err> os: Current thread: 0x20002500 (unknown)
[00:00:01.049,957] <err> fatal_error: Resetting system

Commands used to build and flash:

west build -p auto -b nrf52840dk_nrf52840 samples/bluetooth/hci_pwr_ctrl
west flash

When I tried building and flashing just with zephyr original code, from their master branch, everything worked without any problems. What can be wrong?

[Susheel Nuguru]

Sorry for the late reply.

I just tried to run this on latest master compiling on windows. but did not see this error.

Could you please give me the commit number and your compiler versions so that i can tune into them. 

I will first try those exact versions on windows and on Ubuntu virtual machine later

[vasilje]

Hi,

This is the last commit from the zephyr tree in the ncs workspace:

commit 746d14a3380fb6807afed61c4c024485ae8212f9 (HEAD, manifest-rev)
Author: Joakim Andersson <[email protected]>

Keep in mind that this mistake happens when trying to build this project when building from the `ncs/zephyr` directory

[Susheel Nuguru]

Vasilije,

I have reproduced it, and the memfault seems to happen quite early in the boot up process. I have looking in it for more explanation, and i will come back to you when i have some more info on this.

[Susheel Nuguru]

Hi Vasilije,

Not sure why I did not reproduce this in the first test.

But there seems to be an issue with the main stack size.

Increasing the CONFIG_MAIN_STACK_SIZE from 320 to 640 seems to fix this issue.

I created an internal ticket to follow this up for the next release. Thanks for letting us know.

[vasilje]

Hey, I am not sure why, but it didnt work. Maybe you are in another commit, because I couldnt find CONFIG_MAIN_STACK_SIZE set for nrf52840dk_nrf52840, as well as for the hci_pwr_ctrl project. I tried setting it up to 640 in hci_pwr_ctrl project in prj.conf, as well as in nrf52840dk_nrf52840_defconfig. Still getting the same error.