Trying to figure out a bus fault error (Zephyr + NRF52840)

[Albert_0]

Hey all,

I'm looking for a bit of guidance here to nail a bus fault that happens about 30 minutes into the program. 

The message is the following:

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[00:32:57.663,177] <err> os: ***** BUS FAULT *****

[00:32:57.663,177] <err> os: Precise data bus error

[00:32:57.663,208] <err> os: BFAR Address: 0x80bf68c8

[00:32:57.663,208] <err> os: r0/a1: 0x80bf68b4 r1/a2: 0x20029668 r2/a3: 0x20029640

[00:32:57.663,238] <err> os: r3/a4: 0x00000040 r12/ip: 0x2002158b r14/lr: 0x0004307d

[00:32:57.663,238] <err> os: xpsr: 0x91000000

[00:32:57.663,238] <err> os: Faulting instruction address (r15/pc): 0x00043d9e

[00:32:57.663,299] <err> os: >>> ZEPHYR FATAL ERROR 25: Unknown error on CPU 0

[00:32:57.663,330] <err> os: Current thread: 0x20002828 (unknown)

[00:32:57.724,395] <err> fatal_error: Resetting system

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

[00:32:57.663,177] <err> os: ***** BUS FAULT *****
[00:32:57.663,177] <err> os:   Precise data bus error
[00:32:57.663,208] <err> os:   BFAR Address: 0x80bf68c8
[00:32:57.663,208] <err> os: r0/a1:  0x80bf68b4  r1/a2:  0x20029668  r2/a3:  0x20029640
[00:32:57.663,238] <err> os: r3/a4:  0x00000040 r12/ip:  0x2002158b r14/lr:  0x0004307d
[00:32:57.663,238] <err> os:  xpsr:  0x91000000
[00:32:57.663,238] <err> os: Faulting instruction address (r15/pc): 0x00043d9e
[00:32:57.663,299] <err> os: >>> ZEPHYR FATAL ERROR 25: Unknown error on CPU 0
[00:32:57.663,330] <err> os: Current thread: 0x20002828 (unknown)
[00:32:57.724,395] <err> fatal_error: Resetting system

Reading through previous threads I found some information:

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(base) PS \build\zephyr> arm-none-eabi-addr2line.exe -e .\zephyr.elf 0x4307d

C:/ncs/v2.5.0/zephyr/kernel/sched.c:1959

(base) PS \build\zephyr> arm-none-eabi-addr2line.exe -e .\zephyr.elf 0x43d9e

C:/ncs/v2.5.0/zephyr/kernel/pipes.c:217

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

(base) PS \build\zephyr> arm-none-eabi-addr2line.exe -e .\zephyr.elf 0x4307d
C:/ncs/v2.5.0/zephyr/kernel/sched.c:1959
(base) PS \build\zephyr> arm-none-eabi-addr2line.exe -e .\zephyr.elf 0x43d9e
C:/ncs/v2.5.0/zephyr/kernel/pipes.c:217

That tells me that the error seems to be in one of the pipes. Additionally I found the following:

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0x20029668:

0x20029640:

.noinit."../src/tasks/controller.c".0

0x0000000020028f60 0x800 app/libapp.a(controller.c.obj)

0x0000000020028f60 _k_thread_stack_controller_rx_task_tid

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

0x20029668:
0x20029640:
 .noinit."../src/tasks/controller.c".0
                0x0000000020028f60      0x800 app/libapp.a(controller.c.obj)
                0x0000000020028f60                _k_thread_stack_controller_rx_task_tid

It seems the receiver task (controller_rx_task_tid) is causing the issue, which makes sense because that thread is related to writing to some pipes. So far I think I'm able to narrow it to where the issue is happening. 

What I'm confused about and could not find any information about was:

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[00:32:57.663,208] <err> os: BFAR Address: 0x80bf68c8

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

[00:32:57.663,208] <err> os:   BFAR Address: 0x80bf68c8

Is there a peripheral with that address on the NRF52840 series? I could not find that on the product specification. There are two addresses in that range that I'm not sure where they are:

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[00:32:57.663,208] <err> os: BFAR Address: 0x80bf68c8

[00:32:57.663,208] <err> os: r0/a1: 0x80bf68b4

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

[00:32:57.663,208] <err> os:   BFAR Address: 0x80bf68c8
[00:32:57.663,208] <err> os: r0/a1:  0x80bf68b4

Any suggestions or additional information you can give me that could help me search for other things is appreciated.

Cheers,

Alberto