debug_a_fault: A C repository from Rallare

Debugging faults

Overview

A simple sample that can be used with any nrf board and prints "Hello Faulting in ... 5 4 3 2 1", followed by a fault output to the console.

The purpose of this project is to show how to use tools like addr2line, as well as entering debug mode to watch the CPU register content upon fault.

Exercises

Debugging the fault:

With logging enabled
With logging in secure enabled
Without logging enabled, by entering debug mode and reading the CPU register content upon fault

Use of debug tools, such as addr2line and .map file parsing, find the following:

file:line_number
The thread function/name that caused the fault by parsing the .map file

Understanding the boot process:

Single-stepping through the boot process to see what is invoked before entering your program
Understanding _INIT_PRIORITY of a subsys/driver, which is executed first? Let us look at the GPIO and SERIAL subsys

Reading material

Init procedure in Zephyr:

https://docs.zephyrproject.org/3.6.0/kernel/drivers/index.html#initialization-levels

https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-7-device-driver-model/topic/driver-implementation/

addr2line usage in NCS:

https://academy.nordicsemi.com/courses/nrf-connect-sdk-intermediate/lessons/lesson-2-debugging/topic/build-errors-and-fatal-errors/`

Building and Running

This project is board agnostic, but it is recommended to use nRF5340-DK. Running on a non-secure application allows to show secure faults.

Sample Output