CONFIG_BT_DEBUG_LOG vs atomic_ operations

[novalisek]

Describe the bug
Hi, I ty to use atomic_clear in my app, but it is crashing. I found out that it has something to do with CONFIG_BT_DEBUG_LOG

To Reproduce
Steps to reproduce the behavior:

Add this to prj.conf

CONFIG_BT=y
CONFIG_BT_DEBUG_LOG=y

and those lines to main.c

atomic_t test = ATOMIC_INIT(0);
void main(void)
{
	atomic_val_t last = atomic_clear(test);

then I get

*** Booting Zephyr OS build zephyr-v2.1.0-581-g4e135d76a3c2 ***
[00:00:00.005,126] os: ***** MPU FAULT *****
[00:00:00.005,126] os: Data Access Violation
[00:00:00.005,157] os: MMFAR Address: 0x0
[00:00:00.005,157] os: r0/a1: 0xfffffff5 r1/a2: 0x20001b50 r2/a3: 0x00000000
[00:00:00.005,157] os: r3/a4: 0x00000000 r12/ip: 0xe000ed90 r14/lr: 0x00007681
[00:00:00.005,157] os: xpsr: 0x61000000
[00:00:00.005,157] os: Faulting instruction address (r15/pc): 0x0000058a
[00:00:00.005,157] os: >>> ZEPHYR FATAL ERROR 0: CPU exception on CPU 0
[00:00:00.005,187] os: Current thread: 0x20000c78 (unknown)
[00:00:00.069,976] os: Halting system

When I disable CONFIG_BT_DEBUG_LOG, there is no fault

Expected behavior
There should be no MPU FAULT

Environment (please complete the following information):

• board: nrf52840_pca10040
• OS: W7
• Toolchain: GNU ARM Embedded 9-2019-q4
• Commit SHA or Version used: 4e135d7

[jhedberg]

Your code:

atomic_t test = ATOMIC_INIT(0);
void main(void)
{
	atomic_val_t last = atomic_clear(test);

atomic_clear() takes a pointer to atomic - you seem to be passing by value instead of by reference, which would explain strange behaviour (probably nothing to do with logging)

[novalisek]

Oh sorry,
that was a stupid error, I guess I was overwriting wrong memory. I should better watch the warnings in Eclipse :) Sorry once again for false alarm.