Zephyr 3.7 CONFIG_LOG_LEVEL_DEBUG=4 causes immediate stack overflow

[rcolatobe]

Describe the bug
I have an out of tree board based on the STM32 Nucleo_H743ZI. I recently added the Zephyr Logging Module to the project and have no issues using it with LOG_LEVEL_DEFAULT=3. However if I switch the default to 4 I get the error listed in the console output section.

To ensure it wasn't my application code causing the crash, I built and flash the board with the button sample project and can reproduce the problem.

If I switch the Logging mode to deferred hundreds of messages are dropped, so I assume the IMMEDIATE_MODE is causing the stack overflow at start up.

The stack overflow does go away if I comment out all CONFIG_SHELL=y. Assuming the shell had the stack overflow I included a CONFIG_SHELL_STACK_SIZE and went as high as 32768, but the error persisted.

The following is the board's defconfig file.

# SPDX-License-Identifier: Apache-2.0

# Enable MPU
CONFIG_ARM_MPU=y

# Enable HW stack protection
CONFIG_HW_STACK_PROTECTION=y

# Enable UART
CONFIG_SERIAL=y
CONFIG_SHELL_BACKEND_SERIAL_RX_RING_BUFFER_SIZE=512

# Console
CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=y

# Enable GPIO
CONFIG_GPIO=y

# Enable clocks
CONFIG_CLOCK_CONTROL=y

# enable pin controller
CONFIG_PINCTRL=y

# CPP Config
CONFIG_CPP=y
CONFIG_GLIBCXX_LIBCPP=y
CONFIG_STD_CPP20=y

CONFIG_PRINTK=y
CONFIG_DEBUG=y
CONFIG_MAIN_STACK_SIZE=8192
CONFIG_NEWLIB_LIBC=y
CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y
CONFIG_CBPRINTF_FP_SUPPORT=y

CONFIG_SHELL=y
CONFIG_SHELL_MINIMAL=y
CONFIG_SHELL_HELP=y

CONFIG_USB_DEVICE_STACK=n

CONFIG_LOG=y
CONFIG_LOG_MODE_IMMEDIATE=y
CONFIG_LOG_DEFAULT_LEVEL=4

To Reproduce

west build -b BOARD_NAME zephyr/samples/basic/button -p -DBOARD_ROOT=PATH_TO_OUT_OF_TREE_BOARDS_FOLDER
west flash

Logs and console output
```
[00:00:00.029,000] os: ***** MPU FAULT *****
[00:00:00.046,000] os: Stacking error (context area might be not valid)
[00:00:00.051,000] os: Data Access Violation
[00:00:00.059,000] os: MMFAR Address: 0x24001ca4
[00:00:00.068,000] os: r0/a1: 0x24001d18 r1/a2: 0x0000001c r2/a3: 0x00000008
[00:00:00.085,000] os: r3/a4: 0x080149c8 r12/ip: 0x00000000 r14/lr: 0x00000000
[00:00:00.093,000] os: xpsr: 0x00000000
[00:00:00.099,000] os: Faulting instruction address (r15/pc): 0x00000000
[00:00:00.114,000] os: >>> ZEPHYR FATAL ERROR 2: Stack overflow on CPU 0
[00:00:00.119,000] os: Current thread: 0x24000a50 (shell_uart)
[00:00:00.131,000] os: Halting system
```

Environment

• OS: (e.g. Linux, MacOS, Windows)
• Toolchain (e.g Zephyr SDK, ...)
• Commit SHA or Version used

I am using Zephyr 3.7 (36940db) and docker image (zephyrprojectrtos/ci:v0.27.4)

Please let me know if there is any more information needed.

[FRASTM]

Hi,

the pb you see is probably something already discussed here #39220

Can you test with CONFIG_SHELL_LOG_BACKEND=n in the prj.conf

[rcolatobe]

Adding that to the prj.conf eliminates the stack overflow error.