RE: HardFault_Handler() called when NRF_LOG_ENABLED is disabled

Prasad — Tue, 28 Mar 2017 07:56:02 GMT

Short answer

This is a memory alignment issue and it got fixed by adding . = ALIGN(4) in my linker script.

Long answer

I debugged the code in GDB. Problem gets manifested in the below snippet from fstorage.c

for (uint32_t i = 0; i < total_users; i++)
{
    fs_config_t const * const p_config = FS_SECTION_VARS_GET(i);

    ==>if ((p_config->p_start_addr != NULL) &&
        (p_config->p_end_addr   != NULL))
    {
        configs_to_init--;
    }
}

When I step over from this point I end up in the HardFault_Handler(). After investigation, I found that FS_SECTION_VARS_GET(i) is not returning the correct address of fs_config. Then with objdum I checked the addresses of __start_fs_data and fs_config in the object file.

When NRF_LOG_ENABLED = 1

200029e4 g       .data  00000000 __start_fs_data
200029e4 l     O .data  00000010 fs_config

When NRF_LOG_ENABLED = 0

2000202a g       .data  00000000 __start_fs_data
2000202c l     O .data  00000010 fs_config

You can see that when NRF_LOG_ENABLED = 0, __start_fs_data is not aligned with fs_config and hence the macro FS_SECTION_VARS_GET(i) returns an address where valid data doesn’t exist, causing a hardware fault.

Resolution is to add . = ALIGN(4) in your linker file as show below.

.data : AT(_sidata)
{
	. = ALIGN(4);
	_sdata = .;

	PROVIDE(__data_start__ = _sdata);
	*(.data)
	*(.data*)

==>	. = ALIGN(4);

	PROVIDE(__start_fs_data = .);
	KEEP(*(.fs_data))
	PROVIDE(__stop_fs_data = .);
	
	. = ALIGN(4);
	_edata = .;

	PROVIDE(__data_end__ = _edata);
} > SRAM

I chose to fix it this way, if anyone knows of a better solution then please let me know.

RE: HardFault_Handler() called when NRF_LOG_ENABLED is disabled

Jørgen Holmefjord — Mon, 27 Mar 2017 12:17:01 GMT

Which SDK version are you using? Which example for the SDK are your application built on? Could you try debugging using this method, to check if you get any error codes, or which call is fausing the hardfault?

RE: HardFault_Handler() called when NRF_LOG_ENABLED is disabled

Prasad — Mon, 27 Mar 2017 10:20:27 GMT

This doesn't seem to be the case as I checked it with a clean build.

RE: HardFault_Handler() called when NRF_LOG_ENABLED is disabled

Turbo J — Sat, 25 Mar 2017 20:30:11 GMT

Clean the project and recompile, you may have mixed old and new compiled object files.