Data Bus Hard fault when handling secure connection bonding

[thin_ice]

Hello,
I am working on an application which is freeRTOS based, now I wanted to integrate Glucose sensor app which supports secure connection and bonding. In 

ble_evt_handler, if I take out pm_handler_secure_on_connection(p_ble_evt); then my code still works it's just doesn't bond properly. However, if I leave this line of code in, I got hard fault instantly as soon as the bonding process is initiated. Could you help pointing me to the right direction to troubleshoot this issue ?

I have a feeling it has to do with  freeRTOS but I am not so sure.

Uart output:

<error> hardfault: HARD FAULT at 0x0002C8FC

<error> hardfault: R0: 0x00000000 R1: 0x4605FE50 R2: 0x20009208 R3: 0x20009208

<error> hardfault: R12: 0x200089C0 LR: 0x0002C8F1 PSR: 0x8100000E

<error> hardfault: Cause: Data bus error (PC value stacked for the exception return points to the instruction that caused the fault).

<error> hardfault: Bus Fault Address: 0x4605FE50

Call stack:

void HardFault_c_Handler()   @ 0x00029F58

void PendSV_Handler()         @ 0x0002C8EC

void PendSV_Handler()         @ 0x0002C8EC

Thank you !

[Susheel Nuguru]

Hi,

Which SDK are you using?

There are two parts of investigation 

1) Try to find out if you have applied this patch to softdevice_task as it might cause some deadlocks and wrong states in the statemachine of peer manager

2) The Hardfault address 0x2C8FC is inside the application code. The below line should be able to reveal the instruction that is causing the hardfault. We can take a closer look after understanding what that is.

addr2line -e <src.elf> 0x0002C8FC

[thin_ice]

Hello, I am using SDK 15.2 and the address points to this line (xPortPendSVHandler) as you requested.

nRF5_SDK_15.2.0_9412b96/external/freertos/portable/GCC/nrf52/port.c:104

I am going to try the patch and let you know if it helps

[Susheel Nuguru]

Hmm, This thread slipped my radar, I see that there is no solution discussed here. Could you please upload your project for me to quickly do a test on my desk?

[asaf]

sorry my project is an company code that run on dedicated hardware.

the issue doesn't occurs on optimization level "Debug".

the fault I get while pushing button ( then no issue when call the same function the button call by software).

another fault I get is:

<error> hardfault: HARD FAULT at 0x00000004
<error> hardfault: R0: 0x20006594 R1: 0x200064E8 R2: 0x2000D444 R3: 0x2000D444
<error> hardfault: R12: 0x20008278 LR: 0x00000004 PSR: 0x6000000E
<error> hardfault: Cause: The processor has attempted to execute an instruction that makes illegal use of the EPS

[Susheel Nuguru]

It looks like a register pop has been done from a corrupted stack frame which in turn corrupted the PC value. Check if you have enough stack allocated for each task you have and check if you have enough heap dedicated in FreeRTOSConfig.h file to dedicate bigger chunks of stacks for tasks.

[asaf]

how can I find which task need more stack ? 

[Susheel Nuguru]

That is hard to debug but not impossible. I would rather suggest you to increase stack modestly for every task you have and if that helps, reduce the size back to what it was before to isolate the task in question.