HARDFAULT handler call

[Mikael]

Hello,

we've got a quite unpredictable issue with a hardfault call : actually this is in this function call : app_error_fault_handler (in app_error_weak.c file)

We use SDK 17.02 and bootloader.
this is a custom board.

The issue appears when : BLE is advertising and lora data is sent (but not every time, this is a necessary but not enough condition).
We use as well timer to mange uart transfer from another device which send the data to lora, timer for ble and a timer tick.
All of these timers are created with app_timer_create() function.

Actually, as the issue is not easy to reproduce I suspect that the issue is something linked with a timing issue of one or many of this timer (it is not a code that I have developped, so not so easy to give more details).

When the issue occured, then we are in __WEAK void app_error_fault_handler(uint32_t id, uint32_t pc, uint32_t info), with the following :

- id = 1  so this mean NRF_FAULT_ID_SD_ASSERT : NRF_LOG_ERROR("SOFTDEVICE: ASSERTION FAILED");

- pc = 0x00012976 ==> seems in soft device part

- info : 0

hereunder the cpu registers, sp is 0x2000fd70

hereunder the stack :

the word 0xCAFEBABE seems to be a magic number to maybe help you to debug critical issue?

the callstack is not really help me :

last, the SCB arm registers contains this : where 0xE000ED2C address contains value 0x40000000 which means in "ARMv7-M Architecture
Reference Manual" page 612 HardFault Status Register, HFSR, Purpose Shows the cause of any HardFault.

FORCED, bit[30] Indicates that a fault with configurable priority has been escalated to a HardFault exception,
because it could not be made active, because of priority or because it was disabled:
0 No priority escalation has occurred.
1 Processor has escalated a configurable-priority exception to HardFault.

Hope I give you enough details to help me in my research to find the root cause issue.

Many thanks

Regards

Mikael

[Sigurd]

Hi,

What SoftDevice version and variant are you using ? Is it S112 v.7.2.0?

If yes, then it seems to be the same type of assert that is discussed in e.g. this post, devzone.nordicsemi.com/.../assert-fault-using-softdevice

Are you using the timeslot feature in the SoftDevice ?

Do you have critical regions in your code which temporarily disable interrupts globally?

[Mikael]

Hi,

softdevice S112 v17.0.2

no timeslot but lot of critical CRITICAL_SECTION_BEGIN/END in protocol lora stack. (mac, timer, radio,...)

[Mikael]

maybe the most dangerous one are those located in timer.c file :

/Application/Protocol/lora/system/timer.c:CRITICAL_SECTION_BEGIN();
/Application/Protocol/lora/system/timer.c:CRITICAL_SECTION_END( );
/Protocol/lora/system/timer.c:CRITICAL_SECTION_END( );
/Protocol/lora/system/timer.c:CRITICAL_SECTION_BEGIN( );
/Application/Protocol/lora/system/timer.c:CRITICAL_SECTION_END( );
/Application/Protocol/lora/system/timer.c:CRITICAL_SECTION_END( );

void TimerStart(TimerEvent_t *obj)
{
    uint32_t elapsedTime = 0;

    CRITICAL_SECTION_BEGIN();

    if ((obj == NULL) || (TimerExists(obj) == true))
    {
        CRITICAL_SECTION_END( );
        return;
    }

    obj->Timestamp = obj->ReloadValue;
    obj->IsStarted = true;
    obj->IsNext2Expire = false;

    if( TimerListHead == NULL )
    {
        RtcSetTimerContext();
        
        // Inserts a timer at time now + obj->Timestamp
        TimerInsertNewHeadTimer( obj );
    }
    else
    {
        elapsedTime = RtcGetTimerElapsedTime();
        obj->Timestamp += elapsedTime;

        if( obj->Timestamp < TimerListHead->Timestamp )
        {
            TimerInsertNewHeadTimer(obj);
        }
        else
        {
            TimerInsertTimer(obj);
        }
    }
    CRITICAL_SECTION_END( );

    
}

void TimerStop( TimerEvent_t *obj )
{
    CRITICAL_SECTION_BEGIN( );

    TimerEvent_t* prev = TimerListHead;
    TimerEvent_t* cur = TimerListHead;

    // List is empty or the obj to stop does not exist
    if( ( TimerListHead == NULL ) || ( obj == NULL ) )
    {
        CRITICAL_SECTION_END( );
        return;
    }

    obj->IsStarted = false;

    if( TimerListHead == obj ) // Stop the Head
    {
        if( TimerListHead->IsNext2Expire == true ) // The head is already running
        {
            TimerListHead->IsNext2Expire = false;
            if( TimerListHead->Next != NULL )
            {
                TimerListHead = TimerListHead->Next;
                TimerSetTimeout( TimerListHead );
            }
            else
            {
                RtcStopAlarm( );
                TimerListHead = NULL;
            }
        }
        else // Stop the head before it is started
        {
            if( TimerListHead->Next != NULL )
            {
                TimerListHead = TimerListHead->Next;
            }
            else
            {
                TimerListHead = NULL;
            }
        }
    }
    else // Stop an object within the list
    {
        while( cur != NULL )
        {
            if( cur == obj )
            {
                if( cur->Next != NULL )
                {
                    cur = cur->Next;
                    prev->Next = cur;
                }
                else
                {
                    cur = NULL;
                    prev->Next = cur;
                }
                break;
            }
            else
            {
                prev = cur;
                cur = cur->Next;
            }
        }
    }
    CRITICAL_SECTION_END( );
}