hardfault cJSON cJSON_CreateObject() while LWIP runs

[ronwal]

Hi all

I am facing a really anoying hardfault when calling 

cJSON_CreateObject(...) 

 from the cJSON lib while LWIP TCP server is up and running. If LWIP is not polled, the json creation code works just fine. My hardware ist LPC54018 (baremetal). 

Thanks for any help...

Ron

LPC54018_Project.axf [LPC54018 (cortex-m4)]
    Thread #1 1 (Suspended : Signal : SIGSTOP:Stopped (signal))
      HardFault_Handler() at semihost_hardfault.c:61 0x10016c60
      <signal handler called>() at 0xffffffe9
      ENET_SetMacControl() at fsl_enet.c:397 0x1001010a
      global_hooks() at 0x2


Active faults
Bus Fault (BFSR)
  IMPRECISERR     (2)        Imprecise data bus error
Hard Fault (HFSR)
  FORCED          (30)       Indicates a forced hard fault, generated by 
escalation of a fault with configurable priority that cannot be handled, 
either because of priority or because it is disabled

Fault Status Registers
IPSR            0x00000003      Exception Status Register (Hard Fault)
CFSR            0x00000400      Configurable fault Status Register
MMSR            0x00000000      Memory Manage fault Status Register
BFSR            0x00000004      Bus fault Status Register
UFSR            0x00000000      User fault Status Register
HFSR            0x40000000      Hard fault Status Register
DFSR            0x00000000      Debug fault Status Register
MMAR            0xE000EDF8      Memory Manage fault Address Register
BFAR            0xE000EDF8      Bus fault Address Register
AFSR            0x00000000      Auxiliary fault Status Register

Stacked Registers (MSP LR/EXC_RETURN=0xffffffe9)
R0              0x00000028
R1              0x00020FDE
R2              0x10010101
R3              0x00000011
R12             0x00000011
LR              0x10016073      cJSON_New_Item()  @ 
\LPC54018_Project\source\cjson\cJSON.c line 205
PC              0x1001010A      ENET_SetMacControl()  @ 
\LPC54018_Project\lwip\port\fsl_enet.c line 397
PSR             0x01000000
MSP             0x2FEE0

[ronwal · Accepted solution]

Hi

After some more research I discovered that somehow the global hook function pointer for malloc inside the cJSON lib got overwritten. I do not know why, yet. Calling the cJSON_init(NULL) right before calling CJSON_CreateObject() fixes the problem for now.

BR

Ron

[xiangjun_rong]

Hi,

I suggest you call the ENET_Init() in fsl_enet.c firstly, which call the ENET_SetMacControl().

In other words, before you write the ethernet module register, you have to enable the ethernet module clock with the line CLOCK_EnableClock(s_enetClock[instance]);

Otherwise, the hardfault error will be triggered.

Hope it can help you

BR

XiangJun Rong

void ENET_Init(ENET_Type *base, const enet_config_t *config, uint8_t *macAddr, uint32_t refclkSrc_Hz)
{
assert(config);

uint32_t instance = ENET_GetInstance(base);
#if !(defined(FSL_SDK_DISABLE_DRIVER_CLOCK_CONTROL) && FSL_SDK_DISABLE_DRIVER_CLOCK_CONTROL)
/* Ungate ENET clock. */
CLOCK_EnableClock(s_enetClock[instance]);
#endif /* FSL_SDK_DISABLE_DRIVER_CLOCK_CONTROL */
/* System configure fistly. */
ENET_SetSYSControl(config->miiMode);

/* Initializes the ENET DMA with basic function. */
ENET_SetDMAControl(base, config);

/* Initializes the ENET MTL with basic function. */
ENET_SetMTL(base, config);

/* Initializes the ENET MAC with basic function. */
ENET_SetMacControl(base, config, macAddr);

#ifdef ENET_PTP1588FEATURE_REQUIRED
ENET_SetPtp1588(base, config, refclkSrc_Hz);
#endif /* ENET_PTP1588FEATURE_REQUIRED */
}

[ronwal]

Hi 

Thanks for your answer but my LWIP implementation works just fine. It comes to the hardfault when i am trying to create a cJson object while LWIP is being polled.

I attached a minimized code snippet. 

The first call of cJSON_CreateObject(...) work fine but not the 2nd inside the while.

I really hope, someone can help me here...

Thanks in advance!

int main(void) {

/* Init board hardware. */
BOARD_InitBootPins();
BOARD_InitBootClocks();
BOARD_InitBootPeripherals();

systick_init();

//init LWIP
mdioHandle.resource.csrClock_Hz = EXAMPLE_CLOCK_FREQ;

/* Network interface variables */
ip4_addr_t ipaddr, netmask, gw;

/* Set network address variables */
IP4_ADDR(&gw, 192,168,80,1);
IP4_ADDR(&ipaddr, 192,168,80,80);
IP4_ADDR(&netmask, 255,255,255,0);

/* The lwIP single-threaded core: initialize the network stack */
lwip_init();

ethernetif_config_t enet_config = {
.phyHandle = &phyHandle,
.macAddress = configMAC_ADDR,
.non_dma_memory = non_dma_memory,
};

netif_add(&netif, &ipaddr, &netmask, &gw, &enet_config, ethernetif0_init, ethernet_input);
netif_set_default(&netif);
netif_set_up(&netif);

ping_init();

//this call works just fine!
cJSON *json = cJSON_CreateObject();
cJSON_Delete(json);

struct timer t;
timer_set(&t, 2000);

while(1) {

/* Poll the driver, get any outstanding frames */
ethernetif_input(&netif);

if(timer_expired(&t))
{
//this call will end in a hardfault
cJSON *json = cJSON_CreateObject();
cJSON_Delete(json);

timer_restart(&t);
}

...
}
return 0 ;
}