use malloc, calloc and free memory occurred Hard fault interrupt. why?

[Leimen]

Target: STM32G473RBTX

IDE: STM32CubeIDE v1.4.2

bool read(STRUCT *devInfo)

{

uint8_t readbuf[len];

STRUCT *tmp = (STRUCT *)calloc(1, sizeof( STRUCT ));

if(EEPRomReadNByte(addr, len, readbuf))

{

tmp = (STRUCT *)&readbuf; //implicit convert

memcpy(devInfo, tmp, sizeof( STRUCT ));//make sure

}

free(tmp); //<- HardFault_Handler occurred

}

1.why happened to call free memory will occur Hard fault interrupt?

2.implicit convert some time is work or not, why?

[Tesla DeLorean]

You are trying to free memory that isn't part of the heap.

And the chaining structure contains random junk, which is undefined and unpredictable.​