embedded runtime_error ai_generated partial

HardFault_Handler: FORCED, bus fault at address 0x00000000

ID: embedded/hardfault-handler

Also available as: JSON · Markdown

55%Fix Rate

85%Confidence

3Evidence

2023-01-01First Seen

Version Compatibility

Version	Status	Introduced	Deprecated	Notes
32	active	—	—	—

ARM Cortex-M hard fault. Null pointer, stack overflow, unaligned access, or invalid memory.

generic

85% success Read stacked PC/LR from exception frame to find faulting instruction
```
In handler: read SP, stacked_pc = *(SP+24), look up in .map file
```
88% success Enable BusFault, MemManage, UsageFault handlers for specific info
```
SCB->SHCSR |= (BUSFAULTENA | MEMFAULTENA | USGFAULTENA);
```

80% success Check stack size and add overflow detection

FreeRTOS: configCHECK_FOR_STACK_OVERFLOW=2; Bare metal: fill stack with 0xDEADBEEF

Common approaches that don't work:

Add while(1) in HardFault handler and inspect PC in debugger 72% fail
PC in handler points to handler itself, not faulting instruction. Read stacked PC from exception frame.
Increase heap size assuming memory allocation failure 78% fail
Hard faults are usually stack overflow or dangling pointers. Heap failures return NULL.
Disable fault handlers to prevent stopping 92% fail
Without handlers, faults escalate to lockup; processor halts until hardware reset