Debug it like any other flaw in your code.
Almost certainly due to buffer or pointer corruption, either within existing structures, or those on the stack.
Add sanity checking to the code close to the point of the identified fault, perhaps with asserts or similar methods.
Have and effective Hard Fault Handler that can output actionable information, so you can identify the memory area that triggers the fault. Precise means its a read of some sort. Look at the faulting code, and that immediately prior and relate that to the source, and the code flow at that point,and where those values came from.
