Here is the kernel of the kernel of my answer: write some code.
The kernel of my answer is: If your compiler allocates locals on the stack always, then...
Add blobs to the stack at every function entry that record the name of the function, throw in some magic numbers to maybe catch stack smashes.
typedef struct stack_debug_blob_ {
int magic1;
const char * function_name;
int magic2;
struct stack_debug_blob_ * called_by;
int magic3;
} stack_debug_blob;
stack_debug_blob * top_of_stack_debug_blobs = 0;
Create a macro ENTER(f) taking the name of the function. The macro should be about the first line of code in every function after the opening {. It adds a struct with a pointer to the (const) char * function name, a pointer to the previous struct on the stack, and maybe some magic numbers to check sanity. Make the top of blob stack pointer point at this new struct.
#define ENTER(f) \
stack_debug_blob new_stack_debug_blob = { \
MAGIC1, (f), MAGIC2, top_of_stack_debug_blobs, MAGIC3}; \
stack_debug_blob * evil_hack = (top_of_stack_debug_blobs = (&new_stack_debug_blob))
To keep things as portable as possible, all ENTER can do is declare and initialize variables. Hence the evil_hack to do a little extra computation than just initializing a variable.
Create a function to walk down the list of blobs checking pointers and magic numbers. It should signal an error (maybe print to stderr, maybe lockup the cpu with while (1) { /* nada */ }, maybe enter the debugger... depends on your hardware) if it finds things messed up.
Create a macro EXIT() that checks your stack of blobs, then de-links the topmost from the linked list. It needs to be put at the exit points of all your functions.
#define EXIT() do { \
check_debug_blobs(); \
top_of_stack_debug_blobs = new_stack_debug_blob.called_by; \
new_stack_debug_blob.magic1 -= 1; /* paranoia */ \
} while (0)
Probably will also need to replace all return's with RETURN macro calls, the RETURN macro is just like EXIT, but has a return before the } while (0).
Create a function to walk down the list of blobs printing out the function names, call it something like stacktrace or backtrace maybe.
Write a program to instrument your C code with calls to ENTER(f) and EXIT() and RETURN(x).
Left out a few details to let you have fun with it...
See also http://stackoverflow.com/questions/2536021/any-porting-available-of-backtrace-for-uclibc