unwind_stack
extern unsigned long unwind_stack(struct task_struct *task, unsigned long *sp,
pc = unwind_stack(current, &sp, pc, &ra);
pc = unwind_stack(task, &sp, pc, &ra);
pc = unwind_stack(tsk, &sp, pc, &ra);
pc = unwind_stack(task, &sp, pc, &ra);
void unwind_stack(void *data, unsigned long *stack,
unwind_stack(trace, (unsigned long *) &trace, save_stack_address);
unwind_stack(trace, sp, save_stack_address_nosched);
unwind_stack(trace, (unsigned long *) regs->sp,
unwind_stack((void *)loglvl, esp, print_trace);
extern void unwind_stack(struct task_struct *, struct pt_regs *,
unwind_stack(tsk, regs, sp, &print_trace_ops, (void *)loglvl);
unwind_stack(NULL, regs, NULL, &callchain_ops, entry);
unwind_stack(current, NULL, sp, &save_stack_ops, trace);
unwind_stack(current, NULL, sp, &save_stack_ops_nosched, trace);
EXPORT_SYMBOL_GPL(unwind_stack);