show_trace
show_trace(stack, loglvl);
void show_trace(struct task_struct *task, unsigned long *stack);
void show_trace(struct task_struct *tsk, unsigned long *sp,
show_trace(tsk, sp, NULL, loglvl);
show_trace(NULL, (unsigned long *)regs->regs[15], regs, KERN_DEFAULT);
show_trace(task, sp, loglvl);
goto show_trace;
show_trace: