int __kprobes kprobe_fault_handler()

in kernel/kprobes.c [820:862]

• 25 lines of code
• 7 McCabe index (conditional complexity)

int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
{
	struct kprobe *cur = kprobe_running();
	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();


	switch(kcb->kprobe_status) {
	case KPROBE_HIT_SS:
	case KPROBE_REENTER:
		/*
		 * We are here because the instruction being single
		 * stepped caused a page fault. We reset the current
		 * kprobe and the instruction pointer points back to
		 * the probe address and allow the page fault handler
		 * to continue as a normal page fault.
		 */
		regs->cr_iip = ((unsigned long)cur->addr) & ~0xFULL;
		ia64_psr(regs)->ri = ((unsigned long)cur->addr) & 0xf;
		if (kcb->kprobe_status == KPROBE_REENTER)
			restore_previous_kprobe(kcb);
		else
			reset_current_kprobe();
		preempt_enable_no_resched();
		break;
	case KPROBE_HIT_ACTIVE:
	case KPROBE_HIT_SSDONE:
		/*
		 * In case the user-specified fault handler returned
		 * zero, try to fix up.
		 */
		if (ia64_done_with_exception(regs))
			return 1;

		/*
		 * Let ia64_do_page_fault() fix it.
		 */
		break;
	default:
		break;
	}

	return 0;
}