static bool kvm_vcpu_check_code_breakpoint(struct kvm_vcpu *vcpu, int *r)
{
	if (unlikely(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) &&
	    (vcpu->arch.guest_debug_dr7 & DR7_BP_EN_MASK)) {
		struct kvm_run *kvm_run = vcpu->run;
		unsigned long eip = kvm_get_linear_rip(vcpu);
		u32 dr6 = kvm_vcpu_check_hw_bp(eip, 0,
					   vcpu->arch.guest_debug_dr7,
					   vcpu->arch.eff_db);

		if (dr6 != 0) {
			kvm_run->debug.arch.dr6 = dr6 | DR6_ACTIVE_LOW;
			kvm_run->debug.arch.pc = eip;
			kvm_run->debug.arch.exception = DB_VECTOR;
			kvm_run->exit_reason = KVM_EXIT_DEBUG;
			*r = 0;
			return true;
		}
	}

	if (unlikely(vcpu->arch.dr7 & DR7_BP_EN_MASK) &&
	    !(kvm_get_rflags(vcpu) & X86_EFLAGS_RF)) {
		unsigned long eip = kvm_get_linear_rip(vcpu);
		u32 dr6 = kvm_vcpu_check_hw_bp(eip, 0,
					   vcpu->arch.dr7,
					   vcpu->arch.db);

		if (dr6 != 0) {
			kvm_queue_exception_p(vcpu, DB_VECTOR, dr6);
			*r = 1;
			return true;
		}
	}

	return false;
}
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.