关于获取通讯录权限崩溃的问题

- (void)requestAuthorizationForAddressBook {
    ABAddressBookRef addressBook =ABAddressBookCreateWithOptions(NULL, NULL);
    ABAddressBookRequestAccessWithCompletion(addressBook, ^(bool granted, CFErrorRef error) {
        if (granted) {
            NSLog(@"授权通讯录成功!");
        } else {
            NSLog(@"授权通讯录失败!"); }
    });
       CFRelease(addressBook);
}

CFRelease(addressBook);这行会时不时的崩溃掉，因为adressBook�有时是一个僵尸对象。所以应当判断是否为nil，再选择性去释放