c++ - 大小为 8 的读取无效，但没有内存泄漏

Question

我正在做 C++ Kafka 客户端 https://github.com/edenhill/librdkafka/blob/master/examples/rdkafka_example.cpp .

在我的 KafkaProducer 类中，有几个指针。

RdKafka::Conf* m_conf;
RdKafka::Conf* m_tconf;
RdKafka::Producer* m_producer;
RdKafka::Topic* m_topic;

m_conf = RdKafka::Conf::create(RdKafka::Conf::CONF_GLOBAL);
m_producer = RdKafka::Producer::create(m_conf, m_errstr);
m_tconf = RdKafka::Conf::create(RdKafka::Conf::CONF_TOPIC);
m_topic = RdKafka::Topic::create(m_producer, m_topic_str, m_tconf, m_errstr);

在析构函数中，我做了以下事情:

if(m_producer)
    delete m_producer;

if(m_topic)
    delete m_topic;

if(m_tconf)
    delete m_tconf;

if(m_conf)
    delete m_conf;

我使用 valgrind 检查我的程序，没有泄漏。但存在“无效读取”的一些问题。 一些内存被释放了两次。但我确实知道哪个内存。 以下是 valgrind 输出的一部分。

==4627== 2 errors in context 10 of 12:
==4627== Invalid read of size 8
==4627==    at 0x52887A7: RdKafka::log_cb_trampoline(rd_kafka_s const*, int, char const*, char const*) (in /usr/lib/x86_64-linux-gnu/librdkafka++.so.1)
==4627==    by 0x5493C8F: ??? (in /usr/lib/x86_64-linux-gnu/librdkafka.so.1)
==4627==    by 0x549A531: ??? (in /usr/lib/x86_64-linux-gnu/librdkafka.so.1)
==4627==    by 0x54A0219: ??? (in /usr/lib/x86_64-linux-gnu/librdkafka.so.1)
==4627==    by 0x54A1A13: ??? (in /usr/lib/x86_64-linux-gnu/librdkafka.so.1)
==4627==    by 0x506C181: start_thread (pthread_create.c:312)
==4627==    by 0x5EE747C: clone (clone.S:111)
==4627==  Address 0x68df7f8 is 24 bytes inside a block of size 64 free'd
==4627==    at 0x4C2C2BC: operator delete(void*) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==4627==    by 0x407E90: KafkaProducer::disconnect() (kafkaproducer.cpp:57)
==4627==    by 0x407D29: KafkaProducer::~KafkaProducer() (kafkaproducer.cpp:32)
==4627==    by 0x407DF1: KafkaProducer::~KafkaProducer() (kafkaproducer.cpp:38)
==4627==    by 0x409DC0: KafkaProducerFactory::~KafkaProducerFactory() (kafkaproducerfactory.cpp:22)
==4627==    by 0x4045A8: main (test_kafkaproducerfactory.cpp:14)

kafkaproducer.cpp 第 56-67 行(保留双倍行距):

 if(m_producer)           // line 56
     delete m_producer;

 if(m_topic)
     delete m_topic;


 if(m_tconf)
     delete m_tconf;

 if(m_conf)
     delete m_conf;       // line 67

欢迎任何帮助。

更新

我已经发现以下代码导致了这个问题。如果我评论下面的部分(如果我没有设置事件回调函数。)，问题就会消失。 但我不知道为什么会导致这个问题。我用同样的方法设置了送货回拨功能，没有出现任何问题。是有线的。

//defination
    class MyEventCb : public RdKafka::EventCb
    {
    public:
        void event_cb (RdKafka::Event &event)
        {
        }
    private:

    };

//set the callback function
    if( m_conf->set("event_cb", &m_event_cb, m_errstr) != RdKafka::Conf::CONF_OK)
    {
        DBG_PRINT( 1, "Kafka::Failed to set event callback : %s\n", m_errstr.c_str() );
        return false;
    }
    // Class member
MyEventCb m_event_cb; // event callback

Answer 1

由于 m_topic 使用的是 m_producer，我认为您不应该在 m_topic 之前删除 m_producer...