Crash when using zpoller_wait

[AnitaTang]

Hi,I have defined m_poller using zpoller_new with many arguments and then this m_poller is used in zpoller_wait with setting timeout -1, it will crash if two sockets are receiving messages. I'm not sure of the reason. Look forward to your help.

[somdoron]

Can you include a code that reproduce?
On Jun 19, 2016 17:30, "AnitaTang" notifications@github.com wrote:

Hi,I have defined m_poller using zpoller_new with many arguments and then
this m_poller is used in zpoller_wait with setting timeout -1, it will
crash if two sockets are receiving messages. I'm not sure of the reason.
Look forward to your help.

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[AnitaTang]

Thanks for your reply, the code is as following:
m_poller = zpoller_new(m_sock_pull_lock, m_sock_pull_unlock, m_sock_pull_check,
m_sock_rep_dump, m_sock_rep_get, m_sock_rep_quit, m_sock_rep_modify, nullptr);
zsock_t *whichOne = (zsock_t *) zpoller_wait(m_poller, -1);
Two messages are sent to m_sock_rep_quit and m_sock_pull_lock simultaneously, the app will crash here according to the crash report.

[somdoron]

Which libzmq version are you using?
can you attach the crash report?

[AnitaTang]

Ok.Here is the crash report
#0 0x00007f1bb9ecc8a5 in raise () from /lib64/libc.so.6
#1 0x00007f1bb9ece085 in abort () from /lib64/libc.so.6
#2 0x00007f1bb9ec5a1e in __assert_fail_base () from /lib64/libc.so.6
#3 0x00007f1bb9ec5ae0 in __assert_fail () from /lib64/libc.so.6
#4 0x00000000009687b9 in zsock_vsend () at src/zsock.c:659
#5 0x0000000000968887 in zsock_send () at src/zsock.c:645
#6 0x00000000007c6fac in DataOperator::impl::deal_sock_unlock() ()
#7 0x00000000007c39ac in DataOperator::impl::Loop()::{lambda()#1}::operator()() const ()

[AnitaTang]

And zmq version is 4.1.4 ,czmq version is 3.0.2. we make the files libczmq.a and libzmq.a out of source code by ourselves.

[somdoron]

According to the crash report the exception is in zsock_send, it seems you have error with the picture or array. Can you include the send code?

[AnitaTang]

Thanks again.Here is the send code。
send messages:

    {
    //Two threads keep sending these two messages
        zsock_t *m_sock_push_unlock = zsock_new_push_unlimited(PIPE_PROTOCAL_READY2RETURNDATA);
        zsock_t *m_sock_push_lock = zsock_new_push_unlimited(PIPE_PROTOCAL_READY2ACQUIREDATA);
        //pTask is a class instance
        zsock_send(m_sock_push_unlock, "p", pTask); 
        zsock_send(m_sock_push_lock, "p", pTask);
    }

    {//start to send quit message at some point
        zsock_t *sock_req_quit = zsock_new_req(PIPE_PROTOCAL_QUITER_DATAOPERATOR);
        uint8_t req(1), rep(2);
        zsock_recv(sock_req_quit, "1", &req);
        zsock_send(sock_req_quit, "1", rep);
        LOG4CPLUS_MACRO_FMT_BODY(Logger::getInstance(LOGGER_STATUS), INFO_LOG_LEVEL,"ending 1");//this log is in the log when crash happens
    }

receive messages:

while (true) {
    zsock_t *whichOne = (zsock_t *) zpoller_wait(m_poller, -1);
    if (whichOne == m_sock_pull_lock) {
        zsock_recv(m_sock_pull_unlock, "p", &pTask);
    }
    else if (whichOne == m_sock_pull_unlock) {
        zsock_recv(m_sock_pull_lock, "p", &pTask);
    }
    else if (whichOne == m_sock_rep_quit) {
        zsock_recv(m_sock_rep_quit, "1", &req);
        zsock_send(m_sock_rep_quit, "1", rep);
        LOG4CPLUS_MACRO_FMT_BODY(Logger::getInstance(LOGGER_STATUS), INFO_LOG_LEVEL,"ending 2");//this log is not in the log when crash happens
    }   
}

[AnitaTang]

It seems that something wrong happens when zpoller_wait is accepting the quit message.

[somdoron]

which one is the deal_sock_unlock method?

[AnitaTang]

if (whichOne == m_sock_pull_lock) {
deal_sock_unlock();
}
and in void deal_sock_unlock(){ zsock_recv(m_sock_pull_unlock, "p", &pTask);...}

[somdoron]

This is still unclean for me.

In the stacktrace deal_sock_unlock is calling zsock_send, but in your example the deal_sock_unlock is only calling zsock_recv. I think something is missing from your example.

I suspect it has nothing to do with poller and wrong picture to zsock_send, it will be great if you can attach the full code of deal_sock_unlock, as I don't think poller has nothing to do with it.

[AnitaTang]

Sorry for the trouble, there's something wrong with my multi-thread code while using zmq .Thanks a lot again.

[bluca]

Closing since it was a problem in the application