Hi, I would not recommend making the socket a static instance in the callback function. If you do this, you will likely run into life-time problems because the socket may outlive the context object. This will cause problems when closing the application. Can you make the socket a member of the callback, or capture it in a lambda?
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From: zeromq-dev-boun...@lists.zeromq.org [mailto:zeromq-dev-boun...@lists.zeromq.org] On Behalf Of josh knox Sent: 10 December 2015 23:42 To: ZeroMQ development list Subject: Re: [zeromq-dev] (no subject) OK, its a threading issue in my code. My publication socket is used in a callback triggered from a separate library thread. I create the socket in a separate thread. :( Would it be correct to create my pub socket as a static instance in my callback function so that it is created in the same thread its used in? Is there a better approach? Thanks! Josh On Fri, Dec 4, 2015 at 4:13 PM, winter <alfateam...@nwa.xyz<mailto:alfateam...@nwa.xyz>> wrote: Hello, are you using cppzmq[1]? I remember getting the >check() (src/msg.cpp:248) error when I tried to reuse the same socket from different threads (a classic error). From your explanation, it doesn't seem the case though. Do you create `txDataPub` in a thread and using it in another one? I mean, do you `txDataPub = new zmq::socket_t(*zmqContext, ZMQ_PUB);` in the main thread, create a thread and then passing a reference/pointer of `txDataPub` to that thread? The modification suggested by Peter Krey is correct, try it too. [1]: https://github.com/zeromq/cppzmq/ Il 04/12/2015 17:12, josh knox ha scritto: > Hi, > > > I've been running into a segfault since adding a zmq publication socket > to my application. > > > It usually runs fine, happily publishing various data at a few Hz. > Nothing high stress. > > > There are 2 varieties of segfaults that occur. > > One of the following messages is printed to stderr when the crash occurs. > > Assertion failed: refs_ >= 0 (src/msg.cpp:337) > Assertion failed: check () (src/msg.cpp:248) > > > Sometimes I get this backtrace: > > > [Switching to Thread 0x7fffe57c0700 (LWP 8781)] > 0x00007ffff4d84cc9 in __GI_raise (sig=sig@entry=6) > at ../nptl/sysdeps/unix/sysv/linux/raise.c:56 > 56 ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory. > (gdb) bt > #0 0x00007ffff4d84cc9 in __GI_raise (sig=sig@entry=6) > at ../nptl/sysdeps/unix/sysv/linux/raise.c:56 > #1 0x00007ffff4d880d8 in __GI_abort () at abort.c:89 > #2 0x00007ffff4dc1394 in __libc_message (do_abort=do_abort@entry=1, > fmt=fmt@entry=0x7ffff4ecfb28 "*** Error in `%s': %s: 0x%s ***\n") > at ../sysdeps/posix/libc_fatal.c:175 > #3 0x00007ffff4dcd66e in malloc_printerr (ptr=<optimized out>, > str=0x7ffff4ecbc31 "free(): invalid size", action=1) at malloc.c:4996 > #4 _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at > malloc.c:3840 > #5 0x00007ffff46cba25 in zmq::msg_t::close (this=this@entry=0x7fffd8000920) > at src/msg.cpp:159 > #6 0x00007ffff46e8864 in zmq::stream_engine_t::~stream_engine_t ( > this=0x7fffd8000900, __in_chrg=<optimized out>) at > src/stream_engine.cpp:162 > #7 0x00007ffff46e8d79 in zmq::stream_engine_t::~stream_engine_t ( > this=0x7fffd8000900, __in_chrg=<optimized out>) at > src/stream_engine.cpp:174 > #8 0x00007ffff46e7385 in zmq::stream_engine_t::error ( > this=this@entry=0x7fffd8000900, > reason=reason@entry=zmq::stream_engine_t::connection_error) > at src/stream_engine.cpp:940 > #9 0x00007ffff46e856b in zmq::stream_engine_t::in_event (this=0x7fffd8000900) > at src/stream_engine.cpp:300 > #10 0x00007ffff46c4cfe in zmq::epoll_t::loop (this=0x79c980) at > src/epoll.cpp:168 > #11 0x00007ffff46ef350 in thread_routine (arg_=0x79ca00) at src/thread.cpp:96 > #12 0x00007ffff759e182 in start_thread (arg=0x7fffe57c0700) at > pthread_create.c:312 > #13 0x00007ffff4e4847d in clone () at > ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 > (gdb) > > This is another backtrace I get occasionally: > > > Program terminated with signal SIGSEGV, Segmentation fault. > #0 __memcpy_sse2_unaligned () at > ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S:33 > 33 ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S: No such file > or directory. > (gdb) bt > #0 __memcpy_sse2_unaligned () at > ../sysdeps/x86_64/multiarch/memcpy-sse2-unaligned.S:33 > #1 0x00007f6ac2b26c10 in memcpy (__len=<optimized out>, __src=<optimized > out>, __dest=<optimized out>) > at /usr/include/x86_64-linux-gnu/bits/string3.h:51 > #2 zmq::encoder_base_t<zmq::v2_encoder_t>::encode (this=0x7f6a98008bc0, > data_=0x7f6ab5359108, size_=<optimized out>) > at src/encoder.hpp:123 > #3 0x00007f6ac2b1b89f in zmq::stream_engine_t::out_event > (this=0x7f6aa8000900) at src/stream_engine.cpp:365 > #4 0x00007f6ac2b11563 in zmq::session_base_t::read_activated > (this=0x7f6aa8001050, pipe_=0x7f6a980089e0) > at src/session_base.cpp:264 > #5 0x00007f6ac2afad7c in zmq::io_thread_t::in_event (this=0x1738c20) at > src/io_thread.cpp:83 > #6 0x00007f6ac2af9d3e in zmq::epoll_t::loop (this=0x1737a90) at > src/epoll.cpp:176 > #7 0x00007f6ac2b24350 in thread_routine (arg_=0x1737b10) at > src/thread.cpp:96 > #8 0x00007f6ac59df182 in start_thread (arg=0x7f6ab535a700) at > pthread_create.c:312 > #9 0x00007f6ac328047d in clone () at > ../sysdeps/unix/sysv/linux/x86_64/clone.S:111 > (gdb) > > My zmq usage is pretty simple. Here is the code I've added to my app: > > 1. Initialize zmq stuff: > > std::string statusPubAddress; > > std::string > > // create zmq socket > > zmqContext = new zmq::context_t(2); > // bind the data publication > > // connect the status publication socket > txDataPub = new zmq::socket_t(*zmqContext, ZMQ_PUB); > try { > cerr << "\n Opening Publication on address: " << statusPubAddress; > txDataPub->bind(statusPubAddress.c_str()); > } > catch(zmq::error_t &err) { > > std::cerr << err.what() << ": " << statusPubAddress.c_str(); > > throw(err); > } > > > > 2. I publish stuff like this: > > MyData status = GetStatus(); // simple struct, no pointers > > try { > > zmq::message_t message(sizeof(MyData)); > memcpy(message.data(), &status, message.size()); > txDataPub->send(message, ZMQ_NOBLOCK); > > } > > catch(zmq::error_t &err) { > std::cerr << "\nERROR: " <<err.what(); > } > > If I disable my zmq code, the crash goes away. > > > > Any pointers as to what might be causing this? Let me know if more info > would be helpful. > > > Thanks for any help! > > > Josh > > > > _______________________________________________ > zeromq-dev mailing list > zeromq-dev@lists.zeromq.org<mailto:zeromq-dev@lists.zeromq.org> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev > _______________________________________________ zeromq-dev mailing list zeromq-dev@lists.zeromq.org<mailto:zeromq-dev@lists.zeromq.org> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
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