[zeromq-dev] Possibly a memleak in zframe_new()

[Mathias Hablützel]

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Hi everyone,

ran into a situation where my code seems to leak memory but I can't
tackle it down in _my_ code. Kicked off valgrind to find this:

==2874== 56 bytes in 1 blocks are definitely lost in loss record 34 of 72
==2874==    at 0x4A08121: calloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==2874==    by 0x4E7A968: zframe_new (czmq_prelude.h:443)
==2874==    by 0x4E7AB48: zframe_recv (zframe.c:156)
==2874==    by 0x4E7ED84: zmsg_recv (zmsg.c:101)
==2874==    by 0x401458: _recv_message (kt_server.c:114)

_recv_message() is my function, snippet:

  zmsg_t *m = zmsg_recv(sock);
  assert(m);
  char *msgData = zframe_strdup(zmsg_pop(m));
  zmsg_destroy(&m);
  free (msgData);


So, I tracked this further down to zframe_new() which actually allocates
sizeof(zframe_t) and later passes this to zmq_msg_init(). Since I work
with a ZMQ_REP socket here, this must be in zmq::router_t::xrecv or more
precisely in fq.recvpipe. recvpipe then calls zmq::msg_t::close.

And this is where I suspect the memory leak to happen. The union-struct
u defined in msg.hpp seems not to be freed correctly. But all this is
massive speculation from my side — mostly because I'm just a
beginner/noob and I have no clue about libzmq nor about C++.

Let me know if I'm just a noob with no clue or I found something. :)

Happy Hacking
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