[zeromq-dev] zctx_destroy is hanging

[Stephen Hemminger]

czmq already does this by default.

On Tue, May 21, 2013 at 10:27 PM, Stathis Gkotsis
<stathis.gkotsis at commsquare.com> wrote:
> Hi,
>
> Try setting linger to 0 just before.
>
> Kind regards,
> Stathis
>
> ----- Original Message -----
> From: Stephen Hemminger [mailto:stephen at networkplumber.org]
> Sent: Wednesday, May 22, 2013 12:32 AM
> To: zeromq-dev at lists.zeromq.org <zeromq-dev at lists.zeromq.org>
> Subject: [zeromq-dev] zctx_destroy is hanging
>
> We have a ZMQ based application (in C) using CZMQ and ZMQ 2.2.0
> When daemon is due to be restarted or shutdown
>  1. it receives a SIGTERM
>  2. The signal is caught, and flag is set
>  3. all the worker threads exit
>  4. main thread waits for workers and does some other cleanup
>  5. calls zctx_destroy()
> and hangs there; any clues? maybe the zctx_destroy() is redundant anyway.
>
>
> int
> main(int argc, char **argv)
> {
>    ...
>
>         zctx_destroy(&zmq_ctx); << hang here
>
>         return 0;
> }
>
> There were several ZMQ sockets created, instrumenting CZMQ, it looks
> like ZMQ is hanging in zctx__socket_destroy() of the ZMQ_REQ socket
> which was bound twice, once to an ipc: endpoint and again to a tcp://lo:5910
> endpoint.
>
> Internally it looks like ZMQ reaper isn't working.
>
> The back trace of main thread is:
> [Switching to thread 1 (Thread 0x7f1267625c80 (LWP 2065))]#0  0x00007f126626ec13 in poll () from /lib/libc.so.6
> (gdb) where
> #0  0x00007f126626ec13 in poll () from /lib/libc.so.6
> #1  0x00007f1266bd5df0 in zmq::signaler_t::wait (this=<value optimized out>,
>     timeout_=-1) at signaler.cpp:145
> #2  0x00007f1266bc6aae in zmq::mailbox_t::recv (this=0x1b4c808,
>     cmd_=0x7fff010baee0, timeout_=-1) at mailbox.cpp:74
> #3  0x00007f1266bc059d in zmq::ctx_t::terminate (this=0x1b4c770) at ctx.cpp:146
> #4  0x00007f1266be100c in zmq_term (ctx_=0x1b4c770) at zmq.cpp:292
> #5  0x00007f1266df8efe in zctx_destroy (self_p=0x7107a0) at zctx.c:122
> #6  0x000000000040ae53 in main (argc=<value optimized out>,
>
> Some other threads:
> (gdb) thread 4
> [Switching to thread 4 (Thread 0x7f1241bf9700 (LWP 2149))]#0  0x00007f126627a163 in epoll_wait () from /lib/libc.so.6
> (gdb) where
> #0  0x00007f126627a163 in epoll_wait () from /lib/libc.so.6
> #1  0x00007f1266bc3a90 in zmq::epoll_t::loop (this=0x1b4e680) at epoll.cpp:142
> #2  0x00007f1266bdbdeb in thread_routine (arg_=0x1b4e6f0) at thread.cpp:75
> #3  0x00007f12665128ca in start_thread () from /lib/libpthread.so.0
> #4  0x00007f1266279b6d in clone () from /lib/libc.so.6
> #5  0x0000000000000000 in ?? ()
> (gdb) thread 5
> [Switching to thread 5 (Thread 0x7f12423fa700 (LWP 2148))]#0  0x00007f126627a163 in epoll_wait () from /lib/libc.so.6
> (gdb) where
> #0  0x00007f126627a163 in epoll_wait () from /lib/libc.so.6
> #1  0x00007f1266bc3a90 in zmq::epoll_t::loop (this=0x1b4d050) at epoll.cpp:142
> #2  0x00007f1266bdbdeb in thread_routine (arg_=0x1b4d0c0) at thread.cpp:75
> #3  0x00007f12665128ca in start_thread () from /lib/libpthread.so.0
> #4  0x00007f1266279b6d in clone () from /lib/libc.so.6
> #5  0x0000000000000000 in ?? ()
> (gdb) thread 6
> [Switching to thread 6 (Thread 0x7f1242bfb700 (LWP 2102))]#0  0x00007f126651a14d in read () from /lib/libpthread.so.0
> (gdb) where
> #0  0x00007f126651a14d in read () from /lib/libpthread.so.0
> #1  0x00000000004c6938 in eal_thread_loop ()
> #2  0x00007f12665128ca in start_thread () from /lib/libpthread.so.0
> #3  0x00007f1266279b6d in clone () from /lib/libc.so.6
> #4  0x0000000000000000 in ?? ()
> (gdb) thread 7
> [Switching to thread 7 (Thread 0x7f12433fc700 (LWP 2101))]#0  0x00007f126651a14d in read () from /lib/libpthread.so.0
> (gdb) where
> #0  0x00007f126651a14d in read () from /lib/libpthread.so.0
> #1  0x00000000004c6938 in eal_thread_loop ()
> #2  0x00007f12665128ca in start_thread () from /lib/libpthread.so.0
> #3  0x00007f1266279b6d in clone () from /lib/libc.so.6
> #4  0x0000000000000000 in ?? ()
> (gdb) thread 8
> [Switching to thread 8 (Thread 0x7f1243bfd700 (LWP 2100))]#0  0x00007f126651a14d in read () from /lib/libpthread.so.0
> (gdb) where
> #0  0x00007f126651a14d in read () from /lib/libpthread.so.0
> #1  0x00000000004c6938 in eal_thread_loop ()
> #2  0x00007f12665128ca in start_thread () from /lib/libpthread.so.0
> #3  0x00007f1266279b6d in clone () from /lib/libc.so.6
> #4  0x0000000000000000 in ?? ()
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