zmq_ctx_term is hang when process exit and i set zmq linger to 2

[lymlhhj123]

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Issue description

problem: code was written in 2018-07-04, until 2020-05-13, eveny thing is fine. 2020-05-13, process stopped by systemd, but was hang in zmq_ctx_term

zmq socket create source code:
void* s = NULL;
int r = 0;
int linger = 2;
int ipv6_support = 0;
char end_point[END_POINT];

if (strrchr(address, ':') != NULL) {
    ipv6_support = 1;  // enable ipv6
}

if (ipv6_support == 0) {
    snprintf(end_point, END_POINT, ZMQ_IPV4_ENDPOINT, address, port);
} else {
    snprintf(end_point, END_POINT, ZMQ_IPV6_ENDPOINT, address, port);
}

s = zmq_socket(z_ctx, ZMQ_REQ);
if (s == NULL) {
    errno = ECREATEZSOCK;
    return NULL;
}

if (ipv6_support == 1) {
    zmq_setsockopt(s, ZMQ_IPV6, &ipv6_support, sizeof(ipv6_support));
}

zmq_setsockopt(s, ZMQ_LINGER, &linger, sizeof(linger));

I set zmq linger to 2, not 0

GDB bt:
(gdb) info thread
Id Target Id Frame
18 Thread 0x7f16f13d3700 (LWP 2153208) "log" 0x00007f16f3b25995 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
17 Thread 0x7f16ef3ff700 (LWP 2153225) "io-worker-0" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
16 Thread 0x7f16eebfe700 (LWP 2153226) "io-worker-1" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
15 Thread 0x7f16edbff700 (LWP 2153229) "io-worker-2" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
14 Thread 0x7f16ec7ff700 (LWP 2153232) "hb-worker-0" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
13 Thread 0x7f16eaffe700 (LWP 2153266) "service" 0x00007f16f3b25d42 in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
12 Thread 0x7f16ea7fd700 (LWP 2153267) "admin_socket" 0x00007f16f2c06f0d in poll () from /lib64/libc.so.6
11 Thread 0x7f16e91f4700 (LWP 2154163) "ceph-osd" 0x00007f16f5a11644 in io_getevents_0_4 () from /opt/h3c/lib/libaio.so.1
10 Thread 0x7f16e89f3700 (LWP 2154164) "ceph-osd" 0x00007f16f3b27afb in do_futex_wait.constprop.1 () from /lib64/libpthread.so.0
9 Thread 0x7f16da3fe700 (LWP 2154259) "ceph-osd" 0x00007f16f3b27afb in do_futex_wait.constprop.1 () from /lib64/libpthread.so.0
8 Thread 0x7f16f6d14e80 (LWP 2155828) "ceph-osd" 0x00007f16f4f6fe67 in timer_helper_thread () from /lib64/librt.so.1
7 Thread 0x7f16857ff700 (LWP 2191105) "safe_timer" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
6 Thread 0x7f168b7ff700 (LWP 2191106) "safe_timer" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
5 Thread 0x7f1684ffe700 (LWP 2191110) "safe_timer" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
4 Thread 0x7f16833fe700 (LWP 2191113) "safe_timer" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
3 Thread 0x7f1683bff700 (LWP 2350307) "safe_timer" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
2 Thread 0x7f167fffe700 (LWP 2350308) "safe_timer" 0x00007f16f2c12183 in epoll_wait () from /lib64/libc.so.6
1 Thread 0x7f16f6d38e80 (LWP 2151812) "ceph-osd" 0x00007f16f2c06f0d in poll () from /lib64/libc.so.6
(gdb) list
1 req_adapter.c: No such file or directory.
(gdb) bt
#0 0x00007f16f2c06f0d in poll () from /lib64/libc.so.6
#1 0x00007f16f66fa8ba in zmq::signaler_t::wait (this=this@entry=0x7f16f1dfaef8, timeout=timeout@entry=-1) at signaler.cpp:173
#2 0x00007f16f66ec81f in zmq::mailbox_t::recv (this=this@entry=0x7f16f1dfae98, cmd_=cmd_@entry=0x7ffd937625a0, timeout_=timeout_@entry=-1) at mailbox.cpp:72
#3 0x00007f16f66e3e2c in zmq::ctx_t::terminate (this=0x7f16f1dfae00) at ctx.cpp:142
#4 0x00007f16f6927ef1 in destroy_zmq_ctx () from /opt/h3c/lib/libalarm.so
#5 0x00005575f9271367 in main ()
(gdb) down
Bottom (innermost) frame selected; you cannot go down.
(gdb) up
#1 0x00007f16f66fa8ba in zmq::signaler_t::wait (this=this@entry=0x7f16f1dfaef8, timeout_=timeout_@entry=-1) at signaler.cpp:173
173 signaler.cpp: No such file or directory.
(gdb) up
#2 0x00007f16f66ec81f in zmq::mailbox_t::recv (this=this@entry=0x7f16f1dfae98, cmd_=cmd_@entry=0x7ffd937625a0, timeout_=timeout_@entry=-1) at mailbox.cpp:72
72 mailbox.cpp: No such file or directory.
(gdb) up
#3 0x00007f16f66e3e2c in zmq::ctx_t::terminate (this=0x7f16f1dfae00) at ctx.cpp:142
142 ctx.cpp: No such file or directory.
(gdb) p this
$1 = {tag = 2880293630, sockets = {items = {<std::_Vector_base<zmq::socket_base_t, std::allocatorzmq::socket_base_t* >> = {
_M_impl = {<std::allocatorzmq::socket_base_t*> = {<__gnu_cxx::new_allocatorzmq::socket_base_t*> = {}, },
_M_start = 0x7f168683e0b0, _M_finish = 0x7f168683e0b8, _M_end_of_storage = 0x7f168683e0b8}}, }},
empty_slots = {<std::_Vector_base<unsigned int, std::allocator >> = {
_M_impl = {<std::allocator> = {<__gnu_cxx::new_allocator> = {}, }, _M_start = 0x7f1686886000,
_M_finish = 0x7f1686886ff8, _M_end_of_storage = 0x7f1686887000}}, }, starting = false, terminating = true, slot_sync = {mutex = {__data = {
__lock = 0, __count = 0, __owner = 0, __nusers = 0, __kind = 0, __spins = 0, __elision = 0, __list = {__prev = 0x0, __next = 0x0}},
__size = '\000' <repeats 39 times>, __align = 0}}, reaper = 0x7f1686831720,
io_threads = {<std::_Vector_base<zmq::io_thread_t*, std::allocatorzmq::io_thread_t* >> = {
_M_impl = {<std::allocatorzmq::io_thread_t*> = {<__gnu_cxx::new_allocatorzmq::io_thread_t*> = {}, },
_M_start = 0x7f168683e0a0, _M_finish = 0x7f168683e0a8, _M_end_of_storage = 0x7f168683e0a8}}, }, slot_count = 1026, slots = 0x7f168683f000,
term_mailbox = {cpipe = {<zmq::ypipe_base_t<zmq::command_t, 16>> = {_vptr.ypipe_base_t = 0x7f16f691fe10 <vtable for zmq::ypipe_t<zmq::command_t, 16>+16>}, queue = {
begin_chunk = 0x7f16f1c65e00, begin_pos = 0, back_chunk = 0x7f16f1c65e00, back_pos = 0, end_chunk = 0x7f16f1c65e00, end_pos = 1, spare_chunk = {ptr = 0x0}},
w = 0x7f16f1c65e00, r = 0x7f16f1c65e00, f = 0x7f16f1c65e00, c = {ptr = 0x0}}, signaler = {w = 27, r = 27, pid = 2151812}, sync = {mutex = {__data = {
__lock = 0, __count = 0, __owner = 0, __nusers = 0, __kind = 0, __spins = 0, __elision = 0, __list = {__prev = 0x0, __next = 0x0}},
__size = '\000' <repeats 39 times>, __align = 0}}, active = false}, endpoints = {_M_t = {
_M_impl = {<std::allocator<std::_Rb_tree_node<std::pair<std::basic_string<char, std::char_traits, std::allocator > const, zmq::endpoint_t> > >> = {<__gnu_cxx::new_allocator<std::_Rb_tree_node<std::pair<std::basic_string<char, std::char_traits, std::allocator > const, zmq::endpoint_t> > >> = {}, },
_M_key_compare = {<std::binary_function<std::basic_string<char, std::char_traits, std::allocator >, std::basic_string<char, std::char_traits, std::allocator >, bool>> = {}, }, _M_header = {_M_color = std::_S_red, _M_parent = 0x0, _M_left = 0x7f16f1dfaf40,
_M_right = 0x7f16f1dfaf40}, _M_node_count = 0}}}, pending_connections = {_M_t = {
_M_impl = {<std::allocator<std::_Rb_tree_node<std::pair<std::basic_string<char, std::char_traits, std::allocator > const, zmq::pending_connection_t> > >> = {<__gnu_cxx::new_allocator<std::_Rb_tree_node<std::pair<std::basic_string<char, std::char_traits, std::allocator > const, zmq::pending_connection_t> > >> = {}, },
_M_key_compare = {<std::binary_function<std::basic_string<char, std::char_traits, std::allocator >, std::basic_string<char, std::char_traits, std::allocator >, bool>> = {}, }, _M_header = {_M_color = std::_S_red, _M_parent = 0x0, _M_left = 0x7f16f1dfaf70,
_M_right = 0x7f16f1dfaf70}, _M_node_count = 0}}}, endpoints_sync = {mutex = {__data = {__lock = 0, __count = 0, __owner = 0, __nusers = 0, __kind = 0,
__spins = 0, __elision = 0, __list = {__prev = 0x0, __next = 0x0}}, __size = '\000' <repeats 39 times>, __align = 0}}, static max_socket_id = {value = 5},
max_sockets = 1023, io_thread_count = 1, ipv6 = false, opt_sync = {mutex = {__data = {__lock = 0, __count = 0, __owner = 0, __nusers = 0, __kind = 0, __spins = 0,
__elision = 0, __list = {__prev = 0x0, __next = 0x0}}, __size = '\000' <repeats 39 times>, __align = 0}}, pid = 2151812}

Environment

• libzmq version (commit hash if unreleased): libzmq.3.1.0
• OS: linux 4.14.0-49.9

i don't know why zmq_ctx_term is blocked, i set zmq linger to 2, plsease help me! thank you

[bluca]

libzmq v3 is no longer supported