Hello there,
I have NDB_MONGODB loaded in kamailio with following configurations:

loadmodule "ndb_mongodb"
modparam("ndb_mongodb", "server", "name=mgs1;uri='mongodb://mongodbserver:27017/proxyregistrar'")

Kamailio breaks up on start up and prints the following messages:

Apr 18 13:16:10.464 proxy-registrar[-]: DEBUG: <core> [core/modparam.c:83]: set_mod_param_regex(): 'ndb_mongodb' matches module 'ndb_mongodb'
Apr 18 13:16:10.464 proxy-registrar[-]: DEBUG: <core> [core/sr_module.c:711]: find_param_export(): found <server> in module ndb_mongodb [/usr/lib64/kamailio/modules/ndb_mongodb.so]
Apr 18 13:16:10.464 proxy-registrar[-]: DEBUG: <core> [core/modparam.c:99]: set_mod_param_regex(): found <server> in module ndb_mongodb [/usr/lib64/kamailio/modules/ndb_mongodb.so]
Apr 18 13:16:10.464 proxy-registrar[-]: DEBUG: ndb_mongodb [mongodb_client.c:155]: mongodbc_add_server(): added server[mgs1]=mongodb://10.225.121.12:27017/proxyregistrar

1a7311e30a6793da-3165@10.225.121.93: DEBUG: <core> [core/sr_module.c:942]: init_mod_child(): idx 21 rank 8: ndb_mongodb [tcp receiver (generic) child=3]
1a7311e30a6793da-3165@10.225.121.93: CRITICAL: <core> [core/pass_fd.c:277]: receive_fd(): EOF on 23
1a7311e30a6793da-3165@10.225.121.93: ALERT: <core> [main.c:739]: handle_sigs(): child process 3181 exited by a signal 11
1a7311e30a6793da-3165@10.225.121.93: ALERT: <core> [main.c:742]: handle_sigs(): core was generated
1a7311e30a6793da-3165@10.225.121.93: DEBUG: <core> [core/tcp_main.c:3513]: handle_ser_child(): dead child 16, pid 3181 (shutting down?)
1a7311e30a6793da-3165@10.225.121.93: INFO: <core> [main.c:764]: handle_sigs(): terminating due to SIGCHLD
1a7311e30a6793da-3165@10.225.121.93: DEBUG: <core> [core/io_wait.h:602]: io_watch_del(): DBG: io_watch_del (0xa6d0e0, 23, -1, 0x0) fd_no=23 called
1a7311e30a6793da-3165@10.225.121.93: DEBUG: <core> [main.c:766]: handle_sigs(): terminating due to SIGCHLD
1a7311e30a6793da-3165@10.225.121.93: INFO: <core> [main.c:819]: sig_usr(): signal 15 received
123: INFO: <core> [main.c:819]: sig_usr(): signal 15 received
123: INFO: <core> [main.c:819]: sig_usr(): signal 15 received
123: INFO: <core> [main.c:819]: sig_usr(): signal 15 received
123: INFO: <core> [main.c:819]: sig_usr(): signal 15 received
1a7311e30a6793da-3165@10.225.121.93: DEBUG: ndb_mongodb [ndb_mongodb_mod.c:128]: mod_destroy(): cleaning up 

Core dump back trace output:

(gdb) bt full
#0  0x00007f3daa134f93 in _mongoc_client_new_from_uri () from /lib64/libmongoc-1.0.so.0
No symbol table info available.
#1  0x00007f3daa156553 in mongoc_uri_get_ssl () from /lib64/libmongoc-1.0.so.0
No symbol table info available.
#2  0x00007f3daa134f88 in _mongoc_client_new_from_uri () from /lib64/libmongoc-1.0.so.0
No symbol table info available.
#3  0x00007f3daa135029 in mongoc_client_new () from /lib64/libmongoc-1.0.so.0
No symbol table info available.
#4  0x00007f3daae6d75f in mongodbc_init () at mongodb_client.c:63
        rsrv = 0x7f3db0f86728
        __FUNCTION__ = "mongodbc_init"
#5  0x00007f3daae73c46 in child_init (rank=3) at ndb_mongodb_mod.c:113
        __FUNCTION__ = "child_init"
#6  0x00000000005470d7 in init_mod_child (m=0x7f3db0f85e88, rank=3) at core/sr_module.c:846
        __FUNCTION__ = "init_mod_child"
#7  0x00000000005474b6 in init_child (rank=3) at core/sr_module.c:874
        ret = 32573
#8  0x00000000004b3840 in fork_process (child_id=3, desc=0x7ffecc20c7f0 "udp receiver child=2 sock=10.225.121.93:5060", make_sock=1) at core/pt.c:341
        pid = 0
        child_process_no = 3
        ret = -1
        new_seed1 = 1273263324
        new_seed2 = 1531871627
        sockfd = {14, 15}
        __FUNCTION__ = "fork_process"
#9  0x0000000000424b9b in main_loop () at main.c:1631
        i = 2
        pid = 3807
        si = 0x7f3db123a988
        si_desc = "udp receiver child=2 sock=10.225.121.93:5060\000\177\000\000P\310 \314\376\177\000\000\000e|\261=\177\000\000 \313 \314\376\177\000\000\063\225{\000\000\000\000\000\027\000\000\000\000\000\000\000\000\000\000 \000\000\000\000\000\000\200\000\000\000\000\000\217e|\261=\177\000\000`~x\000\000\000\000\000\230\304\022\261=\177\000"
        nrprocs = 4
        woneinit = 1
        __FUNCTION__ = "main_loop"
#10 0x000000000042c4e9 in main (argc=11, argv=0x7ffecc20cc08) at main.c:2675
        cfg_stream = 0x2893010
        c = -1
        r = 0
        tmp = 0x7ffecc20e6fd ""
        tmp_len = 0
        port = 0
        proto = 2496
        options = 0x7697a0 ":f:cm:M:dVIhEeb:l:L:n:vKrRDTN:W:w:t:u:g:P:G:SQ:O:a:A:x:X:Y:"
        ret = -1
        seed = 173321635
        rfd = 4
        debug_save = 0
        debug_flag = 0
        dont_fork_cnt = 0
        n_lst = 0x7ffecc20cac0
        p = 0x7f3db177497d <intel_check_word+173> "H\205\300t\025\017\266P\003\017\266\312D9\371\017\204", <incomplete sequence \316>
        st = {st_dev = 19, st_ino = 21919, st_nlink = 2, st_mode = 16832, st_uid = 993, st_gid = 2, __pad0 = 0, st_rdev = 0, st_size = 40, st_blksize = 4096, st_blocks = 0, st_atim = {tv_sec = 1551179759, tv_nsec = 561093463}, st_mtim = {tv_sec = 1551179759,
---Type <return> to continue, or q <return> to quit---
            tv_nsec = 561093463}, st_ctim = {tv_sec = 1551179759, tv_nsec = 561093463}, __unused = {0, 0, 0}}
        __FUNCTION__ = "main"
(gdb)

NDB_MONGODB configuration is pretty simples and currently i'm not making any mongodb operations, i'm just loading the module and trying to connect against mongodb.

Any thoughts on this issue?

Thank you

Best regards 
-- 
Cumprimentos
José Seabra