From Fedora bug https://bugzilla.redhat.com/show_bug.cgi?id=2396621#c4

I have tried this snippet:

dlz example {
database "dlopen /usr/lib64/samba/bind9/dlz_bind9_18.so";
search no;
};

That crashes, but at least tries to load the plugin. I am not sure how exactly it should be configured in samba. Is it possible SELinux is blocking permissions perhaps?

In my case, it could not find /var/lib/samba/bind-dns/dns/sam.ldb and crashed when trying to log it. dlz_bind9_state were NULL at that point.

(gdb) bt
#0  0x00007ffff5292f03 in dlz_create (dlzname=<optimized out>, argc=1, argv=0x7ffff007d688, dbdata=0x7ffff007fe08) at ../../source4/dns_server/dlz_bind9.c:730
#1  0x0000555555560fb5 in dlopen_dlz_create (dlzname=0x7ffff0053140 "example", argc=2, argv=0x7ffff007d680, driverarg=<optimized out>, dbdata=<optimized out>) at ../../../bin/named/dlz_dlopen_driver.c:314
#2  0x00007ffff7d315c9 in dns_sdlzcreate (mctx=<optimized out>, dlzname=0x7ffff0053140 "example", argc=2, argv=0x7ffff007d680, driverarg=0x555555645c30, dbdata=0x7ffff007dc68) at ../../../lib/dns/sdlz.c:1627
#3  0x00007ffff7c380cb in dns_dlzcreate (mctx=mctx@entry=0x55555563c860, dlzname=0x7ffff0053140 "example", drivername=drivername@entry=0x7ffff007dbf0 "dlopen", argc=argc@entry=2, 
    argv=argv@entry=0x7ffff007d680, dbp=dbp@entry=0x7ffff6c4c4a0) at ../../../lib/dns/dlz.c:212
#4  0x0000555555576861 in configure_view (view=0x7ffff000f3b0, viewlist=<optimized out>, config=0x7ffff004e560, vconfig=0x0, cachelist=0x7ffff6c4d550, kasplist=<optimized out>, bindkeys=0x0, 
    mctx=0x55555563c860, actx=0x7ffff00052f0, need_hints=true) at ../../../bin/named/server.c:4485
#5  0x00005555555848bf in load_configuration (filename=<optimized out>, server=server@entry=0x555555645d10, first_time=first_time@entry=true) at ../../../bin/named/server.c:9569
#6  0x0000555555586ff7 in run_server (task=<optimized out>, event=<optimized out>) at ../../../bin/named/server.c:10306
#7  0x00007ffff7f64120 in task_run (task=0x555555692990) at ../../../lib/isc/task.c:832
#8  isc_task_run (task=0x555555692990) at ../../../lib/isc/task.c:913
#9  0x00007ffff7f237ec in isc__nm_async_task (worker=0x555555644f30, ev0=0x55555569ce70) at ../../../lib/isc/netmgr/netmgr.c:867
#10 0x00007ffff7f2b74d in process_netievent (worker=worker@entry=0x555555644f30, ievent=0x55555569ce70) at ../../../lib/isc/netmgr/netmgr.c:949
#11 0x00007ffff7f2be6f in process_queue (worker=worker@entry=0x555555644f30, type=type@entry=NETIEVENT_TASK) at ../../../lib/isc/netmgr/netmgr.c:1044
#12 0x00007ffff7f2c088 in process_all_queues (worker=0x555555644f30) at ../../../lib/isc/netmgr/netmgr.c:780
#13 async_cb (handle=0x555555645290) at ../../../lib/isc/netmgr/netmgr.c:809
#14 0x00007ffff7bac60e in uv__async_io (loop=0x555555644f40, w=<optimized out>, events=<optimized out>) at /usr/src/debug/libuv-1.51.0-2.fc43.x86_64/src/unix/async.c:208
#15 0x00007ffff7bcb71e in uv__io_poll (loop=0x555555644f40, timeout=<optimized out>) at /usr/src/debug/libuv-1.51.0-2.fc43.x86_64/src/unix/linux.c:1565
#16 0x00007ffff7bb69e2 in uv_run (loop=loop@entry=0x555555644f40, mode=mode@entry=UV_RUN_DEFAULT) at /usr/src/debug/libuv-1.51.0-2.fc43.x86_64/src/unix/core.c:460
#17 0x00007ffff7f2c57d in nm_thread (worker0=0x555555644f30) at ../../../lib/isc/netmgr/netmgr.c:711
#18 0x00007ffff7f6826c in isc__trampoline_run (arg=0x55555563f620) at ../../../lib/isc/trampoline.c:190
#19 0x00007ffff72f738b in start_thread (arg=<optimized out>) at pthread_create.c:448
#20 0x00007ffff737a46c in __GI___clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78

But it proves bind tried to load something from it.