ADB views crash after refactoring

Job #2422497 failed for bd970746:

S:views:2022-04-04T14:15:20+0000
T:views:1:A
A:views:System test views
I:views:PORTS:31637,31638,31639,31640,31641,31642,31643,31644,31645,31646,31647,31648,31649
I:views:starting servers
I:views:fetching a.example from ns2's initial configuration
I:views:fetching a.example from ns3's initial configuration
I:views:copying in new configurations for ns2 and ns3
I:views:reloading ns2 and ns3 with rndc
I:views:ns2 server reload successful
I:views:ns3 server reload successful
I:views:wait for reload to complete
I:views:fetching a.example from ns2's 10.53.0.4, source address 10.53.0.4
I:views:fetching a.example from ns2's 10.53.0.2, source address 10.53.0.2
I:views:fetching a.example from ns3's 10.53.0.3, source address defaulted
I:views:comparing ns3's initial a.example to one from reconfigured 10.53.0.2
I:views:comparing ns3's initial a.example to one from reconfigured 10.53.0.3
I:views:comparing ns2's initial a.example to one from reconfigured 10.53.0.4
I:views:comparing ns2's initial a.example to one from reconfigured 10.53.0.3
I:views:(should be different)
I:views:updating cloned zone in internal view
I:views:sleeping to allow update to take effect
I:views:verifying update affected both views
I:views:verifying forwarder in cloned zone works
I:views:verifying inline zones work with views
I:views:verifying adding of multiple inline zones followed by reconfiguration works
rndc: connection to remote host closed.
* This may indicate that the
* remote server is using an older
* version of the command protocol,
* this host is not authorized to connect,
* the clocks are not synchronized,
* the key signing algorithm is incorrect,
* or the key is invalid.
I:views:failed
I:views:exit status: 1
I:views:stopping servers
I:views:ns2 died before a SIGTERM was sent
I:views:ns2 didn't die when sent a SIGTERM
I:views:stopping servers failed
I:views:Core dump(s) found: views/ns2/named.core 
D:views:backtrace from views/ns2/named.core:
D:views:--------------------------------------------------------------------------------
D:views:Core was generated by `named'.
D:views:Program terminated with signal SIGSEGV, Segmentation fault.
D:views:#0  _rthread_mutex_timedlock (mutexp=0x20, trywait=0, abs=0x0, timed=0) at /usr/src/lib/libc/thread/rthread_mutex.c:153
D:views:[Current thread is 1 (process 496535)]
D:views:#0  _rthread_mutex_timedlock (mutexp=0x20, trywait=0, abs=0x0, timed=0) at /usr/src/lib/libc/thread/rthread_mutex.c:153
D:views:#1  0x00000502ed4406ff in dns_adb_ednsto (adb=0x50265dd1220, addr=0x5033e9c2220) at adb.c:3668
D:views:#2  0x00000502ed5247c3 in update_edns_stats (query=0x502d2b2fc20) at resolver.c:1234
D:views:#3  fctx_cancelquery (queryp=0x502a51edc68, finish=0x0, no_response=<optimized out>, age_untried=<optimized out>) at resolver.c:1344
D:views:#4  0x00000502ed527d1d in resquery_connected (eresult=ISC_R_SHUTTINGDOWN, region=<error reading variable: Unhandled dwarf expression opcode 0xa3>, arg=<optimized out>) at resolver.c:2896
D:views:#5  0x00000502ed45a554 in udp_connected (handle=<optimized out>, eresult=ISC_R_HOSTUNREACH, arg=0x5028937a420) at dispatch.c:1782
D:views:#6  0x000005025be2a216 in isc__nm_async_connectcb (worker=<optimized out>, ev0=<error reading variable: Unhandled dwarf expression opcode 0xa3>) at netmgr/netmgr.c:2631
D:views:#7  0x000005025be260fb in process_netievent (worker=0x502b3245040, ievent=0x5032300a420) at netmgr/netmgr.c:884
D:views:#8  0x000005025be2b883 in process_queue (worker=0x502b3245040, type=<error reading variable: Unhandled dwarf expression opcode 0xa3>) at netmgr/netmgr.c:921
D:views:#9  0x000005025be20fea in process_all_queues (worker=0x502b3245040) at netmgr/netmgr.c:693
D:views:#10 async_cb (handle=0x502b3245318) at netmgr/netmgr.c:722
D:views:#11 0x00000502ce71592d in uv.async_io () from /usr/local/lib/libuv.so.3.0
D:views:#12 0x00000502ce727829 in uv.io_poll () from /usr/local/lib/libuv.so.3.0
D:views:#13 0x00000502ce716018 in uv_run () from /usr/local/lib/libuv.so.3.0
D:views:#14 0x000005025be210db in nm_thread (worker0=0x502b3245040) at netmgr/netmgr.c:631
D:views:#15 0x000005025be66ff6 in isc__trampoline_run (arg=0x502b324c520) at trampoline.c:187
D:views:#16 0x000005024bad11c1 in _rthread_start (v=<error reading variable: Unhandled dwarf expression opcode 0xa3>) at /usr/src/lib/librthread/rthread.c:96
D:views:#17 0x000005030a65ee0a in __tfork_thread () at /usr/src/lib/libc/arch/amd64/sys/tfork_thread.S:84
D:views:--------------------------------------------------------------------------------
D:views:full backtrace from views/ns2/named.core saved in views/ns2/named.core-backtrace.txt
D:views:core dump views/ns2/named.core archived as views/ns2/named.core.gz
R:views:FAIL
E:views:2022-04-04T14:16:42+0000
FAIL views (exit status: 1)

named.core-backtrace.txt

named.run

I can reproduce this crash locally in VM.

First occurred in 2420928 for d4eef9e8.

@each Might be related to the recent ADB rewrite (!6033 (merged))?

Also there's ADB-related assertion in 2420918, but I was unable to reproduce it locally and artifact are gone from the CI.