FYI, seeing these on the latest 2.7.0-BETA snapshot build from today (06/21/2023).
This is a google fiber system with no VLANs set using genuine Intel i210 NICs. WAN interface is DHCP/DHCP6 and the LAN interface is tracking DHCP6 on WAN. IPv6 still works great after the message, just wanted to post here as an FYI in case it helps the devs. This same lock order message pops up randomly between 20 minutes and 4 hours after the system has booted.
Jun 21 10:46:41 kernel #16 0xffffffff8129035e at fork_trampoline+0xe Jun 21 10:46:41 kernel #15 0xffffffff80ca6cf0 at fork_exit+0x80 Jun 21 10:46:41 kernel #14 0xffffffff80d3c7a2 at gtaskqueue_thread_loop+0xc2 Jun 21 10:46:41 kernel #13 0xffffffff80d3c977 at gtaskqueue_run_locked+0xa7 Jun 21 10:46:41 kernel #12 0xffffffff80e55bda at _task_fn_rx+0x7a Jun 21 10:46:41 kernel #11 0xffffffff80e5bbb9 at iflib_rxeof+0xe59 Jun 21 10:46:41 kernel #10 0xffffffff80e3b1c9 at ether_input+0x99 Jun 21 10:46:41 kernel #9 0xffffffff80e6022d at netisr_dispatch_src+0xad Jun 21 10:46:41 kernel #8 0xffffffff80e3c359 at ether_nh_input+0x349 Jun 21 10:46:41 kernel #7 0xffffffff80e3adba at ether_demux+0x17a Jun 21 10:46:41 kernel #6 0xffffffff80e6039d at netisr_dispatch_src+0x21d Jun 21 10:46:41 kernel #5 0xffffffff80f6c227 at ip6_input+0xc77 Jun 21 10:46:41 kernel #4 0xffffffff80f521b6 at icmp6_input+0x9e6 Jun 21 10:46:41 kernel #3 0xffffffff80f81bf1 at nd6_na_input+0x981 Jun 21 10:46:41 kernel #2 0xffffffff80f84fc1 at defrouter_remove+0x41 Jun 21 10:46:41 kernel #1 0xffffffff80cea087 at _rw_wlock_cookie+0x67 Jun 21 10:46:41 kernel #0 0xffffffff80d615e3 at witness_checkorder+0xbb3 Jun 21 10:46:41 kernel lock order lle -> nd6 list attempted at: Jun 21 10:46:41 kernel #17 0xffffffff80d3c7a2 at gtaskqueue_thread_loop+0xc2 Jun 21 10:46:41 kernel #16 0xffffffff80d3c977 at gtaskqueue_run_locked+0xa7 Jun 21 10:46:41 kernel #15 0xffffffff80e55bda at _task_fn_rx+0x7a Jun 21 10:46:41 kernel #14 0xffffffff80e5bbb9 at iflib_rxeof+0xe59 Jun 21 10:46:41 kernel #13 0xffffffff80e3b1c9 at ether_input+0x99 Jun 21 10:46:41 kernel #12 0xffffffff80e6022d at netisr_dispatch_src+0xad Jun 21 10:46:41 kernel #11 0xffffffff80e3c359 at ether_nh_input+0x349 Jun 21 10:46:41 kernel #10 0xffffffff80e3adba at ether_demux+0x17a Jun 21 10:46:41 kernel #9 0xffffffff80e6039d at netisr_dispatch_src+0x21d Jun 21 10:46:41 kernel #8 0xffffffff80f6c227 at ip6_input+0xc77 Jun 21 10:46:41 kernel #7 0xffffffff80f52068 at icmp6_input+0x898 Jun 21 10:46:41 kernel #6 0xffffffff80f84445 at nd6_ra_input+0x1335 Jun 21 10:46:41 kernel #5 0xffffffff80f7d858 at nd6_cache_lladdr+0x858 Jun 21 10:46:41 kernel #4 0xffffffff80f854ac at defrouter_select_fib+0xdc Jun 21 10:46:41 kernel #3 0xffffffff80f7c023 at nd6_lookup+0x83 Jun 21 10:46:41 kernel #2 0xffffffff80f5a29b at in6_lltable_lookup+0x10b Jun 21 10:46:41 kernel #1 0xffffffff80cead92 at __rw_rlock_int+0x82 Jun 21 10:46:41 kernel #0 0xffffffff80d60d2b at witness_checkorder+0x2fb Jun 21 10:46:41 kernel lock order nd6 list -> lle established at: Jun 21 10:46:41 kernel 2nd 0xfffffe0021de8460 nd6 list (nd6 list, rw) @ /var/jenkins/workspace/pfSense-CE-snapshots-2_7_0-main/sources/FreeBSD-src-RELENG_2_7_0/sys/netinet6/nd6_rtr.c:864 Jun 21 10:46:41 kernel 1st 0xfffff8000218c410 lle (lle, rw) @ /var/jenkins/workspace/pfSense-CE-snapshots-2_7_0-main/sources/FreeBSD-src-RELENG_2_7_0/sys/net/if_llatbl.c:370 Jun 21 10:46:41 kernel lock order reversal: