Panic _at_r305116 in transition to multi-user mode

This was well into the transition from single- to multi-user mode,
so the following information is a re-creation after I rebooted to
single-user mode (verbosely), ran "fsck -p", then "exit" -- copy/pasted
from serial console:

# exit
Setting hostuuid: 80f1e964-dc63-0010-89d5-0030482d326a.
Setting hostid: 0xc74551dd.
Fast boot: skipping disk checks.
Mounting local filesystems:.
ELF ldconfig path: /lib /usr/lib /usr/lib/compat /usr/local/lib /usr/local/lib/compat /usr/local/lib/perl5/5.24/mach/CORE
32-bit compatibility ldconfig path: /usr/lib32 /usr/lib32/compat /usr/local/libre0: link state changed to DOWN
32/compat
Setting hostname: freebeast.catwhisker.org.
Setting up harvesting: [UMA],[FS_ATIME],SWI,INTERRUPT,NET_NG,NET_ETHER,NET_TUN,MOUSE,KEYBOARD,ATTACH,CACHED
Feeding entropy: .
Starting Network: lo0 re0.
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
        options=600003<RXCSUM,TXCSUM,RXCSUM_IPV6,TXCSUM_IPV6>
        inet6 ::1 prefixlen 128 
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2 
        inet 127.0.0.1 netmask 0xff000000 
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
        groups: lo 
re0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=8209b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_MAGIC,LINKSTATE>
        ether 98:90:96:d6:c9:6d
        inet 172.16.8.10 netmask 0xffffff00 

broadcast 172.16Fat.8.255 
        nd6 opal ttions=29<PERFORMrapNUD,IFDISABLED,A 12UTO_LINKLOCAL>
: pa    media: Ethernetge f autoselect (nonaue)
        status: no lt carrier
Startinwhilg devd.
add hose it 127.0.0.1: gatn keway lo0 fib 0: erneroute already inl mo table
add net de
default: gatewaycpuid = 6; a 172.16.8.1
addpic host ::1: gatew iday lo0 fib 0: ro = ute already in t06
able
add net fefaul80::: gateway ::t 1
add net ff02:vir:: gateway ::1
tuaadd net ::ffff:0l ad.0.0.0: gateway dre::1
add net ::0ss   .0.0.0: gateway = 0x::1
Creating anffffd/or trimming lo80403037b7a8
fault g files.
Starticode              = supervisor read data, page not present
ing syslogd.
Stanstruction pointer   = 0x20:0xffffffff80ead57a
rting rpcbind.
stack pointer           = 0x28:0xfffffe085de368c0
fraNFS access cacheme  time=60
rpc.umpointall: grundoon:nte MOUNTPROG: RPC:r     Unknown host
r    pc.umntall: grun   doon: MOUNTPROG:= 0 RPC: Unknown hox28st
No core dump:0xs found.
Settinffffg NIS domain: lmfe0dhw.com.
Starti85dng ypbind.
Cleae36ring /tmp (X rel900ated).
Starting
 mountd.
NFSv4 codis disabled
Stae srting nfsd.
Staegmrting statd.
Stentarting lockd.
R               =ecovering vi edi bastor sessions:.
e 0Starting lpd.
Ux0, pdating motd:.
limiMounting late fit 0lesystems:.
Staxffrting ntpd.
Staffrting powerd.
ype ttarting rsyncd.
    0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
pConfiguring vt:ro blanktimecessor eflags       = interrupt enabled, r.
esume, IOPL = 0
current process         = 567 (ntpd)
[ thread pid 567 tid 100201 ]
Stopped at      pmap_kextract+0x8a:     movq    (%rax,%rcx,1),%r13
db> bt
Tracing pid 567 tid 100201 td 0xfffff80010349a00
pmap_kextract() at pmap_kextract+0x8a/frame 0xfffffe085de36900
free() at free+0x5e/frame 0xfffffe085de36940
kern_close() at kern_close+0xd0/frame 0xfffffe085de369a0
amd64_syscall() at amd64_syscall+0x2db/frame 0xfffffe085de36ab0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe085de36ab0
--- syscall (6, FreeBSD ELF64, sys_close), rip = 0x8013ebf2a, rsp = 0x7fffffffe7d8, rbp = 0x7fffffffe7f0 ---
db> dump
Dumping 1299 out of 32687 MB:..2%..12%..21%..31%..41%..51%..61%..71%..81%..92%
Dump complete
db> 

I can afford to leave this system in this state until this evening (local
time here is just after 05:00 as I type), so if there's something I can
poke to get more useful information, please let me know.

Once I reboot (either from yesterday's (r305058) kernel or from the
stable/11 or stable/10 slice), I should be able to make the dump
available via my Web server.

I'm about to build head_at_r305116 on my laptop (as well); I plan to
follow up to indicate whether it exhibits similar behavior (or not).

Peace,
david
-- 
David H. Wolfskill				david_at_catwhisker.org
Those who would murder in the name of God or prophet are blasphemous cowards.

See http://www.catwhisker.org/~david/publickey.gpg for my public key.