panic: bogus refcnt 0 on lle 0xfffff80121a13a00

Exiting from single-user mode triggers this:

ifa_maintain_loopback_route: deletion failed for interface igb0: 3
panic: bogus refcnt 0 on lle 0xfffff80121a13a00
cpuid = 9
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe1048c63470
vpanic() at vpanic+0x182/frame 0xfffffe1048c634f0
kassert_panic() at kassert_panic+0x126/frame 0xfffffe1048c63560
llentry_free() at llentry_free+0x136/frame 0xfffffe1048c63590
in_lltable_free_entry() at in_lltable_free_entry+0xb0/frame 0xfffffe1048c635c0
htable_prefix_free() at htable_prefix_free+0xce/frame 0xfffffe1048c63620
lltable_prefix_free() at lltable_prefix_free+0x5d/frame 0xfffffe1048c63660
in_scrubprefix() at in_scrubprefix+0x290/frame 0xfffffe1048c63700
in_difaddr_ioctl() at in_difaddr_ioctl+0x285/frame 0xfffffe1048c63750
in_control() at in_control+0x96/frame 0xfffffe1048c637d0
ifioctl() at ifioctl+0xda1/frame 0xfffffe1048c63860
kern_ioctl() at kern_ioctl+0x246/frame 0xfffffe1048c638c0
sys_ioctl() at sys_ioctl+0x171/frame 0xfffffe1048c639a0
amd64_syscall() at amd64_syscall+0x2f6/frame 0xfffffe1048c63ab0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe1048c63ab0
--- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x800fd2eba, rsp = 0x7fffffffe468, rbp = 0x7fffffffe4b0 -

Details _at_ https://people.freebsd.org/~pho/stress/log/bogus_refcnt.txt

-- 
Peter