'no route to host" for cloned lo1 iface 12.0-CURRENT r334376+56a973815425(master) amd64

[Dave Cottlehuber]

I have 10.241.0.0-15/16 bound to lo1 for jails, and I just realised it doesn't work anymore. Boxes at $DAYJOB use the same config and work just fine on 11.1R/amd64, otherwise I'd be fired.... this used to work ~ 1 month ago, both on my desktop, and my laptop, and now doesn't.

​Have I mis-configured something blindingly obvious here before I embark on a lengthy bisect?

# grep -v \# /etc/rc.conf , elided
hostname=akai
kld_list="${kld_list} if_iwm if_axge if_ure if_ue"
ifconfig_ue0=DHCP
ifconfig_ue0_ipv6="inet6 accept_rtadv"
wlans_iwm0="wlan0"
ifconfig_wlan0="WPA DHCP"
ifconfig_wlan0_ipv6="inet6 accept_rtadv"
create_args_wlan0="country AT regdomain ETSI"
cloned_interfaces="${cloned_interfaces} lo1"
ifconfig_lo1_aliases="inet 10.241.0.0-15/16"
ip6addrctl_policy="ipv4_prefer"

# netstat -4rn
Internet:
Destination        Gateway            Flags     Netif Expire
default            172.16.2.1         UGS         ue0
10.241.0.0         link#4             UH          lo1
10.241.0.1         link#4             UH          lo1
10.241.0.2         link#4             UH          lo1
10.241.0.3         link#4             UH          lo1
10.241.0.4         link#4             UH          lo1
10.241.0.5         link#4             UH          lo1
10.241.0.6         link#4             UH          lo1
10.241.0.7         link#4             UH          lo1
10.241.0.8         link#4             UH          lo1
10.241.0.9         link#4             UH          lo1
10.241.0.10        link#4             UH          lo1
10.241.0.11        link#4             UH          lo1
10.241.0.12        link#4             UH          lo1
10.241.0.13        link#4             UH          lo1
10.241.0.14        link#4             UH          lo1
10.241.0.15        link#4             UH          lo1
127.0.0.1          link#1             UH          lo0
172.16.2.0/24      link#2             U           ue0
172.16.2.92        link#3             UHS         lo0
172.16.2.93        link#2             UHS         lo0

# ifconfig
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
	options=680003<RXCSUM,TXCSUM,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6>
	inet6 ::1 prefixlen 128 
	inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 
	inet 127.0.0.1 netmask 0xff000000 
	nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
	groups: lo 
ue0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
	options=8000b<RXCSUM,TXCSUM,VLAN_MTU,LINKSTATE>
	ether 74:da:38:d8:fe:a7
	inet6 fe80::76da:38ff:fed8:fea7%ue0 prefixlen 64 scopeid 0x2 
	inet 172.16.2.93 netmask 0xffffff00 broadcast 172.16.2.255 
	nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
	media: Ethernet autoselect (1000baseT <full-duplex>)
	status: active
wlan0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
	ether 00:28:f8:d0:91:52
	inet6 fe80::228:f8ff:fed0:9152%wlan0 prefixlen 64 scopeid 0x3 
	inet 172.16.2.92 netmask 0xffffff00 broadcast 172.16.2.255 
	nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
	media: IEEE 802.11 Wireless Ethernet OFDM/54Mbps mode 11g
	status: associated
	ssid skunkwerks channel 6 (2437 MHz 11g) bssid 80:2a:a8:5a:bd:3f
	regdomain ETSI country AT authmode WPA2/802.11i privacy ON
	deftxkey UNDEF AES-CCM 2:128-bit txpower 30 bmiss 10 scanvalid 60
	protmode CTS wme roaming MANUAL
	groups: wlan 
lo1: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
	options=680003<RXCSUM,TXCSUM,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6>
	inet 10.241.0.0 netmask 0xffff0000 
	inet 10.241.0.1 netmask 0xffffffff 
	inet 10.241.0.2 netmask 0xffffffff 
	inet 10.241.0.3 netmask 0xffffffff 
	inet 10.241.0.4 netmask 0xffffffff 
	inet 10.241.0.5 netmask 0xffffffff 
	inet 10.241.0.6 netmask 0xffffffff 
	inet 10.241.0.7 netmask 0xffffffff 
	inet 10.241.0.8 netmask 0xffffffff 
	inet 10.241.0.9 netmask 0xffffffff 
	inet 10.241.0.10 netmask 0xffffffff 
	inet 10.241.0.11 netmask 0xffffffff 
	inet 10.241.0.12 netmask 0xffffffff 
	inet 10.241.0.13 netmask 0xffffffff 
	inet 10.241.0.14 netmask 0xffffffff 
	inet 10.241.0.15 netmask 0xffffffff 
	nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
	groups: lo 
bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
	description: vm-public
	ether 02:63:d4:40:fe:00
	nd6 options=1<PERFORMNUD>
	groups: bridge 
	id 00:00:00:00:00:00 priority 0 hellotime 2 fwddelay 15
	maxage 20 holdcnt 6 proto rstp maxaddr 2000 timeout 1200
	root id 00:00:00:00:00:00 priority 0 ifcost 0 port 0
	member: wlan0 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
	        ifmaxaddr 0 port 3 priority 128 path cost 370370