Can't create lagg interfaces on recent HEAD (2012.12.05 based sources)

[Garrett Cooper]

    I can't seem to create a lagg'ed interface on HEAD with ixgbe
(it's failing when creating a cloned interface), whereas creating it
on 9.1-STABLE built from a couple weeks ago just worked. Ideas?
Thanks,
-Garrett

# cat /root/ISI-GENERIC
include         GENERIC
ident           ISI-GENERIC

makeoptions     MODULES_OVERRIDE="bxe cxgb cxgbe em igb ixgbe qlxgb"
nodevice        bxe
nodevice        cxgb
nodevice        cxgbe
nodevice        em
nodevice        igb
nodevice        ixgbe
nodevice        qlxgb

options         OFED
options         SDP
options         IPOIB_CM

device          ipoib
device          mlx4ib
device          mlxen
device          mthca
# uname -a
FreeBSD wf158.west.isilon.com 10.0-CURRENT FreeBSD 10.0-CURRENT #0:
Thu Dec  6 23:41:57 PST 2012
root at wf158.west.isilon.com:/usr/obj/usr/src/sys/ISI-GENERIC  amd64
# service netif restart
Stopping Network: lo0 ix0 ix1.
lo0: flags=8048<LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
        options=600003<RXCSUM,TXCSUM,RXCSUM_IPV6,TXCSUM_IPV6>
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
ix0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 9000
        options=407bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,VLAN_HWTSO>
        ether 00:1b:21:88:51:c4
        inet6 fe80::21b:21ff:fe88:51c4%ix0 prefixlen 64 scopeid 0x2
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: Ethernet autoselect (10Gbase-SR <full-duplex>)
        status: active
ix1: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 9000
        options=407bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,VLAN_HWTSO>
        ether 00:1b:21:88:51:c5
        inet6 fe80::21b:21ff:fe88:51c5%ix1 prefixlen 64 scopeid 0x3
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: Ethernet autoselect (10Gbase-SR <full-duplex>)
        status: active
ifconfig: SIOCIFCREATE2: Invalid argument
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Starting Network: lo0 ix0 ix1.
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 0x1
        inet 127.0.0.1 netmask 0xff000000
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
ix0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 9000
        options=407bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,VLAN_HWTSO>
        ether 00:1b:21:88:51:c4
        inet6 fe80::21b:21ff:fe88:51c4%ix0 prefixlen 64 scopeid 0x2
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: Ethernet autoselect (10Gbase-SR <full-duplex>)
        status: active
ix1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 9000
        options=407bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,VLAN_HWTSO>
        ether 00:1b:21:88:51:c5
        inet6 fe80::21b:21ff:fe88:51c5%ix1 prefixlen 64 scopeid 0x3
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: Ethernet autoselect (10Gbase-SR <full-duplex>)
        status: active
# cat /etc/rc.conf
hostname="wf158.west.isilon.com"
ifconfig_em0="DHCP"
sshd_enable="YES"
ntpd_enable="YES"
# Set dumpdev to "AUTO" to enable crash dumps, "NO" to disable
dumpdev="NO"

nfs_client_enable="YES"
rpc_lockd_enable="YES"
rpc_statd_enable="YES"
rpcbind_enable="YES"

tahi_interface="em1"
#
#ipv6_default_interface="$tahi_interface"
#ipv6_network_interfaces="$tahi_interface"
#
eval "ifconfig_${tahi_interface}_ipv6='inet6 up -accept_rtadv
-auto_linklocal -nud'"

devfs_system_ruleset="tahi_bpf"

kld_list="ixgbe"
ifconfig_ix0="up mtu 9000"
ifconfig_ix1="up mtu 9000"
cloned_interfaces="lagg0"
ifconfig_lagg0="laggproto lacp laggport ix0 laggport ix1 lagghash l3
7.7.6.42 netmask 255.255.255.0"