Problems with lagg interfaces

[Simon Dick]

Hi, I've just seen an odd problem when using the lagg interface (in
FreeBSD 8.1, but I can't see any relevant commits post-8.1) where the
underlying interfaces can see incoming traffic but that doesn't show
up on lagg.

Unfortunately it's not possible to upgrade the OS at this time as the
server is remote and in production.

Here's the rc.conf setup:

ifconfig_igb0="up"
ifconfig_igb1="up"
ifconfig_em0="up"
ifconfig_em1="up"
cloned_interfaces="lagg0 lagg1"
ifconfig_lagg0="laggproto failover laggport igb0 laggport em0 1.2.3.4/25"
ifconfig_lagg1="laggproto failover laggport igb1 laggport em1 5.6.7.8/16"

The strange part is that this happened on two separate machine (same
hardware) at around the same time but not a third identical server.
Some relevant parts of dmesg:

igb0: <Intel(R) PRO/1000 Network Connection version - 1.9.5> port
0xcc00-0xcc1f mem
0xfa3e0000-0xfa3fffff,0xfa800000-0xfabfffff,0xfa3dc000-0xfa3dffff irq
16 at device 0.0 on pci5
igb0: Using MSIX interrupts with 10 vectors
igb0: Ethernet address: 90:e2:ba:00:d5:ca
igb1: <Intel(R) PRO/1000 Network Connection version - 1.9.5> port
0xc880-0xc89f mem
0xf97e0000-0xf97fffff,0xf9c00000-0xf9ffffff,0xf97dc000-0xf97dffff irq
17 at device 0.1 on pci5
igb1: Using MSIX interrupts with 10 vectors
igb1: Ethernet address: 90:e2:ba:00:d5:cb
em0: <Intel(R) PRO/1000 Network Connection 7.0.5> port 0xdc00-0xdc1f
mem 0xfbce0000-0xfbcfffff,0xfbcdc000-0xfbcdffff irq 16 at device 0.0
on pci6
em0: Using MSIX interrupts with 5 vectors
em0: Ethernet address: 00:25:90:62:bd:2a
em1: <Intel(R) PRO/1000 Network Connection 7.0.5> port 0xec00-0xec1f
mem 0xfbde0000-0xfbdfffff,0xfbddc000-0xfbddffff irq 17 at device 0.0
on pci7
em1: Using MSIX interrupts with 5 vectors
em1: Ethernet address: 00:25:90:62:bd:2b

If anyone needs any more information or has any ideas please let me
know, all that fixed it last time was rebooting, destroying and
recreateing the lagg1 interface and even removing totally and creating
a lagg2 with the same details had no effect at all.

Thanks!