lagg member interfaces don't come back after cable pull

[Nagy, Attila]

Hi,

Running stable/9 at r260621, multiple (currently two) igb's connected to 
multiple Cisco Nexus 2ks, forming an LACP port channel.

If I pull one of the cables from the switch, the port immediately goes 
down, and removed from the port channel. Everything works nicely.
When I reconnect the cable, the member interface (igb1) remains down.
On the host side, I see:
igb1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=401bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO>
         ether ac:16:2d:9a:18:cd
         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
         media: Ethernet autoselect
         status: no carrier
igb2: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=401bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO>
         ether ac:16:2d:9a:18:cd
         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
         media: Ethernet autoselect (1000baseT <full-duplex>)
         status: active
admin: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
options=401bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO>
         ether ac:16:2d:9a:18:cd
         inet6 fe80::ae16:2dff:fe9a:18cd%admin prefixlen 64 tentative 
scopeid 0x9
         inet 172.27.79.74 netmask 0xffffff00 broadcast 172.27.79.255
         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
         media: Ethernet autoselect
         status: active
         laggproto lacp lagghash l2,l3,l4
         laggport: igb2 flags=1c<ACTIVE,COLLECTING,DISTRIBUTING>
         laggport: igb1 flags=0<>

Issuing an ifconfig down and up on igb1 fixes the problem, it gets back 
into the port channel.

On the switch side I can see the following:
2014 Jan 17 08:58:11 DP1106-A05-11-N5K %ETH_PORT_CHANNEL-5-PORT_UP: 
port-channel6: Ethernet109/1/47 is up
2014 Jan 17 09:20:42 DP1106-A05-11-N5K %ETH_PORT_CHANNEL-5-PORT_DOWN: 
port-channel6: Ethernet109/1/47 is down
2014 Jan 17 09:31:52 DP1106-A05-11-N5K %ETH_PORT_CHANNEL-5-PORT_UP: 
port-channel6: Ethernet109/1/47 is up

The cable was pulled at 09:20:42 and was reconnected in some seconds. 
ifconfig down and up was issued around 09:31:52, which fixed the access.

 From what I see it may be just the igb and not really connected to 
lagg, but I'm not sure and the machine is far away, so testing is not so 
easy.