em driver woes

[Volcane]

I scanned through the archive and noticed a posting there about an
interrupt storm on the em driver, I am not sure if my symptoms are
related so I decided on a new thread.

I first installed the 6.0-RELEASE using FTP install and everything was
happy, I then CVSUP'd to RELENG_6 which had an em driver update a few
hours ago.

Did the world and kernel and booted, on the boot with the new kernel I
noticed my network was dead.  I could get the initial DHCP from my
server but once it got an IP it wasn't working.

Further investigation with tcpdump showed me a massive amount of arp
requests for my gateway IP, with replies coming back to the card. 
Output of 'arp -an' showed that the gateway ARP was indeed in the arp
table so there shouldnt have been any reason for all the arp requests.

At this point I investigated the driver version and found that the
GENERIC from the installation media was:

em0: <Intel(R) PRO/1000 Network Connection, Version - 2.1.7> port
0x4000-0x403fmem 0xd8000000-0xd801ffff irq 16 at device 10.0 on pci10
em0: Ethernet address: 00:14:85:08:60:c6
em0:  Speed:N/A  Duplex:N/A

The em from the new -STABLE kernel was:

em0: <Intel(R) PRO/1000 Network Connection Version - 3.2.18> port
0x4000-0x403fmem 0xd8000000-0xd801ffff irq 16 at device 10.0 on pci10
em0: [GIANT-LOCKED]
em0: Ethernet address: 00:14:85:08:60:c6

Below is a diff from the config file I used to build -STABLE and the
GENERIC config:

< cpu           I486_CPU
< cpu           I586_CPU
25c23
< ident         GENERIC
---
> ident         WEB1
36d33
< options       INET6                   # IPv6 communications protocols
64a62,72
> options         SMP                     # Symmetric MultiProcessor Kernel
> options         IPSEC
> options         IPSEC_ESP
> options         IPSEC_DEBUG
> options         IPSEC_FILTERGIF
> options         IPFIREWALL
> options         IPFIREWALL_VERBOSE
> options         IPFIREWALL_DEFAULT_TO_ACCEPT
> options         IPFIREWALL_FORWARD_EXTENDED

Hope this helps anyone, for now I'm heading back to -RELEASE