Apparent fxp regression in FreeBSD 8.4-RC3

[YongHyeon PYUN]

On Sat, May 11, 2013 at 10:57:44PM -0400, Michael L. Squires wrote:
> I upgraded to FreeBSD 8.4-RC3 and noticed a problem with the fxp driver on 
> an older Supermicro single CPU single core Xeon motherboard.
> 
> I know that 8.3-Release does not have this issue, but don't know when in
> the updates to that release the regression was introduced.
> 
> I use the fxp driver to connect to a Motorola Surfboard cable modem, and 
> immediately saw the following occur many times:
> 
> May 10 23:00:04 familysquires kernel: fxp0: link state changed to DOWN
> May 10 23:00:04 familysquires dhclient: New Subnet Mask (fxp0): 
> 255.255.240.0
> May 10 23:00:04 familysquires dhclient: New Broadcast Address (fxp0): 
> 255.255.25
> 5.255
> May 10 23:00:04 familysquires dhclient: New Routers (fxp0): xx.xxx.xxx.1
> May 10 23:00:06 familysquires kernel: fxp0: link state changed to UP
> May 10 23:00:22 familysquires dhclient: New IP Address (fxp0): 
> xx.xxx.xxx.163
> May 10 23:00:22 familysquires kernel: fxp0: link state changed to DOWN
> May 10 23:00:22 familysquires dhclient: New Subnet Mask (fxp0): 
> 255.255.240.0
> May 10 23:00:22 familysquires dhclient: New Broadcast Address (fxp0): 
> 255.255.255.255
> May 10 23:00:22 familysquires dhclient: New Routers (fxp0): xx.xxx.xxx.1
> May 10 23:00:24 familysquires kernel: fxp0: link state changed to UP
> 
> repeated without end.

If you assign static IP address, fxp(4) works?

> 
> I reinsalled 8.3-Release p8
> 
> FreeBSD familysquires.net 8.3-RELEASE-p8 FreeBSD 8.3-RELEASE-p8 #46: Sat 
> May 11 00:05:26 EDT 2013
> 
> which ended the string up fxp up/down messages.  This kernel has now 
> operated for 24 hours without generating this error.

There were several fxp(4)changes made since FreeBSD 8.3-RELEASE but
I don't see any fxp(4) commits that may result in DHCP issue above.
I recall there was a dhclient(8) change that makes dhclient track
link state. Could you rebuild dhclient(8) and try again without
that change(i.e. locally back out r247336)?

> 
> I've attached a verbose dmesg from 8.4-RC3 and a standard dmesg from 
> 8.3-Release p8, and can provide whatever else you need.
> 
> This is not a critical issue for me.  The system has an unused bge interface
> (replaced by an Intel em0 interface during a previous bout of a problem with
> the bge driver).
> 
> Mike Squires
> mikes at siralan.org