bogus 0 len IP packet, was: Hang in VOP_LOCK1_APV on 8-STABLE with NFS.

[Brandon Gooch]

On Wed, Jan 19, 2011 at 5:59 PM, Pyun YongHyeon <pyunyh at gmail.com> wrote:
> On Tue, Jan 18, 2011 at 07:35:30PM +0100, sthaug at nethelp.no wrote:
>> > > I'm seeing the same problem with Broadcom NetXtreme (bce) cards:
>> > >
>> > > bce0 at pci0:3:0:0:        class=0x020000 card=0x03421014 chip=0x164c14e4 rev=0x12 hdr=0x00
>> > >     vendor     = 'Broadcom Corporation'
>> > >     device     = 'Broadcom NetXtreme II Gigabit Ethernet Adapter (BCM5708)'
>> > >     class      = network
>> > >     subclass   = ethernet
>> > >
>> > > This is with 8.2-PRERELEASE. Turning off TSO (ifconfig bce0 -tso)
>> > > removes the problem.
>> > >
>> >
>> > Is there a reliable way to trigger this on bce(4)? I don't have
>> > BCM5708 but I have BCM5709 so I can verify that.
>>
>> It showed up pretty much immediately when running a csup sessions
>> against cvsup2.us.freebsd.org.
>>
>> I have a pcap file from the session, if you're interested.
>>
>
> I vaguely guess upper stack might pass less than MSS sized segment
> to TSO capable driver with CSUM_TSO.
> How about merging r212803 to stable/8?

It states in the commit message:

MFC after:	10 days

When I read an MFC, is it more of a suggestion than a promise? I'm not
trying to be sarcastic :|

-Brandon