Date: Sun, 8 Feb 2009 21:47:01 -0600 From: Eric Anderson <anderson@freebsd.org> To: Danny Braniss <danny@cs.huji.ac.il> Cc: Ross Dickey <rdickey@storspeed.com>, Peter Jeremy <peter@vk2pj.dyndns.org>, hackers@freebsd.org, freebsd-stable@freebsd.org Subject: Re: impossible packet length ... Message-ID: <205598DD-B746-4236-9140-855811BAE21C@freebsd.org> In-Reply-To: <E1LW60v-0000zC-B2@kabab.cs.huji.ac.il> References: <E1LW5Ht-0000VH-D8@kabab.cs.huji.ac.il> <20090208091656.GA31876@test71.vk2pj.dyndns.org> <E1LW60v-0000zC-B2@kabab.cs.huji.ac.il>
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On Feb 8, 2009, at 3:31 AM, Danny Braniss wrote:
>>
>> --jI8keyz6grp/JLjh
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>>
>> On 2009-Feb-08 10:45:13 +0200, Danny Braniss <danny@cs.huji.ac.il>
>> wrote:
>>> Feb 6 18:00:13 warhol-00.cs.huji.ac.il kernel: bce0: discard
>>> frame w/o=20
>>> leading ethernet header (len 0 pkt len 0)
>> =2E..
>>> Feb 6 19:00:00 warhol-00.cs.huji.ac.il amd[715]: Unknown $
>>> sequence in=20
>>> "rhost:=3D${RHOST};type:=3Dnfsl;fs:=3D${FS};rfs:=3D$huldig<C0>#^ZM-
>>> ^KoM- a=
>> base"
>>> Feb 6 19:00:00 warhol-00.cs.huji.ac.il kernel: impossible packet
>>> length=
>> =20
>>> (2068989523) from nfs server sunfire:/dist
>>>
>>> which seems to point fingers at bce...
>>
>> It does rather suggest that bce is not behaving. What happens if you
>> turn off checksum off-loading? This should make the kernel drop the
>> corrupt packets instead of trying to process them. If practical, you
>> could also try (temporarily) plugging in a different NIC.
>>
> I have, and now it's a matter of waiting...
> Q: with rxcsum on, and a bad checksum packet is received, is it
> dropped by the NIC? if not, then it somewhat explains the behaviour
>
> changing the nic is tough, but if needed will be done.
> danny
>
>> Peter Jeremy
We were hitting this quite a bit (also bce), and updated to a recent 7-
branch and it seems to be behaving better for now. Running 12 days so
far (which is better than what we had been seeing).
Eric
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