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* network misbehaviour with gplpv and 2.6.30
@ 2009-07-18  3:42 James Harper
  2009-07-18 18:28 ` Andrew Lyon
                   ` (2 more replies)
  0 siblings, 3 replies; 25+ messages in thread
From: James Harper @ 2009-07-18  3:42 UTC (permalink / raw)
  To: xen-devel; +Cc: Andrew Lyon

With GPLPV under 2.6.30, GPLPV gets the following from the ring:

ring slot n (first buffer):
 status (length) = 54 bytes
 offset = 0
 flags = NETRXF_extra_info (possibly csum too but not relevant)
ring slot n + 1 (extra info)
 gso.size (mss) = 1460

Because NETRXF_extra_info is not set, that's all I get for that packet.
In the IP header though, the total length is 1544 (which in itself is a
little strange), but obviously I'm not getting a full packet, just the
ETH+IP+TCP header.

According to Andrew Lyon it works fine in previous versions, so this
problem only arises on 2.6.30. I don't know if netfront on Linux suffers
from a similar problem.

I can't identify any changes that could cause this, but if the problem
is in netback either the frags count isn't being set correctly, or
skb->cb (which appears to be used temporarily to hold nr_frags) is
becoming corrupt (set to 0) somehow, but the window where this could
occur is very small and I can't see where it could happen.

Any suggestions as to where to start looking?

(one nice thing is that I have identified a crash that would occur when
the IP header lied about its length!)

Thanks

James

^ permalink raw reply	[flat|nested] 25+ messages in thread

end of thread, other threads:[~2009-07-29  9:48 UTC | newest]

Thread overview: 25+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-07-18  3:42 network misbehaviour with gplpv and 2.6.30 James Harper
2009-07-18 18:28 ` Andrew Lyon
2009-07-21  9:35 ` Paul Durrant
2009-07-21 10:05   ` James Harper
2009-07-21 10:13     ` Paul Durrant
2009-07-21 11:09       ` James Harper
2009-07-29  9:48       ` Andrew Lyon
2009-07-21 10:53 ` Nerijus Narmontas
2009-07-21 11:01   ` dom0-cpus problem Pasi Kärkkäinen
2009-07-22 15:18     ` Nerijus Narmontas
2009-07-22 15:21       ` dom0-cpus problem with Xen 3.4.1-rc6 Pasi Kärkkäinen
2009-07-22 16:34         ` Nerijus Narmontas
2009-07-22 16:39           ` [Xen-devel] " Pasi Kärkkäinen
2009-07-22 16:42             ` Nerijus Narmontas
2009-07-22 17:01               ` Pasi Kärkkäinen
2009-07-22 17:08                 ` [Xen-devel] " Pasi Kärkkäinen
2009-07-22 17:55                   ` Keir Fraser
2009-07-22 17:15                 ` Keir Fraser
2009-07-22 17:29                   ` [Xen-devel] " Pasi Kärkkäinen
2009-07-22 17:46                     ` Keir Fraser
2009-07-22 18:03                       ` [Xen-devel] " Pasi Kärkkäinen
2009-07-22 17:30                 ` dom0-cpus problem with Xen 3.4.1-rc6 / HVM domains don't die Pasi Kärkkäinen
2009-07-23 13:56                   ` Re: [Xen-devel] " Pasi Kärkkäinen
2009-07-23  9:39       ` [Xen-devel] dom0-cpus problem George Dunlap
2009-07-23 10:03         ` Pasi Kärkkäinen

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