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Message-ID: <1360256716.3605.12.camel@bwh-desktop.uk.solarflarecom.com>
Subject: Re: [PATCHv2-net-3.8 0/3] fix kernel crash with macvtap on top of
 LRO
From: Ben Hutchings <bhutchings@solarflare.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
        "David S. Miller" <davem@davemloft.net>
CC: <netdev@vger.kernel.org>, Eilon Greenstein <eilong@broadcom.com>,
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        John Ronciak <john.ronciak@intel.com>,
        Tushar Dave <tushar.n.dave@intel.com>,
        Jitendra Kalsaria <jitendra.kalsaria@qlogic.com>,
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Date: Thu, 7 Feb 2013 17:05:16 +0000
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On Thu, 2013-02-07 at 15:12 +0200, Michael S. Tsirkin wrote:
> At the moment, macvtap crashes are observed if macvtap is attached
> to an interface with LRO enabled.
> The crash in question is BUG() in macvtap_skb_to_vnet_hdr.
> This happens because several drivers set gso_size but not gso_type
> in incoming skbs.
> This didn't use to be the case: with intel cards on 3.2 and older
> kernels, with qlogic - on 3.4 and older kernels, so it's a regression if
> not a recent one.
> The following patches fix this for qlogic, broadcom and intel drivers.
> 
> I tested that the patch fixes the crash for ixgbe but
> don't have qlogic/broadcom hardware to test.
> I also only tested TCPv4.
> 
> Please review, and consider for 3.8.
> 
> Changes from v1:
> 	- added missing htons as suggested by Eric
> 	- backported the relevant bits from
> 	  cbf1de72324a8105ddcc3d9ce9acbc613faea17e for bnx2x

I still don't think macvtap should behave inconsistently with forwarding
and the bridge device.  We need a consensus as to whether transformation
by LRO is allowable before making changes one way or the other.  If
we're going to allow it then inet_lro also needs this fix.

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.