From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH] net: Check skb->rxhash in gro_receive Date: Wed, 15 Jan 2014 02:43:36 +0000 Message-ID: <1389753816.3720.184.camel@deadeye.wl.decadent.org.uk> References: <1389332287.31367.88.camel@edumazet-glaptop2.roam.corp.google.com> <20140113.115913.1269834557058575064.davem@davemloft.net> <1389644256.31367.223.camel@edumazet-glaptop2.roam.corp.google.com> <1389646213.2025.159.camel@bwh-desktop.uk.level5networks.com> <1389649061.31367.236.camel@edumazet-glaptop2.roam.corp.google.com> <1389749477.3720.173.camel@deadeye.wl.decadent.org.uk> <1389752827.31367.314.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-5bx/bWnsEEhdP3If3zor" Cc: David Miller , therbert@google.com, netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45624 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752317AbaAOCnr (ORCPT ); Tue, 14 Jan 2014 21:43:47 -0500 In-Reply-To: <1389752827.31367.314.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: --=-5bx/bWnsEEhdP3If3zor Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2014-01-14 at 18:27 -0800, Eric Dumazet wrote: > On Wed, 2014-01-15 at 01:31 +0000, Ben Hutchings wrote: >=20 > > When I investigated the scope of this for Debian, I tried sending a > > 'packet of death' to a VM and actually triggered the lockup in the TX > > path of the *host*, running Debian unstable with Linux 3.11. I didn't > > track down exactly why that was but I think that libvirt's default > > networking configuration includes multiqueue devices that use flow > > dissector. >=20 > OK, I take that majority of debian hosts are running some VM then, > nice to know, time to update my hosts and usages I guess. I said that common configurations use flow dissector - not the majority. > Anyway, current flow dissector needs care if we really use it in > unprotected areas. >=20 > Hostile packets can force flow dissection of MTU bytes, > bringing host to abysmal performance. [...] Yes. I think the number of times it can loop should be limited to some small number. Ben. --=20 Ben Hutchings Life is what happens to you while you're busy making other plans. - John Lenno= n --=-5bx/bWnsEEhdP3If3zor Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) iQIVAwUAUtX12Oe/yOyVhhEJAQoLeQ/+NBq7CR9OJYU44+QG2fhLFCViLe2A+BY7 aEO4znlr4ZpwOE70BoJHf5pgFymbq64lGIVUk9fCnt0nXVJtz/8t7cpBtHRH6/hR q1xTrFT1QXEF5gTya2wspOEeEhwHEmEPQ0baLN/wEtloXn5+YoJwZwC7jvi749Jd P8sGb1GcJBTFKVG5AaJrW6IzrF2s2++6hBkSJym2Xn6yNYMfXn2JkFF3psEvtYWZ QyTM3ufHS8dBaGpA3CxoBarVXUR1phS/BAWRqmiK4RAioglYpwVqtgGnZvkSATAT m3xTzENHRKl2DPk2W/SdSUx+4QueD9O2Nbo8m4X9pKy4eVWZUYlzCgG1BrIUwEyc jm+c5Wq9uFrdesOTy5uMu2if6tSHZWxTRf21kx6lmL+vrIXAFboY0/35bO4kCdCY I1X/uooR34Ozhn07up1F8zjnbi16Pq0niDG+RdCotlPC5VWsExy/hKS45HWhL+xW GzzO3eR+rUPPv7/UcVDtuCJVw3AODgC6is32cHaqxiU/11QjqtTqHbjOzVPal2EV S4w1ch+Nn42RteIMTRZNNgHwFq67y3QACuqcY7CbF3nj2JuR3/cYWYZF0lib9flk WBFHvbXmDIN0Rc2Pnm2FAAoxgclE0BuymiPClk0MEDPjrxwplGB7rHkUPLo2Hj8M FZBasFZHK9g= =tLu6 -----END PGP SIGNATURE----- --=-5bx/bWnsEEhdP3If3zor--