From owner-freebsd-net@freebsd.org Wed Dec 9 08:46:01 2015 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 44DCA9D3B50 for ; Wed, 9 Dec 2015 08:46:01 +0000 (UTC) (envelope-from ae@FreeBSD.org) Received: from mx2.freebsd.org (mx2.freebsd.org [IPv6:2001:1900:2254:206a::19:2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mx2.freebsd.org", Issuer "Gandi Standard SSL CA 2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 36F351CF8; Wed, 9 Dec 2015 08:46:01 +0000 (UTC) (envelope-from ae@FreeBSD.org) Received: from butcher-nb.yandex.net (freefall.freebsd.org [IPv6:2001:1900:2254:206c::16:87]) by mx2.freebsd.org (Postfix) with ESMTP id 3C06F66514; Wed, 9 Dec 2015 08:45:58 +0000 (UTC) (envelope-from ae@FreeBSD.org) Subject: Re: Multiple cores/race conditions in IPv6 RA To: Jason , freebsd-net@freebsd.org References: <50cff74ea38f155ae616cf49f5ffb5ae@m.nitrology.com> Cc: kevin.bowling@kev009.com, hiren@strugglingcoder.info, Mark Johnston From: "Andrey V. Elsukov" Message-ID: <5667EA3A.8050200@FreeBSD.org> Date: Wed, 9 Dec 2015 11:45:46 +0300 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: <50cff74ea38f155ae616cf49f5ffb5ae@m.nitrology.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="CA3LqJI7WbNHHaADAAf5o3jSFhroLgeMh" X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Dec 2015 08:46:01 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --CA3LqJI7WbNHHaADAAf5o3jSFhroLgeMh Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable On 08.12.15 08:32, Jason wrote: > Hi, >=20 > It appears the IPv6 router advertisement code paths were written fairly= > lockless, assuming you would never process multiples concurrently. We > are seeing multiple page faults in various places processing the > messages and modifying the routing table. We have multiple L3 devices > and multiple v6 blocks broadcasting these messages to hardware with dua= l > uplinks in the same VLAN, which I believe is making us susceptible to > this. Though I believe the dual uplink is all that's required for this= , > as it can be seen in configurations with a single v6 block. >=20 > We are running stable/10 @ r285800, and it doesn't appear anything > relevant has changed since then. Our other widely deployed version is > 8.3-RELEASE, which does not see this issue. Upon bumping a machine fro= m > 8.3 -> 10 we can see it start to exhibit this behavior. The only chang= e > I see that might be relevant is r243148, but these cores are relatively= > rare, so testing is tough without a considerable deployment. So > basically I'm hoping someone with a trained eye can send us in the righ= t > direction before we go down that road. Hi, some time ago Mark Johnston has published there the patch related to this problem: https://lists.freebsd.org/pipermail/freebsd-net/2013-February/034682.html= Maybe Mark has something to say about it. --=20 WBR, Andrey V. Elsukov --CA3LqJI7WbNHHaADAAf5o3jSFhroLgeMh Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBCAAGBQJWZ+o6AAoJEAHF6gQQyKF6pvgH/iD6n22BzWnTli+pnOc4GkyV UqHl5cnNb6qpZBHJ57zjw4sPubjkog1GaoTDKqMFmXkJ1YjWaMvAQ1XXmdH3Yz4b SV9tOuQUqasI+Pd6d/0u9DwJdnHV17BtvauBr9Ld9u4zL3kEaUpLIY6hIzobRFUv /YKq3mIr5KzrCKwGu6YGcV3Jyiqx8MLOIj07kovllGYMhIe0aaCU034ydIWOlTGR bvuRCXh2eJKMvj+rCozYxOCIfTPZY8gA9tKgu9CwNvfRA9XMdMEiCgnt7NPC0RQV ecmeH6/BU+GpnuNpxjSnKlIW73ipdRFo6bd3/7O7SDXWooU7T407iV2ndzz9hKw= =ZXQo -----END PGP SIGNATURE----- --CA3LqJI7WbNHHaADAAf5o3jSFhroLgeMh--