Date: Wed, 9 Dec 2015 11:45:46 +0300 From: "Andrey V. Elsukov" <ae@FreeBSD.org> To: Jason <j@scre.ws>, freebsd-net@freebsd.org Cc: kevin.bowling@kev009.com, hiren@strugglingcoder.info, Mark Johnston <markj@freebsd.org> Subject: Re: Multiple cores/race conditions in IPv6 RA Message-ID: <5667EA3A.8050200@FreeBSD.org> In-Reply-To: <50cff74ea38f155ae616cf49f5ffb5ae@m.nitrology.com> References: <50cff74ea38f155ae616cf49f5ffb5ae@m.nitrology.com>
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[-- Attachment #1 --] On 08.12.15 08:32, Jason wrote: > Hi, > > 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 dual > 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. > > 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 from > 8.3 -> 10 we can see it start to exhibit this behavior. The only change > 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 right > 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. -- WBR, Andrey V. Elsukov [-- Attachment #2 --] -----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-----
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