Date: Wed, 9 Dec 2015 19:54:29 +1100 From: Kubilay Kocak <koobs@FreeBSD.org> To: "Andrey V. Elsukov" <ae@FreeBSD.org>, Jason <j@scre.ws>, freebsd-net@freebsd.org Cc: Mark Johnston <markj@freebsd.org>, kevin.bowling@kev009.com, hiren@strugglingcoder.info, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Re: Multiple cores/race conditions in IPv6 RA Message-ID: <5667EC45.2050808@FreeBSD.org> In-Reply-To: <5667EA3A.8050200@FreeBSD.org> References: <50cff74ea38f155ae616cf49f5ffb5ae@m.nitrology.com> <5667EA3A.8050200@FreeBSD.org>
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On 9/12/2015 7:45 PM, Andrey V. Elsukov wrote: > 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. > Is it worth creating an issue report to track/resolve this, with 10.3 coming up? ./koobs
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