From owner-freebsd-net@freebsd.org Wed Dec 9 08:54:39 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 D400B9D43D2 for ; Wed, 9 Dec 2015 08:54:39 +0000 (UTC) (envelope-from koobs.freebsd@gmail.com) Received: from mail-pf0-x22d.google.com (mail-pf0-x22d.google.com [IPv6:2607:f8b0:400e:c00::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id AB51E1328; Wed, 9 Dec 2015 08:54:39 +0000 (UTC) (envelope-from koobs.freebsd@gmail.com) Received: by pfnn128 with SMTP id n128so26868482pfn.0; Wed, 09 Dec 2015 00:54:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:reply-to:subject:references:to:cc:from:message-id:date :user-agent:mime-version:in-reply-to:content-type :content-transfer-encoding; bh=80zRfT0B3vVI03sw6o6f2f38rQmhA+u0py3LR1F9cUE=; b=k0qcUNTcpqtvApe75DVO9RFG0XUmvcQ6xQNUhynP3td7W1oA278TEoeuYPiDIdDOeo fe+uR8J8NjuQmc9cyWapOHHXi+iD52UPvVO/wjhEc0nOrQJfTxIDpujLddmDzlLBhZzv JYviHspLUq0YxkzaOshJolSg5oNqJYWaFgd07yWXi5Jfj2jy1HaMdalrBjO6udmKUuaV XuPldgO68xwP1q+OcLmy5l+vfMHQx1FOvT5suGnl4jNyiw0FZDhjy4OJAs1GqlVtz9cg sL/gJPHr/Zok76OD+J9eluloqasQsZM4gxvGMowZjs1oe2ApNXNYZzIYYngZzKn7XFPR E+iw== X-Received: by 10.98.80.22 with SMTP id e22mr11363420pfb.34.1449651279283; Wed, 09 Dec 2015 00:54:39 -0800 (PST) Received: from ?IPv6:2001:44b8:31ae:7b01::2? (2001-44b8-31ae-7b01-0000-0000-0000-0002.static.ipv6.internode.on.net. [2001:44b8:31ae:7b01::2]) by smtp.gmail.com with ESMTPSA id 82sm9807817pfn.76.2015.12.09.00.54.34 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 09 Dec 2015 00:54:38 -0800 (PST) Sender: Kubilay Kocak Reply-To: koobs@FreeBSD.org Subject: Re: Multiple cores/race conditions in IPv6 RA References: <50cff74ea38f155ae616cf49f5ffb5ae@m.nitrology.com> <5667EA3A.8050200@FreeBSD.org> To: "Andrey V. Elsukov" , Jason , freebsd-net@freebsd.org Cc: Mark Johnston , kevin.bowling@kev009.com, hiren@strugglingcoder.info, "freebsd-net@freebsd.org" From: Kubilay Kocak Message-ID: <5667EC45.2050808@FreeBSD.org> Date: Wed, 9 Dec 2015 19:54:29 +1100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:42.0) Gecko/20100101 Thunderbird/42.0 MIME-Version: 1.0 In-Reply-To: <5667EA3A.8050200@FreeBSD.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit 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 08:54:39 -0000 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