From owner-freebsd-net@FreeBSD.ORG Fri Oct 3 10:05:54 2014 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id CA382593; Fri, 3 Oct 2014 10:05:54 +0000 (UTC) Received: from cell.glebius.int.ru (glebius.int.ru [81.19.69.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "cell.glebius.int.ru", Issuer "cell.glebius.int.ru" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4D2935F5; Fri, 3 Oct 2014 10:05:53 +0000 (UTC) Received: from cell.glebius.int.ru (localhost [127.0.0.1]) by cell.glebius.int.ru (8.14.9/8.14.9) with ESMTP id s93A456c096566 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 3 Oct 2014 14:04:05 +0400 (MSK) (envelope-from glebius@FreeBSD.org) Received: (from glebius@localhost) by cell.glebius.int.ru (8.14.9/8.14.9/Submit) id s93A45Fn096565; Fri, 3 Oct 2014 14:04:05 +0400 (MSK) (envelope-from glebius@FreeBSD.org) X-Authentication-Warning: cell.glebius.int.ru: glebius set sender to glebius@FreeBSD.org using -f Date: Fri, 3 Oct 2014 14:04:05 +0400 From: Gleb Smirnoff To: "Alexander V. Chernikov" Subject: Re: Detaching the slave from the lagg interface which has vlan on top of it, hits an panic Message-ID: <20141003100405.GB73266@glebius.int.ru> References: <26E3F92EC670BD429DB5CB319D773C137A8878@nice.asicdesigners.com> <542E71D3.6000500@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <542E71D3.6000500@FreeBSD.org> User-Agent: Mutt/1.5.23 (2014-03-12) Cc: "freebsd-net@freebsd.org" , Hariprasad S X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 03 Oct 2014 10:05:54 -0000 On Fri, Oct 03, 2014 at 01:52:19PM +0400, Alexander V. Chernikov wrote: A> On 03.10.2014 04:40, Hariprasad S wrote: A> > HI, A> > A> > Detaching the slave from the lagg interface which has vlan on top of it, hits an panic. A> > Kernel used: FreeBSD HEAD r272051 A> > A> > Is anyone aware of this issue? A> Yes. What is happening here: A> We acquire lagg WLOCK to set new link layer address (due to "master" A> interface change). A> We propagate this change to vlans on top if lagg (or to lagg itself). A> Then we need to send gratuitous ARP for each UP interface, so we have to A> acquire lagg read lock to actually transmit this frame.. A> A> We can fix this particular case, but I think it should be done more A> generic way via introducing one or more netisr(9) slow path queues A> and making sure "every" locally-originated packet is queued instead of A> being transmitted directly. A> A> Previous proposal: A> https://lists.freebsd.org/pipermail/freebsd-hackers/2014-January/044121.html A> It looks like we should return to the discussion. I agree with Alexander here. However, he is quite aggresive on the question which packets should qualify for slow path :) Well, this is a matter to discuss, but the overall mechanism is needed. And gratuitous ARPs are definitely qualified for that. -- Totus tuus, Glebius.