From owner-freebsd-stable@FreeBSD.ORG Wed Mar 18 11:52:36 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E14E1106566C for ; Wed, 18 Mar 2009 11:52:36 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id BA0608FC22 for ; Wed, 18 Mar 2009 11:52:36 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [65.122.17.41]) by cyrus.watson.org (Postfix) with ESMTPS id 5D7C846B39; Wed, 18 Mar 2009 07:52:36 -0400 (EDT) Date: Wed, 18 Mar 2009 11:52:36 +0000 (GMT) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Nick Withers In-Reply-To: <1237081381.1581.2.camel@localhost> Message-ID: References: <1236920519.1490.30.camel@localhost> <1237020646.1532.24.camel@localhost> <1237081381.1581.2.camel@localhost> User-Agent: Alpine 2.00 (BSF 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Cc: freebsd-stable@freebsd.org Subject: Re: NICs locking up, "*tcp_sc_h" X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 18 Mar 2009 11:52:37 -0000 On Sun, 15 Mar 2009, Nick Withers wrote: >> I'll need to think a bit about a proper fix for this, but you'll find the >> problem likely goes away if you eliminate all uid/gid/jail rules from your >> firewall. You could also tweak the syncache logic not to use a retransmit >> timer, which might slightly extend the time it takes for systems to connect >> to your host in the presence of packet loss, but would eliminate this >> transmission path entirely. We'll need a real and more general fix, >> however, to commit, and I'll look and see what I can come up with. > > Brilliant, thanks very much. I'll work without uid rules for the time being, > then. Could I ask you to file a PR on this problem, btw, with the two traces I singled out as interesting included, then forward me the PR receipt? That will make the problem easier to keep track of. We're currently pondering ways to fix the problem that don't disturb the stability of the ABI, and may have a workaround patch available shortly that's appropriate for MFC. Robert N M Watson Computer Laboratory University of Cambridge