From owner-freebsd-stable@FreeBSD.ORG Fri Sep 29 17:35:47 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2500C16A40F for ; Fri, 29 Sep 2006 17:35:47 +0000 (UTC) (envelope-from chris@vindaloo.com) Received: from corellia.vindaloo.com (corellia.vindaloo.com [64.51.148.100]) by mx1.FreeBSD.org (Postfix) with ESMTP id ED69E43D5F for ; Fri, 29 Sep 2006 17:35:29 +0000 (GMT) (envelope-from chris@vindaloo.com) Received: from yavin.vindaloo.com (yavin.vindaloo.com [172.24.144.34]) by corellia.vindaloo.com (Postfix) with ESMTP id 085505C88; Fri, 29 Sep 2006 13:48:15 -0400 (EDT) Received: from dagobah.vindaloo.com (dagobah.vindaloo.com [172.24.145.68]) by yavin.vindaloo.com (Postfix) with ESMTP id 99B03253AA; Fri, 29 Sep 2006 13:35:21 -0400 (EDT) Received: from localhost.vindaloo.com (localhost.vindaloo.com [IPv6:::1]) by dagobah.vindaloo.com (8.13.8/8.13.8) with ESMTP id k8THXib7077962; Fri, 29 Sep 2006 13:33:44 -0400 (EDT) (envelope-from chris@vindaloo.com) From: Christopher Sean Hilton To: Kris Kennaway In-Reply-To: <20060927203710.GA54541@xor.obsecurity.org> References: <451939DA.3060709@dental-on-line.fr> <451A2E87.6000301@dental-on-line.fr> <451A4045.7020000@dental-on-line.fr> <20060927165109.GA52006@xor.obsecurity.org> <7457F6C0-4E6A-47C4-9981-89627B20B94A@khera.org> <20060927203710.GA54541@xor.obsecurity.org> Content-Type: text/plain Date: Fri, 29 Sep 2006 13:33:43 -0400 Message-Id: <1159551223.1006.42.camel@dagobah.vindaloo.com> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 FreeBSD GNOME Team Port Content-Transfer-Encoding: 7bit Cc: Vivek Khera , freebsd-stable Subject: Re: NFS: freeze during copy 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: Fri, 29 Sep 2006 17:35:47 -0000 On Wed, 2006-09-27 at 16:37 -0400, Kris Kennaway wrote: > > and my luck has it such that i've not had a lockup since i added that > > extra debugging code into the kernel :-) or :-( depending on your > > view... > > Heisenbugs are great! :) > Before I classified this as a Heisenbug I'd switch from NFS over UDP to NFS over TCP. The original poster also hasn't mentioned if he's using soft, or hard mounts or if he has the intr option on. Depending on how these options are tuned NFS lockups are normal. I used keep /usr/src mounted via NFS and do make buildworld/installworld on my laptop. The network was a switched lan and there were no firewalls. Very occasionally the build process would lockup. When I went to debug this a sage wizard suggested that the first step was to switch from UDP to TCP. As it turns out the problem was that the ne2000 driver on my laptop was loosing packets. With udp the means to detect this was weak to non-existant. Changing to TCP meant that not only could the kernel detect that a packet had gotten lost but it only had to resend that one packet, not the entire buffer. From that point on the build process worked flawlessly in fact I was able to extend the process to work between a local NFS server and a remote NFS client located 25 miles away at the other end of an IPsec tunnel. Bottom line: change to TCP and retest. NFS over UDP is very sensitive to packet loss. -- Chris --