From owner-freebsd-net@FreeBSD.ORG Tue Jan 18 08:38:07 2011 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6FF9D106566B for ; Tue, 18 Jan 2011 08:38:07 +0000 (UTC) (envelope-from sthaug@nethelp.no) Received: from bizet.nethelp.no (bizet.nethelp.no [195.1.209.33]) by mx1.freebsd.org (Postfix) with SMTP id A609D8FC08 for ; Tue, 18 Jan 2011 08:38:06 +0000 (UTC) Received: (qmail 87657 invoked from network); 18 Jan 2011 08:38:04 -0000 Received: from bizet.nethelp.no (HELO localhost) (195.1.209.33) by bizet.nethelp.no with SMTP; 18 Jan 2011 08:38:04 -0000 Date: Tue, 18 Jan 2011 09:38:04 +0100 (CET) Message-Id: <20110118.093804.74673434.sthaug@nethelp.no> To: pyunyh@gmail.com From: sthaug@nethelp.no In-Reply-To: <20110117005524.GA1305@michelle.cdnetworks.com> References: <708793006.292748.1295186099577.JavaMail.root@erie.cs.uoguelph.ca> <20110117005524.GA1305@michelle.cdnetworks.com> X-Mailer: Mew version 3.3 on Emacs 21.3 / Mule 5.0 (SAKAKI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org, rmacklem@uoguelph.ca, ronald-freebsd8@klop.yi.org Subject: Re: bogus 0 len IP packet, was: Hang in VOP_LOCK1_APV on 8-STABLE with NFS. X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Jan 2011 08:38:07 -0000 > > So, does anyone have an idea why the IP length field would be set to 0 > > for these TCP/IP packets? > > > > Here's some info from Ronald w.r.t. his hardware. (All I can think of is > > that he could try disabling TSO, etc?) > > > > Thanks in advance for any help with this, rick > > > > It seems that issue came from TSO. Driver will set ip_len and > ip_sum field to 0 before passing the TCP segment to controller. > The failed length were 4446, 5858, 3034 and 4310 and the total > number of such frames are more than 35k within 90 seconds. Since > failed length 4310 is continuously repeated I guess there is edge > case where em(4) didn't free failed TCP segment for TSO. > I remember there was commit to HEAD(r217295) which could be related > with this issue. I'm seeing the same problem with Broadcom NetXtreme (bce) cards: bce0@pci0:3:0:0: class=0x020000 card=0x03421014 chip=0x164c14e4 rev=0x12 hdr=0x00 vendor = 'Broadcom Corporation' device = 'Broadcom NetXtreme II Gigabit Ethernet Adapter (BCM5708)' class = network subclass = ethernet This is with 8.2-PRERELEASE. Turning off TSO (ifconfig bce0 -tso) removes the problem. Steinar Haug, Nethelp consulting, sthaug@nethelp.no