From owner-freebsd-bugs@FreeBSD.ORG Sun Dec 5 21:30:09 2010 Return-Path: Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2892810656A3 for ; Sun, 5 Dec 2010 21:30:09 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id D85598FC12 for ; Sun, 5 Dec 2010 21:30:08 +0000 (UTC) Received: from freefall.freebsd.org (localhost [127.0.0.1]) by freefall.freebsd.org (8.14.4/8.14.4) with ESMTP id oB5LU8EZ080925 for ; Sun, 5 Dec 2010 21:30:08 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.4/8.14.4/Submit) id oB5LU8dn080921; Sun, 5 Dec 2010 21:30:08 GMT (envelope-from gnats) Resent-Date: Sun, 5 Dec 2010 21:30:08 GMT Resent-Message-Id: <201012052130.oB5LU8dn080921@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Mike Andrews Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5E0F9106566B for ; Sun, 5 Dec 2010 21:22:13 +0000 (UTC) (envelope-from mandrews@bit0.com) Received: from magnum.bit0.com (magnum.bit0.com [207.246.88.226]) by mx1.freebsd.org (Postfix) with ESMTP id 34F0F8FC1C for ; Sun, 5 Dec 2010 21:22:13 +0000 (UTC) Received: from magnum.int.bit0.com (localhost [127.0.0.1]) by magnum.bit0.com (Postfix) with ESMTP id D1BC28222 for ; Sun, 5 Dec 2010 16:05:23 -0500 (EST) Received: from magnum.bit0.com ([127.0.0.1]) by magnum.int.bit0.com (magnum.int.bit0.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id V4gp2qtO5D2n for ; Sun, 5 Dec 2010 16:05:21 -0500 (EST) Received: from bat.int.bit0.com (bat.int.bit0.com [172.27.0.5]) by magnum.bit0.com (Postfix) with ESMTP for ; Sun, 5 Dec 2010 16:05:21 -0500 (EST) Received: by bat.int.bit0.com (Postfix, from userid 502) id BF3A914B27; Sun, 5 Dec 2010 16:05:21 -0500 (EST) Message-Id: <20101205210521.BF3A914B27@bat.int.bit0.com> Date: Sun, 5 Dec 2010 16:05:21 -0500 (EST) From: Mike Andrews To: FreeBSD-gnats-submit@FreeBSD.org X-Send-Pr-Version: 3.113 Cc: Subject: kern/152853: tftpd (and likely other udp traffic) fails over em(4) unless rxcsum/txcsum disabled X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Mike Andrews List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 05 Dec 2010 21:30:09 -0000 >Number: 152853 >Category: kern >Synopsis: tftpd (and likely other udp traffic) fails over em(4) unless rxcsum/txcsum disabled >Confidential: no >Severity: serious >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sun Dec 05 21:30:08 UTC 2010 >Closed-Date: >Last-Modified: >Originator: Mike Andrews >Release: FreeBSD 8.2-PRERELEASE amd64 >Organization: Fark, Inc >Environment: System: FreeBSD bat.int.bit0.com 8.2-PRERELEASE FreeBSD 8.2-PRERELEASE #20: Sat Nov 27 23:00:34 EST 2010 mandrews@bat.int.bit0.com:/usr/obj/usr/src/sys/BIT0 amd64 >Description: The tftp server in FreeBSD fails to send any packets -- when a write request comes in (in this example, from a Cisco IOS router), tcpdump shows that FreeBSD receives the write reqeust but then its tftp server never sends a single packet out in response, and the transfer never starts: Dec 5 14:22:29 bat tftpd[453]: Filename: 'moat-confg' Dec 5 14:22:29 bat tftpd[453]: Mode: 'octet' Dec 5 14:22:29 bat tftpd[453]: 172.27.0.1: write request for //moat-confg: success Dec 5 14:22:34 bat tftpd[453]: Timeout #0 on DATA block 1 Dec 5 14:22:39 bat tftpd[453]: Timeout #1 on DATA block 1 Dec 5 14:22:44 bat tftpd[453]: Timeout #2 on DATA block 1 Dec 5 14:22:49 bat tftpd[453]: Timeout #3 on DATA block 1 Dec 5 14:22:54 bat tftpd[453]: Timeout #4 on DATA block 1 Dec 5 14:22:59 bat tftpd[453]: Timeout #5 on DATA block 1, giving up On a complete whim, I tried disabling TSO4, TXCSUM, and RXCSUM on the NIC, and to my surprise I found that disabling the latter two made the problem disappear. TSO had no effect -- as you'd expect since tftp is UDP based :) I have not checked to see if this is em(4) specific or what other UDP based services it might affect. It appears that DNS on the same system works fine... >How-To-Repeat: On a system with an Intel gigabit NIC, start a tftp server (via inetd) and try to write a file to it. >Fix: ifconfig em0 -rxcsum -txcsum (It doesn't appear you can turn just one or the other off.) >Release-Note: >Audit-Trail: >Unformatted: