From owner-freebsd-stable@FreeBSD.ORG Mon Feb 17 02:23:35 2014 Return-Path: Delivered-To: stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 42AF41C9; Mon, 17 Feb 2014 02:23:35 +0000 (UTC) Received: from mail-pb0-x22e.google.com (mail-pb0-x22e.google.com [IPv6:2607:f8b0:400e:c01::22e]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 107D315AE; Mon, 17 Feb 2014 02:23:35 +0000 (UTC) Received: by mail-pb0-f46.google.com with SMTP id um1so14634531pbc.19 for ; Sun, 16 Feb 2014 18:23:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:date:to:cc:subject:message-id:reply-to:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=Wi6bU5WTSAoXTJDWhjemihL8SwFyjYjx4lnCZAwiROE=; b=ngbYes5mUEK+s1NC6bXDQ5SMzljnkKdjGt9gGKPb8dPkYuIkD97a9whcExMTWwJehi mhnsbv6exlAsk+Ta9YHw7gYyiSVkpuE7MS4Zn2ZGpfWkxWgMkid7TO0Ab3v5n9x2fva7 I/ZPkV02osDvimYKTj4o3OQ35SFs7T1cqZobeBoPV65YMaK8XaGhJY6f0hxAgiPKC3B/ XpqQ0Ds7Aobzg3pSJ3YlHAunyhpSOP+JIDkz5FLYBqErJlJT9Q9TUKhg6aO1rMh6u8gL e8mONAMYt54Bmm8xATigpydYEROIA72N51rGAP03jIQGLRCq9h35wF/VQM6DrUZjeEYf 5ByA== X-Received: by 10.66.121.68 with SMTP id li4mr23763635pab.33.1392603814737; Sun, 16 Feb 2014 18:23:34 -0800 (PST) Received: from pyunyh@gmail.com (lpe4.p59-icn.cdngp.net. [114.111.62.249]) by mx.google.com with ESMTPSA id kc9sm40259599pbc.25.2014.02.16.18.23.32 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Sun, 16 Feb 2014 18:23:34 -0800 (PST) Received: by pyunyh@gmail.com (sSMTP sendmail emulation); Mon, 17 Feb 2014 11:23:29 +0900 From: Yonghyeon PYUN Date: Mon, 17 Feb 2014 11:23:29 +0900 To: David Naylor Subject: Re: MPCP Opcode Pause and unresponsive computer Message-ID: <20140217022329.GA3675@michelle.cdnetworks.com> References: <1403963.5sDsKbxfoF@dragon.dg> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1403963.5sDsKbxfoF@dragon.dg> User-Agent: Mutt/1.4.2.3i Cc: stable@freebsd.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list Reply-To: pyunyh@gmail.com List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 Feb 2014 02:23:35 -0000 On Thu, Feb 13, 2014 at 10:01:56PM +0300, David Naylor wrote: > Hi, > > I recently installed FreeBSD 10.0-RELEASE on an headless Intense-PC. I am > experiencing two network related issues with the computer. > > First issue > ----------- > When compiling lang/ruby19 the network freezes. The build was done directly > from the command line using ssh. After a while ssh reports "Write failed: > Broken pipe". I attached the monitor and no messages were displayed on the > output (and the machine was still running). > > The Intense-PC does not respond to pings at this point either. Of note, I was > capable of transferring multiple GB of data and successfully compiled other > ports but compiling lang/ruby19 messes up everything. > > Second issue > ------------ > After a period of uptime (after the freeze from building lang/ruby19) the > entire network stops working, nothing is capable of connecting or > communicating on the network. When I do a tcpdump (from a different, affected > computer) I find the following: > > 20:57:58.254626 MPCP, Opcode Pause, length 46 > > These messages get repeated a few times a second. The moment I disconnect the > Intense-PC from the network functionality is restored (and is clearly > illustrated by the tcpdump). > > Information > ----------- > # uname -a > FreeBSD dragonbsd 10.0-RELEASE FreeBSD 10.0-RELEASE #0 d44ce30(releng/10.0): > Sun Feb 9 20:11:55 SAST 2014 > root@dragon.dg:/tmp/home/freebsd/10.0/src/sys/MODULAR amd64 > > # ifconfig > lo0: flags=8049 metric 0 mtu 16384 > options=600003 > inet6 ::1 prefixlen 128 > inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1 > inet 127.0.0.1 netmask 0xff000000 > nd6 options=21 > em0: flags=8843 metric 0 mtu 1500 > options=4219b > ether XX:XX:XX:XX:XX:XX > inet 192.168.0.160 netmask 0xffffff00 broadcast 192.168.0.255 > nd6 options=29 > media: Ethernet autoselect (100baseTX ) > status: active > re0: flags=8843 metric 0 mtu 1500 > options=8209b > ether XX:XX:XX:XX:XX:XX > nd6 options=29 > media: Ethernet autoselect (none) > status: no carrier > > Any assistance to resolve this issue will be greatly appreciated. > It's not normal to see pause frames with tcpdump. If my memory serves me right, MAC control frames which include pause frames should not be passed to host. Which network driver do you see above pause frames? Some drivers like fxp(4) allow passing pause frames to host but I think that's a bug in driver. I didn't change that behavior of the driver just because it used to enable that feature in the past. I'm not sure what's happening there but receiving pause frames will inhibit sending frames until the pause time expires such that you'll not get any response from the host. Probably you have to know which host is sending these lots of pause frames. Once you identify the guilty host, you have to narrow down what condition makes it send pause frames.