From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752020AbaHSVaA (ORCPT ); Tue, 19 Aug 2014 17:30:00 -0400 Received: from na01-sn2-obe.ptr.o365filtering.com ([157.55.158.27]:4647 "EHLO na01-sn2-obe.outbound.o365filtering.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751208AbaHSV37 convert rfc822-to-8bit (ORCPT ); Tue, 19 Aug 2014 17:29:59 -0400 From: Haiyang Zhang To: Sitsofe Wheeler , KY Srinivasan CC: Greg Kroah-Hartman , "devel@linuxdriverproject.org" , "linux-kernel@vger.kernel.org" , Jason Wang , Daniel Borkmann , "David S. Miller" , "netdev@vger.kernel.org" Subject: RE: [hyperv] BUG at drivers/hv/channel.c:462 while changing MTU Thread-Topic: [hyperv] BUG at drivers/hv/channel.c:462 while changing MTU Thread-Index: AQHPu6pLRTtWHSK0fUa2cFRSCNYsCZvYb1iA Date: Tue, 19 Aug 2014 21:29:44 +0000 Message-ID: <8dcf334714c44eeda54ecb129479719b@DFM-DB3MBX15-06.exchange.corp.microsoft.com> References: <20140819123655.GC12160@sucs.org> In-Reply-To: <20140819123655.GC12160@sucs.org> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [157.54.51.13] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:131.107.159.99;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(10019006)(377454003)(164054003)(189002)(51914003)(13464003)(51704005)(199003)(92566001)(2656002)(6806004)(54356999)(50466002)(74662001)(31966008)(99396002)(76176999)(50986999)(4396001)(106116001)(77096999)(46102001)(107046002)(85852003)(74502001)(87936001)(97736001)(83072002)(86612001)(84676001)(108616004)(83322001)(68736004)(19580395003)(21056001)(80022001)(66066001)(81342001)(79102001)(46406003)(85306004)(20776003)(81542001)(2009001)(23726002)(19580405001)(44976005)(97756001)(64706001)(106466001)(33646002)(77982001)(1511001)(76482001)(2421001)(47776003)(24736002);DIR:OUT;SFP:1102;SCL:1;SRVR:CH1SR01MB599;H:hybrid.exchange.microsoft.com;FPR:;PTR:InfoDomainNonexistent;MX:1;A:1;LANG:en; X-Microsoft-Antispam: BCL:0;PCL:0;RULEID:;UriScan:; X-Forefront-PRVS: 0308EE423E Authentication-Results: spf=pass (sender IP is 131.107.159.99) smtp.mailfrom=haiyangz@microsoft.com; X-OriginatorOrg: msft.ccsctp.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Sitsofe Wheeler [mailto:sitsofe@gmail.com] > Sent: Tuesday, August 19, 2014 8:37 AM > To: KY Srinivasan > Cc: Greg Kroah-Hartman; Haiyang Zhang; devel@linuxdriverproject.org; > linux-kernel@vger.kernel.org; Jason Wang; Daniel Borkmann; David S. > Miller; netdev@vger.kernel.org > Subject: [hyperv] BUG at drivers/hv/channel.c:462 while changing MTU > > Now we get to the issue I've been meaning to report: changing the MTU of > a Hyper-V network interface while traffic is flowing through it triggers > a BUG. I've seen this happen on a variety of kernels but the trace below > is from 3.17.0-rc1. > > Steps to reproduce: > (Guests were customised Fedora 20 cloud images) > 1.On Hyper-V VM 1 run > iperf -s > 2. On Hyper-V VM 2 run > iperf -c -t 200 > 3. On Hyper-V VM 2 run > ip link set dev eth0 mtu 9000 > > Expected results: > MTU of eth0 to be changed, packets to keep flowing or stop, interface to > be at alive enough to be reconfigured. > > Actual results: > Error messages on the console, eth0 winds up dead. > Thanks for the report. I tried changing mtu while iperf is running, but unable to reproduce it. I repeated the changing MTU test 10+ times, the link is stable, and passing traffic at ~8Gbps. Could you try a Distro without customization? I just want to narrow down the possible causes for it. Thanks, - Haiyang