From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752531AbaHYJhL (ORCPT ); Mon, 25 Aug 2014 05:37:11 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:38237 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751127AbaHYJhJ (ORCPT ); Mon, 25 Aug 2014 05:37:09 -0400 Date: Mon, 25 Aug 2014 12:36:48 +0300 From: Dan Carpenter To: Sitsofe Wheeler Cc: "K. Y. Srinivasan" , Greg Kroah-Hartman , Jason Wang , linux-kernel@vger.kernel.org, "David S. Miller" , Daniel Borkmann , netdev@vger.kernel.org, devel@linuxdriverproject.org, Haiyang Zhang Subject: Re: [hyperv] BUG at drivers/hv/channel.c:462 while changing MTU Message-ID: <20140825093648.GB5046@mwanda> References: <20140819123655.GC12160@sucs.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140819123655.GC12160@sucs.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The code here is: drivers/hv/channel.c 460 BUG_ON(ret != 0); 461 t = wait_for_completion_timeout(&info->waitevent, 5*HZ); 462 BUG_ON(t == 0); So it calls BUG_ON() if the teardown takes more than 5 seconds. It's most likely that there is a race condition somewhere. It's also possible that it's just taking longer than 5 seconds for some odd reason and the bug would go away if we raised it to 60 seconds. BUG_ON() after 5 seconds seems like a very aggressive thing. regards, dan carpenter