From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Subject: Re: [hyperv] BUG at drivers/hv/channel.c:462 while changing MTU Date: Mon, 25 Aug 2014 12:36:48 +0300 Message-ID: <20140825093648.GB5046@mwanda> References: <20140819123655.GC12160@sucs.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Greg Kroah-Hartman , Jason Wang , Haiyang Zhang , linux-kernel@vger.kernel.org, Daniel Borkmann , netdev@vger.kernel.org, devel@linuxdriverproject.org, "David S. Miller" To: Sitsofe Wheeler Return-path: Content-Disposition: inline In-Reply-To: <20140819123655.GC12160@sucs.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: driverdev-devel-bounces@linuxdriverproject.org Sender: driverdev-devel-bounces@linuxdriverproject.org List-Id: netdev.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