From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261709AbVHEPHd (ORCPT ); Fri, 5 Aug 2005 11:07:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263042AbVHEPE4 (ORCPT ); Fri, 5 Aug 2005 11:04:56 -0400 Received: from ms-smtp-03.nyroc.rr.com ([24.24.2.57]:16557 "EHLO ms-smtp-03.nyroc.rr.com") by vger.kernel.org with ESMTP id S262307AbVHEPDP (ORCPT ); Fri, 5 Aug 2005 11:03:15 -0400 Subject: Re: lockups with netconsole on e1000 on media insertion From: Steven Rostedt To: "David S. Miller" Cc: ak@suse.de, mingo@elte.hu, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, sandos@home.se In-Reply-To: <20050805.073607.78730729.davem@davemloft.net> References: <1123251013.18332.28.camel@localhost.localdomain> <20050805141426.GU8266@wotan.suse.de> <1123252026.18332.37.camel@localhost.localdomain> <20050805.073607.78730729.davem@davemloft.net> Content-Type: text/plain Organization: Kihon Technologies Date: Fri, 05 Aug 2005 11:02:44 -0400 Message-Id: <1123254164.18332.52.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2005-08-05 at 07:36 -0700, David S. Miller wrote: > From: Steven Rostedt > Date: Fri, 05 Aug 2005 10:27:06 -0400 > > > Darn it, since this should really be reported. Yes, the core netpoll > > should bail out, but it is also a problem with the driver and should be > > fixed. > > I don't get how you can even remotely claim this to > be a problem with the driver. > > If there is no cable plugged in, the link never comes > up, and that is a completely normal thing. The netpoll > code should simply not try forever to wait for the link > to go up. You're right with that case. The problem with the driver is that it doesn't clean up the transmits if it just happened to overflow the transmit buffer and shut down the queue. The netpoll should at least see that the queue can be brought up again. That's what I have a problem with. In other words, I see two bugs: 1. The bug with the netpoll. It locks up if the driver's queue is down and never comes up. Which is fixed with Andi's patch. 2. The bug with the driver. Its netpoll doesn't detect that the queue can come back up again. With the timeout on netpoll this may no longer be a bug, since it should clean itself up after netpoll times out and turns interrupts back on. But if a timeout is avoidable by netpoll being a little smarter, then I believe that it should be fixed. Now do you understand where I'm coming from? -- Steve