From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939734AbXGSPwv (ORCPT ); Thu, 19 Jul 2007 11:52:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935902AbXGSPwn (ORCPT ); Thu, 19 Jul 2007 11:52:43 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:53771 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758850AbXGSPwm (ORCPT ); Thu, 19 Jul 2007 11:52:42 -0400 Date: Thu, 19 Jul 2007 17:52:30 +0200 From: Ingo Molnar To: Olaf Kirch Cc: Jarek Poplawski , Linus Torvalds , linux-kernel@vger.kernel.org, davem@davemloft.net, Auke Kok Subject: Re: [patch] revert: [NET]: Fix races in net_rx_action vs netpoll Message-ID: <20070719155230.GA31267@elte.hu> References: <20070716091236.GA10718@elte.hu> <200707191144.24434.olaf.kirch@oracle.com> <20070719100135.GA2986@elte.hu> <200707191237.56455.olaf.kirch@oracle.com> <20070719104756.GA13769@elte.hu> <20070719105816.GA15852@elte.hu> <20070719150728.GA17000@elte.hu> <20070719153217.GA25544@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070719153217.GA25544@elte.hu> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.0.3 -1.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > ah! Just found the reason: the bug apparently depends on the precise > kernel command-line contents. I accidentally dropped ignore_loglevel > (found this while comparing with the older logs i sent to you), adding > it back in produces hung networking too. So it appears that a > netconsole printout while e1000 is initializing (or while some other > networking component is initializing) might be the culprit? and the WARN_ON() below does not seem to trigger. i'll now check whether removing ignore_on_loglevel (no other changes) makes the hang go away. Maybe ignore_on_loglevel is buggy - or it produces an immediate printk (going out to the interface) during a particularly sensitive period of network initialization. Ingo -----------------> Index: linux/drivers/net/e1000/e1000_main.c =================================================================== --- linux.orig/drivers/net/e1000/e1000_main.c +++ linux/drivers/net/e1000/e1000_main.c @@ -358,6 +358,7 @@ e1000_irq_enable(struct e1000_adapter *a E1000_WRITE_REG(&adapter->hw, IMS, IMS_ENABLE_MASK); E1000_WRITE_FLUSH(&adapter->hw); } + WARN_ON_ONCE(atomic_read(&adapter->irq_sem) < 0); } static void