From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755567AbZAXAjT (ORCPT ); Fri, 23 Jan 2009 19:39:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753143AbZAXAjI (ORCPT ); Fri, 23 Jan 2009 19:39:08 -0500 Received: from wine.ocn.ne.jp ([122.1.235.145]:59722 "EHLO smtp.wine.ocn.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752797AbZAXAjH (ORCPT ); Fri, 23 Jan 2009 19:39:07 -0500 To: frederik.deweerdt@xprog.eu, rjw@sisk.pl Cc: linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org Subject: Re: [Bug #12409] NULL pointer dereference at get_stats() From: Tetsuo Handa References: <20090121161828.GA2739@gambetta> In-Reply-To: <20090121161828.GA2739@gambetta> Message-Id: <200901240939.EFD95330.VLFOStQHOFFMOJ@I-love.SAKURA.ne.jp> X-Mailer: Winbiff [Version 2.50 PL2] X-Accept-Language: ja,en Date: Sat, 24 Jan 2009 09:39:03 +0900 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello. Frederik Deweerdt wrote: > On Mon, Jan 19, 2009 at 10:45:43PM +0100, Rafael J. Wysocki wrote: > > This message has been generated automatically as a part of a report > > of regressions introduced between 2.6.27 and 2.6.28. > > > > The following bug entry is on the current list of known regressions > > introduced between 2.6.27 and 2.6.28. Please verify if it still should > > be listed and let me know (either way). > > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12409 > > Subject : NULL pointer dereference at get_stats() > > Submitter : Tetsuo Handa > > Date : 2008-12-30 12:53 (21 days old) > > References : http://marc.info/?l=linux-kernel&m=123064167008695&w=4 > > Handled-By : Frederik Deweerdt > > > > > Hello Rafael, > > Not sure what the status should be for that one, it sure seems vmware > related, and I don't have one handy. > > Regards, > Frederik > The latest post regarding this problem starts at http://lkml.org/lkml/2009/1/4/349 . It's not a VMware related problem. A patch at http://lkml.org/lkml/2009/1/5/557 reported that "nolapic" option doesn't prevent for_each_possible_cpu() from reaching CPU1, and per-CPU pointer for CPU1 is NULL. --- First call of for_each_possible_cpu() --- Entering get_stats() CPU=0 Leaving get_stats() --- Second call of for_each_possible_cpu() --- Entering get_stats() CPU=0 CPU=1 lb_stats == NULL for CPU 1 Leaving get_stats() Regards.