From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753453AbaDWFpQ (ORCPT ); Wed, 23 Apr 2014 01:45:16 -0400 Received: from mga11.intel.com ([192.55.52.93]:61381 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752481AbaDWFpM (ORCPT ); Wed, 23 Apr 2014 01:45:12 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,910,1389772800"; d="scan'208";a="525347113" Message-ID: <53575360.3010702@linux.intel.com> Date: Wed, 23 Apr 2014 13:45:04 +0800 From: Jiang Liu Organization: Intel User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Peter Zijlstra CC: Andrew Morton , Ingo Molnar , Ingo Molnar , "Rafael J . Wysocki" , Tony Luck , linux-kernel@vger.kernel.org Subject: Re: [Bugfix] sched: fix possible invalid memory access caused by CPU hot-addition References: <1398144435-26271-1-git-send-email-jiang.liu@linux.intel.com> <20140422081515.GF11182@twins.programming.kicks-ass.net> <53572939.7020509@linux.intel.com> <20140423053213.GV26782@laptop.programming.kicks-ass.net> In-Reply-To: <20140423053213.GV26782@laptop.programming.kicks-ass.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014/4/23 13:32, Peter Zijlstra wrote: > On Wed, Apr 23, 2014 at 10:45:13AM +0800, Jiang Liu wrote: >> Hi Peter, >> It's not for memoryless node, but to solve a race window >> in CPU hot-addition. The related CPU hot-addition flow is: >> 1) Handle CPU hot-addition event >> 1.a) gather platform specific information >> 1.b) associate hot-added CPU with a node >> 1.c) create CPU device >> 2) User online hot-added CPUs through sysfs: >> 2.a) cpu_up() >> 2.b) ->try_online_node() >> 2.c) ->hotadd_new_pgdat() >> 2.d) ->node_set_online() >> >> So between 1.b and 2.c, kmalloc_node(nid) may cause invalid >> memory access without the node_online(nid) check. > > Any why was all this not in the Changelog? Sorry, will add above message into changelog. Thanks! Gerry