From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755352AbcESXVM (ORCPT ); Thu, 19 May 2016 19:21:12 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44104 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754458AbcESXVI (ORCPT ); Thu, 19 May 2016 19:21:08 -0400 Date: Thu, 19 May 2016 16:21:07 -0700 From: Andrew Morton To: "Shi, Yang" Cc: iamjoonsoo.kim@lge.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linaro-kernel@lists.linaro.org Subject: Re: [PATCH] mm: move page_ext_init after all struct pages are initialized Message-Id: <20160519162107.372d19eac129d590ea160203@linux-foundation.org> In-Reply-To: <6dd46bac-a0e4-d3c0-ded3-cbacc7f4a4ff@linaro.org> References: <1463693345-30842-1-git-send-email-yang.shi@linaro.org> <20160519153007.322150e4253656a3ac963656@linux-foundation.org> <6dd46bac-a0e4-d3c0-ded3-cbacc7f4a4ff@linaro.org> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 May 2016 15:35:15 -0700 "Shi, Yang" wrote: > On 5/19/2016 3:30 PM, Andrew Morton wrote: > > On Thu, 19 May 2016 14:29:05 -0700 Yang Shi wrote: > > > >> When DEFERRED_STRUCT_PAGE_INIT is enabled, just a subset of memmap at boot > >> are initialized, then the rest are initialized in parallel by starting one-off > >> "pgdatinitX" kernel thread for each node X. > >> > >> If page_ext_init is called before it, some pages will not have valid extension, > >> so move page_ext_init() after it. > >> > > > > When fixing a bug, please fully describe the end-user impact > > of that bug > > The kernel ran into the below oops which is same with the oops reported > in > http://ozlabs.org/~akpm/mmots/broken-out/mm-page_is_guard-return-false-when-page_ext-arrays-are-not-allocated-yet.patch. So this patch makes mm-page_is_guard-return-false-when-page_ext-arrays-are-not-allocated-yet.patch obsolete?