From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CCA47C3279B for ; Mon, 2 Jul 2018 18:56:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F84724E87 for ; Mon, 2 Jul 2018 18:56:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F84724E87 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753447AbeGBS4S (ORCPT ); Mon, 2 Jul 2018 14:56:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:35476 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753162AbeGBS4R (ORCPT ); Mon, 2 Jul 2018 14:56:17 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id A3EC9AD2E; Mon, 2 Jul 2018 18:56:15 +0000 (UTC) Date: Mon, 2 Jul 2018 20:56:12 +0200 From: Michal Hocko To: Pavel Tatashin Cc: steven.sistare@oracle.com, daniel.m.jordan@oracle.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, linux-mm@kvack.org, mgorman@techsingularity.net, gregkh@linuxfoundation.org Subject: Re: [PATCH v2] mm: teach dump_page() to correctly output poisoned struct pages Message-ID: <20180702185612.GJ19043@dhcp22.suse.cz> References: <20180702180536.2552-1-pasha.tatashin@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180702180536.2552-1-pasha.tatashin@oracle.com> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 02-07-18 14:05:36, Pavel Tatashin wrote: [...] > void __dump_page(struct page *page, const char *reason) > { > + bool page_poisoned = PagePoisoned(page); > + int mapcount; > + > + /* > + * If struct page is poisoned don't access Page*() functions as that > + * leads to recursive loop. Page*() check for poisoned pages, and calls > + * dump_page() when detected. > + */ > + if (page_poisoned) { > + pr_emerg("page:%px is uninitialized and poisoned", page); > + goto hex_only; > + } Thanks for the updated comment. Exactly what I was looking for! -- Michal Hocko SUSE Labs