From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 217286B0006 for ; Fri, 16 Feb 2018 04:23:35 -0500 (EST) Received: by mail-wm0-f69.google.com with SMTP id f3so616753wmc.8 for ; Fri, 16 Feb 2018 01:23:35 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id v190sor3772502wme.91.2018.02.16.01.23.33 for (Google Transport Security); Fri, 16 Feb 2018 01:23:33 -0800 (PST) Date: Fri, 16 Feb 2018 10:23:30 +0100 From: Ingo Molnar Subject: Re: [v4 3/6] mm: uninitialized struct page poisoning sanity checking Message-ID: <20180216092330.k7hutkvjmy7nope3@gmail.com> References: <20180215165920.8570-1-pasha.tatashin@oracle.com> <20180215165920.8570-4-pasha.tatashin@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180215165920.8570-4-pasha.tatashin@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: Pavel Tatashin Cc: steven.sistare@oracle.com, daniel.m.jordan@oracle.com, akpm@linux-foundation.org, mgorman@techsingularity.net, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, vbabka@suse.cz, bharata@linux.vnet.ibm.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, dan.j.williams@intel.com, kirill.shutemov@linux.intel.com, bhe@redhat.com * Pavel Tatashin wrote: > During boot we poison struct page memory in order to ensure that no one is > accessing this memory until the struct pages are initialized in > __init_single_page(). > > This patch adds more scrutiny to this checking by making sure that flags > do not equal the poison pattern when they are accessed. The pattern is all > ones. > > Since node id is also stored in struct page, and may be accessed quite > early, we add this enforcement into page_to_nid() function as well. > Note, this is applicable only when NODE_NOT_IN_PAGE_FLAGS=n > > Signed-off-by: Pavel Tatashin > Reviewed-by: Ingo Molnar > Acked-by: Michal Hocko Please always start patch titles with a verb, i.e.: mm: Add uninitialized struct page poisoning sanity check or so. Thanks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org