From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1518773014; cv=none; d=google.com; s=arc-20160816; b=YD2Szc0Cq0cHW6O/8wAJ6nZujo4/78NlnA25skKqN3SFZ6TD9vXMbaQl+YxRmuV7rd gue2GErMK3TDw4RpkceK4Xo8m4ylt+tAraEj14gQNGeIDrDIuzI2LDhADcUpwoy3ztI7 CnwP0l8TWm9KF8LRsH9NSQvvXbTGtCh9/WsNeiXtQhd7dpIL30+GE2DxvikTkfsbkS5H W6eD8LifmQgQto6iJvYukN5odkP0xjI60+XHBhOIgErXceuQO6oe59DIvpau0viJSAUr ZeMBrqbBFuMrRzQuMKlBqP/efuC3HXh1RARpXA8CN+3AMo8gTiGR0KC9oB9F02dUpoh2 +W0w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:sender:dkim-signature :arc-authentication-results; bh=u+MA+OK32Csc/wmGajKbJD/sRB7VRkno5TojvebLEM0=; b=0agDxV8b0DkXlByknf8LhQ6Rrd5dkCK034nbKU9mPAhwAtt6INUBH7VqxwGioFO+co bq3oiHNh2GcyjonxUU5Z6Jmjnm51/pVY/j7Q60X+KppujYxKJZmUF7fa44N+Yt9ej+V7 yRFct8wdu6q9JDvwtkgr7dv+K1+8wfgb3fCcesT3ohDV8us295+rZOS6/t6mEghOuGDQ ke2sb42TADMzjevBxE1AeqV6K1SsehOV2q1PgNjMbxjwZItGDByYo32I9XqeLMvQs8DU 0/o1B/G9FzUuRQwfcm4QC/JLw5I4P6qsKgpSNaN2iOZfF8fXzUN29wsnMpQ1wcpoGODY 7DSw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=AhBrlS2W; spf=pass (google.com: domain of mingo.kernel.org@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=mingo.kernel.org@gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=AhBrlS2W; spf=pass (google.com: domain of mingo.kernel.org@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=mingo.kernel.org@gmail.com X-Google-Smtp-Source: AH8x2274MICIwCIVbimJC8ATtxBhcduSnvrY/u+3F0eA0mCfqECkC/mTlGvBc34ZArdsMKpoinQhgQ== Sender: Ingo Molnar Date: Fri, 16 Feb 2018 10:23:30 +0100 From: Ingo Molnar 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 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> User-Agent: NeoMutt/20170609 (1.8.3) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1592315446423253504?= X-GMAIL-MSGID: =?utf-8?q?1592548931976600703?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: * 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