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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 4F0F7C388F9 for ; Tue, 27 Oct 2020 10:00:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F011C2225C for ; Tue, 27 Oct 2020 10:00:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="TB834nod" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2896695AbgJ0KAn (ORCPT ); Tue, 27 Oct 2020 06:00:43 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:43053 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2896568AbgJ0J7I (ORCPT ); Tue, 27 Oct 2020 05:59:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603792747; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tLtSmreGZ8ivBs0p74ioOfMSZEASbgeofS5XUTejfho=; b=TB834nodNCTfsqAEgotY3j5TlPWF0zO6828DwP+NItZLsyHg7wUnKCG7Wa5NFPFrUACC4L 5GBs5VTWAKkKC9yhfYOvd1V34SC4qSc4lqgAyvfRdgrUV5Rpp68KKwwzEIH2tLktdC4izm MIpnX4Ow3pnktvoAJwV2/Cwrqu9+4+w= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-116-mluE0FvaPgadKX6t8AC3zg-1; Tue, 27 Oct 2020 05:59:05 -0400 X-MC-Unique: mluE0FvaPgadKX6t8AC3zg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 853901009636; Tue, 27 Oct 2020 09:59:00 +0000 (UTC) Received: from [10.36.113.185] (ovpn-113-185.ams2.redhat.com [10.36.113.185]) by smtp.corp.redhat.com (Postfix) with ESMTP id CD79C610F3; Tue, 27 Oct 2020 09:58:58 +0000 (UTC) Subject: Re: [PATCH 1/3] mm, page_alloc: do not rely on the order of page_poison and init_on_alloc/free parameters To: Vlastimil Babka , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Alexander Potapenko , Kees Cook , Michal Hocko , Mateusz Nosek References: <20201026173358.14704-1-vbabka@suse.cz> <20201026173358.14704-2-vbabka@suse.cz> <3784dac7-49cb-006b-7b9d-1244d5c59935@redhat.com> <9a2b88de-3c01-21d0-69ff-08643f7c4b68@suse.cz> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: Date: Tue, 27 Oct 2020 10:58:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <9a2b88de-3c01-21d0-69ff-08643f7c4b68@suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27.10.20 10:58, Vlastimil Babka wrote: > On 10/27/20 10:03 AM, David Hildenbrand wrote: >> On 26.10.20 18:33, Vlastimil Babka wrote: >>> Enabling page_poison=1 together with init_on_alloc=1 or init_on_free=1 produces >>> a warning in dmesg that page_poison takes precendence. However, as these >>> warnings are printed in early_param handlers for init_on_alloc/free, they are >>> not printed if page_poison is enabled later on the command line (handlers are >>> called in the order of their parameters), or when init_on_alloc/free is always >>> enabled by the respective config option - before the page_poison early param >>> handler is called, it is not considered to be enabled. This is inconsistent. >>> >>> We can remove the dependency on order by making the init_on_* parameters only >>> set a boolean variable, and postponing the evaluation after all early params >>> have been processed. Introduce a new init_mem_debugging() function for that, >>> and move the related debug_pagealloc processing there as well. >> >> init_mem_debugging() is somewhat sub-optimal - init_on_alloc=1 or >> init_on_free=1 are rather security hardening mechanisms. > > Well yeah, init_mem_debugging_and_hardening()? Would work for me. -- Thanks, David / dhildenb