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=-10.1 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=unavailable 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 06F4CC433E9 for ; Mon, 28 Dec 2020 19:13:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D2B0322B37 for ; Mon, 28 Dec 2020 19:13:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729086AbgL1TNH (ORCPT ); Mon, 28 Dec 2020 14:13:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729069AbgL1TNG (ORCPT ); Mon, 28 Dec 2020 14:13:06 -0500 Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA0C9C061793 for ; Mon, 28 Dec 2020 11:12:25 -0800 (PST) Received: by mail-wr1-x434.google.com with SMTP id t30so12320778wrb.0 for ; Mon, 28 Dec 2020 11:12:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=m/Wglbh+lTgBxyPrtUFRzs3rkWrSwjCdxL8lF/PAxdg=; b=KHzYIWd41lKdXti3O/ypHc8S0tMeIsfWLC/Bj7B0SzjA8vucJTYN7bHDQbPOIgg+4F fZD18Yty8GCok3qJf1fO63aT/4yXv5IpQqs4zCHs6V8c/hTJ3jaQBAZgI1nNOXy4naTF ahJeKtRt8Pj9o4utY+Oij4Ku95ArtGy+QiPl1IdezaUwqXgj7zMzTDihrmBFRPhv697s bXngRr1a7rkXrFhKxJYOOgbczrc3pA2FODIFky5l5upMPG9SMmchnVyAwlPmjBKrztxo RaTE0yITbMFc9Tl43W6lAhyGoZZ8DqUbKdkwj5EfXs0er0oc6+0O81LxacbGaxM/kkSZ KMhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=m/Wglbh+lTgBxyPrtUFRzs3rkWrSwjCdxL8lF/PAxdg=; b=uexBJrPcWxOGsVTRmQMTjm28K6mCmWuycg+/F6uWpeV+BZaEYftlj/vwX7pGoPQxPS p3jIAS8KhMfZm16+QI1X4g7bVTt0RHrfo7oC76+AZj96JcMzPV8BzSLVeVf6NQ1+3jTK qJMdxWp8YvnKem6RM1HXD3z+I+6F/TIuLH7EFSraOCtPI9rk6ECJS3FSOw8i17UAgfxF 1fiMGh42egq2irRhBZQSotesvqZ1MeVcxfe68OH2sdyEWKBj1pFKrLnstjcgLSP1ujRE EQ9abyLlZrxMmFsVw55lmaUEl9LYyODW9R8QEjRW4rprIOvW72YKRuTp9XDJnyoR0Xlx RVXg== X-Gm-Message-State: AOAM531V0+gfVrZP8JPeFxfPcqTOunCK92N6fOUMk4sMteLBjbr3U9Al KUa5i+GXJiMHBy+vemTbOaKX8uNJgLH53YNy X-Google-Smtp-Source: ABdhPJycPpZJYBqt0uJlm0KWY71lSYtZiAXnw+4FraPx9JOFiEU8hSeGhYPk8VZsjmDtrrKszFFOcA== X-Received: by 2002:a5d:4ccb:: with SMTP id c11mr50075979wrt.324.1609182744412; Mon, 28 Dec 2020 11:12:24 -0800 (PST) Received: from ?IPv6:2a02:8084:e84:2480:228:f8ff:fe6f:83a8? ([2a02:8084:e84:2480:228:f8ff:fe6f:83a8]) by smtp.gmail.com with ESMTPSA id s3sm258209wmc.44.2020.12.28.11.12.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 28 Dec 2020 11:12:23 -0800 (PST) Subject: Re: [PATCH 2/6] mm/mremap: For MREMAP_DONTUNMAP check security_vm_enough_memory_mm() To: Brian Geffon Cc: LKML , Dmitry Safonov <0x7f454c46@gmail.com>, Alexander Viro , Andrew Morton , Andy Lutomirski , Catalin Marinas , Dan Williams , Dave Jiang , Hugh Dickins , Ingo Molnar , "Kirill A. Shutemov" , Mike Kravetz , Minchan Kim , Russell King , Thomas Bogendoerfer , Thomas Gleixner , Vishal Verma , Vlastimil Babka , Will Deacon , linux-aio@kvack.org, linux-fsdevel@vger.kernel.org, linux-mm References: <20201013013416.390574-1-dima@arista.com> <20201013013416.390574-3-dima@arista.com> From: Dmitry Safonov Message-ID: Date: Mon, 28 Dec 2020 19:12:21 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 12/28/20 6:21 PM, Brian Geffon wrote: > This looks good to me with a small comment. > >> if (do_munmap(mm, old_addr, old_len, uf_unmap) < 0) { >> /* OOM: unable to split vma, just get accounts right */ >> - if (vm_flags & VM_ACCOUNT) >> + if (vm_flags & VM_ACCOUNT && !(flags & MREMAP_DONTUNMAP)) >> vm_acct_memory(new_len >> PAGE_SHIFT); > > Checking MREMAP_DONTUNMAP in the do_munmap path is unnecessary as > MREMAP_DONTUNMAP will have already returned by this point. In this code it is also used as err-path. In case move_page_tables() fails to move all page tables or .mremap() callback fails, the new VMA is unmapped. IOW, MREMAP_DONTUNMAP returns under: : if (unlikely(!err && (flags & MREMAP_DONTUNMAP))) { -- Dima