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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 117A8C433E0 for ; Thu, 4 Jun 2020 00:14:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD4082067B for ; Thu, 4 Jun 2020 00:14:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591229640; bh=wJt/E3KOzAbfjnU6Afr8qP51B0SkXgeMthZGOmvjbFk=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=GbdlMJ46+zN39J4tMpHle1wzENrZx71Ujyh3Po2MRVYjvTcZ1BeomcVR+EYS2xK7F 5QwqKHOHrniLrdSKNgxqh3yM/J85MsdbWagE1RadzrJb08Yav9vLkFT1MyYm716BY1 chAbzH3vF+Nkvnz9qoHlv7cpjsMVKx0g5huVM8Tk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726380AbgFDAN7 (ORCPT ); Wed, 3 Jun 2020 20:13:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725946AbgFDAN6 (ORCPT ); Wed, 3 Jun 2020 20:13:58 -0400 Received: from mail-lj1-x244.google.com (mail-lj1-x244.google.com [IPv6:2a00:1450:4864:20::244]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5FBC8C08C5C1 for ; Wed, 3 Jun 2020 17:13:58 -0700 (PDT) Received: by mail-lj1-x244.google.com with SMTP id z9so5000355ljh.13 for ; Wed, 03 Jun 2020 17:13:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=rWe2Q0RVzrp4gR0EET85HSpI5Y5evJHsyhPkQ14mL0k=; b=bt0TGPg3m1SCTLBdHymXFLfl3E3L3r+udH7rn8D+EBhHjSsJezRKQc5I44quK2Ep95 n7O9rGE+x0OuzzxK9JDFKVEZNlNil/zWzB2OtsPvSkq3h3Byx+1A/PbyAJD8T+ACtvtF KVePdWwwaM3XuFRkXqkGtRQjsVdhDo42Nx8Z8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=rWe2Q0RVzrp4gR0EET85HSpI5Y5evJHsyhPkQ14mL0k=; b=ZoCkascaD4PXlHIwDb3puZVEbip8cR7HgUdQvE/Nbm6uWWPAdS46QvwyN9qaTDcPga LX64d/uwfl5C5jErpbFmEJuC3nnx3dK1fnZTeTEGSaNjJi7LXahDhmCzRpj6lj+bgn4+ BcIfZ+pWpulW8G9pMQ8ePDXWwr2noq1AtdH7/GCzuhjLnDXIeFhmLEEg/mY/1sNI9acx xEU8s5rhCE+FS78CiQaqcYWio135jZhscf0M6EDyQTtAbmtOe8+ZlMH1f/ElaI2+es4r H8Q3N1uES+OI0yIS1kgciPBTWaBDkRYcoFzHakETNUuQAsBoAUDv/TmN7+cYlc59yGjb AdBg== X-Gm-Message-State: AOAM532bSIdk3u8YrkEdxhGutGa9E3X5qseGO+VLNzibZmqdmfOm2NOJ gfG7sYiVvbkV7vcyceJZSWC7ZwUDTQk= X-Google-Smtp-Source: ABdhPJwZYDfDLZVIm4Br+CGgDfQtwpj6uJFNLyR/DN3sUl4t5yxG1FVOWXZ3AhROm1+a6s+mbCM6pQ== X-Received: by 2002:a05:651c:544:: with SMTP id q4mr832295ljp.310.1591229635982; Wed, 03 Jun 2020 17:13:55 -0700 (PDT) Received: from mail-lj1-f177.google.com (mail-lj1-f177.google.com. [209.85.208.177]) by smtp.gmail.com with ESMTPSA id t7sm1059215lfq.64.2020.06.03.17.13.52 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 03 Jun 2020 17:13:52 -0700 (PDT) Received: by mail-lj1-f177.google.com with SMTP id b6so5063114ljj.1 for ; Wed, 03 Jun 2020 17:13:52 -0700 (PDT) X-Received: by 2002:a2e:7e0a:: with SMTP id z10mr790807ljc.314.1591229631853; Wed, 03 Jun 2020 17:13:51 -0700 (PDT) MIME-Version: 1.0 References: <20200602204219.186620-1-christian.brauner@ubuntu.com> <20200602233355.zdwcfow3ff4o2dol@wittgenstein> <20200603232410.i3opsbmepv5ktsjq@wittgenstein> In-Reply-To: <20200603232410.i3opsbmepv5ktsjq@wittgenstein> From: Linus Torvalds Date: Wed, 3 Jun 2020 17:13:36 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v5 0/3] close_range() To: Christian Brauner Cc: Linux Kernel Mailing List , Kyle Evans , Victor Stinner , Al Viro , linux-fsdevel , Linux API , Florian Weimer , Jann Horn , Oleg Nesterov , Arnd Bergmann , Shuah Khan , David Howells , "Dmitry V. Levin" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 3, 2020 at 4:24 PM Christian Brauner wrote: > > Ok, here's what I have. Does the below look somewhat sane? Probably. Needs lots of testing. But this one looks wrong: > +int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) > { > + if ((max_fd + 1) >= cur_max) > + max_unshare_fds = fd; A normal value for "close everything starting at X" would have a max_fd value of ~0. So "max_fd+1" would overflow to 0, and then this would never trigger. Other than that it looks what what I imagine my feverdreams were about. Linus