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 EE43CC352A5 for ; Mon, 10 Feb 2020 17:46:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C47262080C for ; Mon, 10 Feb 2020 17:46:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581356811; bh=s36p1l4ZPlQFYPOrfr/fxqnjD5UfABvmtBfZytlVlp4=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=qbk9NHTBNLTZxDF5yUvNrvnsilL0zSN2BCp6bu1W5EDondIoTwRi9idzv5JlmyOBH m3iEESSTBEgM1NJ6ZUABrsTbXIFsHp823AuoY6ZoQeFrIgd43VKS2MyinLVxLifTUD ygPNwOVmGyw8geHWd6swEUFzbIMkGFBgrtd4Gn50= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727582AbgBJRqu (ORCPT ); Mon, 10 Feb 2020 12:46:50 -0500 Received: from mail-lj1-f196.google.com ([209.85.208.196]:39038 "EHLO mail-lj1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728042AbgBJRqs (ORCPT ); Mon, 10 Feb 2020 12:46:48 -0500 Received: by mail-lj1-f196.google.com with SMTP id o15so8220196ljg.6 for ; Mon, 10 Feb 2020 09:46:47 -0800 (PST) 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=cMABvWd/7c4TphsJ+M/Bzt18EBtYsvxejNNk0qYwcjM=; b=AJWGb7viPUuSlXbBtks15QbiGc0V+5N1kFBw6HmGv/BocUHZwmHNnivHvSwIiPeEQm 1fliH10RGyoPY6yV4O5rwY5izrulFkNof0M2GsGbSrfCirug6Mx7f0jNvrzCMioGftQD acWtx/PsAUjj64YLYfwg5kSuWK5If6M0QpBoQ= 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=cMABvWd/7c4TphsJ+M/Bzt18EBtYsvxejNNk0qYwcjM=; b=dLU94MTz8ZCkIdrb+36f64wrdiPA4m9ZM3hBP1f0QlAnOOAB2Z5qfMwYfCpPiNnG7f +bqzJogtdN1r+BBhn8due2QDYJGcXo+niii6+8UJ9PHT4On3yTQaMLnQ8zTKbQNXCkpX fTOOuPYFRQwSG94673bIxZvDCX+CeK+w4q1HGK+LNi78R7kHH7kXIp5KjLqn8QABms1I nEPCHTFKRQy9uf94iQeILZ7m8fAj0KC9h10wavXntDsmEXKzAMRSnnz2+QHoDFrUwkLC 5KFZ6DezQa4kpos5FaLjmms5X7OCdYmFrwYnV+/rhgoOMQAnTWpyYwwTpBxssirNvHGM MX4g== X-Gm-Message-State: APjAAAXlx+af+KNY5F06tmwpVlNkL8JtOupKHPhvPg/3sb2d/uqx5Rfg NWDgAIyhXNilGTfrEuUtsqMsy39Nfuw= X-Google-Smtp-Source: APXvYqwz+PuicCoMRpbEcK9RhtZEXg+Qb56jox8xvgy/uZVlttcM+t+MTlW98tcJzWONdcvN9iNgUg== X-Received: by 2002:a2e:9110:: with SMTP id m16mr1579762ljg.140.1581356804897; Mon, 10 Feb 2020 09:46:44 -0800 (PST) Received: from mail-lj1-f175.google.com (mail-lj1-f175.google.com. [209.85.208.175]) by smtp.gmail.com with ESMTPSA id n206sm485436lfd.50.2020.02.10.09.46.42 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 10 Feb 2020 09:46:43 -0800 (PST) Received: by mail-lj1-f175.google.com with SMTP id x14so8176477ljd.13 for ; Mon, 10 Feb 2020 09:46:42 -0800 (PST) X-Received: by 2002:a2e:461a:: with SMTP id t26mr1591348lja.204.1581356802297; Mon, 10 Feb 2020 09:46:42 -0800 (PST) MIME-Version: 1.0 References: <20200210150519.538333-1-gladkov.alexey@gmail.com> <20200210150519.538333-8-gladkov.alexey@gmail.com> In-Reply-To: <20200210150519.538333-8-gladkov.alexey@gmail.com> From: Linus Torvalds Date: Mon, 10 Feb 2020 09:46:26 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v8 07/11] proc: flush task dcache entries from all procfs instances To: Alexey Gladkov Cc: LKML , Kernel Hardening , Linux API , Linux FS Devel , Linux Security Module , Akinobu Mita , Alexander Viro , Alexey Dobriyan , Andrew Morton , Andy Lutomirski , Daniel Micay , Djalal Harouni , "Dmitry V . Levin" , "Eric W . Biederman" , Greg Kroah-Hartman , Ingo Molnar , "J . Bruce Fields" , Jeff Layton , Jonathan Corbet , Kees Cook , Oleg Nesterov , Solar Designer Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Mon, Feb 10, 2020 at 7:06 AM Alexey Gladkov wrote: > > This allows to flush dcache entries of a task on multiple procfs mounts > per pid namespace. > > The RCU lock is used because the number of reads at the task exit time > is much larger than the number of procfs mounts. Ok, this looks better to me than the previous version. But that may be the "pee-in-the-snow" effect, and I _really_ want others to take a good look at the whole series. The right people seem to be cc'd, but this is pretty core, and /proc has a tendency to cause interesting issues because of how it's involved in a lot of areas indirectly. Al, Oleg, Andy, Eric? Linus