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=-1.0 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 2E1E9C2D0F2 for ; Tue, 31 Mar 2020 18:26:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 072592145D for ; Tue, 31 Mar 2020 18:26:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="LPlrAqLP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726282AbgCaS05 (ORCPT ); Tue, 31 Mar 2020 14:26:57 -0400 Received: from mail-pj1-f66.google.com ([209.85.216.66]:54419 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726000AbgCaS04 (ORCPT ); Tue, 31 Mar 2020 14:26:56 -0400 Received: by mail-pj1-f66.google.com with SMTP id np9so1424669pjb.4 for ; Tue, 31 Mar 2020 11:26:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=64CGxkVCN+tpcc5h0TLuNJ8a0+sAEqYpYu5ixxZ2mkg=; b=LPlrAqLP/r1SwN4Ni33l2KQkmUbmZQ5e2B8/T0hekORvqd7ZHsRdfVBuFJ+71qMGlI iNcSc7h4BDQPrR6lBAbeSfC2UjMpqitCX+rfJozQiFTo44sIVa9v3gYfOM6/hxSNwtAc SVRlyESM7ogE4R8gp9eKC7Bd4vn/+TDLdg1jM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=64CGxkVCN+tpcc5h0TLuNJ8a0+sAEqYpYu5ixxZ2mkg=; b=SrQ9kHbmZzuJ0ONxGzltIoi9acypYYuW1Hu0+TU48cUyHgOiiSbDb+oM/pr3J3Xuti QwRgJtTkK41I7s9IAl/1qDpAo5viJoo1DS9FB8FjClPPz78osH287s/ZATdRykZJz8QG e+F375uqjWG/JOPqbEuyCTa1XQmyK9C3RJn+HdQt9/cJk07yIjEBh6VTDlc7xxHWN3R0 Xq8z/1JV+UI4Vpo03o2kTV9vvLfz9GaB/qzdWCol+SeSFqhNyUCW3m/O6MxJs88o17ml pAIzFkuDBopcuVnBw5mJUnodR1GwCXGZD9MNFCWNElJBWWpG8kTgvSU7UV2bGnxMIs+j Gb3g== X-Gm-Message-State: AGi0PuYSloBk+WqL8ImUNs51v6E4RHPh6SDU3W4BJ/P4sX7446gZDMx2 /4EgksD8YuM6fOllpyZKCj48Gw== X-Google-Smtp-Source: APiQypKI94JfKPIkpz/wT7WensQDX/0VxvYe7qtJDDSNIyHzhN59+sKmEZbVAOJ/tlrINrMpXAwDwA== X-Received: by 2002:a17:90a:3606:: with SMTP id s6mr172866pjb.195.1585679213559; Tue, 31 Mar 2020 11:26:53 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id r9sm8228895pfg.2.2020.03.31.11.26.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 31 Mar 2020 11:26:52 -0700 (PDT) Date: Tue, 31 Mar 2020 11:26:51 -0700 From: Kees Cook To: Michal Hocko Cc: Vlastimil Babka , Luis Chamberlain , Iurii Zaikin , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, Ivan Teterevkov , David Rientjes , Matthew Wilcox , "Eric W . Biederman" , "Guilherme G . Piccoli" , Alexey Dobriyan , Thomas Gleixner , Greg Kroah-Hartman , Christian Brauner Subject: Re: [PATCH 1/3] kernel/sysctl: support setting sysctl parameters from kernel command line Message-ID: <202003311125.939F851A6@keescook> References: <20200330115535.3215-1-vbabka@suse.cz> <20200330115535.3215-2-vbabka@suse.cz> <20200330224422.GX11244@42.do-not-panic.com> <8146e3d0-89c3-7f79-f786-084c58282c85@suse.cz> <20200331074836.GB30449@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200331074836.GB30449@dhcp22.suse.cz> Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Tue, Mar 31, 2020 at 09:48:36AM +0200, Michal Hocko wrote: > On Tue 31-03-20 09:42:46, Vlastimil Babka wrote: > [...] > > > Should we not do this, we'll have to live with the consequences of > > > supporting the full swoop of sysctls are boot params, whatever > > > consequences those may be. > > > > Of course when the first user tries to set some particular sysctl as boot param > > and finds and reports it doesn't work as intended, then it can be fixed or > > blacklisted and it can't break anyone else? > > Absolutely agreed. I would be really careful to not overengineer this > whole thing. Right -- this is supposed to be _simple_, and I think that's the primary benefit here. If we encounter problems we can fix those cases. The careful place, I think, needs to be with converting existing boot params to be aliases. That's when timing considerations need to be taken into account carefully. -- Kees Cook