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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 B84A0C43603 for ; Wed, 27 Jan 2021 00:28:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9CA5020679 for ; Wed, 27 Jan 2021 00:28:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390559AbhA0AZQ (ORCPT ); Tue, 26 Jan 2021 19:25:16 -0500 Received: from mail.kernel.org ([198.145.29.99]:34034 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389426AbhAZROr (ORCPT ); Tue, 26 Jan 2021 12:14:47 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BFF2D230FC; Tue, 26 Jan 2021 17:14:05 +0000 (UTC) Date: Tue, 26 Jan 2021 12:14:04 -0500 From: Steven Rostedt To: Timur Tabi Cc: Vlastimil Babka , Sergey Senozhatsky , Matthew Wilcox , Andrew Morton , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, Petr Mladek , roman.fietze@magna.com, keescook@chromium.org, John Ogness , linux-mm@kvack.org, Akinobu Mita Subject: Re: [PATCH 0/2] introduce DUMP_PREFIX_UNHASHED for hex dumps Message-ID: <20210126121404.016117fd@gandalf.local.home> In-Reply-To: References: <20210116220950.47078-1-timur@kernel.org> <20210118182635.GD2260413@casper.infradead.org> <20210119014725.GH2260413@casper.infradead.org> <09c70d6b-c989-ca23-7ee8-b404bb0490f0@suse.cz> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 26 Jan 2021 10:59:12 -0600 Timur Tabi wrote: > The only drawback to this idea is: what happens if distros start > enabling CONFIG_PRINTK_NEVER_HASH by default, just because it makes > debugging easier? I do believe distros should be more concerned about security than using this for making debugging easier. Perhaps we should add the same banner print if that config is set as trace_printk() has if it is detected in the kernel or a module: ********************************************************** ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** ** ** ** trace_printk() being used. Allocating extra memory. ** ** ** ** This means that this is a DEBUG kernel and it is ** ** unsafe for production use. ** ** ** ** If you see this message and you are not debugging ** ** the kernel, report this immediately to your vendor! ** ** ** ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** ********************************************************** But have: ********************************************************** ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** ** ** ** CONFIG_PRINTK_NEVER_HASH enabled ** ** ** ** This means that this is a DEBUG kernel and it is ** ** unsafe for production use. ** ** ** ** If you see this message and you are not debugging ** ** the kernel, report this immediately to your vendor! ** ** ** ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE ** ********************************************************** The above appears to keep people from using trace_printk(), I don't see why it wouldn't work for this config ;-) -- Steve