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 7857EC433DB for ; Tue, 26 Jan 2021 17:14:10 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DCB6E230FE for ; Tue, 26 Jan 2021 17:14:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DCB6E230FE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 269EE8D00F6; Tue, 26 Jan 2021 12:14:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 219E48D00B0; Tue, 26 Jan 2021 12:14:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 12F888D00F6; Tue, 26 Jan 2021 12:14:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0208.hostedemail.com [216.40.44.208]) by kanga.kvack.org (Postfix) with ESMTP id F20BF8D00B0 for ; Tue, 26 Jan 2021 12:14:08 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id A6BC0180AD5C5 for ; Tue, 26 Jan 2021 17:14:08 +0000 (UTC) X-FDA: 77748574176.23.food37_211803427590 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id 7E23E37610 for ; Tue, 26 Jan 2021 17:14:08 +0000 (UTC) X-HE-Tag: food37_211803427590 X-Filterd-Recvd-Size: 3986 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Tue, 26 Jan 2021 17:14:07 +0000 (UTC) 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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