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=-7.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A26C7C433E0 for ; Tue, 26 Jan 2021 16:59:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4663622B51 for ; Tue, 26 Jan 2021 16:59:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4663622B51 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 827058D00F5; Tue, 26 Jan 2021 11:59:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7D6B78D00B0; Tue, 26 Jan 2021 11:59:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69C778D00F5; Tue, 26 Jan 2021 11:59:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0105.hostedemail.com [216.40.44.105]) by kanga.kvack.org (Postfix) with ESMTP id 512BC8D00B0 for ; Tue, 26 Jan 2021 11:59:18 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id C96611EE6 for ; Tue, 26 Jan 2021 16:59:17 +0000 (UTC) X-FDA: 77748536754.24.play75_480a62a27590 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id ABBBB1A4A0 for ; Tue, 26 Jan 2021 16:59:17 +0000 (UTC) X-HE-Tag: play75_480a62a27590 X-Filterd-Recvd-Size: 3219 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Tue, 26 Jan 2021 16:59:17 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id CB71B229C9; Tue, 26 Jan 2021 16:59:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611680356; bh=gRAls07DrECuk0X0leeEk0d93d6mXj1Kwan1fuByVy4=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=KnsAUeIzrJGXRzJY+SVSVSHHly5KZhwzKAKGXMOQbNrc25Rf4hcm8Y3aKAWQePl/Q wK7AoNr5g1J9hj6sXlI1UbimdA3jPsBFvAvpcpBlfg3VoTBBGLZkXyNIvfhtYuKJUi B+ZaiJzg2TcYC78+tx2kQHFsLWgvSz3QNUILUKK6278zNms2bXei6lBLzylxT4rCL5 0vUK9RCVSvwL0bNBU/cKIjGn88iKuzL+TMPC3uq2uzqWkAPt5F0bUCFnKURybuvoCP Ow47Xqgnoib42p33vuyp2KIPpIQ2EuFzYXuT5Fv/Shu5T+rCCgRZs6420ck63l/iTm hqqZ9ftMU7Yeg== Subject: Re: [PATCH 0/2] introduce DUMP_PREFIX_UNHASHED for hex dumps To: Vlastimil Babka , Sergey Senozhatsky , Matthew Wilcox Cc: Andrew Morton , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, Petr Mladek , roman.fietze@magna.com, keescook@chromium.org, Steven Rostedt , John Ogness , linux-mm@kvack.org, Akinobu Mita References: <20210116220950.47078-1-timur@kernel.org> <20210118182635.GD2260413@casper.infradead.org> <20210119014725.GH2260413@casper.infradead.org> <09c70d6b-c989-ca23-7ee8-b404bb0490f0@suse.cz> From: Timur Tabi Message-ID: Date: Tue, 26 Jan 2021 10:59:12 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <09c70d6b-c989-ca23-7ee8-b404bb0490f0@suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000275, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 1/26/21 10:47 AM, Vlastimil Babka wrote: > Given Linus' current stance later in this thread, could we revive the idea of a > boot time option, or at least a CONFIG (I assume a runtime toggle would be too > much, even if limited to !kernel_lockdown:) , that would disable all hashing? > It would be really useful for a development/active debugging, as evidenced > below. Thanks. So you're saying: if CONFIG_PRINTK_NEVER_HASH is disabled, then %p prints hashed addresses and %px prints unhashed. If CONFIG_PRINTK_NEVER_HASH is enabled, then %p and %px both print unhashed addresses. I like this idea, and I would accept it as a solution if I had to, but I still would also like for an option for print_hex_dump() to print unhashed addresses even when CONFIG_PRINTK_NEVER_HASH is disabled. I can't always recompile the entire kernel for my testing purposes. 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?