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=-10.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 E900DC433E9 for ; Wed, 10 Feb 2021 17:43:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7700B64ED3 for ; Wed, 10 Feb 2021 17:43:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7700B64ED3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=i-love.sakura.ne.jp Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 11E2E6B006C; Wed, 10 Feb 2021 12:43:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0A7956B006E; Wed, 10 Feb 2021 12:43:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E8DF46B0070; Wed, 10 Feb 2021 12:43:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0001.hostedemail.com [216.40.44.1]) by kanga.kvack.org (Postfix) with ESMTP id CFAD56B006C for ; Wed, 10 Feb 2021 12:43:15 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 9C27C10FD1 for ; Wed, 10 Feb 2021 17:43:15 +0000 (UTC) X-FDA: 77803079550.26.sand93_240a9a627611 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id 841AA181070DB for ; Wed, 10 Feb 2021 17:43:14 +0000 (UTC) X-HE-Tag: sand93_240a9a627611 X-Filterd-Recvd-Size: 4008 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Wed, 10 Feb 2021 17:43:13 +0000 (UTC) Received: from fsav301.sakura.ne.jp (fsav301.sakura.ne.jp [153.120.85.132]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 11AHfZjc062357; Thu, 11 Feb 2021 02:41:35 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav301.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav301.sakura.ne.jp); Thu, 11 Feb 2021 02:41:35 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav301.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 11AHfZVx062313 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Thu, 11 Feb 2021 02:41:35 +0900 (JST) (envelope-from penguin-kernel@i-love.sakura.ne.jp) Subject: Re: [PATCH 0/3][RESEND] add support for never printing hashed addresses To: Andy Shevchenko Cc: Steven Rostedt , Timur Tabi , Petr Mladek , Sergey Senozhatsky , Vlastimil Babka , Matthew Wilcox , akpm@linux-foundation.org, Linus Torvalds , roman.fietze@magna.com, Kees Cook , John Ogness , akinobu.mita@gmail.com, glider@google.com, Andrey Konovalov , Marco Elver , Rasmus Villemoes , Pavel Machek , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20210210051814.845713-1-timur@kernel.org> <6da0be5a-7cb0-4943-e61f-7c3275e60cb6@i-love.sakura.ne.jp> <20210210111836.2468f10a@gandalf.local.home> From: Tetsuo Handa Message-ID: Date: Thu, 11 Feb 2021 02:41:29 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US 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 2021/02/11 1:54, Andy Shevchenko wrote: > On Thu, Feb 11, 2021 at 01:39:41AM +0900, Tetsuo Handa wrote: >> On 2021/02/11 1:18, Steven Rostedt wrote: >>> The point of this exercise is to be able to debug the *same* kernel that >>> someone is having issues with. And this is to facilitate that debugging. >> >> That's too difficult to use. If a problem is not reproducible, we will have >> no choice but always specify "never hash pointers" command line option. If a >> problem is reproducible, we can rebuild that kernel with "never hash pointers" >> config option turned on. > > I think what you are targeting is something like dynamic debug approach where > you can choose which prints to enable/disable and what enable/disable in them. What I'm targeting is "zero interaction from kernel command line options" like https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/usb/usbip?id=f1bdf414e7dd0cbc26460425719fc3ea479947a2 . > > In that case you specifically apply a command line option and enable only files > / lines in the files. While there is boot-config feature for specifying very long kernel command line options, I can't enforce syzkaller users (including syzbot) to switch what to enable/disable via kernel command line options. Let alone defining a kernel command line option for single-purpose debug printk() changes like shown above.