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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 47327C433E0 for ; Wed, 10 Feb 2021 16:18:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 899B064E77 for ; Wed, 10 Feb 2021 16:18:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 899B064E77 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 E30DE6B006C; Wed, 10 Feb 2021 11:18:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DB9A76B006E; Wed, 10 Feb 2021 11:18:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C82286B0070; Wed, 10 Feb 2021 11:18:41 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0219.hostedemail.com [216.40.44.219]) by kanga.kvack.org (Postfix) with ESMTP id AC24A6B006C for ; Wed, 10 Feb 2021 11:18:41 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 6058FFB6E for ; Wed, 10 Feb 2021 16:18:41 +0000 (UTC) X-FDA: 77802866442.01.D982BF2 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf12.hostedemail.com (Postfix) with ESMTP id CB4A3135 for ; Wed, 10 Feb 2021 16:18:39 +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 A479164E05; Wed, 10 Feb 2021 16:18:37 +0000 (UTC) Date: Wed, 10 Feb 2021 11:18:36 -0500 From: Steven Rostedt To: Tetsuo Handa Cc: Timur Tabi , Petr Mladek , Sergey Senozhatsky , Vlastimil Babka , Andy Shevchenko , 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 Subject: Re: [PATCH 0/3][RESEND] add support for never printing hashed addresses Message-ID: <20210210111836.2468f10a@gandalf.local.home> In-Reply-To: <6da0be5a-7cb0-4943-e61f-7c3275e60cb6@i-love.sakura.ne.jp> References: <20210210051814.845713-1-timur@kernel.org> <6da0be5a-7cb0-4943-e61f-7c3275e60cb6@i-love.sakura.ne.jp> 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-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: CB4A3135 X-Stat-Signature: bm35utfmgqyccn111gp9o7y8ftkta7fd Received-SPF: none (kernel.org>: No applicable sender policy available) receiver=imf12; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: none/none X-HE-Tag: 1612973919-786957 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 Thu, 11 Feb 2021 00:46:15 +0900 Tetsuo Handa wrote: > Oh, I was wishing > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > index 3b53c73580c5..34c7e145ac3c 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -802,7 +802,7 @@ static char *ptr_to_id(char *buf, char *end, const void *ptr, > * Print the real pointer value for NULL and error pointers, > * as they are not actual addresses. > */ > - if (IS_ERR_OR_NULL(ptr)) > + if (IS_ERR_OR_NULL(ptr) || IS_ENABLED(CONFIG_DEBUG_DONT_HASH_POINTERS)) > return pointer_string(buf, end, ptr, spec); > > /* When debugging early boot use non-cryptographically secure hash. */ > > change as a kernel config option, for more we try to switch using kernel command line options, > more we likely make errors with sharing appropriate kernel command line options > (e.g. https://github.com/google/syzkaller/commit/99c64d5c672700d6c0de63d11db25a0678e47a75 ). The entire point of this exercise is not to make it easy to add this feature. Linus was absolutely against a config option, and I am too. 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. Whereas the example you show, the command line modifies how the kernel works. This command line only modifies what the kernel displays. Big difference. -- Steve