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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 BD55CC04AB1 for ; Mon, 13 May 2019 09:13:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99DE520989 for ; Mon, 13 May 2019 09:13:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728632AbfEMJN3 (ORCPT ); Mon, 13 May 2019 05:13:29 -0400 Received: from mga07.intel.com ([134.134.136.100]:34770 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728616AbfEMJN1 (ORCPT ); Mon, 13 May 2019 05:13:27 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 May 2019 02:13:26 -0700 X-ExtLoop1: 1 Received: from smile.fi.intel.com (HELO smile) ([10.237.72.86]) by orsmga007.jf.intel.com with ESMTP; 13 May 2019 02:13:21 -0700 Received: from andy by smile with local (Exim 4.92) (envelope-from ) id 1hQ71M-0007f0-23; Mon, 13 May 2019 12:13:20 +0300 Date: Mon, 13 May 2019 12:13:20 +0300 From: Andy Shevchenko To: David Laight Cc: 'christophe leroy' , Steven Rostedt , Petr Mladek , Linus Torvalds , Rasmus Villemoes , "Tobin C . Harding" , Michal Hocko , Sergey Senozhatsky , Sergey Senozhatsky , "linux-kernel@vger.kernel.org" , Michael Ellerman , "linuxppc-dev@lists.ozlabs.org" , Russell Currey , Stephen Rothwell , Heiko Carstens , "linux-arch@vger.kernel.org" , "linux-s390@vger.kernel.org" , Martin Schwidefsky Subject: Re: [PATCH] vsprintf: Do not break early boot with probing addresses Message-ID: <20190513091320.GK9224@smile.fi.intel.com> References: <20190510081635.GA4533@jagdpanzerIV> <20190510084213.22149-1-pmladek@suse.com> <20190510122401.21a598f6@gandalf.local.home> <096d6c9c17b3484484d9d9d3f3aa3a7c@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <096d6c9c17b3484484d9d9d3f3aa3a7c@AcuMS.aculab.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 13, 2019 at 08:52:41AM +0000, David Laight wrote: > From: christophe leroy > > Sent: 10 May 2019 18:35 > > Le 10/05/2019 à 18:24, Steven Rostedt a écrit : > > > On Fri, 10 May 2019 10:42:13 +0200 > > > Petr Mladek wrote: > > >> - if (probe_kernel_address(ptr, byte)) > > >> + if ((unsigned long)ptr < PAGE_SIZE || IS_ERR_VALUE(ptr)) > > >> return "(efault)"; > > "efault" looks a bit like a spellling mistake for "default". It's a special, thus it's in parenthesis, though somebody can be misguided. > > Usually, < PAGE_SIZE means NULL pointer dereference (via the member of a > > struct) > > Maybe the caller should pass in a short buffer so that you can return > "(err-%d)" > or "(null+%#x)" ? In both cases it should be limited to the size of pointer (8 or 16 characters). Something like "(e:%4d)" would work for error codes. The "(null)" is good enough by itself and already an established practice.. -- With Best Regards, Andy Shevchenko