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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 A859AC10F14 for ; Thu, 10 Oct 2019 14:22:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7E98120B7C for ; Thu, 10 Oct 2019 14:22:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E98120B7C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1496D8E0003; Thu, 10 Oct 2019 10:22:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0FABC6B0006; Thu, 10 Oct 2019 10:22:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 010238E0003; Thu, 10 Oct 2019 10:22:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0192.hostedemail.com [216.40.44.192]) by kanga.kvack.org (Postfix) with ESMTP id D60D46B0003 for ; Thu, 10 Oct 2019 10:22:41 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 5F96652CF for ; Thu, 10 Oct 2019 14:22:41 +0000 (UTC) X-FDA: 76028090922.03.story32_348b9ab6ffb1b X-HE-Tag: story32_348b9ab6ffb1b X-Filterd-Recvd-Size: 1608 Received: from gentwo.org (gentwo.org [3.19.106.255]) by imf27.hostedemail.com (Postfix) with ESMTP for ; Thu, 10 Oct 2019 14:22:40 +0000 (UTC) Received: by gentwo.org (Postfix, from userid 1002) id 573553F1BF; Thu, 10 Oct 2019 14:22:40 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id 545473E86A; Thu, 10 Oct 2019 14:22:40 +0000 (UTC) Date: Thu, 10 Oct 2019 14:22:40 +0000 (UTC) From: Christopher Lameter X-X-Sender: cl@www.lameter.com To: Shyam Saini cc: linux-mm@kvack.org, kernel-hardening@lists.openwall.com, Matthew Wilcox , Kees Cook Subject: Re: [PATCH] slab: Redefine ZERO_SIZE_PTR to include ERR_PTR range In-Reply-To: <20191010103151.7708-1-mayhs11saini@gmail.com> Message-ID: References: <20191010103151.7708-1-mayhs11saini@gmail.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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, 10 Oct 2019, Shyam Saini wrote: > This will help error related to ERR_PTR stand out better. Maybe make ZERO_SIZE_PTR an ERRNO value instead? Then allow ERR_PTRs to be used instead of ZERO_SIZE_PTRs ERRNO_ZERO_OBJECT or something like that? > */ > -#define ZERO_SIZE_PTR ((void *)16) #define ZERO_SIZE_PTR ((void *)-ERRNO_ZERO_OBJECT) > + > +#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) - 1 >= \ > + (unsigned long)ZERO_SIZE_PTR - 1) And call this something different?