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_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 73E8DC433F5 for ; Mon, 27 Aug 2018 02:35:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A1E5208B7 for ; Mon, 27 Aug 2018 02:35:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A1E5208B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ZenIV.linux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727247AbeH0GUG (ORCPT ); Mon, 27 Aug 2018 02:20:06 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:43212 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726822AbeH0GUG (ORCPT ); Mon, 27 Aug 2018 02:20:06 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.87 #1 (Red Hat Linux)) id 1fu7NG-0001S8-Pe; Mon, 27 Aug 2018 02:35:26 +0000 Date: Mon, 27 Aug 2018 03:35:26 +0100 From: Al Viro To: Julia Lawall Cc: Joe Perches , Kees Cook , LKML , Jamal Hadi Salim , Cong Wang , Jiri Pirko , "David S. Miller" , Network Development Subject: Re: [PATCH] net: sched: Fix memory exposure from short TCA_U32_SEL Message-ID: <20180827023526.GA6515@ZenIV.linux.org.uk> References: <20180826055801.GA42063@beast> <20180826061534.GT6515@ZenIV.linux.org.uk> <20180826173236.GU6515@ZenIV.linux.org.uk> <20180826212421.GW6515@ZenIV.linux.org.uk> <20180826224322.GX6515@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 26, 2018 at 10:00:46PM -0400, Julia Lawall wrote: > > > On Sun, 26 Aug 2018, Al Viro wrote: > > > On Sun, Aug 26, 2018 at 03:26:54PM -0700, Joe Perches wrote: > > > On Sun, 2018-08-26 at 22:24 +0100, Al Viro wrote: > > > > On Sun, Aug 26, 2018 at 11:57:57AM -0700, Joe Perches wrote: > > > > > > > > > > That, BTW, is why I hate the use of sizeof(*p) in kmalloc, etc. > > > > > > arguments. typeof is even worse in that respect. > > > > > > > > > > True. Semantic searches via tools like coccinelle could help here > > > > > but those searches are quite a bit slower than straightforward greps. > > > > > > > > Those searches are .config-sensitive as well, which can be much more > > > > unpleasant than being slow... > > > > > > Are they? Julia? > > > > They work pretty much on preprocessor output level; if something it ifdef'ed > > out on given config, it won't be seen... > > Coccinelle doesn't care what is ifdef'd out. It only misses the things it > can't parse. Very strange ifdefs could indeed cause that, but it should > be a minor problem. OK, but... what does it do when it sees two definitions of a structure in different branches of #if/#else/#endif? I think I'm confused about what it can and cannot do; to restate the original problem: * we need to find all places where instances of given type are created. Assume it never is a member of struct/union/array and no static or auto duration instances exist - everything is dynamically allocated somewhere. Can coccinelle do that and if it can, what are the limitations?