From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030432AbcJQVdY (ORCPT ); Mon, 17 Oct 2016 17:33:24 -0400 Received: from smtprelay0038.hostedemail.com ([216.40.44.38]:33219 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932340AbcJQVdP (ORCPT ); Mon, 17 Oct 2016 17:33:15 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1541:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:2689:2692:2693:3138:3139:3140:3141:3142:3353:3622:3865:3866:3867:3868:3870:3871:3872:3873:3874:4250:5007:6117:6119:6261:7875:7903:10004:10400:10848:10967:11232:11658:11914:12740:12760:13069:13161:13199:13229:13311:13357:13439:14096:14097:14180:14181:14659:14721:14777:21060:21080:21433:30003:30012:30026:30054:30064:30090:30091,0,RBL:error,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:error,Custom_rules:0:0:0,LFtime:2000,LUA_SUMMARY:none X-HE-Tag: run16_903ec3642ac55 X-Filterd-Recvd-Size: 2569 Date: Mon, 17 Oct 2016 17:33:09 -0400 From: Steven Rostedt To: Vegard Nossum Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Jiri Slaby , Linus Torvalds , "Luis R . Rodriguez" , Jason Baron Subject: Re: [PATCH 11/12] jump_label: declare jump table as external array Message-ID: <20161017173309.7020e084@gandalf.local.home> In-Reply-To: <79893565-c7bb-6abc-0a18-de78c1a0c9cc@oracle.com> References: <20161016151616.31451-1-vegard.nossum@oracle.com> <20161016151616.31451-12-vegard.nossum@oracle.com> <20161016162545.GM3142@twins.programming.kicks-ass.net> <79893565-c7bb-6abc-0a18-de78c1a0c9cc@oracle.com> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 16 Oct 2016 18:50:55 +0200 Vegard Nossum wrote: > > > > NAK, -ENOCHANGELOG. Agreed. > > > > Hi Peter, > > It's true I didn't put an RFC tag on this (mostly because git-send-email > doesn't seem to have an option for it?), but the whole point of doing I would think it does, although I never use it (I always use quilt mail). > these other patches (03-12) was to demonstrate what the patches would > look like for some other kernel code and ask for feedback on the overall > interface/approach. I don't know if you read the introduction and first > patch in the series, but I'd expect that to be more than enough to > understand the problem. But we were not Cc'd on those. If we are not on the Cc to the introduction nor the other patches, we will most likely not be reading them. > > If we really have to repeat the rationale for every patch, can we reuse > this? > > "Comparisons between pointers to different arrays is technically > undefined behaviour and recent GCCs may incorrectly optimise away loop > termination conditions. Use the external array accessor macros to > prevent this from happening." > So basically gcc will break on these array address calculations? Which version of gcc started this, and has this actually been an issue? -- Steve