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=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 3CAB8C433DF for ; Tue, 30 Jun 2020 14:35:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 18A83206BE for ; Tue, 30 Jun 2020 14:35:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="jkaecJKR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389017AbgF3Ofn (ORCPT ); Tue, 30 Jun 2020 10:35:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54630 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731427AbgF3Ofm (ORCPT ); Tue, 30 Jun 2020 10:35:42 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D3D8C061755 for ; Tue, 30 Jun 2020 07:35:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=msmi1zI7qJmIO1xU9ZUIcrr2D+GhO7V+5RJpm/YLang=; b=jkaecJKRZofrkbCxWq9hxE9DRZ n3MUA5fvMNsvXDPWnDT4XugDA1B5p4HLY3LouFyiPGaCUN0BAtz2SUb3d4MnPH9fxi5Lx+I9g8H6C 5lCJar8YRINo1qhn4AP6ID514IJZiMxnxroOn+5QuU7eQU0CM/oEAjPdgG6PH4nkRLb6mr8EKFtBi 2IYQU4NRRBoJuEwSkOQV60JT7MfA1B2W6+2bjFPszRZ2KW9HvaLNyfwKEWp4Ta5rDazKuGiJss4wd IU+Gtdx+DwKKww4lLqzFR1OTgKFbxtH2LjS9iNiy9GBAhoS0AiZXOdBzg22v3M3guJ7Mbq0z9LuyT y654MGTw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jqHLl-0003Ky-FQ; Tue, 30 Jun 2020 14:35:05 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 7F0F6303CE9; Tue, 30 Jun 2020 16:35:04 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 72BCE20CF397A; Tue, 30 Jun 2020 16:35:04 +0200 (CEST) Date: Tue, 30 Jun 2020 16:35:04 +0200 From: Peter Zijlstra To: Rasmus Villemoes Cc: kernel test robot , Steven Rostedt , LKML , x86@kernel.org, lkp@lists.01.org, keescook@chromium.org, hjl.tools@gmail.com Subject: Re: [sched] c3a340f7e7: invalid_opcode:#[##] Message-ID: <20200630143504.GI117543@hirez.programming.kicks-ass.net> References: <20200629003127.GB5535@shao2-debian> <20200630124628.GV4817@hirez.programming.kicks-ass.net> <5b7286c9-ef4f-c1d0-fae3-ebb198aa0742@rasmusvillemoes.dk> <20200630140231.GW4817@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200630140231.GW4817@hirez.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 30, 2020 at 04:02:31PM +0200, Peter Zijlstra wrote: > On Tue, Jun 30, 2020 at 03:55:05PM +0200, Rasmus Villemoes wrote: > > > > Consistently so with GCC-4.9. Any other GCC I tried does the sane thing. > > > > Does that include gcc 4.8, or is it only "anything newer than 4.9"? > > It includes 4.8 :-) > > > so the section it was put in has an alignment of 64. The generated > > assembly is indeed > > > > .globl fair_sched_class > > .section __fair_sched_class,"a",@progbits > > .align 64 > > > > /me goes brew coffee > > Right.. so I now have the below patch, and with that I get: > > 62931: c1e62c20 0 NOTYPE GLOBAL DEFAULT 2 __begin_sched_classes > 65736: c1e62e40 128 OBJECT GLOBAL DEFAULT 2 stop_sched_class > 71813: c1e62cc0 128 OBJECT GLOBAL DEFAULT 2 fair_sched_class > 78689: c1e62c40 128 OBJECT GLOBAL DEFAULT 2 idle_sched_class > 78953: c1e62ec0 0 NOTYPE GLOBAL DEFAULT 2 __end_sched_classes > 79090: c1e62d40 128 OBJECT GLOBAL DEFAULT 2 rt_sched_class > 79431: c1e62dc0 128 OBJECT GLOBAL DEFAULT 2 dl_sched_class > > > Which has me stumped on __begin_sched_classes being on a 32byte edge > (and crashes differently due to that). OK, when I look at defconfig-build/arch/x86/kernel/vmlinux.lds I get: . = ALIGN(32); *(__dummy_sched_class) __begin_sched_classes = .; So I'm thinking the GCC_VERSION thing works for sched.h but not for arch//x86/kernel/vmlinux.lds.S, lovely. Let me try and figure out why.