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=-3.8 required=3.0 tests=BAYES_00, 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 17D6BC433ED for ; Wed, 5 May 2021 14:34:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D0FE4610A7 for ; Wed, 5 May 2021 14:34:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232882AbhEEOfp (ORCPT ); Wed, 5 May 2021 10:35:45 -0400 Received: from mga05.intel.com ([192.55.52.43]:40976 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229763AbhEEOfm (ORCPT ); Wed, 5 May 2021 10:35:42 -0400 IronPort-SDR: gBM/ZxI60QbQQWNLOPKQjJryURnBABog0/hPRwzaP0KXbJISIt9yq2K326wXtBDsPrs1eoR+kC T7aiVzwKWyYg== X-IronPort-AV: E=McAfee;i="6200,9189,9975"; a="283648490" X-IronPort-AV: E=Sophos;i="5.82,275,1613462400"; d="scan'208";a="283648490" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 May 2021 07:34:44 -0700 IronPort-SDR: DrKoOWa5eJeqAiNbrQBDhagwD7L0gMC68nrfbJKLatMj5DI+/j4uq9ePLhp2EllddUoVIycVHu 7WJnpOjDgHiQ== X-IronPort-AV: E=Sophos;i="5.82,275,1613462400"; d="scan'208";a="433848058" Received: from tassilo.jf.intel.com ([10.54.74.11]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 May 2021 07:34:43 -0700 Date: Wed, 5 May 2021 07:34:42 -0700 From: Andi Kleen To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, Andi Kleen , linux-toolchains@vger.kernel.org Subject: Re: [PATCH] sched: Work around undefined behavior in sched class checking Message-ID: <20210505143442.GR4032392@tassilo.jf.intel.com> References: <20210505033945.1282851-1-ak@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org > > Use RELOC_HIDE to make this work. This hides the symbols from gcc, > > so the optimizer won't make these assumption. I also split > > the BUG_ONs in multiple. > > Urgh, that insanity again :/ Can't we pretty please get a GCC flag to > disable that? Even if that was done (I could totally see the gcc people pushing back on this; why should they add special flags just for Linux developers not understanding ISO-C?) you would still need the fix for already shipping compilers. -Andi