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=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 EDAFDC2D0DB for ; Mon, 27 Jan 2020 17:35:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4AAC207FD for ; Mon, 27 Jan 2020 17:35:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728998AbgA0Rff convert rfc822-to-8bit (ORCPT ); Mon, 27 Jan 2020 12:35:35 -0500 Received: from mga11.intel.com ([192.55.52.93]:56628 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726303AbgA0Rff (ORCPT ); Mon, 27 Jan 2020 12:35:35 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Jan 2020 09:35:34 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,370,1574150400"; d="scan'208";a="401394432" Received: from orsmsx106.amr.corp.intel.com ([10.22.225.133]) by orsmga005.jf.intel.com with ESMTP; 27 Jan 2020 09:35:34 -0800 Received: from orsmsx156.amr.corp.intel.com (10.22.240.22) by ORSMSX106.amr.corp.intel.com (10.22.225.133) with Microsoft SMTP Server (TLS) id 14.3.439.0; Mon, 27 Jan 2020 09:35:34 -0800 Received: from orsmsx114.amr.corp.intel.com ([169.254.8.4]) by ORSMSX156.amr.corp.intel.com ([169.254.8.118]) with mapi id 14.03.0439.000; Mon, 27 Jan 2020 09:35:34 -0800 From: "Luck, Tony" To: Peter Zijlstra CC: Arvind Sankar , Thomas Gleixner , "Christopherson, Sean J" , Ingo Molnar , "Yu, Fenghua" , Ingo Molnar , "Borislav Petkov" , H Peter Anvin , "Raj, Ashok" , "Shankar, Ravi V" , linux-kernel , x86 Subject: RE: [PATCH v15] x86/split_lock: Enable split lock detection by kernel Thread-Topic: [PATCH v15] x86/split_lock: Enable split lock detection by kernel Thread-Index: AQHV0ynJ1/MagQqLD0a5ZArbKBEXmKf8a7KA//+AyICAAsQPgIAAGKGg Date: Mon, 27 Jan 2020 17:35:33 +0000 Message-ID: <3908561D78D1C84285E8C5FCA982C28F7F54F399@ORSMSX114.amr.corp.intel.com> References: <20200122224245.GA2331824@rani.riverdale.lan> <3908561D78D1C84285E8C5FCA982C28F7F54887A@ORSMSX114.amr.corp.intel.com> <20200123004507.GA2403906@rani.riverdale.lan> <20200123035359.GA23659@agluck-desk2.amr.corp.intel.com> <20200123044514.GA2453000@rani.riverdale.lan> <20200123231652.GA4457@agluck-desk2.amr.corp.intel.com> <87h80kmta4.fsf@nanos.tec.linutronix.de> <20200125024727.GA32483@agluck-desk2.amr.corp.intel.com> <20200125212524.GA538225@rani.riverdale.lan> <20200125215003.GB17914@agluck-desk2.amr.corp.intel.com> <20200127080419.GG14914@hirez.programming.kicks-ass.net> In-Reply-To: <20200127080419.GG14914@hirez.programming.kicks-ass.net> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.2.0.6 dlp-reaction: no-action x-originating-ip: [10.22.254.138] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Have you found any actual bad software ? The only way I could trigger > was by explicitly writing a program to tickle it. No application or library issues found so far (though I'm not running the kind of multi-threaded applications that might be using atomic operations for synchronization). Only Linux kernel seems to have APIs that make it easy for programmers to accidently split an atomic operation between cache lines. -Tony