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=-2.5 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 BD122C169C4 for ; Mon, 11 Feb 2019 18:16:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E87D21B68 for ; Mon, 11 Feb 2019 18:16:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731327AbfBKSQh (ORCPT ); Mon, 11 Feb 2019 13:16:37 -0500 Received: from mga12.intel.com ([192.55.52.136]:56729 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728123AbfBKSQg (ORCPT ); Mon, 11 Feb 2019 13:16:36 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Feb 2019 10:16:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,359,1544515200"; d="scan'208";a="125617011" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by orsmga003.jf.intel.com with ESMTP; 11 Feb 2019 10:16:35 -0800 Date: Mon, 11 Feb 2019 10:10:13 -0800 From: Fenghua Yu To: Ingo Molnar Cc: Thomas Gleixner , Ingo Molnar , H Peter Anvin , Dave Hansen , Ashok Raj , Peter Zijlstra , Michael Chan , Ravi V Shankar , Ricardo Neri , linux-kernel , x86 Subject: Re: [PATCH v3 10/10] x86/split_lock: Handle #AC exception for split lock Message-ID: <20190211181013.GA103371@romley-ivt3.sc.intel.com> References: <1549084491-57808-1-git-send-email-fenghua.yu@intel.com> <1549084491-57808-11-git-send-email-fenghua.yu@intel.com> <20190211105339.GA40840@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190211105339.GA40840@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 11, 2019 at 11:53:39AM +0100, Ingo Molnar wrote: > > + do_trap(trapnr, signr, str, regs, error_code, BUS_ADRALN, NULL); > > + } > > +} > > Is there any experience with how frequently this signal is killing > user-space processes on a modern distro? Any expectation of how frequent > such SIGBUS task terminations are going to be in the field? We did pretty intensive testing internally (zero day tests, many engineers and testers use the patches in their dailly work, etc). So far I'm not aware of any user space process hiting split lock issue. I guess GCC or other compilers takes care of the issue already. Inline assembly code may hit the issue if code is not right, but there are fewer inline assembly code in user space. So far we only find two kernel split lock issues and fix them in the first two patches in this patch set. We also find one BIOS split lock issue internally which has been fixed in production BIOS. Thanks. -Fenghua