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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 BA6C4C433DB for ; Mon, 8 Feb 2021 21:23:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6AAD664E6C for ; Mon, 8 Feb 2021 21:23:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236687AbhBHVXN (ORCPT ); Mon, 8 Feb 2021 16:23:13 -0500 Received: from mga11.intel.com ([192.55.52.93]:26309 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236599AbhBHUMT (ORCPT ); Mon, 8 Feb 2021 15:12:19 -0500 IronPort-SDR: /2UpJp6CCowbRitHjeLFTPCOKK5ar+DwkpPiUpRwTJZd/YqgecYhafHP3bbJh11R89zyTwwT2N PonpbnHMdbVA== X-IronPort-AV: E=McAfee;i="6000,8403,9889"; a="178262980" X-IronPort-AV: E=Sophos;i="5.81,163,1610438400"; d="scan'208";a="178262980" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2021 12:11:36 -0800 IronPort-SDR: FvGwoSxWRzF4E22TLsPk5Oq5ub9aCuUNYVsQ16qDvTKMmDkANo5/BNExWtb6eKkve17QuOBXbk Inp+fnpUwetw== X-IronPort-AV: E=Sophos;i="5.81,163,1610438400"; d="scan'208";a="374625160" Received: from yyu32-mobl1.amr.corp.intel.com (HELO [10.251.11.33]) ([10.251.11.33]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2021 12:11:34 -0800 Subject: Re: [PATCH v19 06/25] x86/cet: Add control-protection fault handler To: Borislav Petkov Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu , Michael Kerrisk References: <20210203225547.32221-1-yu-cheng.yu@intel.com> <20210203225547.32221-7-yu-cheng.yu@intel.com> <20210205135927.GH17488@zn.tnic> <2d829cba-784e-635a-e0c5-a7b334fa9b40@intel.com> <20210208182009.GE18227@zn.tnic> <690bc3b9-2890-e68d-5e4b-cda5c21b496b@intel.com> <20210208185341.GF18227@zn.tnic> <0e0c9e9d-aee1-ad1e-6c63-21b58a52163f@intel.com> <20210208194854.GI18227@zn.tnic> From: "Yu, Yu-cheng" Message-ID: Date: Mon, 8 Feb 2021 12:11:32 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <20210208194854.GI18227@zn.tnic> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/8/2021 11:48 AM, Borislav Petkov wrote: > On Mon, Feb 08, 2021 at 11:23:18AM -0800, Yu, Yu-cheng wrote: >> exc_general_protection() and do_trap() both call show_signal(), which >> then calls printk_ratelimit(). > > You could've done some git archeology and could've found > > abd4f7505baf ("x86: i386-show-unhandled-signals-v3") > > which explains why that ratelimiting is needed. > >> For example, if a shell script, in a loop re-starts an app when it >> exits, and the app is causing control-protection fault. The log >> messages should be rate limited. > > I think you should be able to get where I'm going with this, by now: > please put a comment over the ratelimiting to explain why it is there, > just like the above commit explains. I will add that. > > Thx. >