From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751882AbdIUWBX (ORCPT ); Thu, 21 Sep 2017 18:01:23 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:33376 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751707AbdIUWBV (ORCPT ); Thu, 21 Sep 2017 18:01:21 -0400 Subject: Re: [PATCH -tip v3 0/7] kprobes/x86: Preempt related enhancements To: Masami Hiramatsu , Ingo Molnar , References: <150581509713.32348.1905525476438163954.stgit@devbox> CC: , Steven Rostedt , , Peter Zijlstra , Ananth N Mavinakayanahalli , Thomas Gleixner , "H . Peter Anvin" , "Paul E . McKenney" , Alexei Starovoitov From: Alexei Starovoitov Message-ID: <099fb3cf-b439-4a5d-b8c2-de691a32ed06@fb.com> Date: Thu, 21 Sep 2017 15:00:35 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <150581509713.32348.1905525476438163954.stgit@devbox> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [2620:10d:c090:180::1:9b42] X-ClientProxiedBy: MWHPR18CA0047.namprd18.prod.outlook.com (2603:10b6:320:31::33) To DM3PR15MB0969.namprd15.prod.outlook.com (2603:10b6:0:10::23) X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 84eff89e-1252-49a4-4aeb-08d5013c32bf X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(300000500095)(300135000095)(300000501095)(300135300095)(22001)(300000502095)(300135100095)(2017030254152)(300000503095)(300135400095)(2017052603199)(201703131423075)(201703031133081)(201702281549075)(300000504095)(300135200095)(300000505095)(300135600095)(300000506095)(300135500095);SRVR:DM3PR15MB0969; 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This actually includes > many enhancements/fixes from the 2nd version, which is > > https://lkml.org/lkml/2017/9/11/482 > > With the previous patch, lkp-bot reported that an issue > ( https://lkml.org/lkml/2017/9/14/3 ) and I couldn't > reproduce it. However, I found a suspicious bug and fixed > it ([2/7]). > > Also, while I was checking the correct condition for > *probe handlers in Documentation/kprobes.txt, I also > found that current implementations for ftrace-based kprobe > and optprobe were mis-reading the document. >>>From the document, handlers must be run with preempt- > disabled, but interrupt disabling is not guaranteed. > So in the middle of this series, patches ([4/7],[5/7], > [6/7]) adding preempt-disabling and removing irq-disabling. > > And at last, I placed the original patch (Enable optprobe > with CONFIG_PREEMPT). > > The others are just for making sure this fix works well. > - [1/7] is just adding preemptible checker in kprobe > smake tests so that we can easily find mistake. > - [3/7] is adding an assert if user tries to change > execution path in optprobe, which is obviously > prohibited in the document (there also be how to > avoid it.) all patches look great to me. Acked-by: Alexei Starovoitov