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 80A5EC433DF for ; Tue, 11 Aug 2020 08:31:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64D5C20658 for ; Tue, 11 Aug 2020 08:31:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728423AbgHKIbP (ORCPT ); Tue, 11 Aug 2020 04:31:15 -0400 Received: from mga06.intel.com ([134.134.136.31]:4022 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728253AbgHKIbO (ORCPT ); Tue, 11 Aug 2020 04:31:14 -0400 IronPort-SDR: EzjumHhA0vfJSzcWhrURY5AzS/N5Y4W+8omHF9qBJuQyM5E8PrtUG1tDZU9WRFCQ7GgtFSNLEy AQYITUjakcsg== X-IronPort-AV: E=McAfee;i="6000,8403,9709"; a="215208699" X-IronPort-AV: E=Sophos;i="5.75,460,1589266800"; d="scan'208";a="215208699" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Aug 2020 01:31:13 -0700 IronPort-SDR: 9zq5r3W0sHvV7xfmGV1CvrJkriUqsZ+mqJiUYv5GjpqQgGo5IZJgXzakXfOefWphenHKWQSh0L MlFQON98Va6Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,460,1589266800"; d="scan'208";a="324699337" Received: from yjin15-mobl1.ccr.corp.intel.com (HELO [10.238.5.239]) ([10.238.5.239]) by orsmga008.jf.intel.com with ESMTP; 11 Aug 2020 01:31:10 -0700 Subject: Re: [PATCH v1 2/2] perf/core: Fake regs for leaked kernel samples To: Peter Zijlstra Cc: mingo@redhat.com, oleg@redhat.com, acme@kernel.org, jolsa@kernel.org, Linux-kernel@vger.kernel.org, ak@linux.intel.com, kan.liang@intel.com, yao.jin@intel.com, alexander.shishkin@linux.intel.com, mark.rutland@arm.com References: <20200731025617.16243-1-yao.jin@linux.intel.com> <20200731025617.16243-2-yao.jin@linux.intel.com> <20200804114900.GI2657@hirez.programming.kicks-ass.net> <4c958d61-11a7-9f3e-9e7d-d733270144a1@linux.intel.com> <20200805124454.GP2657@hirez.programming.kicks-ass.net> <797aa4de-c618-f340-ad7b-cef38c96b035@linux.intel.com> <56957a58-6292-e075-8c30-6230450e3518@linux.intel.com> <20200811075924.GU3982@worktop.programming.kicks-ass.net> From: "Jin, Yao" Message-ID: Date: Tue, 11 Aug 2020 16:31:10 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200811075924.GU3982@worktop.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, On 8/11/2020 3:59 PM, Peter Zijlstra wrote: > On Tue, Aug 11, 2020 at 03:50:43PM +0800, Jin, Yao wrote: >> Could I post v2 which basically refers to your patch but removes some >> conditions since I see some issues in test if we use these conditions. >> >> 1. Remove '!event->attr.exclude_hv || !event->attr.exclude_host || >> !event->attr.exclude_guest' at the entry of sanitize_sample_regs(). >> >> 2. Remove '!attr.exclude_hv || !attr.exclude_host || !attr.exclude_guest' >> at the perf_event_open syscall entry. > > exclude_host, maybe -- due to the dodgy semantics of it, but the others > should definitely be there. > exclude_guest and exclude_hv are tricky too. If we do 'perf record -e cycles:u' in both host and guest, we can see: event->attr.exclude_guest = 0 thus sanitize_sample_regs() returns regs directly even if exclude_kernel = 1. And in guest, exclude_hv = 0, it's out of my expectation too. Thanks Jin Yao