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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B781EC433EF for ; Tue, 14 Dec 2021 11:00:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233370AbhLNLAC (ORCPT ); Tue, 14 Dec 2021 06:00:02 -0500 Received: from foss.arm.com ([217.140.110.172]:51970 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233336AbhLNLAB (ORCPT ); Tue, 14 Dec 2021 06:00:01 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 1E0C2106F; Tue, 14 Dec 2021 03:00:01 -0800 (PST) Received: from [10.57.84.72] (unknown [10.57.84.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 048533F5A1; Tue, 14 Dec 2021 02:59:59 -0800 (PST) Message-ID: <38b167f2-d055-9618-62b7-c65363d06d29@arm.com> Date: Tue, 14 Dec 2021 10:59:58 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: [PATCH v2 0/4] coresight: etm: Correct PID tracing for non-root namespace To: Leo Yan , Mathieu Poirier , Mike Leach , Alexander Shishkin , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20211213121323.1887180-1-leo.yan@linaro.org> From: Suzuki K Poulose In-Reply-To: <20211213121323.1887180-1-leo.yan@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/12/2021 12:13, Leo Yan wrote: > If a profiling program runs in a non-root PID namespace, if CoreSight > driver enables PID tracing (with contextID), it can lead to mismatching > issue between the context ID traced in hardware (from the root > namespace) and the PIDs gathered by profiling tool (e.g. perf) in its > non-root namespace. > > CoreSight driver has tried to address this issue for the contextID > related interfaces under sysfs, but it misses to prevent user to set > VMID (virtual contextID) for kernel runs in EL2 with VHE; furthermore, > it misses to handle the case when the profiling tool runs in the > non-root PID namespace. > > For this reason, this patch series is to correct contextID tracing for > non-root namespace. After applied this patchset, patch 02 doesn't > permit users to access virtual contextID via sysfs nodes in the non-root > PID namespace, patch 03 and 04 stop to trace PID packet for non-root PID > namespace. > > This patch is dependent on the patchset "pid: Introduce helper > task_is_in_root_ns()" [1]. > > [1] https://lore.kernel.org/lkml/20211208083320.472503-1-leo.yan@linaro.org/ > > > Leo Yan (4): > coresight: etm4x: Add lock for reading virtual context ID comparator > coresight: etm4x: Don't use virtual contextID for non-root PID > namespace > coresight: etm4x: Don't trace PID for non-root PID namespace > coresight: etm3x: Don't trace PID for non-root PID namespace > For the series, Reviewed-by: Suzuki K Poulose