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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 DF519C3279B for ; Fri, 6 Jul 2018 23:22:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9625C20870 for ; Fri, 6 Jul 2018 23:22:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9625C20870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933059AbeGFXW0 (ORCPT ); Fri, 6 Jul 2018 19:22:26 -0400 Received: from foss.arm.com ([217.140.101.70]:43822 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932650AbeGFXWY (ORCPT ); Fri, 6 Jul 2018 19:22:24 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 29E1C7A9; Fri, 6 Jul 2018 16:22:24 -0700 (PDT) Received: from dupont (dupont.austin.arm.com [10.118.16.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 583D43F2EA; Fri, 6 Jul 2018 16:22:23 -0700 (PDT) Date: Fri, 6 Jul 2018 18:22:22 -0500 From: Kim Phillips To: Mathieu Poirier Cc: peterz@infradead.org, acme@kernel.org, mark.rutland@arm.com, linux-s390@vger.kernel.org, alexander.shishkin@linux.intel.com, will.deacon@arm.com, hpa@zytor.com, heiko.carstens@de.ibm.com, adrian.hunter@intel.com, ast@kernel.org, mingo@redhat.com, linux-arm-kernel@lists.infradead.org, gregkh@linuxfoundation.org, schwidefsky@de.ibm.com, namhyung@kernel.org, tglx@linutronix.de, jolsa@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/7] perf/core: Use ioctl to communicate driver configuration to kernel Message-Id: <20180706182222.8af97a96d613c90415cb202f@arm.com> In-Reply-To: <1530828827-11604-3-git-send-email-mathieu.poirier@linaro.org> References: <1530828827-11604-1-git-send-email-mathieu.poirier@linaro.org> <1530828827-11604-3-git-send-email-mathieu.poirier@linaro.org> Organization: Arm X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 5 Jul 2018 16:13:42 -0600 Mathieu Poirier wrote: Hi Mathieu, > This patch adds the mechanic needed for user space to send PMU specific ^^^^^^^^ I think you meant 'mechanism' here: mechanics fix cars :) > +static void perf_drv_config_replace(struct perf_event *event, void *drv_data) > +{ > + unsigned long flags; > + void *old_drv_data; > + struct pmu_drv_config *drv_config = &event->hw.drv_config; > + > + if (!has_drv_config(event)) > + return; > + > + /* Children take their configuration from their parent */ > + if (event->parent) > + return; > + > + /* Make sure the PMU doesn't get a handle on the data */ > + raw_spin_lock_irqsave(&drv_config->lock, flags); > + > + old_drv_data = drv_config->config; > + drv_config->config = drv_data; > + > + raw_spin_unlock_irqrestore(&drv_config->lock, flags); > + > + /* Free PMU private data allocated by pmu::drv_config_validate() */ > + event->pmu->drv_config_free(old_drv_data); > +} I got this stacktrace whilst testing a perf tool *without* this series applied, running on a kernel *with* this series applied: [ 132.942054] INFO: trying to register non-static key. [ 132.946964] the code is fine but needs lockdep annotation. [ 132.952389] turning off the locking correctness validator. [ 132.957818] CPU: 2 PID: 2835 Comm: perf64-sans Not tainted 4.18.0-rc3-00196-g5b5d957532a8-dirty #146 [ 132.966856] Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Jan 23 2017 [ 132.977527] Call trace: [ 132.979947] dump_backtrace+0x0/0x1c0 [ 132.983567] show_stack+0x24/0x30 [ 132.986845] dump_stack+0x90/0xb4 [ 132.990122] register_lock_class+0x57c/0x580 [ 132.994343] __lock_acquire.isra.12+0x6c/0x980 [ 132.998736] lock_acquire+0x100/0x1e8 [ 133.002357] _raw_spin_lock_irqsave+0x58/0x78 [ 133.006667] perf_drv_config_replace+0x4c/0x80 [ 133.011061] _free_event+0xbc/0x460 [ 133.014507] put_event+0x2c/0x38 [ 133.017697] perf_event_release_kernel+0x1ac/0x300 [ 133.022434] perf_release+0x10/0x20 [ 133.025883] __fput+0xa8/0x1e0 [ 133.028901] ____fput+0x20/0x30 [ 133.032006] task_work_run+0xa0/0xd0 [ 133.035539] do_notify_resume+0x118/0x120 [ 133.039503] work_pending+0x8/0x10 Is a raw_spin_lock_init missing perhaps? Thanks, Kim