From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755272AbcEaQ2X (ORCPT ); Tue, 31 May 2016 12:28:23 -0400 Received: from foss.arm.com ([217.140.101.70]:60281 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755154AbcEaQ2U (ORCPT ); Tue, 31 May 2016 12:28:20 -0400 Date: Tue, 31 May 2016 17:28:34 +0100 From: Will Deacon To: Julien Grall Cc: mark.rutland@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/3] drivers/perf: arm_pmu: Defer the setting of __oprofile_cpu_pmu Message-ID: <20160531162834.GR24936@arm.com> References: <1464694883-26298-1-git-send-email-julien.grall@arm.com> <1464694883-26298-3-git-send-email-julien.grall@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1464694883-26298-3-git-send-email-julien.grall@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 31, 2016 at 12:41:22PM +0100, Julien Grall wrote: > The global variable __oprofile_cpu_pmu is set before the PMU is fully > initialized. If an error occurs before the end of the initialization, > the PMU will be freed and the variable will contain an invalid pointer. > > This will result in a kernel crash when perf will be used. > > Fix it by moving the setting of __oprofile_cpu_pmu when the PMU is fully > initialized (i.e when it is no longer possible to fail). > > Signed-off-by: Julien Grall > Acked-by: Mark Rutland > --- > drivers/perf/arm_pmu.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) Should this one go to -stable too? Will > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c > index 6401f0c..95614d2 100644 > --- a/drivers/perf/arm_pmu.c > +++ b/drivers/perf/arm_pmu.c > @@ -992,9 +992,6 @@ int arm_pmu_device_probe(struct platform_device *pdev, > > armpmu_init(pmu); > > - if (!__oprofile_cpu_pmu) > - __oprofile_cpu_pmu = pmu; > - > pmu->plat_device = pdev; > > if (node && (of_id = of_match_node(of_table, pdev->dev.of_node))) { > @@ -1030,6 +1027,9 @@ int arm_pmu_device_probe(struct platform_device *pdev, > if (ret) > goto out_destroy; > > + if (!__oprofile_cpu_pmu) > + __oprofile_cpu_pmu = pmu; > + > pr_info("enabled with %s PMU driver, %d counters available\n", > pmu->name, pmu->num_events); > > -- > 1.9.1 >