Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753657AbcCRNaa (ORCPT ); Fri, 18 Mar 2016 09:30:30 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:49385 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752056AbcCRNa2 (ORCPT ); Fri, 18 Mar 2016 09:30:28 -0400 Subject: Re: linux-next: Crash in arm_pmu_device_probe() due to 'drivers/perf: arm_pmu: make info messages more verbose' To: Dirk Behme References: <56EBA3C3.10907@roeck-us.net> <56EBC7EC.6000907@de.bosch.com> Cc: "linux-kernel@vger.kernel.org" , "linux-next@vger.kernel.org" , Will Deacon From: Guenter Roeck Message-ID: <56EC02F1.90903@roeck-us.net> Date: Fri, 18 Mar 2016 06:30:25 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <56EBC7EC.6000907@de.bosch.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: private@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: private@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: private@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2831 Lines: 98 Hi Dirk, On 03/18/2016 02:18 AM, Dirk Behme wrote: > Hi Guenter, > > On 18.03.2016 07:44, Guenter Roeck wrote: >> Hi, >> >> I am seeing the attached crash when running a realview-pb-a8 image with >> realview_defconfig in qemu. >> bisect wasn't successful, but a commit analysis identified commit >> 'drivers/perf: arm_pmu: make info >> messages more verbose' as the culprit. Reverting this commit fixes the >> problem. >> >> The code roughly looks as follows. >> >> int arm_pmu_device_probe() >> { >> ... >> if (node && ..) { >> } else { >> } >> >> if (ret) { >> pr_info("%s: failed to probe PMU! Error %i\n", >> node->full_name, ret); >> goto out_free; >> } >> .... >> out_free: >> pr_info("%s: failed to register PMU devices! Error %i\n", >> node->full_name, ret); >> .... >> } >> >> Note that 'node' is dereferenced even though it was previously checked >> if it is NULL. >> The configuration I am testing does not use devicetree. >> >> Can you use dev_info() instead ? > > > Does anything like below [1] does work for you? > > If so, could you please share the output? I.e. what it prints in your non-devicetree non-pmu case? > This is what I get: hw perfevents: probing PMU on CPU 0 armv7-pmu armv7-pmu: failed to probe PMU! Error -6 armv7-pmu armv7-pmu: failed to register PMU devices! Error -6 Another option might be to use of_node_full_name() (or even better both dev_info() and of_node_full_name()). Not sure though what you are looking for. '/soc/pmu_a53' doesn't tell (me) much either, and I am not sure I understand the context of the bug description. Why would the kernel try to initialize PMU for a CPU which isn't online ? And if it really does, wouldn't it make more sense to print CPU number and CPU ID instead of a devicetree node name ? Thanks, Guenter > Best regards > > Dirk > > [1] > > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c > index 11bacc7..bda3502 100644 > --- a/drivers/perf/arm_pmu.c > +++ b/drivers/perf/arm_pmu.c > @@ -1002,8 +1002,7 @@ int arm_pmu_device_probe(struct platform_device *pdev, > } > > if (ret) { > - pr_info("%s: failed to probe PMU! Error %i\n", > - node->full_name, ret); > + dev_info(&pdev->dev, "failed to probe PMU! Error %i\n", ret); > goto out_free; > } > > @@ -1023,8 +1022,7 @@ int arm_pmu_device_probe(struct platform_device *pdev, > out_destroy: > cpu_pmu_destroy(pmu); > out_free: > - pr_info("%s: failed to register PMU devices! Error %i\n", > - node->full_name, ret); > + dev_info(&pdev->dev, "failed to register PMU devices! Error %i\n", ret); > kfree(pmu); > return ret; > } > >