Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752855AbcKHO5e (ORCPT ); Tue, 8 Nov 2016 09:57:34 -0500 Received: from mx0a-000f0801.pphosted.com ([67.231.144.122]:36457 "EHLO mx0a-000f0801.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751266AbcKHO5c (ORCPT ); Tue, 8 Nov 2016 09:57:32 -0500 Subject: Re: [RFC PATCH] perf/x86/intel/rapl: avoid access unallocate memory To: Thomas Gleixner References: <20161102122557.qs4rl6mb7n7l7j7p@linutronix.de> <24e69019-60d0-29e7-e31f-c6f00f9ed98a@brocade.com> <58e229e2-91f4-a97f-1b9f-089f48ef994a@brocade.com> From: "Charles (Chas) Williams" CC: Sebastian Andrzej Siewior , , , "M. Vefa Bicakci" Message-ID: <86609338-2b45-ed7e-fb07-99421e43a2f1@brocade.com> Date: Tue, 8 Nov 2016 09:57:19 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: hq1wp-excas11.corp.brocade.com (10.70.36.102) To BRMWP-EXMB12.corp.brocade.com (172.16.59.130) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-11-08_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1609300000 definitions=main-1611080261 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2398 Lines: 55 On 11/08/2016 09:31 AM, Thomas Gleixner wrote: > On Tue, 8 Nov 2016, Charles (Chas) Williams wrote: >> [ 0.016335] topology_update_package_map: apicid 0 pkg 0 cpu 0 >> [ 0.016398] smpboot: APIC(0) Converting physical 0 to logical >> package 0, cpu 0 (ffff88023fc0a040) >> [ 0.016399] topology_update_package_map: apicid 1 pkg 1 cpu 1 >> [ 0.016462] smpboot: APIC(1) Converting physical 1 to logical >> package 1, cpu 1 (ffff88023fd0a040) >> >> So, I don't know where apic->cpu_present_to_apicid(cpu) is getting its >> apicid but it certainly doesn't seem to the match the apicid in the >> CPU's registers. For whatever reason, my VMware system is reporting >> that the second CPU has a local APIC ID of 2: > > The initial information comes from MP tables or ACPI. > >> [ 0.009115] identify_cpu: cpu_index 0 phys_proc_id is now 0, >> apicid 0, initial_apicid 0 >> ... >> [ 0.237401] identify_cpu: cpu_index 1 phys_proc_id is now 2, >> apicid 2, initial_apicid 2 > > And the CPUID emulation tells something different. Sigh! > >> I was thinking it might be better to call topology_update_package_map() >> at the bottom of identify_cpu() to setup the secondary CPU's. The boot >> cpu could be setup during smp_init_package_map(). > > Perhaps, but that does not make the inconsistencies go away.... By the time I know it's not consistent, there isn't anything I can do about it. I can't update the table to remove the bad information. The other alternative, is to trust the ACPI and just update the cpu_data's apicid in identify_cpu() to the value from the table. The earlier kernels didn't seem to rely as much on this information. But it does appear to be "wrong" in the APIC table. From acpidump: [02Ch 0044 1] Subtable Type : 00 [Processor Local APIC] [02Dh 0045 1] Length : 08 [02Eh 0046 1] Processor ID : 00 [02Fh 0047 1] Local Apic ID : 00 [030h 0048 4] Flags (decoded below) : 00000001 Processor Enabled : 1 [034h 0052 1] Subtable Type : 00 [Processor Local APIC] [035h 0053 1] Length : 08 [036h 0054 1] Processor ID : 01 [037h 0055 1] Local Apic ID : 01 [038h 0056 4] Flags (decoded below) : 00000001 Processor Enabled : 1