From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753988AbdKNMnJ (ORCPT ); Tue, 14 Nov 2017 07:43:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48674 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752704AbdKNMnB (ORCPT ); Tue, 14 Nov 2017 07:43:01 -0500 From: Prarit Bhargava To: linux-kernel@vger.kernel.org Cc: Prarit Bhargava , Andi Kleen , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Peter Zijlstra , Dave Hansen , Piotr Luc , Kan Liang , Borislav Petkov , Stephane Eranian , Arvind Yadav , Andy Lutomirski , Christian Borntraeger , "Kirill A. Shutemov" , Tom Lendacky , He Chen , Mathias Krause , Tim Chen , Vitaly Kuznetsov Subject: [PATCH v6 0/3] Fix panic in logical packages calculation Date: Tue, 14 Nov 2017 07:42:54 -0500 Message-Id: <20171114124257.22013-1-prarit@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Tue, 14 Nov 2017 12:43:01 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A system booted with a small number of cores enabled per package panics because the estimate of __max_logical_packages is too low. This occurs when the total number of active cores across all packages is less than the maximum core count for a single package. Andi noted that the logical_packages calculation wastes 128k on 64-bit x86 systems and posted patches to fix the allocation. His patches result in significant memory size savings, and I have put my fix on top of those patches. Here's an example of the panic: smpboot: Booting Node 1, Processors #1 OK smpboot: Package 1 of CPU 1 exceeds BIOS package data 1. ------------[ cut here ]------------ kernel BUG at arch/x86/kernel/cpu/common.c:1087! invalid opcode: 0000 [#1] SMP Modules linked in: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.14.0-rc2+ #4 This was tested by dropping the number of active cores across all packages to reproduce the bug above. Additional testing included 2 socket and 4 socket systems and hotplugging entire sockets in different order. Signed-off-by: Andi Kleen Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: Peter Zijlstra Cc: Andi Kleen Cc: Dave Hansen Cc: Piotr Luc Cc: Kan Liang Cc: Borislav Petkov Cc: Stephane Eranian Cc: Prarit Bhargava Cc: Arvind Yadav Cc: Andy Lutomirski Cc: Christian Borntraeger Cc: "Kirill A. Shutemov" Cc: Tom Lendacky Cc: He Chen Cc: Mathias Krause Cc: Tim Chen Cc: Vitaly Kuznetsov Andi Kleen (2): perf/x86/intel/uncore: Cache logical pkg id in uncore driver x86/topology: Avoid wasting 128k for package id array Prarit Bhargava (1): x86/smpboot: Fix __max_logical_packages estimate arch/x86/events/intel/uncore.c | 4 +- arch/x86/events/intel/uncore.h | 2 +- arch/x86/events/intel/uncore_snbep.c | 2 +- arch/x86/include/asm/processor.h | 1 + arch/x86/kernel/smpboot.c | 130 +++++++++++------------------------ 5 files changed, 44 insertions(+), 95 deletions(-) -- 2.15.0.rc0.39.g2f0e14e64