Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753093AbaG2JY5 (ORCPT ); Tue, 29 Jul 2014 05:24:57 -0400 Received: from mga11.intel.com ([192.55.52.93]:50328 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752240AbaG2JY4 (ORCPT ); Tue, 29 Jul 2014 05:24:56 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,755,1400050800"; d="scan'208";a="568822416" From: Wanpeng Li To: Cc: Ingo Molnar , Peter Zijlstra , x86@kernel.org, Borislav Petkov , Yasuaki Ishimatsu , David Rientjes , Prarit Bhargava , Steven Rostedt , Jan Kiszka , Toshi Kani , linux-kernel@vger.kernel.org, Zhang Yang , Konrad Rzeszutek Wilk , Wanpeng Li Subject: [PATCH v4] x86, hotplug: fix llc shared map unreleased during cpu hotplug Date: Tue, 29 Jul 2014 17:24:43 +0800 Message-Id: <1406625883-4972-1-git-send-email-wanpeng.li@linux.intel.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [..] find_busiest_group PGD 5a9d5067 PUD 13067 PMD 0 Oops: 0000 [#3] SMP [...] Call Trace: load_balance ? _raw_spin_unlock_irqrestore idle_balance __schedule schedule schedule_timeout ? lock_timer_base schedule_timeout_uninterruptible msleep lock_device_hotplug_sysfs online_store dev_attr_store sysfs_write_file vfs_write SyS_write system_call_fastpath Last level cache shared map is built during cpu up and build sched domain routine takes advantage of it to setup sched domain cpu topology, however, llc shared map is unreleased during cpu disable which lead to invalid sched domain cpu topology. This patch fix it by release llc shared map correctly during cpu disable. Reviewed-by: Yasuaki Ishimatsu Signed-off-by: Wanpeng Li --- v1 -> v2: * fix subject line v2 -> v3: * simplify backtrace arch/x86/kernel/smpboot.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 5492798..0134ec7 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1292,6 +1292,9 @@ static void remove_siblinginfo(int cpu) for_each_cpu(sibling, cpu_sibling_mask(cpu)) cpumask_clear_cpu(cpu, cpu_sibling_mask(sibling)); + for_each_cpu(sibling, cpu_llc_shared_mask(cpu)) + cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling)); + cpumask_clear(cpu_llc_shared_mask(cpu)); cpumask_clear(cpu_sibling_mask(cpu)); cpumask_clear(cpu_core_mask(cpu)); c->phys_proc_id = 0; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/