Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758870AbaDJRRf (ORCPT ); Thu, 10 Apr 2014 13:17:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33772 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751235AbaDJRPF (ORCPT ); Thu, 10 Apr 2014 13:15:05 -0400 From: Igor Mammedov To: linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, imammedo@redhat.com, bp@suse.de, paul.gortmaker@windriver.com, JBeulich@suse.com, prarit@redhat.com, drjones@redhat.com, toshi.kani@hp.com, riel@redhat.com, gong.chen@linux.intel.com, andi@firstfloor.org, lenb@kernel.org, rjw@rjwysocki.net, linux-acpi@vger.kernel.org Subject: [PATCH v3 3/5] x86: fix list corruption on CPU hotplug Date: Thu, 10 Apr 2014 19:14:19 +0200 Message-Id: <1397150061-29735-4-git-send-email-imammedo@redhat.com> In-Reply-To: <1397150061-29735-1-git-send-email-imammedo@redhat.com> References: <1397150061-29735-1-git-send-email-imammedo@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org currently if AP wake up is failed, master CPU marks AP as not present in do_boot_cpu() by calling set_cpu_present(cpu, false). That leads to following list corruption on the next physical CPU hotplug: [ 418.107336] WARNING: CPU: 1 PID: 45 at lib/list_debug.c:33 __list_add+0xbe/0xd0() [ 418.115268] list_add corruption. prev->next should be next (ffff88003dc57600), but was ffff88003e20c3a0. (prev=ffff88003e20c3a0). [ 418.123693] Modules linked in: nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6t_REJECT ipt_REJECT cfg80211 xt_conntrack rfkill ee [ 418.138979] CPU: 1 PID: 45 Comm: kworker/u10:1 Not tainted 3.14.0-rc6+ #387 [ 418.149989] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2007 [ 418.165750] Workqueue: kacpi_hotplug acpi_hotplug_work_fn [ 418.166433] 0000000000000021 ffff880038ca7988 ffffffff8159b22d 0000000000000021 [ 418.176460] ffff880038ca79d8 ffff880038ca79c8 ffffffff8106942c ffff880038ca79e8 [ 418.177453] ffff88003e20c3a0 ffff88003dc57600 ffff88003e20c3a0 00000000ffffffea [ 418.178445] Call Trace: [ 418.185811] [] dump_stack+0x49/0x5c [ 418.186440] [] warn_slowpath_common+0x8c/0xc0 [ 418.187192] [] warn_slowpath_fmt+0x46/0x50 [ 418.191231] [] ? acpi_ns_get_node+0xb7/0xc7 [ 418.193889] [] __list_add+0xbe/0xd0 [ 418.196649] [] kobject_add_internal+0x79/0x200 [ 418.208610] [] kobject_add_varg+0x38/0x60 [ 418.213831] [] kobject_add+0x44/0x70 [ 418.229961] [] device_add+0xd0/0x550 [ 418.234991] [] ? pm_runtime_init+0xe5/0xf0 [ 418.250226] [] device_register+0x1e/0x30 [ 418.255296] [] register_cpu+0xe3/0x130 [ 418.266539] [] arch_register_cpu+0x65/0x150 [ 418.285845] [] acpi_processor_hotadd_init+0x5a/0x9b ... Which is caused by the fact that generic_processor_info() allocates logical CPU id by calling: cpu = cpumask_next_zero(-1, cpu_present_mask); which returns id of previously failed to wake up CPU, since its bit is cleared by do_boot_cpu() and as result register_cpu() tries to register another CPU with the same id as already present but failed to be onlined CPU. Taking in account that AP will not do anything if master CPU failed to wake it up, there is no reason to mark that AP as not present and break next cpu hotplug attempts. As a side effect of not marking AP as not present, user would be allowed to online it again later. Signed-off-by: Igor Mammedov --- arch/x86/kernel/smpboot.c | 1 - 1 files changed, 0 insertions(+), 1 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 853473d..e7c15d7 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -822,7 +822,6 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle) schedule(); } } else { - set_cpu_present(cpu, false); per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID; } -- 1.7.1 -- 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/