From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751487AbaCaULt (ORCPT ); Mon, 31 Mar 2014 16:11:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:65480 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751398AbaCaULp (ORCPT ); Mon, 31 Mar 2014 16:11:45 -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 Subject: [PATCH v2 5/5] x86: fix memory corruption in acpi_unmap_lsapic() Date: Mon, 31 Mar 2014 22:09:25 +0200 Message-Id: <1396296565-19709-6-git-send-email-imammedo@redhat.com> In-Reply-To: <1396296565-19709-1-git-send-email-imammedo@redhat.com> References: <1396296565-19709-1-git-send-email-imammedo@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org if during CPU hotplug master CPU failed to wake up AP it set percpu x86_cpu_to_apicid to BAD_APICID=0xFFFF for AP. However following attempt to unplug that CPU will lead to out of bound write access to __apicid_to_node[] which is 32768 items long on x86_64 kernel. So drop setting x86_cpu_to_apicid to BAD_APICID in do_boot_cpu() and allow acpi_processor_remove()->acpi_unmap_lsapic() cleanly remove CPU. Signed-off-by: Igor Mammedov --- arch/x86/kernel/smpboot.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 0400418..2b0b8ee 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -796,8 +796,6 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle) */ schedule(); } - } else { - per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID; } /* mark "stuck" area as not stuck */ -- 1.7.1