From mboxrd@z Thu Jan 1 00:00:00 1970 From: Igor Mammedov Subject: [PATCH v4 2/5] x86: fix memory corruption in acpi_unmap_lsapic() Date: Mon, 14 Apr 2014 17:11:14 +0200 Message-ID: <1397488277-14865-3-git-send-email-imammedo@redhat.com> References: <1397488277-14865-1-git-send-email-imammedo@redhat.com> Return-path: In-Reply-To: <1397488277-14865-1-git-send-email-imammedo@redhat.com> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-acpi@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 6124f15..2988f69 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -859,8 +859,6 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle) /* was set by cpu_init() */ cpumask_clear_cpu(cpu, cpu_initialized_mask); - - per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID; } /* mark "stuck" area as not stuck */ -- 1.7.1