From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754635AbbLaQeW (ORCPT ); Thu, 31 Dec 2015 11:34:22 -0500 Received: from www.linutronix.de ([62.245.132.108]:46660 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751359AbbLaQbo (ORCPT ); Thu, 31 Dec 2015 11:31:44 -0500 Message-Id: <20151231160106.151314722@linutronix.de> User-Agent: quilt/0.63-1 Date: Thu, 31 Dec 2015 16:30:44 -0000 From: Thomas Gleixner To: LKML Cc: Ingo Molnar , Peter Anvin , Jiang Liu , Joe Lawrence , Jeremiah Mahler , Borislav Petkov , andy.shevchenko@gmail.com, Guenter Roeck Subject: [patch 01/14] x86/irq: Fix a race in x86_vector_free_irqs() References: <20151231155849.772553760@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=x86-irq-fix-a-race-window-in-x86_vector_free_irqs.patch X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org There's a race condition between x86_vector_free_irqs() { free_apic_chip_data(irq_data->chip_data); xxxxx //irq_data->chip_data has been freed, but the pointer //hasn't been reset yet irq_domain_reset_irq_data(irq_data); } and smp_irq_move_cleanup_interrupt() { raw_spin_lock(&vector_lock); data = apic_chip_data(irq_desc_get_irq_data(desc)); access data->xxxx // may access freed memory raw_spin_unlock(&desc->lock); } which may cause smp_irq_move_cleanup_interrupt() to access freed memory. Call irq_domain_reset_irq_data(), which clears the pointer with vector lock held. [ tglx: Free memory outside of lock held region. ] Signed-off-by: Jiang Liu Cc: Jeremiah Mahler Cc: Borislav Petkov Cc: andy.shevchenko@gmail.com Cc: Guenter Roeck Cc: Joe Lawrence Link: http://lkml.kernel.org/r/1450880014-11741-3-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner --- arch/x86/kernel/apic/vector.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) --- a/arch/x86/kernel/apic/vector.c +++ b/arch/x86/kernel/apic/vector.c @@ -224,10 +224,8 @@ static int assign_irq_vector_policy(int static void clear_irq_vector(int irq, struct apic_chip_data *data) { struct irq_desc *desc; - unsigned long flags; int cpu, vector; - raw_spin_lock_irqsave(&vector_lock, flags); BUG_ON(!data->cfg.vector); vector = data->cfg.vector; @@ -237,10 +235,8 @@ static void clear_irq_vector(int irq, st data->cfg.vector = 0; cpumask_clear(data->domain); - if (likely(!data->move_in_progress)) { - raw_spin_unlock_irqrestore(&vector_lock, flags); + if (likely(!data->move_in_progress)) return; - } desc = irq_to_desc(irq); for_each_cpu_and(cpu, data->old_domain, cpu_online_mask) { @@ -253,7 +249,6 @@ static void clear_irq_vector(int irq, st } } data->move_in_progress = 0; - raw_spin_unlock_irqrestore(&vector_lock, flags); } void init_irq_alloc_info(struct irq_alloc_info *info, @@ -274,19 +269,24 @@ void copy_irq_alloc_info(struct irq_allo static void x86_vector_free_irqs(struct irq_domain *domain, unsigned int virq, unsigned int nr_irqs) { + struct apic_chip_data *apic_data; struct irq_data *irq_data; + unsigned long flags; int i; for (i = 0; i < nr_irqs; i++) { irq_data = irq_domain_get_irq_data(x86_vector_domain, virq + i); if (irq_data && irq_data->chip_data) { + raw_spin_lock_irqsave(&vector_lock, flags); clear_irq_vector(virq + i, irq_data->chip_data); - free_apic_chip_data(irq_data->chip_data); + apic_data = irq_data->chip_data; + irq_domain_reset_irq_data(irq_data); + raw_spin_unlock_irqrestore(&vector_lock, flags); + free_apic_chip_data(apic_data); #ifdef CONFIG_X86_IO_APIC if (virq + i < nr_legacy_irqs()) legacy_irq_data[virq + i] = NULL; #endif - irq_domain_reset_irq_data(irq_data); } } }