Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756373AbcCBABA (ORCPT ); Tue, 1 Mar 2016 19:01:00 -0500 Received: from mail177-1.suw61.mandrillapp.com ([198.2.177.1]:59827 "EHLO mail177-1.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932594AbcCAX6m (ORCPT ); Tue, 1 Mar 2016 18:58:42 -0500 From: Greg Kroah-Hartman Subject: [PATCH 4.4 323/342] x86/irq: Fix a race in x86_vector_free_irqs() X-Mailer: git-send-email 2.7.2 To: Cc: Greg Kroah-Hartman , , Jiang Liu , Borislav Petkov , Joe Lawrence , Jeremiah Mahler , , Guenter Roeck , Thomas Gleixner Message-Id: <20160301234538.306442002@linuxfoundation.org> In-Reply-To: <20160301234527.990448862@linuxfoundation.org> References: <20160301234527.990448862@linuxfoundation.org> X-Report-Abuse: Please forward a copy of this message, including all headers, to abuse@mandrill.com X-Report-Abuse: You can also report abuse here: http://mandrillapp.com/contact/abuse?id=30481620.9f33e1376eb74194886adb1a0937c538 X-Mandrill-User: md_30481620 Date: Tue, 01 Mar 2016 23:55:40 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3256 Lines: 109 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiang Liu commit 111abeba67e0dbdc26537429de9155e4f1d807d8 upstream. 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 Tested-by: Borislav Petkov Tested-by: Joe Lawrence Cc: Jeremiah Mahler Cc: andy.shevchenko@gmail.com Cc: Guenter Roeck Link: http://lkml.kernel.org/r/1450880014-11741-3-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- 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); } } }