This is a note to let you know that I've just added the patch titled x86/irq: Fix a race in x86_vector_free_irqs() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-irq-fix-a-race-in-x86_vector_free_irqs.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 111abeba67e0dbdc26537429de9155e4f1d807d8 Mon Sep 17 00:00:00 2001 From: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx> Date: Thu, 31 Dec 2015 16:30:44 +0000 Subject: x86/irq: Fix a race in x86_vector_free_irqs() From: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx> 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 <jiang.liu@xxxxxxxxxxxxxxx> Tested-by: Borislav Petkov <bp@xxxxxxxxx> Tested-by: Joe Lawrence <joe.lawrence@xxxxxxxxxxx> Cc: Jeremiah Mahler <jmmahler@xxxxxxxxx> Cc: andy.shevchenko@xxxxxxxxx Cc: Guenter Roeck <linux@xxxxxxxxxxxx> Link: http://lkml.kernel.org/r/1450880014-11741-3-git-send-email-jiang.liu@xxxxxxxxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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); } } } Patches currently in stable-queue which might be from jiang.liu@xxxxxxxxxxxxxxx are queue-4.4/x86-irq-validate-that-irq-descriptor-is-still-active.patch queue-4.4/x86-irq-remove-outgoing-cpu-from-vector-cleanup-mask.patch queue-4.4/x86-irq-get-rid-of-code-duplication.patch queue-4.4/genirq-validate-action-before-dereferencing-it-in-handle_irq_event_percpu.patch queue-4.4/x86-irq-remove-offline-cpus-from-vector-cleanup.patch queue-4.4/x86-irq-reorganize-the-return-path-in-assign_irq_vector.patch queue-4.4/x86-irq-copy-vectormask-instead-of-an-and-operation.patch queue-4.4/x86-irq-call-irq_force_move_complete-with-irq-descriptor.patch queue-4.4/x86-irq-call-chip-irq_set_affinity-in-proper-context.patch queue-4.4/x86-irq-plug-vector-cleanup-race.patch queue-4.4/x86-irq-do-not-use-apic_chip_data.old_domain-as-temporary-buffer.patch queue-4.4/x86-irq-reorganize-the-search-in-assign_irq_vector.patch queue-4.4/x86-irq-remove-the-cpumask-allocation-from-send_cleanup_vector.patch queue-4.4/x86-irq-fix-a-race-in-x86_vector_free_irqs.patch queue-4.4/x86-irq-check-vector-allocation-early.patch queue-4.4/x86-irq-clear-move_in_progress-before-sending-cleanup-ipi.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html