4.2.8-ckt10 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------ From: Jiang Liu <[email protected]> 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 <[email protected]> Tested-by: Borislav Petkov <[email protected]> Tested-by: Joe Lawrence <[email protected]> Cc: Jeremiah Mahler <[email protected]> Cc: [email protected] Cc: Guenter Roeck <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]> [ kamal: backport to 4.2-stable; prereq for 1bdb897 x86/apic: Handle zero vector gracefully in clear_vector_irq() ] Signed-off-by: Kamal Mostafa <[email protected]> --- arch/x86/kernel/apic/vector.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c index ea4ba83..7889bec 100644 --- a/arch/x86/kernel/apic/vector.c +++ b/arch/x86/kernel/apic/vector.c @@ -225,9 +225,7 @@ static int assign_irq_vector_policy(int irq, int node, static void clear_irq_vector(int irq, struct apic_chip_data *data) { int cpu, vector; - unsigned long flags; - 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, struct apic_chip_data *data) 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; - } for_each_cpu_and(cpu, data->old_domain, cpu_online_mask) { for (vector = FIRST_EXTERNAL_VECTOR; vector < NR_VECTORS; @@ -252,7 +248,6 @@ static void clear_irq_vector(int irq, struct apic_chip_data *data) } } data->move_in_progress = 0; - raw_spin_unlock_irqrestore(&vector_lock, flags); } void init_irq_alloc_info(struct irq_alloc_info *info, @@ -273,19 +268,24 @@ void copy_irq_alloc_info(struct irq_alloc_info *dst, struct irq_alloc_info *src) 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); } } } -- 2.7.4
