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Groups > linux.kernel > #1297484

[Bugfix v2 3/5] x86/irq: Fix a race window in x86_vector_free_irqs()

From Jiang Liu <jiang.liu@linux.intel.com>
Newsgroups linux.kernel
Subject [Bugfix v2 3/5] x86/irq: Fix a race window in x86_vector_free_irqs()
Date 2015-12-23 15:20 +0100
Message-ID <qISqJ-2fv-13@gated-at.bofh.it> (permalink)
References <qHwsh-7Xj-15@gated-at.bofh.it> <qISqJ-2fv-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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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() accesses freed memory.
So use vector_lock to guard all memory free code in x86_vector_free_irqs().

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
---
 arch/x86/kernel/apic/vector.c |   20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index b32c6ef7b4b0..f648fce39d5e 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -228,23 +228,16 @@ static int assign_irq_vector_policy(int irq, int node,
 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);
+	int cpu, vector = data->cfg.vector;
 
-	vector = data->cfg.vector;
+	BUG_ON(!vector);
 	for_each_cpu_and(cpu, data->domain, cpu_online_mask)
 		per_cpu(vector_irq, cpu)[vector] = VECTOR_UNUSED;
-
 	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) {
@@ -257,7 +250,7 @@ static void clear_irq_vector(int irq, struct apic_chip_data *data)
 		}
 	}
 	data->move_in_progress = 0;
-	raw_spin_unlock_irqrestore(&vector_lock, flags);
+	cpumask_clear(data->old_domain);
 }
 
 void init_irq_alloc_info(struct irq_alloc_info *info,
@@ -279,18 +272,21 @@ static void x86_vector_free_irqs(struct irq_domain *domain,
 				 unsigned int virq, unsigned int nr_irqs)
 {
 	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);
+			irq_domain_reset_irq_data(irq_data);
+			raw_spin_unlock_irqrestore(&vector_lock, flags);
 #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);
 		}
 	}
 }
-- 
1.7.10.4

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Thread

Re: [lkp] [x86/irq] 4c24cee6b2: IP-Config: Auto-configuration of  network failed Jiang Liu <jiang.liu@linux.intel.com> - 2015-12-14 07:40 +0100
  Re: [LKP] [lkp] [x86/irq] 4c24cee6b2: IP-Config: Auto-configuration of network failed "Huang\, Ying" <ying.huang@intel.com> - 2015-12-14 08:00 +0100
    Re: [LKP] [lkp] [x86/irq] 4c24cee6b2: IP-Config: Auto-configuration  of network failed Borislav Petkov <bp@alien8.de> - 2015-12-14 11:00 +0100
      Re: [LKP] [lkp] [x86/irq] 4c24cee6b2: IP-Config: Auto-configuration  of network failed Jiang Liu <jiang.liu@linux.intel.com> - 2015-12-15 09:00 +0100
        Re: [LKP] [lkp] [x86/irq] 4c24cee6b2: IP-Config: Auto-configuration  of network failed Borislav Petkov <bp@alien8.de> - 2015-12-15 11:10 +0100
        Re: [LKP] [lkp] [x86/irq] 4c24cee6b2: IP-Config: Auto-configuration  of network failed Thomas Gleixner <tglx@linutronix.de> - 2015-12-19 21:40 +0100
          [Bugfix v2 5/5] x86/irq: Trivial cleanups for x86 vector allocation code Jiang Liu <jiang.liu@linux.intel.com> - 2015-12-23 15:20 +0100
          [Bugfix v2 1/5] x86/irq: Do not reuse struct apic_chip_data.old_domain as temporary buffer Jiang Liu <jiang.liu@linux.intel.com> - 2015-12-23 15:20 +0100
            [Bugfix v2 3/5] x86/irq: Fix a race window in x86_vector_free_irqs() Jiang Liu <jiang.liu@linux.intel.com> - 2015-12-23 15:20 +0100
              Re: [Bugfix v2 3/5] x86/irq: Fix a race window in  x86_vector_free_irqs() Thomas Gleixner <tglx@linutronix.de> - 2015-12-29 14:50 +0100
            [Bugfix v2 2/5] x86/irq: Enhance __assign_irq_vector() to rollback in case of failure Jiang Liu <jiang.liu@linux.intel.com> - 2015-12-23 15:20 +0100
              Re: [Bugfix v2 2/5] x86/irq: Enhance __assign_irq_vector() to rollback  in case of failure Thomas Gleixner <tglx@linutronix.de> - 2015-12-30 20:00 +0100
            [Bugfix v2 4/5] x86/irq: Fix a race condition between vector assigning and cleanup Jiang Liu <jiang.liu@linux.intel.com> - 2015-12-23 15:20 +0100
              Re: [Bugfix v2 4/5] x86/irq: Fix a race condition between vector  assigning and cleanup Borislav Petkov <bp@alien8.de> - 2015-12-23 19:50 +0100
              Re: [Bugfix v2 4/5] x86/irq: Fix a race condition between vector  assigning and cleanup Thomas Gleixner <tglx@linutronix.de> - 2015-12-30 18:30 +0100
              Re: [Bugfix v2 4/5] x86/irq: Fix a race condition between vector  assigning and cleanup Thomas Gleixner <tglx@linutronix.de> - 2015-12-31 00:00 +0100
            Re: [Bugfix v2 1/5] x86/irq: Do not reuse struct  apic_chip_data.old_domain as temporary buffer Borislav Petkov <bp@alien8.de> - 2015-12-23 20:20 +0100
            Re: [Bugfix v2 1/5] x86/irq: Do not reuse struct  apic_chip_data.old_domain as temporary buffer Jeremiah Mahler <jmmahler@gmail.com> - 2015-12-24 06:20 +0100
              Re: [Bugfix v2 1/5] x86/irq: Do not reuse struct  apic_chip_data.old_domain as temporary buffer Jiang Liu <jiang.liu@linux.intel.com> - 2015-12-28 09:30 +0100
                Re: [Bugfix v2 1/5] x86/irq: Do not reuse struct  apic_chip_data.old_domain as temporary buffer Jeremiah Mahler <jmmahler@gmail.com> - 2015-12-29 04:30 +0100
            Re: [Bugfix v2 1/5] x86/irq: Do not reuse struct  apic_chip_data.old_domain as temporary buffer Joe Lawrence <joe.lawrence@stratus.com> - 2015-12-24 15:40 +0100

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