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x86/PCI: VMD: Fix infinite loop executing irq's

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We can't initialize the list head on deletion as this causes the node to
point to itself, which causes an infinite loop if vmd_irq() happens to be
servicing that node.

The list initialization was trying to fix a bug from multiple calls to
disable the same IRQ.  Fix this instead by having the VMD driver track if
the interrupt is enabled.

[bhelgaas: changelog, add "Fixes"]
Fixes: 97e923063575 ("x86/PCI: VMD: Initialize list item in IRQ disable")
Reported-by: Grzegorz Koczot <grzegorz.koczot@intel.com>
Tested-by: Miroslaw Drost <miroslaw.drost@intel.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by Jon Derrick: <jonathan.derrick@intel.com>
This commit is contained in:
Keith Busch 2016-08-23 16:36:42 -05:00 committed by Bjorn Helgaas
parent 5d0bdf2867
commit 21c80c9fef
1 changed files with 8 additions and 2 deletions
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10
arch/x86/pci/vmd.c
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@ -41,6 +41,7 @@ static DEFINE_RAW_SPINLOCK(list_lock);
* @node: list item for parent traversal.
* @rcu: RCU callback item for freeing.
* @irq: back pointer to parent.
* @enabled: true if driver enabled IRQ
* @virq: the virtual IRQ value provided to the requesting driver.
*
* Every MSI/MSI-X IRQ requested for a device in a VMD domain will be mapped to
@ -50,6 +51,7 @@ struct vmd_irq {
struct list_head node;
struct rcu_head rcu;
struct vmd_irq_list *irq;
bool enabled;
unsigned int virq;
};
@ -122,7 +124,9 @@ static void vmd_irq_enable(struct irq_data *data)
unsigned long flags;
raw_spin_lock_irqsave(&list_lock, flags);
WARN_ON(vmdirq->enabled);
list_add_tail_rcu(&vmdirq->node, &vmdirq->irq->irq_list);
vmdirq->enabled = true;
raw_spin_unlock_irqrestore(&list_lock, flags);
data->chip->irq_unmask(data);
@ -136,8 +140,10 @@ static void vmd_irq_disable(struct irq_data *data)
data->chip->irq_mask(data);
raw_spin_lock_irqsave(&list_lock, flags);
list_del_rcu(&vmdirq->node);
INIT_LIST_HEAD_RCU(&vmdirq->node);
if (vmdirq->enabled) {
list_del_rcu(&vmdirq->node);
vmdirq->enabled = false;
}
raw_spin_unlock_irqrestore(&list_lock, flags);
}