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Commit 21c80c9f authored by Keith Busch's avatar Keith Busch Committed by Bjorn Helgaas
Browse files

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



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: 97e92306 ("x86/PCI: VMD: Initialize list item in IRQ disable")
Reported-by: default avatarGrzegorz Koczot <grzegorz.koczot@intel.com>
Tested-by: default avatarMiroslaw Drost <miroslaw.drost@intel.com>
Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Acked-by Jon Derrick: <jonathan.derrick@intel.com>
parent 5d0bdf28

arch/x86/pci/vmd.c

+8 −2
Original line number Diff line number Diff line
@@ -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);

	if (vmdirq->enabled) {

		list_del_rcu(&vmdirq->node);

	INIT_LIST_HEAD_RCU(&vmdirq->node);

		vmdirq->enabled = false;

	}

	raw_spin_unlock_irqrestore(&list_lock, flags);

}