From 21c80c9fefc3db10b530a96eb0478c29eb28bf77 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Tue, 23 Aug 2016 16:36:42 -0500 Subject: 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: 97e923063575 ("x86/PCI: VMD: Initialize list item in IRQ disable") Reported-by: Grzegorz Koczot Tested-by: Miroslaw Drost Signed-off-by: Keith Busch Signed-off-by: Bjorn Helgaas Acked-by Jon Derrick: --- arch/x86/pci/vmd.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'arch/x86/pci') diff --git a/arch/x86/pci/vmd.c b/arch/x86/pci/vmd.c index b814ca675131..7948be342ee9 100644 --- a/arch/x86/pci/vmd.c +++ b/arch/x86/pci/vmd.c @@ -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); } -- cgit v1.2.3