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authorKeith Busch <keith.busch@intel.com>2016-08-23 16:36:42 -0500
committerBjorn Helgaas <bhelgaas@google.com>2016-08-23 16:36:42 -0500
commit21c80c9fefc3db10b530a96eb0478c29eb28bf77 (patch)
treef04f76432839643639668f8b9e011fa3dffdf741 /arch
parent5d0bdf2867825a92c0a563957a2fb059149ab0d4 (diff)
downloadlinux-21c80c9fefc3db10b530a96eb0478c29eb28bf77.tar.bz2
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 <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>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/pci/vmd.c10
1 files changed, 8 insertions, 2 deletions
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);
}