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>
diff --git a/arch/x86/pci/vmd.c b/arch/x86/pci/vmd.c
index b814ca6..7948be3 100644
--- a/arch/x86/pci/vmd.c
+++ b/arch/x86/pci/vmd.c
@@ -41,6 +41,7 @@
* @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 list_head node;
struct rcu_head rcu;
struct vmd_irq_list *irq;
+ bool enabled;
unsigned int virq;
};
@@ -122,7 +124,9 @@
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 @@
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);
}