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PCI: vmd: Prevent recursive locking on interrupt allocation

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Tejas reported the following recursive locking issue:

 swapper/0/1 is trying to acquire lock:
 ffff8881074fd0a0 (&md->mutex){+.+.}-{3:3}, at: msi_get_virq+0x30/0xc0
 
 but task is already holding lock:
 ffff8881017cd6a0 (&md->mutex){+.+.}-{3:3}, at: __pci_enable_msi_range+0xf2/0x290
 
 stack backtrace:
  __mutex_lock+0x9d/0x920
  msi_get_virq+0x30/0xc0
  pci_irq_vector+0x26/0x30
  vmd_msi_init+0xcc/0x210
  msi_domain_alloc+0xbf/0x150
  msi_domain_alloc_irqs_descs_locked+0x3e/0xb0
  __pci_enable_msi_range+0x155/0x290
  pci_alloc_irq_vectors_affinity+0xba/0x100
  pcie_port_device_register+0x307/0x550
  pcie_portdrv_probe+0x3c/0xd0
  pci_device_probe+0x95/0x110

This is caused by the VMD MSI code which does a lookup of the Linux
interrupt number for an VMD managed MSI[X] vector. The lookup function
tries to acquire the already held mutex.

Avoid that by caching the Linux interrupt number at initialization time
instead of looking it up over and over.

Fixes: 82ff8e6b78 ("PCI/MSI: Use msi_get_virq() in pci_get_vector()")
Reported-by: "Surendrakumar Upadhyay, TejaskumarX" <tejaskumarx.surendrakumar.upadhyay@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: "Surendrakumar Upadhyay, TejaskumarX" <tejaskumarx.surendrakumar.upadhyay@intel.com>
Cc: linux-pci@vger.kernel.org
Link: https://lore.kernel.org/r/87a6euub2a.ffs@tglx
This commit is contained in:
Thomas Gleixner 2022-02-13 14:54:05 +01:00
parent cfb92440ee
commit ba1366f3d0
1 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/pci/controller/vmd.c
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@ -99,11 +99,13 @@ struct vmd_irq {
* @srcu: SRCU struct for local synchronization.
* @count: number of child IRQs assigned to this vector; used to track
* sharing.
* @virq: The underlying VMD Linux interrupt number
*/
struct vmd_irq_list {
struct list_head irq_list;
struct srcu_struct srcu;
unsigned int count;
unsigned int virq;
};
struct vmd_dev {
@ -253,7 +255,6 @@ static int vmd_msi_init(struct irq_domain *domain, struct msi_domain_info *info,
struct msi_desc *desc = arg->desc;
struct vmd_dev *vmd = vmd_from_bus(msi_desc_to_pci_dev(desc)->bus);
struct vmd_irq *vmdirq = kzalloc(sizeof(*vmdirq), GFP_KERNEL);
unsigned int index, vector;
if (!vmdirq)
return -ENOMEM;
@ -261,10 +262,8 @@ static int vmd_msi_init(struct irq_domain *domain, struct msi_domain_info *info,
INIT_LIST_HEAD(&vmdirq->node);
vmdirq->irq = vmd_next_irq(vmd, desc);
vmdirq->virq = virq;
index = index_from_irqs(vmd, vmdirq->irq);
vector = pci_irq_vector(vmd->dev, index);
irq_domain_set_info(domain, virq, vector, info->chip, vmdirq,
irq_domain_set_info(domain, virq, vmdirq->irq->virq, info->chip, vmdirq,
handle_untracked_irq, vmd, NULL);
return 0;
}
@ -685,7 +684,8 @@ static int vmd_alloc_irqs(struct vmd_dev *vmd)
return err;
INIT_LIST_HEAD(&vmd->irqs[i].irq_list);
err = devm_request_irq(&dev->dev, pci_irq_vector(dev, i),
vmd->irqs[i].virq = pci_irq_vector(dev, i);
err = devm_request_irq(&dev->dev, vmd->irqs[i].virq,
vmd_irq, IRQF_NO_THREAD,
vmd->name, &vmd->irqs[i]);
if (err)
@ -969,7 +969,7 @@ static int vmd_suspend(struct device *dev)
int i;
for (i = 0; i < vmd->msix_count; i++)
devm_free_irq(dev, pci_irq_vector(pdev, i), &vmd->irqs[i]);
devm_free_irq(dev, vmd->irqs[i].virq, &vmd->irqs[i]);
return 0;
}
@ -981,7 +981,7 @@ static int vmd_resume(struct device *dev)
int err, i;
for (i = 0; i < vmd->msix_count; i++) {
err = devm_request_irq(dev, pci_irq_vector(pdev, i),
err = devm_request_irq(dev, vmd->irqs[i].virq,
vmd_irq, IRQF_NO_THREAD,
vmd->name, &vmd->irqs[i]);
if (err)