On Sun, Feb 13, 2022 at 02:54:05PM +0100, Thomas Gleixner wrote:
> 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: 82ff8e6b78fc ("PCI/MSI: Use msi_get_virq() in pci_get_vector()")
> Reported-by: "Surendrakumar Upadhyay, TejaskumarX" <tejaskumarx.surendrakumar.upadhyay@xxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Bjorn, this is a fix for a patch we merged in the last cycle,
if possible we should be sending it before v5.17 is released,
please.
Thanks,
Lorenzo
> drivers/pci/controller/vmd.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -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_domai
> 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_domai
> 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
> 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 *de
> 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)
