On Tue, Mar 01, 2022 at 05:25:09PM +0000, Lorenzo Pieralisi wrote:
> 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.
Agreed. I think Thomas merged 82ff8e6b78fc, and it looks like he's
just merged this fix to irq/urgent of tip, so I think this should be
already taken care of:
https://lore.kernel.org/r/164542867635.16921.13795049956787158926.tip-bot2@tip-bot2
> > 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)
