Hi Jason,
On 3/13/21 1:56 AM, Jason Gunthorpe wrote:
> vfio_add_group_dev() must be called only after all of the private data in
> vdev is fully setup and ready, otherwise there could be races with user
> space instantiating a device file descriptor and starting to call ops.
>
> For instance vfio_pci_reflck_attach() sets vdev->reflck and
> vfio_pci_open(), called by fops open, unconditionally derefs it, which
> will crash if things get out of order.>
> Fixes: cc20d7999000 ("vfio/pci: Introduce VF token")
> Fixes: e309df5b0c9e ("vfio/pci: Parallelize device open and release")
> Fixes: 6eb7018705de ("vfio-pci: Move idle devices to D3hot power state")
> Fixes: ecaa1f6a0154 ("vfio-pci: Add VGA arbiter client")
> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Thanks
Eric
> ---
> drivers/vfio/pci/vfio_pci.c | 17 +++++++++--------
> 1 file changed, 9 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> index f95b58376156a0..0e7682e7a0b478 100644
> --- a/drivers/vfio/pci/vfio_pci.c
> +++ b/drivers/vfio/pci/vfio_pci.c
> @@ -2030,13 +2030,9 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> INIT_LIST_HEAD(&vdev->vma_list);
> init_rwsem(&vdev->memory_lock);
>
> - ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
> - if (ret)
> - goto out_free;
> -
> ret = vfio_pci_reflck_attach(vdev);
> if (ret)
> - goto out_del_group_dev;
> + goto out_free;
> ret = vfio_pci_vf_init(vdev);
> if (ret)
> goto out_reflck;
> @@ -2060,15 +2056,20 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> vfio_pci_set_power_state(vdev, PCI_D3hot);
> }
>
> - return ret;
> + ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
> + if (ret)
> + goto out_power;
> + return 0;
>
> +out_power:
> + if (!disable_idle_d3)
> + vfio_pci_set_power_state(vdev, PCI_D0);
> out_vf:
> vfio_pci_vf_uninit(vdev);
> out_reflck:
> vfio_pci_reflck_put(vdev->reflck);
> -out_del_group_dev:
> - vfio_del_group_dev(&pdev->dev);
> out_free:
> + kfree(vdev->pm_save);
> kfree(vdev);
> out_group_put:
> vfio_iommu_group_put(group, &pdev->dev);
>
