[PATCH 5.11 353/601] vfio/pci: Re-order vfio_pci_probe()

Greg Kroah-Hartman
2021-05-12T17:39:23Z

From: Jason Gunthorpe <jgg@nvidia.com>

[ Upstream commit 4aeec3984ddc853f7c65903bde472ffdef738bae ]

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")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <8-v3-225de1400dfc+4e074-vfio1_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 f31aa25f361c..48b048edf1ee 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -2034,13 +2034,9 @@ 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;
@@ -2064,15 +2060,20 @@ 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);
--
2.30.2