Hi,
I will test the fsl-mc related changes in the next couple of days.
Thanks,
Diana
On 3/13/2021 2:55 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_fsl_mc_reflck_attach() sets vdev->reflck and
vfio_fsl_mc_open(), called by fops open, unconditionally derefs it, which
will crash if things get out of order.
This driver started life with the right sequence, but three commits added
stuff after vfio_add_group_dev().
Fixes: 2e0d29561f59 ("vfio/fsl-mc: Add irq infrastructure for fsl-mc devices")
Fixes: f2ba7e8c947b ("vfio/fsl-mc: Added lock support in preparation for interrupt handling")
Fixes: 704f5082d845 ("vfio/fsl-mc: Scan DPRC objects on vfio-fsl-mc driver bind")
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/vfio/fsl-mc/vfio_fsl_mc.c | 43 ++++++++++++++++---------------
1 file changed, 22 insertions(+), 21 deletions(-)
diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
index f27e25112c4037..881849723b4dfb 100644
--- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
+++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
@@ -582,11 +582,21 @@ static int vfio_fsl_mc_init_device(struct vfio_fsl_mc_device *vdev)
dprc_cleanup(mc_dev);
out_nc_unreg:
bus_unregister_notifier(&fsl_mc_bus_type, &vdev->nb);
- vdev->nb.notifier_call = NULL;
-
return ret;
}
+static void vfio_fsl_uninit_device(struct vfio_fsl_mc_device *vdev)
+{
+ struct fsl_mc_device *mc_dev = vdev->mc_dev;
+
+ if (!is_fsl_mc_bus_dprc(mc_dev))
+ return;
+
+ dprc_remove_devices(mc_dev, NULL, 0);
+ dprc_cleanup(mc_dev);
+ bus_unregister_notifier(&fsl_mc_bus_type, &vdev->nb);
+}
+
static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
{
struct iommu_group *group;
@@ -607,29 +617,27 @@ static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
}
vdev->mc_dev = mc_dev;
-
- ret = vfio_add_group_dev(dev, &vfio_fsl_mc_ops, vdev);
- if (ret) {
- dev_err(dev, "VFIO_FSL_MC: Failed to add to vfio group\n");
- goto out_group_put;
- }
+ mutex_init(&vdev->igate);
ret = vfio_fsl_mc_reflck_attach(vdev);
if (ret)
- goto out_group_dev;
+ goto out_group_put;
ret = vfio_fsl_mc_init_device(vdev);
if (ret)
goto out_reflck;
- mutex_init(&vdev->igate);
-
+ ret = vfio_add_group_dev(dev, &vfio_fsl_mc_ops, vdev);
+ if (ret) {
+ dev_err(dev, "VFIO_FSL_MC: Failed to add to vfio group\n");
+ goto out_device;
+ }
return 0;
+out_device:
+ vfio_fsl_uninit_device(vdev);
out_reflck:
vfio_fsl_mc_reflck_put(vdev->reflck);
-out_group_dev:
- vfio_del_group_dev(dev);
out_group_put:
vfio_iommu_group_put(group, dev);
return ret;
@@ -646,16 +654,9 @@ static int vfio_fsl_mc_remove(struct fsl_mc_device *mc_dev)
mutex_destroy(&vdev->igate);
+ vfio_fsl_uninit_device(vdev);
vfio_fsl_mc_reflck_put(vdev->reflck);
- if (is_fsl_mc_bus_dprc(mc_dev)) {
- dprc_remove_devices(mc_dev, NULL, 0);
- dprc_cleanup(mc_dev);
- }
-
- if (vdev->nb.notifier_call)
- bus_unregister_notifier(&fsl_mc_bus_type, &vdev->nb);
-
vfio_iommu_group_put(mc_dev->dev.iommu_group, dev);
return 0;
