vdpa: fix use-after-free on vp_vdpa_remove

stable inclusion
from stable-v5.17
commit eb057b44
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5WXCZ
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=eb057b44dbe35ae14527830236a92f51de8f9184
----------------------------------------------------------------------

When vp_vdpa driver is unbind, vp_vdpa is freed in vdpa_unregister_device
and then vp_vdpa->mdev.pci_dev is dereferenced in vp_modern_remove,
triggering use-after-free.

Call Trace of unbinding driver free vp_vdpa :
do_syscall_64
  vfs_write
    kernfs_fop_write_iter
      device_release_driver_internal
        pci_device_remove
          vp_vdpa_remove
            vdpa_unregister_device
              kobject_release
                device_release
                  kfree

Call Trace of dereference vp_vdpa->mdev.pci_dev:
vp_modern_remove
  pci_release_selected_regions
    pci_release_region
      pci_resource_len
        pci_resource_end
          (dev)->resource[(bar)].end
Signed-off-by: NZhang Min <zhang.min9@zte.com.cn>
Signed-off-by: NYi Wang <wang.yi59@zte.com.cn>
Link: https://lore.kernel.org/r/20220301091059.46869-1-wang.yi59@zte.com.cnSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>
Fixes: 64b9f64f ("vdpa: introduce virtio pci driver")
Reviewed-by: NStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: NPengyuan Zhao <zhaopengyuan@hisilicon.com>

drivers/vdpa/virtio_pci/vp_vdpa.c

@@ -524,8 +524,8 @@ static void vp_vdpa_remove(struct pci_dev *pdev)
 {
 	struct vp_vdpa *vp_vdpa = pci_get_drvdata(pdev);
 
-	vdpa_unregister_device(&vp_vdpa->vdpa);
 	vp_modern_remove(&vp_vdpa->mdev);
+	vdpa_unregister_device(&vp_vdpa->vdpa);
 }
 
 static struct pci_driver vp_vdpa_driver = {