[PATCH] vfio/pci: Clear error and request eventfd ctx after releasing

[Alex Williamson]

The next use of the device will generate an underflow from the
stale reference.

Cc: Qian Cai <c...@lca.pw>
Fixes: 1518ac272e78 ("vfio/pci: fix memory leaks of eventfd ctx")
Reported-by: Daniel Wagner <dwag...@suse.de>
Signed-off-by: Alex Williamson <alex.william...@redhat.com>
---
 drivers/vfio/pci/vfio_pci.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 7c0779018b1b..f634c81998bb 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -521,10 +521,14 @@ static void vfio_pci_release(void *device_data)
                vfio_pci_vf_token_user_add(vdev, -1);
                vfio_spapr_pci_eeh_release(vdev->pdev);
                vfio_pci_disable(vdev);
-               if (vdev->err_trigger)
+               if (vdev->err_trigger) {
                        eventfd_ctx_put(vdev->err_trigger);
-               if (vdev->req_trigger)
+                       vdev->err_trigger = NULL;
+               }
+               if (vdev->req_trigger) {
                        eventfd_ctx_put(vdev->req_trigger);
+                       vdev->req_trigger = NULL;
+               }
        }
 
        mutex_unlock(&vdev->reflck->lock);