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

[ Upstream commit 5c5866c593bbd444d0339ede6a8fb5f14ff66d72 ]

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

Cc: Qian Cai <cai@lca.pw>
Fixes: 1518ac272e78 ("vfio/pci: fix memory leaks of eventfd ctx")
Reported-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Tested-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index c9c0af9a571f67923b98c5c09732c83ab64b2f8c..c08cff0ca08dfa6c741f32c6d8728886ec413b4a 100644 (file)
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -392,10 +392,14 @@ static void vfio_pci_release(void *device_data)
        if (!(--vdev->refcnt)) {
                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(&driver_lock);