[PATCH AUTOSEL 4.14 121/127] vfio/pci: Clear error and request eventfd ctx after releasing

[Sasha Levin]

From: Alex Williamson <alex.william...@redhat.com>

[ Upstream commit 5c5866c593bbd444d0339ede6a8fb5f14ff66d72 ]

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>
Reviewed-by: Cornelia Huck <coh...@redhat.com>
Tested-by: Daniel Wagner <dwag...@suse.de>
Signed-off-by: Alex Williamson <alex.william...@redhat.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 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 902854a013521..4fbc38b955ad8 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -399,10 +399,14 @@ 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);
-- 
2.25.1