[PATCH AUTOSEL 4.4 63/64] vfio/pci: Clear error and request eventfd ctx after releasing

Sasha Levin
2020-09-18T02:18:15Z

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

[ 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>
---
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 ab765770e8dd6..662ea7ec82926 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -255,10 +255,14 @@ 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