In vcc_probe(), we should check the return value of
mdesc_grab() as it may return NULL. While the
vio_vdev_node() has the NULL-check, but if there
is still a call to mdesc_release() which may cause
a NPD bug.
Fixes: 5d171050e28f ("sparc64: vcc: Enable VCC port probe and removal")
Signed-off-by: Liang He <windhl@xxxxxxx>
---
drivers/tty/vcc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/tty/vcc.c b/drivers/tty/vcc.c
index 34ba6e54789a..e3ba63d0a91f 100644
--- a/drivers/tty/vcc.c
+++ b/drivers/tty/vcc.c
@@ -610,6 +610,9 @@ static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
hp = mdesc_grab();
+ if (!hp)
+ return -ENODEV;
+
node = vio_vdev_node(hp, vdev);
if (node == MDESC_NODE_NULL) {
rv = -ENXIO;
--
2.25.1
