Using device_find_child() to locate a probed virtual-device-port node
causes a device refcount imbalance, as device_find_child() internally
calls get_device() to increment the device’s reference count before
returning its pointer. vdc_port_mpgroup_check() directly returns true
upon finding a matching device without releasing the reference via
put_device(). We should call put_device() to decrement refcount.
As comment of device_find_child() says, 'NOTE: you will need to drop
the reference with put_device() after use'.
Found by code review.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 3ee70591d6c4 ("sunvdc: prevent sunvdc panic when mpgroup disk added to guest domain")
Signed-off-by: Ma Ke <make24@xxxxxxxxxxx>
---
Changes in v2:
- keep the change style simple as suggestions.
---
drivers/block/sunvdc.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
index b5727dea15bd..7af21fe67671 100644
--- a/drivers/block/sunvdc.c
+++ b/drivers/block/sunvdc.c
@@ -957,8 +957,10 @@ static bool vdc_port_mpgroup_check(struct vio_dev *vdev)
dev = device_find_child(vdev->dev.parent, &port_data,
vdc_device_probed);
- if (dev)
+ if (dev) {
+ put_device(dev);
return true;
+ }
return false;
}
--
2.25.1
