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@vger.kernel.org Fixes: 3ee70591d6c4 ("sunvdc: prevent sunvdc panic when mpgroup disk added to guest domain") Signed-off-by: Ma Ke make24@iscas.ac.cn --- 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; }