[PATCH] s390: cio: fix two use-after-free bugs in device.c

[Qinglang Miao]

put_device calls release function which do kfree() inside.
So following use of sch&cdev would cause use-after-free bugs.

Fix these by simply adjusting the position of put_device.

Fixes: 37db8985b211 ("s390/cio: add basic protected virtualization support")
Fixes: 74bd0d859dc3 ("s390/cio: fix unlocked access of online member")
Reported-by: Hulk Robot <hul...@huawei.com>
Signed-off-by: Qinglang Miao <miaoqingl...@huawei.com>
---
 drivers/s390/cio/device.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index b29fe8d50..69492417b 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -1664,10 +1664,10 @@ void __init ccw_device_destroy_console(struct 
ccw_device *cdev)
        struct io_subchannel_private *io_priv = to_io_private(sch);
 
        set_io_private(sch, NULL);
-       put_device(&sch->dev);
-       put_device(&cdev->dev);
        dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
                          io_priv->dma_area, io_priv->dma_area_dma);
+       put_device(&sch->dev);
+       put_device(&cdev->dev);
        kfree(io_priv);
 }
 
@@ -1774,8 +1774,8 @@ static int ccw_device_remove(struct device *dev)
                                      ret, cdev->private->dev_id.ssid,
                                      cdev->private->dev_id.devno);
                /* Give up reference obtained in ccw_device_set_online(). */
-               put_device(&cdev->dev);
                spin_lock_irq(cdev->ccwlock);
+               put_device(&cdev->dev);
        }
        ccw_device_set_timeout(cdev, 0);
        cdev->drv = NULL;
-- 
2.23.0