[PATCH] cpia2_usb: first wake up, then free in disconnect

[Oliver Neukum]

Kasan reported a use after free in cpia2_usb_disconnect()
It first freed everything and then woke up those waiting.
The reverse order is correct.

Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
Reported-by: syzbot+0c90fc937c84f97d0aa6@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 6c493f8b28c67 ("[media] cpia2: major overhaul to get it in a working state again")
---
 drivers/media/usb/cpia2/cpia2_usb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/cpia2/cpia2_usb.c b/drivers/media/usb/cpia2/cpia2_usb.c
index e5d8dee38fe4..44bd7e5ad3eb 100644
--- a/drivers/media/usb/cpia2/cpia2_usb.c
+++ b/drivers/media/usb/cpia2/cpia2_usb.c
@@ -902,7 +902,6 @@ static void cpia2_usb_disconnect(struct usb_interface *intf)
 	cpia2_unregister_camera(cam);
 	v4l2_device_disconnect(&cam->v4l2_dev);
 	mutex_unlock(&cam->v4l2_lock);
-	v4l2_device_put(&cam->v4l2_dev);
 
 	if(cam->buffers) {
 		DBG("Wakeup waiting processes\n");
@@ -911,6 +910,8 @@ static void cpia2_usb_disconnect(struct usb_interface *intf)
 		wake_up_interruptible(&cam->wq_stream);
 	}
 
+	v4l2_device_put(&cam->v4l2_dev);
+
 	LOG("CPiA2 camera disconnected.\n");
 }
 
-- 
2.16.4