Firstly, .shutdown callback may touch a uninitialized hardware
if dev->driver is set and .probe is not completed.
Secondly, device_shutdown() may dereference a null pointer to cause
oops when dev->driver is cleared after it has been checked in
device_shutdown().
So just hold device lock and its parent lock(if it has) to
fix the races.
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
d1c6c030fc