copy_to_user() copies the struct the pointer is pointing to, but the
length check compares against sizeof(pointer) and not sizeof(struct).
On 32-bit the size is probably the same, so it might have worked
accidentally.
Signed-off-by: Matthias Rosenfelder <mrosenfelder.lkml@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>