Description: vt_do_kdgkb_ioctl use-after-free
References:
 https://www.openwall.com/lists/oss-security/2020/10/16/1
Notes:
Bugs:
upstream: needed
4.19-upstream-stable: needed
4.9-upstream-stable: needed
sid:d needed
4.19-buster-security: needed
4.9-stretch-security: needed