I have the exact same issue now at 16.04 LTS. This started to happen recently (~1 month).
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.5 LTS
Release: 16.04
Codename: xenial
$ uname -a
Linux lngrad031 4.4.0-139-generic #165-Ubuntu SMP Wed Oct 24 10:58:50 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
System is completely unresponsive (even REISUB doesn't work). I didn't know if I had to start a new bug report. So far I tested it with LUKS encrypted drive.
I have the exact same issue now at 16.04 LTS. This started to happen recently (~1 month).
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.5 LTS
Release: 16.04
Codename: xenial
$ uname -a
Linux lngrad031 4.4.0-139-generic #165-Ubuntu SMP Wed Oct 24 10:58:50 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
System is completely unresponsive (even REISUB doesn't work). I didn't know if I had to start a new bug report. So far I tested it with LUKS encrypted drive.