Comment 36 for bug 1768139

Few final comments on the work I did to narrow this:

* Issue is present in ubuntu but not in mainline (4.15.17 I think is closest? I have tried a bunch though 4.15.0, 4.15.18, 4.15.16...)
* I compiled mainline kernel 4.15.17 from linux-stable with ubuntu config from /boot/config-4.15.0-22-generic, that did not show issue.
* I attempted to go backwards in ubuntu-bionic git history and made it back to 4.15.0-1_4.15.0-1.2 which was the last build that succeeded for me. This exhibited the issue.

Let me know if I can do any more testing.