Hi Tycho. I was The Guy at LSS who tested positive for COVID about 12 hours after we sat next to each other at that Japanese restaurant in Vancouver the week before last. I really hope you didn't catch it. So far, to my knowledge, my "blast radius" is just me.

As somebody who has written a non-trivial amount of upstream Linux filesystem code and who is leading the containers team at my current employer, I've found your writing more interesting than perhaps most people on the face the planet might. I'm also a bit surprised at how often companies write their own custom FUSE filesystems. A lot of them I only hear about as former employees from those companies join mine and then clue me in about their existence. It seems like every large-ish company these days has at least one now.

It looks like you were able to figure things out through some combination of /proc poking, code inspection, and LKML querying. Out of curiosity, would it be feasible for you to have tried enabling some of the kernel hacking options such as WQ_WATCHDOG or DETECT_HUNG_TASK? Do you think that would have sped up your investigation?

Also, my whole career I've been doing ps aux, but TIL about ps awwfux. Which I guess goes to show there's always some gap in one's basic knowledge of Linux foo!