I am experiencing deadlocks related to preparing cache mounts.

Here is a stack trace from one of my build agents:
https://gist.github.com/cpuguy83/0e79cd121c780df71eb1cbbcbcc8f1e1

This has wedged most of my build agents (when they try to lookup a particular cache mount) and seems to happen rather easily.

I have setup my builds to generate stack dumps any time we end up cancelling (e.g. due to timeout) the build so I can get more of these pretty easily.