recovery elides too greedily and too deep; awakens eventfd

[jclulow]

tokio 1.39 and above use eventfd(7) instead of the more traditional self-pipe mechanism for injecting wake-ups into the event loop. We are, regrettably, not including the eventfd.conf configuration file for the eventfd kernel module in the recovery image. This causes the installinator to fail to start:

BRM42220062 # svcs -a | grep oxide
online          0:00:34 svc:/oxide/installinator:default
BRM42220062 # tail -F $(svcs -L installinator)
[ Dec 28 00:00:02 Enabled. ]
[ Dec 28 00:00:34 Executing start method ("ctrun -l child -o noorphan,regent /opt/oxide/installinator/installinator install --bootstrap-sled --from-ipcc --install-on-gimlet --stay-alive &"). ]
[ Dec 28 00:00:34 Method "start" exited with status 0. ]
thread 'main' panicked at installinator/src/main.rs:15:7:
Failed building the Runtime: Os { code: 2, kind: NotFound, message: "No such file or directory" }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Interestingly this didn't cause the service to fail, or even to retry... It seems like the service uses the "transient" duration, which may be another (separate) bug.

[hawkw]

This should (hopefully) fix oxidecomputer/omicron#6391.

[rmustacc]

The dark event will not avail you, flame of Udûn.