Reboot/shutdown was hanging because ui-post-stop was stuck in "while ! sudo -u chronos kill -9 -- -1 ; do" loop because cros_embedded's sudo-to-su wrapper doesn't handle -u.

UI is coming from chromeos-base/chromeos-login, which is pulled in by chromeos-base/debugd.

So fix for reboot is to remove UI by removing debugd.

I see the jetstream overlay already disables the debugd USE flag (as do several other embedded targets). Could be OK to do the same.

What's pulling in debugd? Just the defaults in target-chromium-os? Would all 'embedded' profiles be broken, if they don't explicitly disable debugd?

Additionally, jetstream actually *enables* a proper sudo:

# Use pam so that sudo is pulled in properly.
USE="${USE} pam"

And I note that the existing images have *no* debugd (or chromeos-login), but they *do* have 'pam' (and therefore sudo).

I believe debugd is coming from the target-chromium-os defaults.
I'm testing out a change to do USE="${USE} -debugd" in overlay-whirlwind-private's make.defaults (like -transparent_hugepage).
I could pull in real sudo. That would match normal whirlwind more closely, although then I might have missed the fact that debugd and login UI needed to be removed.

Yeah, testing with USE="-debugd" seems like the right approach.

I wonder if debugd should just be removed in the base embedded feature profile, since it makes the default build (i.e., without USE=pam) broken. And many profiles end up manually fixing this up anyway, often by disabling debugd themselves.

We could figure out the sudo question independently; it seems like we should definitely at least avoid the chromeos-login dependency, if not the entirety of debugd.

we should either extend our dumb wrapper to handle -u, or just throw it away and always install the full sudo.  i'd lean towards doing that now.

the sudo/pam binding has larger been cleaned now with the move to chromeos-auth-config

as for the debugd->chromeos-login dep, that should get resolved.  perhaps by just deleting it.

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/overlays/overlay-whirlwind-private/+/bede133dbb6ff00be764bdc7f7ae703b917c2660

commit bede133dbb6ff00be764bdc7f7ae703b917c2660
Author: Edward Hill <ecgh@chromium.org>
Date: Wed Aug 09 00:34:10 2017

I filed this to follow up on the chromeos-login vs. fake sudo conflict:

https://bugs.chromium.org/p/chromium/issues/detail?id=753626