Newly upgraded -CURRENT box does not boot

[Kyle Evans]

On Mon, Aug 20, 2018 at 4:27 PM, Brett Gmoser
<freebsdcurrent at codexterous.com> wrote:
> Hi there,
>
> I was told to e-mail these addresses with this.
>
> I did an `svn update` on /usr/src last night, build world and kernel as
> usual. This morning I installed the kernel, booted into single user,
> installed world and did mergemaster -Ui as usual. The new kernel had booted
> fine. Upon reboot, the machine will no longer boot:
>
>     Startup error in /boot/lua/loader.lua:
>     LUA ERROR: cannot open /boot/lua/loader.lua: no such file or directory
>
>     can't load 'kernel'
>
> Many things in the bootloader do not work, including "boot kernel.old", "ls
> /boot", and various other things (most if not all just result in "Command
> failed"). Interestingly, "ls /mnt" works, other directories do not. That's
> the only clue I have.
>
> I'm able to reboot in an installer image and mount the drive just fine.
> Everything is there and is as expected, including /boot/lua/loader.lua.
>
> I re-installed everything in /usr/src/stand (chroot'd on the installer
> image, and "cd /usr/src/stand && make clean all install"). This did not fix
> the problem.
>
> Does anybody happen to have any ideas?
>

To briefly follow up and summarize the current standing here following
some more discussion/attempts to fix on IRC:

1.) x86 BIOS boot
2.) Problem appears for both forthloader and lualoader
3.) Early March loader works, recent loader does not [Only tried
loader from the past ~day]
4.) ls / works, ls /mnt works, ls /boot and other directories fails
5.) However, /boot is confirmed intact and populated by booting via
11.2 install media and inspecting local disk

We'll hopefully be having a bisect session tomorrow to figure out
where exactly this broke so that maybe Brett has a chance to upgrade
to 12.0, unless this sounds familiar to someone and the cause is
obvious. =)

Thanks,

Kyle Evans