Ujail Strangeness

For Developers
1

Hello,
So for a while I have tried rolling my own initramfs firmware images for x86_64, running them in virtual machines.
These images include ujail and the busybox sysntpd for getting the time.
However, while running them, I see a lot of:-

user.err : jail: pivot_root(/tmp/ujail-HCLaGk, /tmp/ujail-HCLaGk/old) failed: Invalid argument

The system time also never synchronises with the downstream NTP server.

There was a patch committed in October 2019 to the init script for initramfs images, which tried to ensure that the initial switch_root used a tmpfs as the destination for the new root, which apparently was causing the problem then, but I am running that code and it is still an issue.
Do x86_64 images have an additional package requirement that I've missed, or is there an initialisation somewhere that I haven't done?

2

What is in ubus call system board inside vm?
chrony(d) is much better at logging various "hardware" glitches.
Also most svripts go unsandboced just uninstalling ujail.

3 
"kernel": "5.15.167",
"hostname": "OpenWrt",
"system": "Intel(R) Celeron(R) J4125 CPU @ 2.00GHz",
"model": "Fanless Mini PC PCG02 Pro",
"board_name": "fanless-mini-pc-pcg02-pro",
"rootfs_type": "rootfs",
"release": {
	"distribution": "OpenWrt",
	"version": "23.05.5",
	"revision": "r24106-10cc5fcd00",
	"target": "x86/64",
	"description": "OpenWrt 23.05.5 r24106-10cc5fcd00"
}

I presume that sysntpd is by default configured to work within a ujail, but I don't understand why it continually crashes.

4

Backtrace from dmesg please.