Comment # 4 on bug 1129487 from Franck Bui

(In reply to Franck Bui from comment #2)
> It's surprising that udev itself takes so long to start.

So I misread your initial comment: the hang happens just before switching to
rootfs when all services are requested to stop.

Since the full debug logs have a negative side effect for reproducing, can you
try to enable udev debug logs only and see if you can still reproduce ? (append
"rd.udev.log_priority=debug" to the kernel command line).

Also frpm the last logs you showed:

> Mar 21 08:59:25 Orion-15 kernel: sd 6:0:0:3: [sdg] Attached SCSI removable disk

Can you try to remove this disk before booting and see if it helps ?

Thanks.