Comment # 33 on bug 1200461 from Thomas Blume

(In reply to Mike DeMicco from comment #32)
> > When I Google this error, I get a lot of hits. Mostly say the error message
> > is informative and harmless and bugs were closed saying the same.
> 
> I blacklisted those modules in the grub command line
> (module_blacklist=lpc_ich,gpio_ich), and the error/warning messages went
> away in dmesg, but the hang still occurs when I do an #udevadm info -a
> /dev/block/8:16

Strange, I thought that lpc_ich is the driver for your storage device.
If so, the machine shouldn't even boot when the driver is blacklisted, because
the system shouldn't find the hard disks.

However, I was asking our systemd expert. 
He will take a look.
Could you provide meanwhile the output of:

strace -f udevadm info -a /dev/block/8:16 &>strace-udevadm-info.txt

If possible please write the output to an usb stick or such.
Otherwise it might be gone when the system hangs and you need to hard reset.