Comment # 32 on bug 1200461 from Mike DeMicco

(In reply to Mike DeMicco from comment #31)
> (In reply to Thomas Blume from comment #29)
> > (In reply to Mike DeMicco from comment #28)
> > > FYI, there was a change to dracut-functions.sh that invoked "udevadm info
> > > -a." Older versions of this shell script do not do this (e.g., the 15.3
> > > version of Leap, vs. latter versions). This is the change that caused the
> > > problem on my system.
> > 
> > Ok, still, 'updevadm info -a' should not hang your computer.
> > Unfortunately, the udev debug logs didn't make it into the dmesg output.
> > But I've found a resource conflict with your i/o controller:
> > 
> > -->
> > [   13.209692] ACPI Warning: SystemIO range
> > 0x0000000000000428-0x000000000000042F conflicts with OpRegion
> > 0x000000000000042C-0x000000000000042D (\GP2C) (20211217/utaddress-204)
> > [   13.209701] ACPI: OSL: Resource conflict; ACPI support missing from
> > driver?
> > [   13.211431] lpc_ich: Resource conflict(s) found affecting gpio_ich
> > --<
> > 
> > Such conflicting resources could probably cause a system hang when they are
> > accessed by udevadm via sysfs.
> 
> 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