UML kernel panic on initialization

[subashab at codeaurora.org]

> [snip]
> 
> And as yet another experiment in this area, does it work again if you
> apply this patch?
> 
> https://patchwork.ozlabs.org/project/linux-um/patch/20210303155523.124277-11-benjamin@sipsolutions.net/
> 
> Not sure it applies as-is, but you can see the schema there.
> 
> johannes

If this patch is applied without any reverts the crash is seen.
If patch is applied with the 3 reverts applied, the initialization
is hanging.