[dm-devel] Infinite recursion when creating devices

[Alasdair G Kergon]

You need sysadmin privileges to do this and I reckon that offers many
other ways of causing crashes too:)

It didn't seem worth attempting to prevent all device loops as it's not
a cheap thing to detect and not something likely to occur in practice. 

Nevertheless, some userspace tools do contain some checks to avoid some
cases like this already.

Alasdair