Comment 38 for bug 78455

And the root cause, presumably in the hook library /usr/lib/checkinstall[64]/installwatch.so, pre-loaded in the installwatch script before running the install command passed into it:

# installwatch -t mkdir -p /usr/doc/test

INFO : Using a default root directory : /tmp/tmp.INhvkPHuIR

mkdir: cannot create directory ‘/usr/doc’: No such file or directory