Updates in JDK-8327114 to the attach API ( 
src/jdk.attach/linux/classes/sun/tools/attach/VirtualMachineImpl.java ) access the /proc filesystem using readlink().

A policy file update enables the test to run, but this area should be using AccessController.doPrivileged(), in case this happens with a Security Manager, and there's untrusted code which then calls into attach (with whatever policy permits that to happen...).

While SM is planned for removal very soon, it would be good have the doPrivileged in the implementation so any backports can benefit.