Default profiles should allow:
@{PROC}/sys/kernel/yama/ptrace_scope r,
https://www.kernel.org/doc/Documentation/security/Yama.txt
This is fixed in b4c0d6010ab9a0419c745e8bb1a752981ae49da3
This was fixed in 2.0.3 in xenial-updates.
Bug watches keep track of this bug in other bug trackers.
This is fixed in b4c0d6010ab9a04 19c745e8bb1a752 981ae49da3