Description

An application that uses the io_pgetevents system call fails with -EPERM

Steps to reproduce the issue:

1. Build such an application (e.g. https://github.com/scylladb/seastar) in a container
2. Run it
3. Look at the pretty errors

Describe the results you received:
io_pgetevents() fails with -EPERM

Describe the results you expected:
io_pgetevents() does not fail with -EPERM

Output of docker version:

18.06.0-dev