Tracepoints not available from network namespace

Question

I want to use the linux tracepoints for a bpf application. However when I enter a network namespace no tracepoints/tracing events are available, e.g. ls /sys/kernel/tracing is empty.

Why is that and how can I access them from a network namespace?

Steps to reproduce (as root):

ip netns add x
ip netns exec x bash
ls /sys/kernel/tracing