[$] A possible path for cancelable BPF programs

The Linux kernel supports attaching BPF programs to many operations.
This is generally safe because the BPF verifier ensures
that BPF programs can't misuse kernel resources, run indefinitely, or otherwise
escape their boundaries. There is continuing tension, however, between trying
to expand the capabilities of BPF programs and ensuring that the verifier can
handle every edge case. On February 14, Juntong Deng

shared a proof-of-concept patch set that
adds some run-time checks to BPF to make it possible in the future to interrupt
a running BPF program.