[$] 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 ensuresthat BPF programs can't misuse kernel resources, run indefinitely, or otherwiseescape their boundaries. There is continuing tension, however, between tryingto expand the capabilities of BPF programs and ensuring that the verifier canhandle every edge case. On February14, Juntong Dengshared a proof-of-concept patch set thatadds some run-time checks to BPF to make it possible in the future to interrupta running BPF program.