[$] KRSI and proprietary BPF programs

The "kernel runtime security instrumentation" (or KRSI) patch set enables the attachment of BPF programs to every security hook in the kernel; LWN covered this work in December. That article focused on ABI issues, but it deferred another potential problem to our 2020 predictions: the possibility that vendors could start shipping proprietary BPF programs for use with frameworks like KRSI. Other developers did pick up on the possibility that KRSI could be abused this way, though, leading to a discussion on whether KRSI should continue to allow the loading of BPF programs that do not carry a GPL-compatible license.