[$] Type checking for BPF tracing
The BPF in-kernel virtual machine hasbrought a new set of capabilities to a number of functional areas in thekernel, including, significantly, tracing.Since BPF programs run in the kernel, much effort goes into ensuring thatthey will not cause problems for the running system;to that end, the BPF verifier checks every possible aspect of each BPF program'sbehavior to ensure that it is safe to run in the kernel - with one notableexception. With a patch set titled "revolutionizebpf tracing", Alexei Starovoitov aims to close that loophole andeliminate a set of potential problems in a widely used class of BPFprograms.