Re: [PATCH bpf-next 1/2] bpf, x86: patch tail-call fentry slot on non-IBT JITs

[Takeru Hayasaka]

Sorry about the top-posting.

That makes sense, thanks. I agree perf can provide visibility into which
BPF programs are running, including tail-called ones.

What I am still unsure about is packet-level / structured-data
observability. My use case is closer to xdpdump-style debugging, where I
want to inspect packet-related context from specific XDP leaf programs
in a live pipeline.

That feels harder to express with perf alone, so I am trying to
understand what the preferred direction would be for that kind of use
case in tailcall-heavy XDP deployments.