Re: [PATCH v2 10/15] tools/rv: Add BPF monitors

[Tomas Glozar]

On Mon, Oct 19, 2026 at 2:48 PM Gabriele Monaco <gmonaco@xxxxxxxxxx> wrote:
> >
> > Do I understand it correctly that the idea is to modify existing
> > tracefs instances when enabling an RV monitor to filter our RV-related
> > bpf_trace_printk events?
>
> Not quite. The initial issue is that the current iteration of RV BPF monitor
> don't cooperate well with trace-cmd/perf. Alexei suggested we use bpf_printk and
> filter out the desired events with plain ftrace glob filters (from trace-
> cmd/perf).
>
> I believe this would be usually equivalent to having a dedicated tracepoint for
> RV BPF monitors.
>
> E.g. you'd do (roughly):
>
>   trace-cmd -e bpf_prink --filter 'bpf_string ~ "rv: sleep: * violation"
>
> instead of (with a new kfunc)
>
>   trace-cmd -e rv:error_bpf --filter 'monitor = "sleep"'
>

I was talking about preventing other (non-RV) consumers of
bpf_trace_printk from seeing the RV prints. Eg. if I create a tracefs
instance and enable bpf_trace_printk, intending to see my own debug
prints, I will also see debug prints for RV, unless I explicitly
filter them out. I get that on the RV side, these are mostly
equivalent.

Tomas