Re: [PATCH bpf-next 0/2] selftests/bpf: port test_ftrace.sh into test_progs

["Alexei Starovoitov" <alexei.starovoitov@gmail.com>]

On Tue, Nov 03, 2026 at 01:13 AM Alexis Lothoré <alexis.lothore@bootlin.com> wrote:
> I initially went with a ftrace instance, but I came back to global
> ftrace because graph function filters (set_graph_function,
> set_graph_notrace) are not handled at instance level, only at global
> level. But maybe setting only set_ftrace_filter and set_ftrace_notrace
> is enough for this test ? That would indeed simplify a lot the setup.

Yes. set_ftrace_filter alone is enough.
The test needs function_graph and a trampoline on the same function.
set_ftrace_filter of the instance does that.

>>   all functions are patched       only the filtered functions
>
> Are all functions really patched with the current series ? It is still
> applying filters.

Yes. All but the ones in set_ftrace_notrace.
Only set_ftrace_filter and set_ftrace_notrace decide what is patched,
and set_ftrace_filter is empty in the series.
set_graph_function is a run time check. Every patched function calls
into fgraph. Then graph_entry() -> ftrace_graph_addr() drops the ones
that are not below bpf_prog_test*.
enabled_functions shows what is patched.