On Mon, Jul 22, 2024 at 1:28 PM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Adding test that attaches/detaches multiple consumers on
> single uprobe and verifies all were hit as expected.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> .../bpf/prog_tests/uprobe_multi_test.c | 213 ++++++++++++++++++
> .../bpf/progs/uprobe_multi_consumers.c | 39 ++++
> 2 files changed, 252 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/uprobe_multi_consumers.c
>
[...]
> + } else {
> + /*
> + * uprobe return is tricky ;-)
> + *
> + * to trigger uretprobe consumer, the uretprobe needs to be installed,
> + * which means one of the 'return' uprobes was alive when probe was hit:
> + *
> + * idxs: 2/3 uprobe return in 'installed' mask
> + *
> + * in addition if 'after' state removes everything that was installed in
> + * 'before' state, then uprobe kernel object goes away and return uprobe
> + * is not installed and we won't hit it even if it's in 'after' state.
> + */
> + unsigned long had_uretprobes = before & 0b1100; // is uretprobe installed
> + unsigned long probe_preserved = before & after; // did uprobe go away
fixed C++-style comments, pushed to bpf-next
> +
> + if (had_uretprobes && probe_preserved && test_bit(idx, after))
> + val++;
> + fmt = "idx 2/3: uretprobe";
> + }
> +
> + ASSERT_EQ(skel->bss->uprobe_result[idx], val, fmt);
> + skel->bss->uprobe_result[idx] = 0;
> + }
> +
> +cleanup:
> + for (idx = 0; idx < 4; idx++)
> + uprobe_detach(skel, idx);
> +}
[...]
