On Monday, July 22nd, 2024 at 1:27 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
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
> index e6255d4df81d..27708110ea20 100644
> --- a/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
> +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
> @@ -6,6 +6,7 @@
> #include "uprobe_multi.skel.h"
> #include "uprobe_multi_bench.skel.h"
> #include "uprobe_multi_usdt.skel.h"
> +#include "uprobe_multi_consumers.skel.h"
> #include "bpf/libbpf_internal.h"
> #include "testing_helpers.h"
> #include "../sdt.h"
> @@ -731,6 +732,216 @@ static void test_link_api(void)
> __test_link_api(child);
> }
>
[...]
> +
> +static void consumer_test(struct uprobe_multi_consumers skel,
> + unsigned long before, unsigned long after)
> +{
> + int err, idx;
> +
> + printf("consumer_test before %lu after %lu\n", before, after);
> +
> + / 'before' is each, we attach uprobe for every set idx */
> + for (idx = 0; idx < 4; idx++) {
> + if (test_bit(idx, before)) {
> + if (!ASSERT_OK(uprobe_attach(skel, idx), "uprobe_attach_before"))
> + goto cleanup;
> + }
> + }
> +
> + err = uprobe_consumer_test(skel, before, after);
> + if (!ASSERT_EQ(err, 0, "uprobe_consumer_test"))
> + goto cleanup;
> +
> + for (idx = 0; idx < 4; idx++) {
> + const char fmt = "BUG";
> + __u64 val = 0;
> +
> + if (idx < 2) {
> + /
> + * uprobe entry
> + * +1 if define in 'before'
> + /
> + if (test_bit(idx, before))
> + val++;
> + fmt = "prog 0/1: uprobe";
> + } 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
> +
> + if (had_uretprobes && probe_preserved && test_bit(idx, after))
> + val++;
> + fmt = "idx 2/3: uretprobe";
> + }
Jiri, Andrii,
This test case started failing since upstream got merged into bpf-next,
starting from commit https://git.kernel.org/bpf/bpf-next/c/440b65232829
A snippet from the test log:
consumer_test before 4 after 8
uprobe_attach:PASS:bpf_program__attach_uprobe_multi 0 nsec
consumer_test:PASS:uprobe_attach_before 0 nsec
uprobe_attach:PASS:bpf_program__attach_uprobe_multi 0 nsec
uprobe_consumer_test:PASS:uprobe_attach_after 0 nsec
consumer_test:PASS:uprobe_consumer_test 0 nsec
consumer_test:PASS:prog 0/1: uprobe 0 nsec
consumer_test:PASS:prog 0/1: uprobe 0 nsec
consumer_test:PASS:idx 2/3: uretprobe 0 nsec
consumer_test:FAIL:idx 2/3: uretprobe unexpected idx 2/3: uretprobe: actual 1 != expected 0
consumer_test before 4 after 9
uprobe_attach:PASS:bpf_program__attach_uprobe_multi 0 nsec
consumer_test:PASS:uprobe_attach_before 0 nsec
uprobe_attach:PASS:bpf_program__attach_uprobe_multi 0 nsec
uprobe_consumer_test:PASS:uprobe_attach_after 0 nsec
uprobe_attach:PASS:bpf_program__attach_uprobe_multi 0 nsec
uprobe_consumer_test:PASS:uprobe_attach_after 0 nsec
consumer_test:PASS:uprobe_consumer_test 0 nsec
consumer_test:PASS:prog 0/1: uprobe 0 nsec
consumer_test:PASS:prog 0/1: uprobe 0 nsec
consumer_test:PASS:idx 2/3: uretprobe 0 nsec
consumer_test:FAIL:idx 2/3: uretprobe unexpected idx 2/3: uretprobe: actual 1 != expected 0
consumer_test before 4 after 10
uprobe_attach:PASS:bpf_program__attach_uprobe_multi 0 nsec
consumer_test:PASS:uprobe_attach_before 0 nsec
uprobe_attach:PASS:bpf_program__attach_uprobe_multi 0 nsec
uprobe_consumer_test:PASS:uprobe_attach_after 0 nsec
uprobe_attach:PASS:bpf_program__attach_uprobe_multi 0 nsec
uprobe_consumer_test:PASS:uprobe_attach_after 0 nsec
consumer_test:PASS:uprobe_consumer_test 0 nsec
consumer_test:PASS:prog 0/1: uprobe 0 nsec
consumer_test:PASS:prog 0/1: uprobe 0 nsec
consumer_test:PASS:idx 2/3: uretprobe 0 nsec
consumer_test:FAIL:idx 2/3: uretprobe unexpected idx 2/3: uretprobe: actual 1 != expected 0
I couldn't figure out the reason as I have very shallow understanding
of what's happening in the test.
Jiri, could you please look into it?
I excluded this test from BPF CI for now.
Thank you!
> +
> + 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);
> +}
[...]
