On 24/3/26 16:18, Jiri Olsa wrote:
> Adding tests for the rollback code when the tracing_multi
> link won't get attached, covering 2 reasons:
>
> - wrong btf id passed by user, where all previously allocated
> trampolines will be released
> - trampoline for requested function is fully attached (has already
> maximum programs attached) and the link fails, the rollback code
> needs to release all previously link-ed trampolines and release
> them
>
> We need the bpf_fentry_test* unattached for the tests to pass,
> so the rollback tests are serial.
>
> Signed-off-by: Jiri Olsa <[email protected]>
> ---
> .../selftests/bpf/prog_tests/tracing_multi.c | 213 ++++++++++++++++++
> .../bpf/progs/tracing_multi_rollback.c | 43 ++++
> 2 files changed, 256 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/tracing_multi_rollback.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/tracing_multi.c
> b/tools/testing/selftests/bpf/prog_tests/tracing_multi.c
> index 6917471e329c..6ff0f72f8c46 100644
> --- a/tools/testing/selftests/bpf/prog_tests/tracing_multi.c
> +++ b/tools/testing/selftests/bpf/prog_tests/tracing_multi.c
> @@ -10,6 +10,7 @@
> #include "tracing_multi_session.skel.h"
> #include "tracing_multi_fail.skel.h"
> #include "tracing_multi_bench.skel.h"
> +#include "tracing_multi_rollback.skel.h"
> #include "trace_helpers.h"
>
> static __u64 bpf_fentry_test_cookies[] = {
> @@ -669,6 +670,218 @@ void serial_test_tracing_multi_bench_attach(void)
> free(ids);
> }
>
> +static void tracing_multi_rollback_run(struct tracing_multi_rollback *skel)
> +{
> + LIBBPF_OPTS(bpf_test_run_opts, topts);
> + int err, prog_fd;
> +
> + prog_fd = bpf_program__fd(skel->progs.test_fentry);
> + err = bpf_prog_test_run_opts(prog_fd, &topts);
> + ASSERT_OK(err, "test_run");
> +
> + /* make sure the rollback code did not leave any program attached */
> + ASSERT_EQ(skel->bss->test_result_fentry, 0, "test_result_fentry");
> + ASSERT_EQ(skel->bss->test_result_fexit, 0, "test_result_fexit");
> +}
> +
> +static void test_rollback_put(void)
> +{
> + LIBBPF_OPTS(bpf_tracing_multi_opts, opts);
> + struct tracing_multi_rollback *skel = NULL;
> + size_t cnt = FUNCS_CNT;
> + __u32 *ids = NULL;
> + int err;
> +
> + skel = tracing_multi_rollback__open();
> + if (!ASSERT_OK_PTR(skel, "tracing_multi_rollback__open"))
> + return;
> +
> + bpf_program__set_autoload(skel->progs.test_fentry, true);
> + bpf_program__set_autoload(skel->progs.test_fexit, true);
> +
> + err = tracing_multi_rollback__load(skel);
> + if (!ASSERT_OK(err, "tracing_multi_rollback__load"))
> + goto cleanup;
> +
> + ids = get_ids(bpf_fentry_test, cnt, NULL);
> + if (!ASSERT_OK_PTR(ids, "get_ids"))
> + goto cleanup;
> +
> + /*
> + * Mangle last id to trigger rollback, which needs to do put
> + * on get-ed trampolines.
> + */
> + ids[9] = 0;
> +
> + opts.ids = ids;
> + opts.cnt = cnt;
> +
> + skel->bss->pid = getpid();
> +
> + skel->links.test_fentry =
> bpf_program__attach_tracing_multi(skel->progs.test_fentry,
> + NULL, &opts);
> + if (!ASSERT_ERR_PTR(skel->links.test_fentry,
> "bpf_program__attach_tracing_multi"))
> + goto cleanup;
> +
> + skel->links.test_fexit =
> bpf_program__attach_tracing_multi(skel->progs.test_fexit,
> + NULL, &opts);
> + if (!ASSERT_ERR_PTR(skel->links.test_fexit,
> "bpf_program__attach_tracing_multi"))
> + goto cleanup;
> +
> + /* We don't really attach any program, but let's make sure. */
> + tracing_multi_rollback_run(skel);
> +
> +cleanup:
> + tracing_multi_rollback__destroy(skel);
> + free(ids);
> +}
> +
> +
NIT: keep one blank line here.
> +static void fillers_cleanup(struct tracing_multi_rollback **skels, int cnt)
> +{
> + int i;
> +
> + for (i = 0; i < cnt; i++)
> + tracing_multi_rollback__destroy(skels[i]);
> +
> + free(skels);
> +}
> +
> +static struct tracing_multi_rollback *extra_load_and_link(void)
> +{
> + struct tracing_multi_rollback *skel;
> + int err;
> +
> + skel = tracing_multi_rollback__open();
> + if (!ASSERT_OK_PTR(skel, "tracing_multi_rollback__open"))
> + goto cleanup;
> +
> + bpf_program__set_autoload(skel->progs.extra, true);
> +
> + err = tracing_multi_rollback__load(skel);
> + if (!ASSERT_OK(err, "tracing_multi_rollback__load"))
> + goto cleanup;
> +
> + skel->links.extra = bpf_program__attach_trace(skel->progs.extra);
> + if (!ASSERT_OK_PTR(skel->links.extra, "bpf_program__attach_trace"))
> + goto cleanup;
> +
> + return skel;
> +
> +cleanup:
> + tracing_multi_rollback__destroy(skel);
> + return NULL;
> +}
> +
> +static struct tracing_multi_rollback **fillers_load_and_link(int max)
> +{
> + struct tracing_multi_rollback **skels, *skel;
> + int i, err;
> +
> + skels = calloc(max + 1, sizeof(*skels));
> + if (!ASSERT_OK_PTR(skels, "calloc"))
> + return NULL;
> +
> + for (i = 0; i < max; i++) {
> + skel = skels[i] = tracing_multi_rollback__open();
> + if (!ASSERT_OK_PTR(skels[i], "tracing_multi_rollback__open"))
> + goto cleanup;
> +
> + bpf_program__set_autoload(skel->progs.filler, true);
> +
> + err = tracing_multi_rollback__load(skel);
> + if (!ASSERT_OK(err, "tracing_multi_rollback__load"))
> + goto cleanup;
> +
> + skel->links.filler =
> bpf_program__attach_trace(skel->progs.filler);
> + if (!ASSERT_OK_PTR(skels[i]->links.filler,
> "bpf_program__attach_trace"))
> + goto cleanup;
> + }
> +
> + return skels;
> +
> +cleanup:
> + fillers_cleanup(skels, i);
> + return NULL;
> +}
> +
> +static void test_rollback_unlink(void)
> +{
> + struct tracing_multi_rollback *skel, *extra;
> + LIBBPF_OPTS(bpf_tracing_multi_opts, opts);
> + struct tracing_multi_rollback **fillers;
> + size_t cnt = FUNCS_CNT;
> + __u32 *ids = NULL;
> + int err, max;
> +
> + max = get_bpf_max_tramp_links();
> + if (!ASSERT_GE(max, 1, "bpf_max_tramp_links"))
> + return;
> +
> + /* Attach maximum allowed programs to bpf_fentry_test10 */
> + fillers = fillers_load_and_link(max);
> + if (!ASSERT_OK_PTR(fillers, "fillers_load_and_link"))
> + return;
> +
> + extra = extra_load_and_link();
> + if (!ASSERT_OK_PTR(extra, "extra_load_and_link"))
Should cleanup fillers here?
Thanks,
Leon
> + return;
> +
> + skel = tracing_multi_rollback__open();
> + if (!ASSERT_OK_PTR(skel, "tracing_multi_rollback__open"))
> + goto cleanup;
> +
[...]
