diff options
| -rw-r--r-- | tools/testing/selftests/bpf/prog_tests/tracing_multi.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/tracing_multi.c b/tools/testing/selftests/bpf/prog_tests/tracing_multi.c index 0aa9532a05cf..cc727011f3a2 100644 --- a/tools/testing/selftests/bpf/prog_tests/tracing_multi.c +++ b/tools/testing/selftests/bpf/prog_tests/tracing_multi.c @@ -662,6 +662,97 @@ cleanup: free(ids2); } +/* + * Find two BTF ids that resolve to the same address. The stub of a syscall + * without arguments is an alias of its __do_sys_ function. + */ +static bool get_same_addr_ids(__u32 *ids) +{ + const char *prefix = "__x64_sys_"; + __u32 nr, type_id; + bool found = false; + struct btf *btf; + char alias[128]; + + btf = btf__load_vmlinux_btf(); + if (!ASSERT_OK_PTR(btf, "btf__load_vmlinux_btf")) + return false; + + nr = btf__type_cnt(btf); + for (type_id = 1; type_id < nr && !found; type_id++) { + const struct btf_type *type = btf__type_by_id(btf, type_id); + const char *str; + long addr; + __s32 id; + + if (!btf_is_func(type)) + continue; + + str = btf__name_by_offset(btf, type->name_off); + if (!str || strncmp(str, prefix, strlen(prefix))) + continue; + + snprintf(alias, sizeof(alias), "__do_sys_%s", str + strlen(prefix)); + id = btf__find_by_name_kind(btf, alias, BTF_KIND_FUNC); + if (id <= 0) + continue; + + addr = ksym_get_addr(str); + if (!addr || addr != ksym_get_addr(alias)) + continue; + + ids[0] = type_id; + ids[1] = id; + found = true; + } + + btf__free(btf); + return found; +} + +static void test_attach_same_addr(void) +{ + LIBBPF_OPTS(bpf_tracing_multi_opts, opts); + struct tracing_multi_fail *skel; + struct bpf_link *link; + __u32 ids[2]; + int i; + + if (!ASSERT_OK(load_kallsyms(), "load_kallsyms")) + return; + + if (!get_same_addr_ids(ids)) { + test__skip(); + return; + } + + skel = tracing_multi_fail__open_and_load(); + if (!ASSERT_OK_PTR(skel, "tracing_multi_fail__open_and_load")) + return; + + /* Each id attaches fine on its own.. */ + for (i = 0; i < 2; i++) { + opts.ids = &ids[i]; + opts.cnt = 1; + + link = bpf_program__attach_tracing_multi(skel->progs.test_fentry, NULL, &opts); + if (!ASSERT_OK_PTR(link, "attach_single")) + goto cleanup; + bpf_link__destroy(link); + } + + /* ..but there's only one call site, so not both of them. */ + opts.ids = ids; + opts.cnt = 2; + + link = bpf_program__attach_tracing_multi(skel->progs.test_fentry, NULL, &opts); + if (!ASSERT_EQ(libbpf_get_error(link), -EINVAL, "attach_same_addr")) + bpf_link__destroy(link); + +cleanup: + tracing_multi_fail__destroy(skel); +} + void serial_test_tracing_multi_bench_attach(void) { LIBBPF_OPTS(bpf_tracing_multi_opts, opts); @@ -748,6 +839,12 @@ void serial_test_tracing_multi_bench_attach(void) if (!btf_type_is_traceable_func(btf, type)) continue; + /* + * BTF can have more functions of the same name and they all + * resolve to the same address, take just the first one. + */ + tdelete(&str, &root, compare); + err = libbpf_ensure_mem((void **) &ids, &cap, sizeof(*ids), cnt + 1); if (err) goto cleanup; @@ -1023,6 +1120,8 @@ void test_tracing_multi_test(void) test_session(); if (test__start_subtest("attach_api_fails")) test_attach_api_fails(); + if (test__start_subtest("attach_same_addr")) + test_attach_same_addr(); RUN_TESTS(tracing_multi_verifier); if (test__start_subtest("fentry_after_multi")) test_fentry_after_multi(); |