On Wed Jul 15, 2026 at 11:32 AM EDT, Leon Hwang wrote: > Add a test to verify that it is OK to iter the percpu_array map used for > global percpu data. > > Signed-off-by: Leon Hwang <[email protected]>
Reviewed-by: Emil Tsalapatis <[email protected]> > --- > .../bpf/prog_tests/global_data_init.c | 52 +++++++++++++++++++ > .../bpf/progs/test_global_percpu_data.c | 25 +++++++++ > 2 files changed, 77 insertions(+) > > diff --git a/tools/testing/selftests/bpf/prog_tests/global_data_init.c > b/tools/testing/selftests/bpf/prog_tests/global_data_init.c > index 598b7dde6581..e5a40ea36ee7 100644 > --- a/tools/testing/selftests/bpf/prog_tests/global_data_init.c > +++ b/tools/testing/selftests/bpf/prog_tests/global_data_init.c > @@ -283,6 +283,56 @@ static void test_global_percpu_data_verifier_log(void) > RUN_TESTS(test_global_percpu_data); > } > > +static void test_global_percpu_data_iter(void) > +{ > + DECLARE_LIBBPF_OPTS(bpf_iter_attach_opts, opts); > + struct test_global_percpu_data *skel; > + union bpf_iter_link_info linfo = {}; > + struct bpf_link *link = NULL; > + int fd, num_cpus, len, err; > + char buf[16]; > + > + num_cpus = libbpf_num_possible_cpus(); > + if (!ASSERT_GT(num_cpus, 0, "libbpf_num_possible_cpus")) > + return; > + > + skel = test_global_percpu_data__open(); > + if (!ASSERT_OK_PTR(skel, "test_global_percpu_data__open")) > + return; > + > + skel->rodata->num_cpus = num_cpus; > + skel->rodata->offsetof_num = offsetof(struct > test_global_percpu_data__percpu, struct_data); > + skel->rodata->offsetof_num += sizeof(skel->percpu->struct_data) - > sizeof(int); > + skel->rodata->elem_sz = roundup(sizeof(struct > test_global_percpu_data__percpu), 8); > + skel->percpu->struct_data.nums[6] = 0xc0de; > + > + err = test_global_percpu_data__load(skel); > + if (!ASSERT_OK(err, "test_global_percpu_data__load")) > + goto out; > + > + linfo.map.map_fd = bpf_map__fd(skel->maps.percpu); > + opts.link_info = &linfo; > + opts.link_info_len = sizeof(linfo); > + link = bpf_program__attach_iter(skel->progs.dump_percpu_data, &opts); > + if (!ASSERT_OK_PTR(link, "bpf_program__attach_iter")) > + goto out; > + > + fd = bpf_iter_create(bpf_link__fd(link)); > + if (!ASSERT_GE(fd, 0, "bpf_iter_create")) > + goto out; > + > + while ((len = read(fd, buf, sizeof(buf))) > 0) > + do { } while (0); > + ASSERT_EQ(len, 0, "read iter"); > + ASSERT_TRUE(skel->bss->run_iter, "run_iter"); > + ASSERT_EQ(skel->bss->percpu_data_sum, 0xc0de * num_cpus, > "percpu_data_sum"); > + > + close(fd); > +out: > + bpf_link__destroy(link); > + test_global_percpu_data__destroy(skel); > +} > + > void test_global_percpu_data(void) > { > if (!feat_supported(NULL, FEAT_PERCPU_DATA)) { > @@ -299,4 +349,6 @@ void test_global_percpu_data(void) > if (test__start_subtest("rdonly_direct_write")) > test_global_percpu_data_rdonly_direct_write(); > test_global_percpu_data_verifier_log(); > + if (test__start_subtest("iter")) > + test_global_percpu_data_iter(); > } > diff --git a/tools/testing/selftests/bpf/progs/test_global_percpu_data.c > b/tools/testing/selftests/bpf/progs/test_global_percpu_data.c > index b852a0b07508..8b1f625017d1 100644 > --- a/tools/testing/selftests/bpf/progs/test_global_percpu_data.c > +++ b/tools/testing/selftests/bpf/progs/test_global_percpu_data.c > @@ -53,4 +53,29 @@ int verifier_snprintf(void *ctx) > return 0; > } > > +volatile const __u32 num_cpus = 0; > +volatile const int offsetof_num; > +volatile const int elem_sz; > +__u32 percpu_data_sum = 0; > +bool run_iter = false; > + > +SEC("iter/bpf_map_elem") > +__auxiliary > +int dump_percpu_data(struct bpf_iter__bpf_map_elem *ctx) > +{ > + void *pptr = ctx->value; > + int i; > + > + if (!pptr) > + return 0; > + > + run_iter = true; > + > + for (i = 0; i < num_cpus; i++) { > + percpu_data_sum += *(int *) (pptr + offsetof_num); > + pptr += elem_sz; > + } > + return 0; > +} > + > char _license[] SEC("license") = "GPL";
