[PATCH RFCv3 16/23] selftests/bpf: Add hit/attach/detach race optimized uprobe test

Jiri Olsa
2025-03-20T11:45:05Z

Adding test that makes sure parallel execution of the uprobe and
attach/detach of optimized uprobe on it works properly.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../selftests/bpf/prog_tests/uprobe_syscall.c | 74 +++++++++++++++++++
1 file changed, 74 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index d648bf8eca64..5c10cf173e6d 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
@@ -600,6 +600,78 @@ static void test_uprobe_usdt(void)
uprobe_syscall_executed__destroy(skel);
}

+static volatile bool race_stop;
+
+static void *worker_trigger(void *arg)
+{
+ unsigned long rounds = 0;
+
+ while (!race_stop) {
+ uprobe_test();
+ rounds++;
+ }
+
+ printf("tid %d trigger rounds: %lu\n", gettid(), rounds);
+ return NULL;
+}
+
+static void *worker_attach(void *arg)
+{
+ struct uprobe_syscall_executed *skel;
+ unsigned long rounds = 0, offset;
+
+ offset = get_uprobe_offset(&uprobe_test);
+ if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
+ return NULL;
+
+ skel = uprobe_syscall_executed__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
+ return NULL;
+
+ while (!race_stop) {
+ skel->links.test_uprobe = bpf_program__attach_uprobe_opts(skel->progs.test_uprobe,
+ 0, "/proc/self/exe", offset, NULL);
+ if (!ASSERT_OK_PTR(skel->links.test_uprobe, "bpf_program__attach_uprobe_opts"))
+ break;
+
+ bpf_link__destroy(skel->links.test_uprobe);
+ skel->links.test_uprobe = NULL;
+ rounds++;
+ }
+
+ printf("tid %d attach rounds: %lu hits: %d\n", gettid(), rounds, skel->bss->executed);
+ uprobe_syscall_executed__destroy(skel);
+ return NULL;
+}
+
+static void test_uprobe_race(void)
+{
+ int err, i, nr_threads;
+ pthread_t *threads;
+
+ nr_threads = libbpf_num_possible_cpus();
+ if (!ASSERT_GE(nr_threads, 0, "libbpf_num_possible_cpus"))
+ return;
+
+ threads = malloc(sizeof(*threads) * nr_threads);
+ if (!ASSERT_OK_PTR(threads, "malloc"))
+ return;
+
+ for (i = 0; i < nr_threads; i++) {
+ err = pthread_create(&threads[i], NULL, i % 2 ? worker_trigger : worker_attach,
+ NULL);
+ if (!ASSERT_OK(err, "pthread_create"))
+ goto cleanup;
+ }
+
+ sleep(4);
+
+cleanup:
+ race_stop = true;
+ for (nr_threads = i, i = 0; i < nr_threads; i++)
+ pthread_join(threads[i], NULL);
+}
+
static void __test_uprobe_syscall(void)
{
if (test__start_subtest("uretprobe_regs_equal"))
@@ -618,6 +690,8 @@ static void __test_uprobe_syscall(void)
test_uprobe_session();
if (test__start_subtest("uprobe_usdt"))
test_uprobe_usdt();
+ if (test__start_subtest("uprobe_race"))
+ test_uprobe_race();
}
#else
static void __test_uprobe_syscall(void)
--
2.49.0