Test thread-safety of tld_create_key(). Since tld_create_key() does
not rely on locks but memory barriers and atomic operations to protect
the shared metadata, the thread-safety of the function is non-trivial.
Make sure concurrent tld_key_create(), both valid and invalid, can not
race and corrupt metatada, which may leads to TLDs not being thread-
specific or duplicate TLDs with the same name.
Signed-off-by: Amery Hung <ameryhung@xxxxxxxxx>
---
.../bpf/prog_tests/test_task_local_data.c | 91 +++++++++++++++++++
1 file changed, 91 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c b/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c
index 738fc1c9d8a4..5743b753a4a1 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c
@@ -156,8 +156,99 @@ static void test_task_local_data_basic(void)
pthread_join(thread[i], NULL);
}
+#define TEST_RACE_THREAD_NUM 61
+
+void *test_task_local_data_race_thread(void *arg)
+{
+ char key_name[32];
+ tld_key_t key;
+ int id, fd;
+
+ id = (intptr_t)arg & 0x0000ffff;
+ fd = ((intptr_t)arg & 0xffff0000) >> 16;
+
+ key = tld_create_key(fd, "value_not_exist", PAGE_SIZE + 1);
+ ASSERT_EQ(tld_key_err_or_zero(key), -E2BIG, "tld_create_key");
+
+ /*
+ * If more than one thread succeed in creating value1 or value2,
+ * some threads will fail to create thread_<id> later.
+ */
+ key = tld_create_key(fd, "value1", sizeof(int));
+ if (!tld_key_is_err(key))
+ tld_keys[TEST_RACE_THREAD_NUM] = key;
+ key = tld_create_key(fd, "value2", sizeof(struct test_struct));
+ if (!tld_key_is_err(key))
+ tld_keys[TEST_RACE_THREAD_NUM + 1] = key;
+
+ snprintf(key_name, 32, "thread_%d", id);
+ tld_keys[id] = tld_create_key(fd, key_name, sizeof(int));
+ ASSERT_FALSE(tld_key_is_err(tld_keys[id]), "tld_create_key");
+
+ pthread_exit(NULL);
+}
+
+static void test_task_local_data_race(void)
+{
+ LIBBPF_OPTS(bpf_test_run_opts, opts);
+ pthread_t thread[TEST_RACE_THREAD_NUM];
+ struct test_task_local_data *skel;
+ int fd, i, j, err, *data, arg;
+
+ skel = test_task_local_data__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
+ return;
+
+ fd = bpf_map__fd(skel->maps.tld_data_map);
+
+ for (j = 0; j < 100; j++) {
+ reset_tld();
+
+ for (i = 0; i < TEST_RACE_THREAD_NUM; i++) {
+ /*
+ * Try to make tld_create_key() race with each other. Call
+ * tld_create_key(), both valid and invalid, from different threads.
+ */
+ arg = i | fd << 16;
+ err = pthread_create(&thread[i], NULL, test_task_local_data_race_thread,
+ (void *)(intptr_t)arg);
+ if (!ASSERT_OK(err, "pthread_create"))
+ goto out;
+ }
+
+ /* Wait for all tld_create_key() to return */
+ for (i = 0; i < TEST_RACE_THREAD_NUM; i++)
+ pthread_join(thread[i], NULL);
+
+ /* Run task_init to make sure no invalid TLDs are added */
+ err = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.task_init), &opts);
+ ASSERT_OK(err, "run task_init");
+ ASSERT_OK(opts.retval, "task_init retval");
+
+ /* Write a unique number in the range of [0, TEST_RACE_THREAD_NUM) to each TLD */
+ for (i = 0; i < TEST_RACE_THREAD_NUM; i++) {
+ data = tld_get_data(fd, tld_keys[i]);
+ if (!ASSERT_OK_PTR(data, "tld_get_data"))
+ goto out;
+ *data = i;
+ }
+
+ /* Read TLDs and check the value to see if any address collides with another */
+ for (i = 0; i < TEST_RACE_THREAD_NUM; i++) {
+ data = tld_get_data(fd, tld_keys[i]);
+ if (!ASSERT_OK_PTR(data, "tld_get_data"))
+ goto out;
+ ASSERT_EQ(*data, i, "check TLD");
+ }
+ }
+out:
+ tld_free();
+}
+
void test_task_local_data(void)
{
if (test__start_subtest("task_local_data_basic"))
test_task_local_data_basic();
+ if (test__start_subtest("task_local_data_race"))
+ test_task_local_data_race();
}
--
2.47.1
