On Thu, Jul 17, 2025 at 12:49 PM Amery Hung <ameryhung@xxxxxxxxx> wrote:
>
> Test basic operations of task local data with valid and invalid
> tld_create_key().
>
> For invalid calls, make sure they return the right error code and check
> that the TLDs are not inserted by running tld_get_data("
> value_not_exists") on the bpf side. The call should a null pointer.
>
> For valid calls, first make sure the TLDs are created by calling
> tld_get_data() on the bpf side. The call should return a valid pointer.
>
> Finally, verify that the TLDs are indeed task-specific (i.e., their
> addresses do not overlap) with multiple user threads. This done by
> writing values unique to each thread, reading them from both user space
> and bpf, and checking if the value read back matches the value written.
>
> Signed-off-by: Amery Hung <ameryhung@xxxxxxxxx>
Reviewed-by: Emil Tsalapatis <emil@xxxxxxxxxxxxxxx>
> ---
> .../bpf/prog_tests/test_task_local_data.c | 192 ++++++++++++++++++
> .../bpf/progs/test_task_local_data.c | 65 ++++++
> 2 files changed, 257 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/test_task_local_data.c
> create mode 100644 tools/testing/selftests/bpf/progs/test_task_local_data.c
>
> 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
> new file mode 100644
> index 000000000000..fde4a030ab42
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c
> @@ -0,0 +1,192 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <pthread.h>
> +#include <bpf/btf.h>
> +#include <test_progs.h>
> +
> +#define TLD_FREE_DATA_ON_THREAD_EXIT
> +#define TLD_DYN_DATA_SIZE 4096
> +#include "task_local_data.h"
> +
> +struct test_tld_struct {
> + __u64 a;
> + __u64 b;
> + __u64 c;
> + __u64 d;
> +};
> +
> +#include "test_task_local_data.skel.h"
> +
> +TLD_DEFINE_KEY(value0_key, "value0", sizeof(int));
> +
> +/*
> + * Reset task local data between subtests by clearing metadata other
> + * than the statically defined value0. This is safe as subtests run
> + * sequentially. Users of task local data library should not touch
> + * library internal.
> + */
> +static void reset_tld(void)
> +{
> + if (TLD_READ_ONCE(tld_metadata_p)) {
> + /* Remove TLDs created by tld_create_key() */
> + tld_metadata_p->cnt = 1;
> + tld_metadata_p->size = TLD_DYN_DATA_SIZE;
> + memset(&tld_metadata_p->metadata[1], 0,
> + (TLD_MAX_DATA_CNT - 1) * sizeof(struct tld_metadata));
> + }
> +}
> +
> +/* Serialize access to bpf program's global variables */
> +static pthread_mutex_t global_mutex;
> +
> +static tld_key_t *tld_keys;
> +
> +#define TEST_BASIC_THREAD_NUM 32
> +
> +void *test_task_local_data_basic_thread(void *arg)
> +{
> + LIBBPF_OPTS(bpf_test_run_opts, opts);
> + struct test_task_local_data *skel = (struct test_task_local_data *)arg;
> + int fd, err, tid, *value0, *value1;
> + struct test_tld_struct *value2;
> +
> + fd = bpf_map__fd(skel->maps.tld_data_map);
> +
> + value0 = tld_get_data(fd, value0_key);
> + if (!ASSERT_OK_PTR(value0, "tld_get_data"))
> + goto out;
> +
> + value1 = tld_get_data(fd, tld_keys[1]);
> + if (!ASSERT_OK_PTR(value1, "tld_get_data"))
> + goto out;
> +
> + value2 = tld_get_data(fd, tld_keys[2]);
> + if (!ASSERT_OK_PTR(value2, "tld_get_data"))
> + goto out;
> +
> + tid = gettid();
> +
> + *value0 = tid + 0;
> + *value1 = tid + 1;
> + value2->a = tid + 2;
> + value2->b = tid + 3;
> + value2->c = tid + 4;
> + value2->d = tid + 5;
> +
> + pthread_mutex_lock(&global_mutex);
> + /* Run task_main that read task local data and save to global variables */
> + err = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.task_main), &opts);
> + ASSERT_OK(err, "run task_main");
> + ASSERT_OK(opts.retval, "task_main retval");
> +
> + ASSERT_EQ(skel->bss->test_value0, tid + 0, "tld_get_data value0");
> + ASSERT_EQ(skel->bss->test_value1, tid + 1, "tld_get_data value1");
> + ASSERT_EQ(skel->bss->test_value2.a, tid + 2, "tld_get_data value2.a");
> + ASSERT_EQ(skel->bss->test_value2.b, tid + 3, "tld_get_data value2.b");
> + ASSERT_EQ(skel->bss->test_value2.c, tid + 4, "tld_get_data value2.c");
> + ASSERT_EQ(skel->bss->test_value2.d, tid + 5, "tld_get_data value2.d");
> + pthread_mutex_unlock(&global_mutex);
> +
> + /* Make sure valueX are indeed local to threads */
> + ASSERT_EQ(*value0, tid + 0, "value0");
> + ASSERT_EQ(*value1, tid + 1, "value1");
> + ASSERT_EQ(value2->a, tid + 2, "value2.a");
> + ASSERT_EQ(value2->b, tid + 3, "value2.b");
> + ASSERT_EQ(value2->c, tid + 4, "value2.c");
> + ASSERT_EQ(value2->d, tid + 5, "value2.d");
> +
> + *value0 = tid + 5;
> + *value1 = tid + 4;
> + value2->a = tid + 3;
> + value2->b = tid + 2;
> + value2->c = tid + 1;
> + value2->d = tid + 0;
> +
> + /* Run task_main again */
> + pthread_mutex_lock(&global_mutex);
> + err = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.task_main), &opts);
> + ASSERT_OK(err, "run task_main");
> + ASSERT_OK(opts.retval, "task_main retval");
> +
> + ASSERT_EQ(skel->bss->test_value0, tid + 5, "tld_get_data value0");
> + ASSERT_EQ(skel->bss->test_value1, tid + 4, "tld_get_data value1");
> + ASSERT_EQ(skel->bss->test_value2.a, tid + 3, "tld_get_data value2.a");
> + ASSERT_EQ(skel->bss->test_value2.b, tid + 2, "tld_get_data value2.b");
> + ASSERT_EQ(skel->bss->test_value2.c, tid + 1, "tld_get_data value2.c");
> + ASSERT_EQ(skel->bss->test_value2.d, tid + 0, "tld_get_data value2.d");
> + pthread_mutex_unlock(&global_mutex);
> +
> +out:
> + pthread_exit(NULL);
> +}
> +
> +static void test_task_local_data_basic(void)
> +{
> + struct test_task_local_data *skel;
> + pthread_t thread[TEST_BASIC_THREAD_NUM];
> + char dummy_key_name[TLD_NAME_LEN];
> + tld_key_t key;
> + int i, err;
> +
> + reset_tld();
> +
> + ASSERT_OK(pthread_mutex_init(&global_mutex, NULL), "pthread_mutex_init");
> +
> + skel = test_task_local_data__open_and_load();
> + if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
> + return;
> +
> + tld_keys = calloc(TLD_MAX_DATA_CNT, sizeof(tld_key_t));
> + if (!ASSERT_OK_PTR(tld_keys, "calloc tld_keys"))
> + goto out;
> +
> + ASSERT_FALSE(tld_key_is_err(value0_key), "TLD_DEFINE_KEY");
> + tld_keys[1] = tld_create_key("value1", sizeof(int));
> + ASSERT_FALSE(tld_key_is_err(tld_keys[1]), "tld_create_key");
> + tld_keys[2] = tld_create_key("value2", sizeof(struct test_tld_struct));
> + ASSERT_FALSE(tld_key_is_err(tld_keys[2]), "tld_create_key");
> +
> + /*
> + * Shouldn't be able to store data exceed a page. Create a TLD just big
> + * enough to exceed a page. TLDs already created are int value0, int
> + * value1, and struct test_tld_struct value2.
> + */
> + key = tld_create_key("value_not_exist",
> + TLD_PAGE_SIZE - 2 * sizeof(int) - sizeof(struct test_tld_struct) + 1);
> + ASSERT_EQ(tld_key_err_or_zero(key), -E2BIG, "tld_create_key");
> +
> + key = tld_create_key("value2", sizeof(struct test_tld_struct));
> + ASSERT_EQ(tld_key_err_or_zero(key), -EEXIST, "tld_create_key");
> +
> + /* Shouldn't be able to create the (TLD_MAX_DATA_CNT+1)-th TLD */
> + for (i = 3; i < TLD_MAX_DATA_CNT; i++) {
> + snprintf(dummy_key_name, TLD_NAME_LEN, "dummy_value%d", i);
> + tld_keys[i] = tld_create_key(dummy_key_name, sizeof(int));
> + ASSERT_FALSE(tld_key_is_err(tld_keys[i]), "tld_create_key");
> + }
> + key = tld_create_key("value_not_exist", sizeof(struct test_tld_struct));
> + ASSERT_EQ(tld_key_err_or_zero(key), -ENOSPC, "tld_create_key");
> +
> + /* Access TLDs from multiple threads and check if they are thread-specific */
> + for (i = 0; i < TEST_BASIC_THREAD_NUM; i++) {
> + err = pthread_create(&thread[i], NULL, test_task_local_data_basic_thread, skel);
> + if (!ASSERT_OK(err, "pthread_create"))
> + goto out;
> + }
> +
> +out:
> + for (i = 0; i < TEST_BASIC_THREAD_NUM; i++)
> + pthread_join(thread[i], NULL);
> +
> + if (tld_keys) {
> + free(tld_keys);
> + tld_keys = NULL;
> + }
> + tld_free();
> + test_task_local_data__destroy(skel);
> +}
> +
> +void test_task_local_data(void)
> +{
> + if (test__start_subtest("task_local_data_basic"))
> + test_task_local_data_basic();
> +}
> diff --git a/tools/testing/selftests/bpf/progs/test_task_local_data.c b/tools/testing/selftests/bpf/progs/test_task_local_data.c
> new file mode 100644
> index 000000000000..fffafc013044
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_task_local_data.c
> @@ -0,0 +1,65 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <vmlinux.h>
> +#include <errno.h>
> +#include <bpf/bpf_helpers.h>
> +
> +#include "task_local_data.bpf.h"
> +
> +struct tld_keys {
> + tld_key_t value0;
> + tld_key_t value1;
> + tld_key_t value2;
> + tld_key_t value_not_exist;
> +};
> +
> +struct test_tld_struct {
> + __u64 a;
> + __u64 b;
> + __u64 c;
> + __u64 d;
> +};
> +
> +int test_value0;
> +int test_value1;
> +struct test_tld_struct test_value2;
> +
> +SEC("syscall")
> +int task_main(void *ctx)
> +{
> + struct tld_object tld_obj;
> + struct test_tld_struct *struct_p;
> + struct task_struct *task;
> + int err, *int_p;
> +
> + task = bpf_get_current_task_btf();
> + err = tld_object_init(task, &tld_obj);
> + if (err)
> + return 1;
> +
> + int_p = tld_get_data(&tld_obj, value0, "value0", sizeof(int));
> + if (int_p)
> + test_value0 = *int_p;
> + else
> + return 2;
> +
> + int_p = tld_get_data(&tld_obj, value1, "value1", sizeof(int));
> + if (int_p)
> + test_value1 = *int_p;
> + else
> + return 3;
> +
> + struct_p = tld_get_data(&tld_obj, value2, "value2", sizeof(struct test_tld_struct));
> + if (struct_p)
> + test_value2 = *struct_p;
> + else
> + return 4;
> +
> + int_p = tld_get_data(&tld_obj, value_not_exist, "value_not_exist", sizeof(int));
> + if (int_p)
> + return 5;
> +
> + return 0;
> +}
> +
> +char _license[] SEC("license") = "GPL";
> --
> 2.47.1
>
>
