[bpf-next,11/13] selftests/bpf: Add hit/attach/detach race optimized uprobe test

Commit Message

Jiri Olsa Dec. 11, 2024, 1:34 p.m. UTC

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 <[e-mail]>
---
 .../selftests/bpf/prog_tests/uprobe_syscall.c | 82 +++++++++++++++++++
 1 file changed, 82 insertions(+)

Comments

Andrii Nakryiko Dec. 13, 2024, 9:58 p.m. UTC | #1

On Wed, Dec 11, 2024 at 5:36 AM Jiri Olsa <[e-mail]> wrote:
>
> 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 <[e-mail]>
> ---
>  .../selftests/bpf/prog_tests/uprobe_syscall.c | 82 +++++++++++++++++++
>  1 file changed, 82 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
> index 1dbc26a1130c..eacd14db8f8d 100644
> --- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
> +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
> @@ -532,6 +532,81 @@ static void test_uprobe_usdt(void)
>  cleanup:
>         uprobe_optimized__destroy(skel);
>  }
> +
> +static bool race_stop;

volatile?

> +
> +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_optimized *skel;
> +       unsigned long rounds = 0;
> +
> +       skel = uprobe_optimized__open_and_load();
> +       if (!ASSERT_OK_PTR(skel, "uprobe_optimized__open_and_load"))
> +               goto cleanup;
> +
> +       while (!race_stop) {
> +               skel->links.test_2 = bpf_program__attach_uprobe_multi(skel->progs.test_2, -1,
> +                                               "/proc/self/exe", "uprobe_test_nop5", NULL);
> +               if (!ASSERT_OK_PTR(skel->links.test_2, "bpf_program__attach_uprobe_multi"))
> +                       break;
> +               bpf_link__destroy(skel->links.test_2);
> +               skel->links.test_2 = NULL;
> +               rounds++;
> +       }
> +
> +       printf("tid %d attach rounds: %lu hits: %lu\n", gettid(), rounds, skel->bss->executed);
> +
> +cleanup:
> +       uprobe_optimized__destroy(skel);
> +       return NULL;
> +}
> +
> +static void test_uprobe_race(void)
> +{
> +       int err, i, nr_cpus, nr;
> +       pthread_t *threads;
> +
> +        nr_cpus = libbpf_num_possible_cpus();

check whitespaces

> +       if (!ASSERT_GE(nr_cpus, 0, "nr_cpus"))
> +               return;
> +
> +       nr = nr_cpus * 2;
> +       threads = malloc(sizeof(*threads) * nr);
> +       if (!ASSERT_OK_PTR(threads, "malloc"))
> +               return;
> +
> +       for (i = 0; i < nr_cpus; i++) {
> +               err = pthread_create(&threads[i], NULL, worker_trigger, NULL);
> +               if (!ASSERT_OK(err, "pthread_create"))
> +                       goto cleanup;
> +       }
> +
> +       for (; i < nr; i++) {
> +               err = pthread_create(&threads[i], NULL, worker_attach, NULL);
> +               if (!ASSERT_OK(err, "pthread_create"))
> +                       goto cleanup;
> +       }
> +
> +       sleep(4);
> +
> +cleanup:
> +       race_stop = true;
> +       for (i = 0; i < nr; i++)
> +               pthread_join(threads[i], NULL);

what happens with pthread_join() when called with uninitialized
threads[i] (e.g., when error happens in the middle of creating
threads)?


> +}
>  #else
>  static void test_uretprobe_regs_equal(void)
>  {
> @@ -567,6 +642,11 @@ static void test_uprobe_usdt(void)
>  {
>         test__skip();
>  }
> +
> +static void test_uprobe_race(void)
> +{
> +       test__skip();
> +}
>  #endif
>
>  void test_uprobe_syscall(void)
> @@ -585,4 +665,6 @@ void test_uprobe_syscall(void)
>                 test_uprobe_multi();
>         if (test__start_subtest("uprobe_usdt"))
>                 test_uprobe_usdt();
> +       if (test__start_subtest("uprobe_race"))
> +               test_uprobe_race();
>  }
> --
> 2.47.0
>

Jiri Olsa Dec. 16, 2024, 7:59 a.m. UTC | #2

On Fri, Dec 13, 2024 at 01:58:43PM -0800, Andrii Nakryiko wrote:
> On Wed, Dec 11, 2024 at 5:36 AM Jiri Olsa <[e-mail]> wrote:
> >
> > 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 <[e-mail]>
> > ---
> >  .../selftests/bpf/prog_tests/uprobe_syscall.c | 82 +++++++++++++++++++
> >  1 file changed, 82 insertions(+)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
> > index 1dbc26a1130c..eacd14db8f8d 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
> > @@ -532,6 +532,81 @@ static void test_uprobe_usdt(void)
> >  cleanup:
> >         uprobe_optimized__destroy(skel);
> >  }
> > +
> > +static bool race_stop;
> 
> volatile?

ok

> 
> > +
> > +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_optimized *skel;
> > +       unsigned long rounds = 0;
> > +
> > +       skel = uprobe_optimized__open_and_load();
> > +       if (!ASSERT_OK_PTR(skel, "uprobe_optimized__open_and_load"))
> > +               goto cleanup;
> > +
> > +       while (!race_stop) {
> > +               skel->links.test_2 = bpf_program__attach_uprobe_multi(skel->progs.test_2, -1,
> > +                                               "/proc/self/exe", "uprobe_test_nop5", NULL);
> > +               if (!ASSERT_OK_PTR(skel->links.test_2, "bpf_program__attach_uprobe_multi"))
> > +                       break;
> > +               bpf_link__destroy(skel->links.test_2);
> > +               skel->links.test_2 = NULL;
> > +               rounds++;
> > +       }
> > +
> > +       printf("tid %d attach rounds: %lu hits: %lu\n", gettid(), rounds, skel->bss->executed);
> > +
> > +cleanup:
> > +       uprobe_optimized__destroy(skel);
> > +       return NULL;
> > +}
> > +
> > +static void test_uprobe_race(void)
> > +{
> > +       int err, i, nr_cpus, nr;
> > +       pthread_t *threads;
> > +
> > +        nr_cpus = libbpf_num_possible_cpus();
> 
> check whitespaces

ok

> 
> > +       if (!ASSERT_GE(nr_cpus, 0, "nr_cpus"))
> > +               return;
> > +
> > +       nr = nr_cpus * 2;
> > +       threads = malloc(sizeof(*threads) * nr);
> > +       if (!ASSERT_OK_PTR(threads, "malloc"))
> > +               return;
> > +
> > +       for (i = 0; i < nr_cpus; i++) {
> > +               err = pthread_create(&threads[i], NULL, worker_trigger, NULL);
> > +               if (!ASSERT_OK(err, "pthread_create"))
> > +                       goto cleanup;
> > +       }
> > +
> > +       for (; i < nr; i++) {
> > +               err = pthread_create(&threads[i], NULL, worker_attach, NULL);
> > +               if (!ASSERT_OK(err, "pthread_create"))
> > +                       goto cleanup;
> > +       }
> > +
> > +       sleep(4);
> > +
> > +cleanup:
> > +       race_stop = true;
> > +       for (i = 0; i < nr; i++)
> > +               pthread_join(threads[i], NULL);
> 
> what happens with pthread_join() when called with uninitialized
> threads[i] (e.g., when error happens in the middle of creating
> threads)?

yes, I'll do the proper cleanup in new version

thanks,
jirka

Patch

diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index 1dbc26a1130c..eacd14db8f8d 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
@@ -532,6 +532,81 @@  static void test_uprobe_usdt(void)
 cleanup:
 	uprobe_optimized__destroy(skel);
 }
+
+static 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_optimized *skel;
+	unsigned long rounds = 0;
+
+	skel = uprobe_optimized__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_optimized__open_and_load"))
+		goto cleanup;
+
+	while (!race_stop) {
+		skel->links.test_2 = bpf_program__attach_uprobe_multi(skel->progs.test_2, -1,
+						"/proc/self/exe", "uprobe_test_nop5", NULL);
+		if (!ASSERT_OK_PTR(skel->links.test_2, "bpf_program__attach_uprobe_multi"))
+			break;
+		bpf_link__destroy(skel->links.test_2);
+		skel->links.test_2 = NULL;
+		rounds++;
+	}
+
+	printf("tid %d attach rounds: %lu hits: %lu\n", gettid(), rounds, skel->bss->executed);
+
+cleanup:
+	uprobe_optimized__destroy(skel);
+	return NULL;
+}
+
+static void test_uprobe_race(void)
+{
+	int err, i, nr_cpus, nr;
+	pthread_t *threads;
+
+        nr_cpus = libbpf_num_possible_cpus();
+	if (!ASSERT_GE(nr_cpus, 0, "nr_cpus"))
+		return;
+
+	nr = nr_cpus * 2;
+	threads = malloc(sizeof(*threads) * nr);
+	if (!ASSERT_OK_PTR(threads, "malloc"))
+		return;
+
+	for (i = 0; i < nr_cpus; i++) {
+		err = pthread_create(&threads[i], NULL, worker_trigger, NULL);
+		if (!ASSERT_OK(err, "pthread_create"))
+			goto cleanup;
+	}
+
+	for (; i < nr; i++) {
+		err = pthread_create(&threads[i], NULL, worker_attach, NULL);
+		if (!ASSERT_OK(err, "pthread_create"))
+			goto cleanup;
+	}
+
+	sleep(4);
+
+cleanup:
+	race_stop = true;
+	for (i = 0; i < nr; i++)
+		pthread_join(threads[i], NULL);
+}
 #else
 static void test_uretprobe_regs_equal(void)
 {
@@ -567,6 +642,11 @@  static void test_uprobe_usdt(void)
 {
 	test__skip();
 }
+
+static void test_uprobe_race(void)
+{
+	test__skip();
+}
 #endif
 
 void test_uprobe_syscall(void)
@@ -585,4 +665,6 @@  void test_uprobe_syscall(void)
 		test_uprobe_multi();
 	if (test__start_subtest("uprobe_usdt"))
 		test_uprobe_usdt();
+	if (test__start_subtest("uprobe_race"))
+		test_uprobe_race();
 }