Commit 6302bdeb authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add a kprobe_multi subtest to use addrs instead of syms 



Get addrs directly from available_filter_functions_addrs and
send to the kernel during kprobe_multi_attach. This avoids
consultation of /proc/kallsyms. But available_filter_functions_addrs
is introduced in 6.5, i.e., it is introduced recently,
so I skip the test if the kernel does not support it.

Signed-off-by: default avatarYonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240326041523.1200301-1-yonghong.song@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 9edaafad

tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c

+98 −0
Original line number Diff line number Diff line
@@ -477,6 +477,69 @@ static int get_syms(char ***symsp, size_t *cntp, bool kernel) 
	return err;

}



static int get_addrs(unsigned long **addrsp, size_t *cntp, bool kernel)

{

	unsigned long *addr, *addrs, *tmp_addrs;

	int err = 0, max_cnt, inc_cnt;

	char *name = NULL;

	size_t cnt = 0;

	char buf[256];

	FILE *f;



	if (access("/sys/kernel/tracing/trace", F_OK) == 0)

		f = fopen("/sys/kernel/tracing/available_filter_functions_addrs", "r");

	else

		f = fopen("/sys/kernel/debug/tracing/available_filter_functions_addrs", "r");



	if (!f)

		return -ENOENT;



	/* In my local setup, the number of entries is 50k+ so Let us initially

	 * allocate space to hold 64k entries. If 64k is not enough, incrementally

	 * increase 1k each time.

	 */

	max_cnt = 65536;

	inc_cnt = 1024;

	addrs = malloc(max_cnt * sizeof(long));

	if (addrs == NULL) {

		err = -ENOMEM;

		goto error;

	}



	while (fgets(buf, sizeof(buf), f)) {

		if (is_invalid_entry(buf, kernel))

			continue;



		free(name);

		if (sscanf(buf, "%p %ms$*[^\n]\n", &addr, &name) != 2)

			continue;

		if (skip_entry(name))

			continue;



		if (cnt == max_cnt) {

			max_cnt += inc_cnt;

			tmp_addrs = realloc(addrs, max_cnt);

			if (!tmp_addrs) {

				err = -ENOMEM;

				goto error;

			}

			addrs = tmp_addrs;

		}



		addrs[cnt++] = (unsigned long)addr;

	}



	*addrsp = addrs;

	*cntp = cnt;



error:

	free(name);

	fclose(f);

	if (err)

		free(addrs);

	return err;

}



static void do_bench_test(struct kprobe_multi_empty *skel, struct bpf_kprobe_multi_opts *opts)

{

	long attach_start_ns, attach_end_ns;
@@ -529,6 +592,37 @@ static void test_kprobe_multi_bench_attach(bool kernel) 
		free(syms);

}



static void test_kprobe_multi_bench_attach_addr(bool kernel)

{

	LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);

	struct kprobe_multi_empty *skel = NULL;

	unsigned long *addrs = NULL;

	size_t cnt = 0;

	int err;



	err = get_addrs(&addrs, &cnt, kernel);

	if (err == -ENOENT) {

		test__skip();

		return;

	}



	if (!ASSERT_OK(err, "get_addrs"))

		return;



	skel = kprobe_multi_empty__open_and_load();

	if (!ASSERT_OK_PTR(skel, "kprobe_multi_empty__open_and_load"))

		goto cleanup;



	opts.addrs = addrs;

	opts.cnt = cnt;



	do_bench_test(skel, &opts);



cleanup:

	kprobe_multi_empty__destroy(skel);

	free(addrs);

}



static void test_attach_override(void)

{

	struct kprobe_multi_override *skel = NULL;
@@ -569,6 +663,10 @@ void serial_test_kprobe_multi_bench_attach(void) 
		test_kprobe_multi_bench_attach(true);

	if (test__start_subtest("modules"))

		test_kprobe_multi_bench_attach(false);

	if (test__start_subtest("kernel"))

		test_kprobe_multi_bench_attach_addr(true);

	if (test__start_subtest("modules"))

		test_kprobe_multi_bench_attach_addr(false);

}



void test_kprobe_multi_test(void)