Commit 41df0733 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Martin KaFai Lau
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selftests/bpf: validate struct_ops early failure detection logic 



Add a simple test that validates that libbpf will reject isolated
struct_ops program early with helpful warning message.

Also validate that explicit use of such BPF program through BPF skeleton
after BPF object is open won't trigger any warnings.

Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240507001335.1445325-7-andrii@kernel.org


Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parent c78420ba

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

+45 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 


#include "struct_ops_module.skel.h"

#include "struct_ops_nulled_out_cb.skel.h"

#include "struct_ops_forgotten_cb.skel.h"



static void check_map_info(struct bpf_map_info *info)

{
@@ -199,6 +200,48 @@ static void test_struct_ops_nulled_out_cb(void) 
	struct_ops_nulled_out_cb__destroy(skel);

}



/* validate that libbpf generates reasonable error message if struct_ops is

 * not referenced in any struct_ops map

 */

static void test_struct_ops_forgotten_cb(void)

{

	struct struct_ops_forgotten_cb *skel;

	char *log;

	int err;



	skel = struct_ops_forgotten_cb__open();

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

		return;



	start_libbpf_log_capture();



	err = struct_ops_forgotten_cb__load(skel);

	if (!ASSERT_ERR(err, "skel_load"))

		goto cleanup;



	log = stop_libbpf_log_capture();

	ASSERT_HAS_SUBSTR(log,

			  "prog 'test_1_forgotten': SEC(\"struct_ops\") program isn't referenced anywhere, did you forget to use it?",

			  "libbpf_log");

	free(log);



	struct_ops_forgotten_cb__destroy(skel);



	/* now let's programmatically use it, we should be fine now */

	skel = struct_ops_forgotten_cb__open();

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

		return;



	skel->struct_ops.ops->test_1 = skel->progs.test_1_forgotten; /* not anymore */



	err = struct_ops_forgotten_cb__load(skel);

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

		goto cleanup;



cleanup:

	struct_ops_forgotten_cb__destroy(skel);

}



void serial_test_struct_ops_module(void)

{

	if (test__start_subtest("test_struct_ops_load"))
@@ -209,5 +252,7 @@ void serial_test_struct_ops_module(void) 
		test_struct_ops_incompatible();

	if (test__start_subtest("test_struct_ops_null_out_cb"))

		test_struct_ops_nulled_out_cb();

	if (test__start_subtest("struct_ops_forgotten_cb"))

		test_struct_ops_forgotten_cb();

}

tools/testing/selftests/bpf/progs/struct_ops_forgotten_cb.c

0 → 100644
+19 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */

#include <vmlinux.h>

#include <bpf/bpf_tracing.h>

#include "../bpf_testmod/bpf_testmod.h"



char _license[] SEC("license") = "GPL";



SEC("struct_ops/test_1")

int BPF_PROG(test_1_forgotten)

{

	return 0;

}



SEC(".struct_ops.link")

struct bpf_testmod_ops ops = {

	/* we forgot to reference test_1_forgotten above, oops */

};