Commit 406c557e authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann
Browse files

selftest/bpf: Add a recursion test 



Add recursive non-sleepable fentry program as a test.
All attach points where sleepable progs can execute are non recursive so far.
The recursion protection mechanism for sleepable cannot be activated yet.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-6-alexei.starovoitov@gmail.com
parent ca06f55b

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2021 Facebook */

#include <test_progs.h>

#include "recursion.skel.h"



void test_recursion(void)

{

	struct recursion *skel;

	int key = 0;

	int err;



	skel = recursion__open_and_load();

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

		return;



	err = recursion__attach(skel);

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

		goto out;



	ASSERT_EQ(skel->bss->pass1, 0, "pass1 == 0");

	bpf_map_lookup_elem(bpf_map__fd(skel->maps.hash1), &key, 0);

	ASSERT_EQ(skel->bss->pass1, 1, "pass1 == 1");

	bpf_map_lookup_elem(bpf_map__fd(skel->maps.hash1), &key, 0);

	ASSERT_EQ(skel->bss->pass1, 2, "pass1 == 2");



	ASSERT_EQ(skel->bss->pass2, 0, "pass2 == 0");

	bpf_map_lookup_elem(bpf_map__fd(skel->maps.hash2), &key, 0);

	ASSERT_EQ(skel->bss->pass2, 1, "pass2 == 1");

	bpf_map_lookup_elem(bpf_map__fd(skel->maps.hash2), &key, 0);

	ASSERT_EQ(skel->bss->pass2, 2, "pass2 == 2");

out:

	recursion__destroy(skel);

}

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

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// SPDX-License-Identifier: GPL-2.0

/* Copyright (c) 2021 Facebook */



#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>



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



struct {

	__uint(type, BPF_MAP_TYPE_HASH);

	__uint(max_entries, 1);

	__type(key, int);

	__type(value, long);

} hash1 SEC(".maps");



struct {

	__uint(type, BPF_MAP_TYPE_HASH);

	__uint(max_entries, 1);

	__type(key, int);

	__type(value, long);

} hash2 SEC(".maps");



int pass1 = 0;

int pass2 = 0;



SEC("fentry/__htab_map_lookup_elem")

int BPF_PROG(on_lookup, struct bpf_map *map)

{

	int key = 0;



	if (map == (void *)&hash1) {

		pass1++;

		return 0;

	}

	if (map == (void *)&hash2) {

		pass2++;

		/* htab_map_gen_lookup() will inline below call

		 * into direct call to __htab_map_lookup_elem()

		 */

		bpf_map_lookup_elem(&hash2, &key);

		return 0;

	}



	return 0;

}