linux/tools/testing/selftests/bpf/prog_tests/fexit_stress.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019 Facebook */
#include <test_progs.h>
#include "bpf_util.h"

void serial_test_fexit_stress(void)
{
	int bpf_max_tramp_links, err, i;
	int *fd, *fexit_fd, *link_fd;

	bpf_max_tramp_links = get_bpf_max_tramp_links();
	if (!ASSERT_GE(bpf_max_tramp_links, 1, "bpf_max_tramp_links"))
		return;
	fd = calloc(bpf_max_tramp_links * 2, sizeof(*fd));
	if (!ASSERT_OK_PTR(fd, "fd"))
		return;
	fexit_fd = fd;
	link_fd = fd + bpf_max_tramp_links;

	const struct bpf_insn trace_program[] = {
		BPF_MOV64_IMM(BPF_REG_0, 0),
		BPF_EXIT_INSN(),
	};

	LIBBPF_OPTS(bpf_prog_load_opts, trace_opts,
		.expected_attach_type = BPF_TRACE_FEXIT,
	);

	LIBBPF_OPTS(bpf_test_run_opts, topts);

	err = libbpf_find_vmlinux_btf_id("bpf_fentry_test1",
					 trace_opts.expected_attach_type);
	if (!ASSERT_GT(err, 0, "find_vmlinux_btf_id"))
		goto out;
	trace_opts.attach_btf_id = err;

	for (i = 0; i < bpf_max_tramp_links; i++) {
		fexit_fd[i] = bpf_prog_load(BPF_PROG_TYPE_TRACING, NULL, "GPL",
					    trace_program,
					    ARRAY_SIZE(trace_program),
					    &trace_opts);
		if (!ASSERT_GE(fexit_fd[i], 0, "fexit load"))
			goto out;
		link_fd[i] = bpf_link_create(fexit_fd[i], 0, BPF_TRACE_FEXIT, NULL);
		if (!ASSERT_GE(link_fd[i], 0, "fexit attach"))
			goto out;
	}

	err = bpf_prog_test_run_opts(fexit_fd[0], &topts);
	ASSERT_OK(err, "bpf_prog_test_run_opts");

out:
	for (i = 0; i < bpf_max_tramp_links; i++) {
		if (link_fd[i] > 0)
			close(link_fd[i]);
		if (fexit_fd[i] > 0)
			close(fexit_fd[i]);
	}
	free(fd);
}