struct_ops_refcounted_fail__tail_call.c

 1// SPDX-License-Identifier: GPL-2.0
 2/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
 3#include <vmlinux.h>
 4#include <bpf/bpf_tracing.h>
 5#include "../test_kmods/bpf_testmod.h"
 6#include "bpf_misc.h"
 7
 8char _license[] SEC("license") = "GPL";
 9
10struct {
11	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
12	__uint(max_entries, 1);
13	__uint(key_size, sizeof(__u32));
14	__uint(value_size, sizeof(__u32));
15} prog_array SEC(".maps");
16
17/* Test that the verifier rejects a program with referenced kptr arguments
18 * that tail call
19 */
20SEC("struct_ops/test_refcounted")
21__failure __msg("program with __ref argument cannot tail call")
22int refcounted_fail__tail_call(unsigned long long *ctx)
23{
24	struct task_struct *task = (struct task_struct *)ctx[1];
25
26	bpf_task_release(task);
27	bpf_tail_call(ctx, &prog_array, 0);
28
29	return 0;
30}
31
32SEC(".struct_ops.link")
33struct bpf_testmod_ops testmod_ref_acquire = {
34	.test_refcounted = (void *)refcounted_fail__tail_call,
35};
36