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 
8 char _license[] SEC("license") = "GPL";
9 
10 struct {
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  */
20 SEC("struct_ops/test_refcounted")
21 __failure __msg("program with __ref argument cannot tail call")
refcounted_fail__tail_call(unsigned long long * ctx)22 int 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 
32 SEC(".struct_ops.link")
33 struct bpf_testmod_ops testmod_ref_acquire = {
34 	.test_refcounted = (void *)refcounted_fail__tail_call,
35 };
36 
37