1// SPDX-License-Identifier: GPL-2.0
2#include <vmlinux.h>
3#include <bpf/bpf_tracing.h>
4#include <bpf/bpf_helpers.h>
5#include "../bpf_testmod/bpf_testmod_kfunc.h"
6
7struct map_value {
8 struct prog_test_ref_kfunc __kptr *ptr;
9};
10
11struct {
12 __uint(type, BPF_MAP_TYPE_ARRAY);
13 __type(key, int);
14 __type(value, struct map_value);
15 __uint(max_entries, 16);
16} array_map SEC(".maps");
17
18static __noinline int cb1(void *map, void *key, void *value, void *ctx)
19{
20 void *p = *(void **)ctx;
21 bpf_kfunc_call_test_release(p);
22 /* Without the fix this would cause underflow */
23 return 0;
24}
25
26SEC("?tc")
27int underflow_prog(void *ctx)
28{
29 struct prog_test_ref_kfunc *p;
30 unsigned long sl = 0;
31
32 p = bpf_kfunc_call_test_acquire(scalar_ptr: &sl);
33 if (!p)
34 return 0;
35 bpf_for_each_map_elem(&array_map, cb1, &p, 0);
36 bpf_kfunc_call_test_release(p);
37 return 0;
38}
39
40static __always_inline int cb2(void *map, void *key, void *value, void *ctx)
41{
42 unsigned long sl = 0;
43
44 *(void **)ctx = bpf_kfunc_call_test_acquire(scalar_ptr: &sl);
45 /* Without the fix this would leak memory */
46 return 0;
47}
48
49SEC("?tc")
50int leak_prog(void *ctx)
51{
52 struct prog_test_ref_kfunc *p;
53 struct map_value *v;
54
55 v = bpf_map_lookup_elem(&array_map, &(int){0});
56 if (!v)
57 return 0;
58
59 p = NULL;
60 bpf_for_each_map_elem(&array_map, cb2, &p, 0);
61 p = bpf_kptr_xchg(&v->ptr, p);
62 if (p)
63 bpf_kfunc_call_test_release(p);
64 return 0;
65}
66
67static __always_inline int cb(void *map, void *key, void *value, void *ctx)
68{
69 return 0;
70}
71
72static __always_inline int cb3(void *map, void *key, void *value, void *ctx)
73{
74 unsigned long sl = 0;
75 void *p;
76
77 bpf_kfunc_call_test_acquire(scalar_ptr: &sl);
78 bpf_for_each_map_elem(&array_map, cb, &p, 0);
79 /* It should only complain here, not in cb. This is why we need
80 * callback_ref to be set to frameno.
81 */
82 return 0;
83}
84
85SEC("?tc")
86int nested_cb(void *ctx)
87{
88 struct prog_test_ref_kfunc *p;
89 unsigned long sl = 0;
90 int sp = 0;
91
92 p = bpf_kfunc_call_test_acquire(scalar_ptr: &sl);
93 if (!p)
94 return 0;
95 bpf_for_each_map_elem(&array_map, cb3, &sp, 0);
96 bpf_kfunc_call_test_release(p);
97 return 0;
98}
99
100SEC("?tc")
101int non_cb_transfer_ref(void *ctx)
102{
103 struct prog_test_ref_kfunc *p;
104 unsigned long sl = 0;
105
106 p = bpf_kfunc_call_test_acquire(scalar_ptr: &sl);
107 if (!p)
108 return 0;
109 cb1(NULL, NULL, NULL, &p);
110 bpf_kfunc_call_test_acquire(scalar_ptr: &sl);
111 return 0;
112}
113
114char _license[] SEC("license") = "GPL";
115

source code of linux/tools/testing/selftests/bpf/progs/cb_refs.c