1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
3
4 #include <vmlinux.h>
5 #include <bpf/bpf_helpers.h>
6 #include <bpf/bpf_tracing.h>
7 #include <bpf/bpf_core_read.h>
8 #include "../bpf_experimental.h"
9 #include "bpf_misc.h"
10
11 struct node_data {
12 long key;
13 long data;
14 struct bpf_rb_node node;
15 };
16
17 struct map_value {
18 struct node_data __kptr *node;
19 };
20
21 struct node_data2 {
22 long key[4];
23 };
24
25 /* This is necessary so that LLVM generates BTF for node_data struct
26 * If it's not included, a fwd reference for node_data will be generated but
27 * no struct. Example BTF of "node" field in map_value when not included:
28 *
29 * [10] PTR '(anon)' type_id=35
30 * [34] FWD 'node_data' fwd_kind=struct
31 * [35] TYPE_TAG 'kptr_ref' type_id=34
32 */
33 struct node_data *just_here_because_btf_bug;
34
35 struct {
36 __uint(type, BPF_MAP_TYPE_ARRAY);
37 __type(key, int);
38 __type(value, struct map_value);
39 __uint(max_entries, 2);
40 } some_nodes SEC(".maps");
41
42 SEC("tc")
43 __failure __msg("invalid kptr access, R2 type=ptr_node_data2 expected=ptr_node_data")
stash_rb_nodes(void * ctx)44 long stash_rb_nodes(void *ctx)
45 {
46 struct map_value *mapval;
47 struct node_data2 *res;
48 int idx = 0;
49
50 mapval = bpf_map_lookup_elem(&some_nodes, &idx);
51 if (!mapval)
52 return 1;
53
54 res = bpf_obj_new(typeof(*res));
55 if (!res)
56 return 1;
57 res->key[0] = 40;
58
59 res = bpf_kptr_xchg(&mapval->node, res);
60 if (res)
61 bpf_obj_drop(res);
62 return 0;
63 }
64
65 SEC("tc")
66 __failure __msg("R1 must have zero offset when passed to release func")
drop_rb_node_off(void * ctx)67 long drop_rb_node_off(void *ctx)
68 {
69 struct map_value *mapval;
70 struct node_data *res;
71 int idx = 0;
72
73 mapval = bpf_map_lookup_elem(&some_nodes, &idx);
74 if (!mapval)
75 return 1;
76
77 res = bpf_obj_new(typeof(*res));
78 if (!res)
79 return 1;
80 /* Try releasing with graph node offset */
81 bpf_obj_drop(&res->node);
82 return 0;
83 }
84
85 char _license[] SEC("license") = "GPL";
86