1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
3
4 #include <vmlinux.h>
5 #include <bpf/bpf_tracing.h>
6 #include <bpf/bpf_helpers.h>
7 #include <bpf/bpf_core_read.h>
8 #include "bpf_experimental.h"
9
10 struct node_data {
11 long key;
12 long data;
13 struct bpf_rb_node node;
14 };
15
16 struct root_nested_inner {
17 struct bpf_spin_lock glock;
18 struct bpf_rb_root root __contains(node_data, node);
19 };
20
21 struct root_nested {
22 struct root_nested_inner inner;
23 };
24
25 long less_callback_ran = -1;
26 long removed_key = -1;
27 long first_data[2] = {-1, -1};
28
29 #define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
30 private(A) struct bpf_spin_lock glock;
31 private(A) struct bpf_rb_root groot __contains(node_data, node);
32 private(A) struct bpf_rb_root groot_array[2] __contains(node_data, node);
33 private(A) struct bpf_rb_root groot_array_one[1] __contains(node_data, node);
34 private(B) struct root_nested groot_nested;
35
36 static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)
37 {
38 struct node_data *node_a;
39 struct node_data *node_b;
40
41 node_a = container_of(a, struct node_data, node);
42 node_b = container_of(b, struct node_data, node);
43 less_callback_ran = 1;
44
45 return node_a->key < node_b->key;
46 }
47
48 static long __add_three(struct bpf_rb_root *root, struct bpf_spin_lock *lock)
49 {
50 struct node_data *n, *m;
51
52 n = bpf_obj_new(typeof(*n));
53 if (!n)
54 return 1;
55 n->key = 5;
56
57 m = bpf_obj_new(typeof(*m));
58 if (!m) {
59 bpf_obj_drop(n);
60 return 2;
61 }
62 m->key = 1;
63
64 bpf_spin_lock(&glock);
65 bpf_rbtree_add(&groot, &n->node, less);
66 bpf_rbtree_add(&groot, &m->node, less);
67 bpf_spin_unlock(&glock);
68
69 n = bpf_obj_new(typeof(*n));
70 if (!n)
71 return 3;
72 n->key = 3;
73
74 bpf_spin_lock(&glock);
75 bpf_rbtree_add(&groot, &n->node, less);
76 bpf_spin_unlock(&glock);
77 return 0;
78 }
79
80 SEC("tc")
81 long rbtree_add_nodes(void *ctx)
82 {
83 return __add_three(&groot, &glock);
84 }
85
86 SEC("tc")
87 long rbtree_add_nodes_nested(void *ctx)
88 {
89 return __add_three(&groot_nested.inner.root, &groot_nested.inner.glock);
90 }
91
92 SEC("tc")
93 long rbtree_add_and_remove(void *ctx)
94 {
95 struct bpf_rb_node *res = NULL;
96 struct node_data *n, *m = NULL;
97
98 n = bpf_obj_new(typeof(*n));
99 if (!n)
100 goto err_out;
101 n->key = 5;
102
103 m = bpf_obj_new(typeof(*m));
104 if (!m)
105 goto err_out;
106 m->key = 3;
107
108 bpf_spin_lock(&glock);
109 bpf_rbtree_add(&groot, &n->node, less);
110 bpf_rbtree_add(&groot, &m->node, less);
111 res = bpf_rbtree_remove(&groot, &n->node);
112 bpf_spin_unlock(&glock);
113
114 if (!res)
115 return 1;
116
117 n = container_of(res, struct node_data, node);
118 removed_key = n->key;
119 bpf_obj_drop(n);
120
121 return 0;
122 err_out:
123 if (n)
124 bpf_obj_drop(n);
125 if (m)
126 bpf_obj_drop(m);
127 return 1;
128 }
129
130 SEC("tc")
131 long rbtree_add_and_remove_array(void *ctx)
132 {
133 struct bpf_rb_node *res1 = NULL, *res2 = NULL, *res3 = NULL;
134 struct node_data *nodes[3][2] = {{NULL, NULL}, {NULL, NULL}, {NULL, NULL}};
135 struct node_data *n;
136 long k1 = -1, k2 = -1, k3 = -1;
137 int i, j;
138
139 for (i = 0; i < 3; i++) {
140 for (j = 0; j < 2; j++) {
141 nodes[i][j] = bpf_obj_new(typeof(*nodes[i][j]));
142 if (!nodes[i][j])
143 goto err_out;
144 nodes[i][j]->key = i * 2 + j;
145 }
146 }
147
148 bpf_spin_lock(&glock);
149 for (i = 0; i < 2; i++)
150 for (j = 0; j < 2; j++)
151 bpf_rbtree_add(&groot_array[i], &nodes[i][j]->node, less);
152 for (j = 0; j < 2; j++)
153 bpf_rbtree_add(&groot_array_one[0], &nodes[2][j]->node, less);
154 res1 = bpf_rbtree_remove(&groot_array[0], &nodes[0][0]->node);
155 res2 = bpf_rbtree_remove(&groot_array[1], &nodes[1][0]->node);
156 res3 = bpf_rbtree_remove(&groot_array_one[0], &nodes[2][0]->node);
157 bpf_spin_unlock(&glock);
158
159 if (res1) {
160 n = container_of(res1, struct node_data, node);
161 k1 = n->key;
162 bpf_obj_drop(n);
163 }
164 if (res2) {
165 n = container_of(res2, struct node_data, node);
166 k2 = n->key;
167 bpf_obj_drop(n);
168 }
169 if (res3) {
170 n = container_of(res3, struct node_data, node);
171 k3 = n->key;
172 bpf_obj_drop(n);
173 }
174 if (k1 != 0 || k2 != 2 || k3 != 4)
175 return 2;
176
177 return 0;
178
179 err_out:
180 for (i = 0; i < 3; i++) {
181 for (j = 0; j < 2; j++) {
182 if (nodes[i][j])
183 bpf_obj_drop(nodes[i][j]);
184 }
185 }
186 return 1;
187 }
188
189 SEC("tc")
190 long rbtree_first_and_remove(void *ctx)
191 {
192 struct bpf_rb_node *res = NULL;
193 struct node_data *n, *m, *o;
194
195 n = bpf_obj_new(typeof(*n));
196 if (!n)
197 return 1;
198 n->key = 3;
199 n->data = 4;
200
201 m = bpf_obj_new(typeof(*m));
202 if (!m)
203 goto err_out;
204 m->key = 5;
205 m->data = 6;
206
207 o = bpf_obj_new(typeof(*o));
208 if (!o)
209 goto err_out;
210 o->key = 1;
211 o->data = 2;
212
213 bpf_spin_lock(&glock);
214 bpf_rbtree_add(&groot, &n->node, less);
215 bpf_rbtree_add(&groot, &m->node, less);
216 bpf_rbtree_add(&groot, &o->node, less);
217
218 res = bpf_rbtree_first(&groot);
219 if (!res) {
220 bpf_spin_unlock(&glock);
221 return 2;
222 }
223
224 o = container_of(res, struct node_data, node);
225 first_data[0] = o->data;
226
227 res = bpf_rbtree_remove(&groot, &o->node);
228 bpf_spin_unlock(&glock);
229
230 if (!res)
231 return 5;
232
233 o = container_of(res, struct node_data, node);
234 removed_key = o->key;
235 bpf_obj_drop(o);
236
237 bpf_spin_lock(&glock);
238 res = bpf_rbtree_first(&groot);
239 if (!res) {
240 bpf_spin_unlock(&glock);
241 return 3;
242 }
243
244 o = container_of(res, struct node_data, node);
245 first_data[1] = o->data;
246 bpf_spin_unlock(&glock);
247
248 return 0;
249 err_out:
250 if (n)
251 bpf_obj_drop(n);
252 if (m)
253 bpf_obj_drop(m);
254 return 1;
255 }
256
257 SEC("tc")
258 long rbtree_api_release_aliasing(void *ctx)
259 {
260 struct node_data *n, *m, *o;
261 struct bpf_rb_node *res, *res2;
262
263 n = bpf_obj_new(typeof(*n));
264 if (!n)
265 return 1;
266 n->key = 41;
267 n->data = 42;
268
269 bpf_spin_lock(&glock);
270 bpf_rbtree_add(&groot, &n->node, less);
271 bpf_spin_unlock(&glock);
272
273 bpf_spin_lock(&glock);
274
275 /* m and o point to the same node,
276 * but verifier doesn't know this
277 */
278 res = bpf_rbtree_first(&groot);
279 if (!res)
280 goto err_out;
281 o = container_of(res, struct node_data, node);
282
283 res = bpf_rbtree_first(&groot);
284 if (!res)
285 goto err_out;
286 m = container_of(res, struct node_data, node);
287
288 res = bpf_rbtree_remove(&groot, &m->node);
289 /* Retval of previous remove returns an owning reference to m,
290 * which is the same node non-owning ref o is pointing at.
291 * We can safely try to remove o as the second rbtree_remove will
292 * return NULL since the node isn't in a tree.
293 *
294 * Previously we relied on the verifier type system + rbtree_remove
295 * invalidating non-owning refs to ensure that rbtree_remove couldn't
296 * fail, but now rbtree_remove does runtime checking so we no longer
297 * invalidate non-owning refs after remove.
298 */
299 res2 = bpf_rbtree_remove(&groot, &o->node);
300
301 bpf_spin_unlock(&glock);
302
303 if (res) {
304 o = container_of(res, struct node_data, node);
305 first_data[0] = o->data;
306 bpf_obj_drop(o);
307 }
308 if (res2) {
309 /* The second remove fails, so res2 is null and this doesn't
310 * execute
311 */
312 m = container_of(res2, struct node_data, node);
313 first_data[1] = m->data;
314 bpf_obj_drop(m);
315 }
316 return 0;
317
318 err_out:
319 bpf_spin_unlock(&glock);
320 return 1;
321 }
322
323 char _license[] SEC("license") = "GPL";
324
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