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 long less_callback_ran = -1; 17 long removed_key = -1; 18 long first_data[2] = {-1, -1}; 19 20 #define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8))) 21 private(A) struct bpf_spin_lock glock; 22 private(A) struct bpf_rb_root groot __contains(node_data, node); 23 24 static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b) 25 { 26 struct node_data *node_a; 27 struct node_data *node_b; 28 29 node_a = container_of(a, struct node_data, node); 30 node_b = container_of(b, struct node_data, node); 31 less_callback_ran = 1; 32 33 return node_a->key < node_b->key; 34 } 35 36 static long __add_three(struct bpf_rb_root *root, struct bpf_spin_lock *lock) 37 { 38 struct node_data *n, *m; 39 40 n = bpf_obj_new(typeof(*n)); 41 if (!n) 42 return 1; 43 n->key = 5; 44 45 m = bpf_obj_new(typeof(*m)); 46 if (!m) { 47 bpf_obj_drop(n); 48 return 2; 49 } 50 m->key = 1; 51 52 bpf_spin_lock(&glock); 53 bpf_rbtree_add(&groot, &n->node, less); 54 bpf_rbtree_add(&groot, &m->node, less); 55 bpf_spin_unlock(&glock); 56 57 n = bpf_obj_new(typeof(*n)); 58 if (!n) 59 return 3; 60 n->key = 3; 61 62 bpf_spin_lock(&glock); 63 bpf_rbtree_add(&groot, &n->node, less); 64 bpf_spin_unlock(&glock); 65 return 0; 66 } 67 68 SEC("tc") 69 long rbtree_add_nodes(void *ctx) 70 { 71 return __add_three(&groot, &glock); 72 } 73 74 SEC("tc") 75 long rbtree_add_and_remove(void *ctx) 76 { 77 struct bpf_rb_node *res = NULL; 78 struct node_data *n, *m = NULL; 79 80 n = bpf_obj_new(typeof(*n)); 81 if (!n) 82 goto err_out; 83 n->key = 5; 84 85 m = bpf_obj_new(typeof(*m)); 86 if (!m) 87 goto err_out; 88 m->key = 3; 89 90 bpf_spin_lock(&glock); 91 bpf_rbtree_add(&groot, &n->node, less); 92 bpf_rbtree_add(&groot, &m->node, less); 93 res = bpf_rbtree_remove(&groot, &n->node); 94 bpf_spin_unlock(&glock); 95 96 if (!res) 97 return 1; 98 99 n = container_of(res, struct node_data, node); 100 removed_key = n->key; 101 bpf_obj_drop(n); 102 103 return 0; 104 err_out: 105 if (n) 106 bpf_obj_drop(n); 107 if (m) 108 bpf_obj_drop(m); 109 return 1; 110 } 111 112 SEC("tc") 113 long rbtree_first_and_remove(void *ctx) 114 { 115 struct bpf_rb_node *res = NULL; 116 struct node_data *n, *m, *o; 117 118 n = bpf_obj_new(typeof(*n)); 119 if (!n) 120 return 1; 121 n->key = 3; 122 n->data = 4; 123 124 m = bpf_obj_new(typeof(*m)); 125 if (!m) 126 goto err_out; 127 m->key = 5; 128 m->data = 6; 129 130 o = bpf_obj_new(typeof(*o)); 131 if (!o) 132 goto err_out; 133 o->key = 1; 134 o->data = 2; 135 136 bpf_spin_lock(&glock); 137 bpf_rbtree_add(&groot, &n->node, less); 138 bpf_rbtree_add(&groot, &m->node, less); 139 bpf_rbtree_add(&groot, &o->node, less); 140 141 res = bpf_rbtree_first(&groot); 142 if (!res) { 143 bpf_spin_unlock(&glock); 144 return 2; 145 } 146 147 o = container_of(res, struct node_data, node); 148 first_data[0] = o->data; 149 150 res = bpf_rbtree_remove(&groot, &o->node); 151 bpf_spin_unlock(&glock); 152 153 if (!res) 154 return 5; 155 156 o = container_of(res, struct node_data, node); 157 removed_key = o->key; 158 bpf_obj_drop(o); 159 160 bpf_spin_lock(&glock); 161 res = bpf_rbtree_first(&groot); 162 if (!res) { 163 bpf_spin_unlock(&glock); 164 return 3; 165 } 166 167 o = container_of(res, struct node_data, node); 168 first_data[1] = o->data; 169 bpf_spin_unlock(&glock); 170 171 return 0; 172 err_out: 173 if (n) 174 bpf_obj_drop(n); 175 if (m) 176 bpf_obj_drop(m); 177 return 1; 178 } 179 180 SEC("tc") 181 long rbtree_api_release_aliasing(void *ctx) 182 { 183 struct node_data *n, *m, *o; 184 struct bpf_rb_node *res, *res2; 185 186 n = bpf_obj_new(typeof(*n)); 187 if (!n) 188 return 1; 189 n->key = 41; 190 n->data = 42; 191 192 bpf_spin_lock(&glock); 193 bpf_rbtree_add(&groot, &n->node, less); 194 bpf_spin_unlock(&glock); 195 196 bpf_spin_lock(&glock); 197 198 /* m and o point to the same node, 199 * but verifier doesn't know this 200 */ 201 res = bpf_rbtree_first(&groot); 202 if (!res) 203 goto err_out; 204 o = container_of(res, struct node_data, node); 205 206 res = bpf_rbtree_first(&groot); 207 if (!res) 208 goto err_out; 209 m = container_of(res, struct node_data, node); 210 211 res = bpf_rbtree_remove(&groot, &m->node); 212 /* Retval of previous remove returns an owning reference to m, 213 * which is the same node non-owning ref o is pointing at. 214 * We can safely try to remove o as the second rbtree_remove will 215 * return NULL since the node isn't in a tree. 216 * 217 * Previously we relied on the verifier type system + rbtree_remove 218 * invalidating non-owning refs to ensure that rbtree_remove couldn't 219 * fail, but now rbtree_remove does runtime checking so we no longer 220 * invalidate non-owning refs after remove. 221 */ 222 res2 = bpf_rbtree_remove(&groot, &o->node); 223 224 bpf_spin_unlock(&glock); 225 226 if (res) { 227 o = container_of(res, struct node_data, node); 228 first_data[0] = o->data; 229 bpf_obj_drop(o); 230 } 231 if (res2) { 232 /* The second remove fails, so res2 is null and this doesn't 233 * execute 234 */ 235 m = container_of(res2, struct node_data, node); 236 first_data[1] = m->data; 237 bpf_obj_drop(m); 238 } 239 return 0; 240 241 err_out: 242 bpf_spin_unlock(&glock); 243 return 1; 244 } 245 246 char _license[] SEC("license") = "GPL"; 247