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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#include "bpf_experimental.h"
struct node_data {
struct bpf_refcount ref;
struct bpf_rb_node r0;
struct bpf_rb_node r1;
int key0;
int key1;
};
#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
private(A) struct bpf_spin_lock glock0;
private(A) struct bpf_rb_root groot0 __contains(node_data, r0);
private(B) struct bpf_spin_lock glock1;
private(B) struct bpf_rb_root groot1 __contains(node_data, r1);
#define rb_entry(ptr, type, member) container_of(ptr, type, member)
#define NR_NODES 16
int zero = 0;
static bool less0(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
struct node_data *node_a;
struct node_data *node_b;
node_a = rb_entry(a, struct node_data, r0);
node_b = rb_entry(b, struct node_data, r0);
return node_a->key0 < node_b->key0;
}
static bool less1(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
struct node_data *node_a;
struct node_data *node_b;
node_a = rb_entry(a, struct node_data, r1);
node_b = rb_entry(b, struct node_data, r1);
return node_a->key1 < node_b->key1;
}
SEC("syscall")
__retval(0)
long rbtree_search(void *ctx)
{
struct bpf_rb_node *rb_n, *rb_m, *gc_ns[NR_NODES];
long lookup_key = NR_NODES / 2;
struct node_data *n, *m;
int i, nr_gc = 0;
for (i = zero; i < NR_NODES && can_loop; i++) {
n = bpf_obj_new(typeof(*n));
if (!n)
return __LINE__;
m = bpf_refcount_acquire(n);
n->key0 = i;
m->key1 = i;
bpf_spin_lock(&glock0);
bpf_rbtree_add(&groot0, &n->r0, less0);
bpf_spin_unlock(&glock0);
bpf_spin_lock(&glock1);
bpf_rbtree_add(&groot1, &m->r1, less1);
bpf_spin_unlock(&glock1);
}
n = NULL;
bpf_spin_lock(&glock0);
rb_n = bpf_rbtree_root(&groot0);
while (can_loop) {
if (!rb_n) {
bpf_spin_unlock(&glock0);
return __LINE__;
}
n = rb_entry(rb_n, struct node_data, r0);
if (lookup_key == n->key0)
break;
if (nr_gc < NR_NODES)
gc_ns[nr_gc++] = rb_n;
if (lookup_key < n->key0)
rb_n = bpf_rbtree_left(&groot0, rb_n);
else
rb_n = bpf_rbtree_right(&groot0, rb_n);
}
if (!n || lookup_key != n->key0) {
bpf_spin_unlock(&glock0);
return __LINE__;
}
for (i = 0; i < nr_gc; i++) {
rb_n = gc_ns[i];
gc_ns[i] = bpf_rbtree_remove(&groot0, rb_n);
}
m = bpf_refcount_acquire(n);
bpf_spin_unlock(&glock0);
for (i = 0; i < nr_gc; i++) {
rb_n = gc_ns[i];
if (rb_n) {
n = rb_entry(rb_n, struct node_data, r0);
bpf_obj_drop(n);
}
}
if (!m)
return __LINE__;
bpf_spin_lock(&glock1);
rb_m = bpf_rbtree_remove(&groot1, &m->r1);
bpf_spin_unlock(&glock1);
bpf_obj_drop(m);
if (!rb_m)
return __LINE__;
bpf_obj_drop(rb_entry(rb_m, struct node_data, r1));
return 0;
}
#define TEST_ROOT(dolock) \
SEC("syscall") \
__failure __msg(MSG) \
long test_root_spinlock_##dolock(void *ctx) \
{ \
struct bpf_rb_node *rb_n; \
__u64 jiffies = 0; \
\
if (dolock) \
bpf_spin_lock(&glock0); \
rb_n = bpf_rbtree_root(&groot0); \
if (rb_n) \
jiffies = bpf_jiffies64(); \
if (dolock) \
bpf_spin_unlock(&glock0); \
\
return !!jiffies; \
}
#define TEST_LR(op, dolock) \
SEC("syscall") \
__failure __msg(MSG) \
long test_##op##_spinlock_##dolock(void *ctx) \
{ \
struct bpf_rb_node *rb_n; \
struct node_data *n; \
__u64 jiffies = 0; \
\
bpf_spin_lock(&glock0); \
rb_n = bpf_rbtree_root(&groot0); \
if (!rb_n) { \
bpf_spin_unlock(&glock0); \
return 1; \
} \
n = rb_entry(rb_n, struct node_data, r0); \
n = bpf_refcount_acquire(n); \
bpf_spin_unlock(&glock0); \
if (!n) \
return 1; \
\
if (dolock) \
bpf_spin_lock(&glock0); \
rb_n = bpf_rbtree_##op(&groot0, &n->r0); \
if (rb_n) \
jiffies = bpf_jiffies64(); \
if (dolock) \
bpf_spin_unlock(&glock0); \
\
return !!jiffies; \
}
/*
* Use a spearate MSG macro instead of passing to TEST_XXX(..., MSG)
* to ensure the message itself is not in the bpf prog lineinfo
* which the verifier includes in its log.
* Otherwise, the test_loader will incorrectly match the prog lineinfo
* instead of the log generated by the verifier.
*/
#define MSG "call bpf_rbtree_root{{.+}}; R0{{(_w)?}}=rcu_ptr_or_null_node_data(id={{[0-9]+}},non_own_ref"
TEST_ROOT(true)
#undef MSG
#define MSG "call bpf_rbtree_{{(left|right).+}}; R0{{(_w)?}}=rcu_ptr_or_null_node_data(id={{[0-9]+}},non_own_ref"
TEST_LR(left, true)
TEST_LR(right, true)
#undef MSG
#define MSG "bpf_spin_lock at off=0 must be held for bpf_rb_root"
TEST_ROOT(false)
TEST_LR(left, false)
TEST_LR(right, false)
#undef MSG
char _license[] SEC("license") = "GPL";
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