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// SPDX-License-Identifier: GPL-2.0
#include <vmlinux.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>
#include "bpf_experimental.h"
#include "bpf_misc.h"
struct node_acquire {
long key;
long data;
struct bpf_rb_node node;
struct bpf_refcount refcount;
};
struct node_refcounted {
long key;
struct bpf_list_node list;
struct bpf_refcount refcount;
};
extern void bpf_rcu_read_lock(void) __ksym;
extern void bpf_rcu_read_unlock(void) __ksym;
#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
private(A) struct bpf_spin_lock glock;
private(A) struct bpf_rb_root groot __contains(node_acquire, node);
private(B) struct bpf_spin_lock lock;
private(B) struct bpf_list_head head __contains(node_refcounted, list);
static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
struct node_acquire *node_a;
struct node_acquire *node_b;
node_a = container_of(a, struct node_acquire, node);
node_b = container_of(b, struct node_acquire, node);
return node_a->key < node_b->key;
}
SEC("?tc")
__failure __msg("Unreleased reference id=4 alloc_insn={{[0-9]+}}")
long rbtree_refcounted_node_ref_escapes(void *ctx)
{
struct node_acquire *n, *m;
n = bpf_obj_new(typeof(*n));
if (!n)
return 1;
bpf_spin_lock(&glock);
bpf_rbtree_add(&groot, &n->node, less);
/* m becomes an owning ref but is never drop'd or added to a tree */
m = bpf_refcount_acquire(n);
bpf_spin_unlock(&glock);
if (!m)
return 2;
m->key = 2;
return 0;
}
SEC("?tc")
__failure __msg("Possibly NULL pointer passed to trusted R1")
__msg("requires a non-NULL value of type (void *)")
long refcount_acquire_maybe_null(void *ctx)
{
struct node_acquire *n, *m;
n = bpf_obj_new(typeof(*n));
/* Intentionally not testing !n
* it's MAYBE_NULL for refcount_acquire
*/
m = bpf_refcount_acquire(n);
if (m)
bpf_obj_drop(m);
if (n)
bpf_obj_drop(n);
return 0;
}
SEC("?tc")
__failure __msg("R1 is neither owning or non-owning ref")
__msg("expects a pointer to a BPF-managed refcounted object, but R1 is a context pointer")
long refcount_acquire_non_object(void *ctx)
{
return bpf_refcount_acquire(ctx) != NULL;
}
SEC("?tc")
__failure __msg("Unreleased reference id=3 alloc_insn={{[0-9]+}}")
long rbtree_refcounted_node_ref_escapes_owning_input(void *ctx)
{
struct node_acquire *n, *m;
n = bpf_obj_new(typeof(*n));
if (!n)
return 1;
/* m becomes an owning ref but is never drop'd or added to a tree */
m = bpf_refcount_acquire(n);
m->key = 2;
bpf_spin_lock(&glock);
bpf_rbtree_add(&groot, &n->node, less);
bpf_spin_unlock(&glock);
return 0;
}
SEC("?tc")
__failure __msg("dereference of modified ptr_ ptr R1")
long refcount_acquire_list_node_offset(void *ctx)
{
struct node_refcounted *node, *base, *ref;
struct bpf_list_node *list_node;
node = bpf_obj_new(typeof(*node));
if (!node)
return 1;
bpf_spin_lock(&lock);
bpf_list_push_front(&head, &node->list);
list_node = bpf_list_pop_front(&head);
bpf_spin_unlock(&lock);
if (!list_node)
return 2;
base = container_of(list_node, struct node_refcounted, list);
ref = bpf_refcount_acquire(list_node);
if (ref)
bpf_obj_drop(ref);
bpf_obj_drop(base);
return 0;
}
SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
__failure __msg("function calls are not allowed while holding a lock")
int BPF_PROG(rbtree_fail_sleepable_lock_across_rcu,
struct file *file, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf, loff_t off, size_t len)
{
struct node_acquire *n;
n = bpf_obj_new(typeof(*n));
if (!n)
return 0;
/* spin_{lock,unlock} are in different RCU CS */
bpf_rcu_read_lock();
bpf_spin_lock(&glock);
bpf_rbtree_add(&groot, &n->node, less);
bpf_rcu_read_unlock();
bpf_rcu_read_lock();
bpf_spin_unlock(&glock);
bpf_rcu_read_unlock();
return 0;
}
char _license[] SEC("license") = "GPL";
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