// 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;
};

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);

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 arg0")
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("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("?fentry.s/bpf_testmod_test_read")
__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";