struct_ops_refcounted.c

 1#include <vmlinux.h>
 2#include <bpf/bpf_tracing.h>
 3#include "../test_kmods/bpf_testmod.h"
 4#include "bpf_misc.h"
 5
 6char _license[] SEC("license") = "GPL";
 7
 8__attribute__((nomerge)) extern void bpf_task_release(struct task_struct *p) __ksym;
 9
10/* This is a test BPF program that uses struct_ops to access a referenced
11 * kptr argument. This is a test for the verifier to ensure that it
12 * 1) recognizes the task as a referenced object (i.e., ref_obj_id > 0), and
13 * 2) the same reference can be acquired from multiple paths as long as it
14 *    has not been released.
15 */
16SEC("struct_ops/test_refcounted")
17int BPF_PROG(refcounted, int dummy, struct task_struct *task)
18{
19	if (dummy == 1)
20		bpf_task_release(task);
21	else
22		bpf_task_release(task);
23	return 0;
24}
25
26SEC(".struct_ops.link")
27struct bpf_testmod_ops testmod_refcounted = {
28	.test_refcounted = (void *)refcounted,
29};
30
31