tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3
4#include "vmlinux.h"
5#include <bpf/bpf_helpers.h>
6#include <bpf/bpf_tracing.h>
7
8#ifndef EBUSY
9#define EBUSY 16
10#endif
11
12char _license[] SEC("license") = "GPL";
13int nr_del_errs = 0;
14int test_pid = 0;
15
16struct {
17 __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
18 __uint(map_flags, BPF_F_NO_PREALLOC);
19 __type(key, int);
20 __type(value, long);
21} map_a SEC(".maps");
22
23struct {
24 __uint(type, BPF_MAP_TYPE_TASK_STORAGE);
25 __uint(map_flags, BPF_F_NO_PREALLOC);
26 __type(key, int);
27 __type(value, long);
28} map_b SEC(".maps");
29
30SEC("fentry/bpf_local_storage_update")
31int BPF_PROG(on_update)
32{
33 struct task_struct *task = bpf_get_current_task_btf();
34 long *ptr;
35
36 if (!test_pid || task->pid != test_pid)
37 return 0;
38
39 /* This will succeed as there is no real deadlock */
40 ptr = bpf_task_storage_get(&map_a, task, 0,
41 BPF_LOCAL_STORAGE_GET_F_CREATE);
42 if (ptr) {
43 int err;
44
45 *ptr += 1;
46 err = bpf_task_storage_delete(&map_a, task);
47 if (err == -EBUSY)
48 nr_del_errs++;
49 }
50
51 /* This will succeed as there is no real deadlock */
52 ptr = bpf_task_storage_get(&map_b, task, 0,
53 BPF_LOCAL_STORAGE_GET_F_CREATE);
54 if (ptr)
55 *ptr += 1;
56
57 return 0;
58}
59
60SEC("tp_btf/sys_enter")
61int BPF_PROG(on_enter, struct pt_regs *regs, long id)
62{
63 struct task_struct *task;
64 long *ptr;
65
66 task = bpf_get_current_task_btf();
67 if (!test_pid || task->pid != test_pid)
68 return 0;
69
70 ptr = bpf_task_storage_get(&map_a, task, 0,
71 BPF_LOCAL_STORAGE_GET_F_CREATE);
72 if (ptr && !*ptr)
73 *ptr = 200;
74
75 ptr = bpf_task_storage_get(&map_b, task, 0,
76 BPF_LOCAL_STORAGE_GET_F_CREATE);
77 if (ptr && !*ptr)
78 *ptr = 100;
79 return 0;
80}