test_global_map_resize.c

 1// SPDX-License-Identifier: GPL-2.0
 2/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
 3
 4#include "vmlinux.h"
 5#include <bpf/bpf_helpers.h>
 6#include <bpf/bpf_tracing.h>
 7
 8char _license[] SEC("license") = "GPL";
 9
10/* rodata section */
11const volatile pid_t pid;
12const volatile size_t bss_array_len;
13const volatile size_t data_array_len;
14
15/* bss section */
16int sum = 0;
17int array[1];
18
19/* custom data section */
20int my_array[1] SEC(".data.custom");
21
22/* custom data section which should NOT be resizable,
23 * since it contains a single var which is not an array
24 */
25int my_int SEC(".data.non_array");
26
27/* custom data section which should NOT be resizable,
28 * since its last var is not an array
29 */
30int my_array_first[1] SEC(".data.array_not_last");
31int my_int_last SEC(".data.array_not_last");
32
33int percpu_arr[1] SEC(".data.percpu_arr");
34
35/* at least one extern is included, to ensure that a specific
36 * regression is tested whereby resizing resulted in a free-after-use
37 * bug after type information is invalidated by the resize operation.
38 *
39 * There isn't a particularly good API to test for this specific condition,
40 * but by having externs for the resizing tests it will cover this path.
41 */
42extern int LINUX_KERNEL_VERSION __kconfig;
43long version_sink;
44
45SEC("tp/syscalls/sys_enter_getpid")
46int bss_array_sum(void *ctx)
47{
48	if (pid != (bpf_get_current_pid_tgid() >> 32))
49		return 0;
50
51	/* this will be zero, we just rely on verifier not rejecting this */
52	sum = percpu_arr[bpf_get_smp_processor_id()];
53
54	for (size_t i = 0; i < bss_array_len; ++i)
55		sum += array[i];
56
57	/* see above; ensure this is not optimized out */
58	version_sink = LINUX_KERNEL_VERSION;
59
60	return 0;
61}
62
63SEC("tp/syscalls/sys_enter_getuid")
64int data_array_sum(void *ctx)
65{
66	if (pid != (bpf_get_current_pid_tgid() >> 32))
67		return 0;
68
69	/* this will be zero, we just rely on verifier not rejecting this */
70	sum = percpu_arr[bpf_get_smp_processor_id()];
71
72	for (size_t i = 0; i < data_array_len; ++i)
73		sum += my_array[i];
74
75	/* see above; ensure this is not optimized out */
76	version_sink = LINUX_KERNEL_VERSION;
77
78	return 0;
79}
80
81SEC("struct_ops/test_1")
82int BPF_PROG(test_1)
83{
84	return 0;
85}
86
87struct bpf_testmod_ops {
88	int (*test_1)(void);
89};
90
91SEC(".struct_ops.link")
92struct bpf_testmod_ops st_ops_resize = {
93	.test_1 = (void *)test_1
94};