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) 2020 Facebook */
3
4#include <test_progs.h>
5
6#include "test_btf_map_in_map.skel.h"
7
8static int duration;
9
10static __u32 bpf_map_id(struct bpf_map *map)
11{
12 struct bpf_map_info info;
13 __u32 info_len = sizeof(info);
14 int err;
15
16 memset(&info, 0, info_len);
17 err = bpf_obj_get_info_by_fd(bpf_map__fd(map), &info, &info_len);
18 if (err)
19 return 0;
20 return info.id;
21}
22
23/*
24 * Trigger synchronize_rcu() in kernel.
25 *
26 * ARRAY_OF_MAPS/HASH_OF_MAPS lookup/update operations trigger synchronize_rcu()
27 * if looking up an existing non-NULL element or updating the map with a valid
28 * inner map FD. Use this fact to trigger synchronize_rcu(): create map-in-map,
29 * create a trivial ARRAY map, update map-in-map with ARRAY inner map. Then
30 * cleanup. At the end, at least one synchronize_rcu() would be called.
31 */
32static int kern_sync_rcu(void)
33{
34 int inner_map_fd, outer_map_fd, err, zero = 0;
35
36 inner_map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, 4, 4, 1, 0);
37 if (CHECK(inner_map_fd < 0, "inner_map_create", "failed %d\n", -errno))
38 return -1;
39
40 outer_map_fd = bpf_create_map_in_map(BPF_MAP_TYPE_ARRAY_OF_MAPS, NULL,
41 sizeof(int), inner_map_fd, 1, 0);
42 if (CHECK(outer_map_fd < 0, "outer_map_create", "failed %d\n", -errno)) {
43 close(inner_map_fd);
44 return -1;
45 }
46
47 err = bpf_map_update_elem(outer_map_fd, &zero, &inner_map_fd, 0);
48 if (err)
49 err = -errno;
50 CHECK(err, "outer_map_update", "failed %d\n", err);
51 close(inner_map_fd);
52 close(outer_map_fd);
53 return err;
54}
55
56static void test_lookup_update(void)
57{
58 int map1_fd, map2_fd, map3_fd, map4_fd, map5_fd, map1_id, map2_id;
59 int outer_arr_fd, outer_hash_fd, outer_arr_dyn_fd;
60 struct test_btf_map_in_map *skel;
61 int err, key = 0, val, i, fd;
62
63 skel = test_btf_map_in_map__open_and_load();
64 if (CHECK(!skel, "skel_open", "failed to open&load skeleton\n"))
65 return;
66
67 err = test_btf_map_in_map__attach(skel);
68 if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
69 goto cleanup;
70
71 map1_fd = bpf_map__fd(skel->maps.inner_map1);
72 map2_fd = bpf_map__fd(skel->maps.inner_map2);
73 map3_fd = bpf_map__fd(skel->maps.inner_map3);
74 map4_fd = bpf_map__fd(skel->maps.inner_map4);
75 map5_fd = bpf_map__fd(skel->maps.inner_map5);
76 outer_arr_dyn_fd = bpf_map__fd(skel->maps.outer_arr_dyn);
77 outer_arr_fd = bpf_map__fd(skel->maps.outer_arr);
78 outer_hash_fd = bpf_map__fd(skel->maps.outer_hash);
79
80 /* inner1 = input, inner2 = input + 1, inner3 = input + 2 */
81 bpf_map_update_elem(outer_arr_fd, &key, &map1_fd, 0);
82 bpf_map_update_elem(outer_hash_fd, &key, &map2_fd, 0);
83 bpf_map_update_elem(outer_arr_dyn_fd, &key, &map3_fd, 0);
84 skel->bss->input = 1;
85 usleep(1);
86 bpf_map_lookup_elem(map1_fd, &key, &val);
87 CHECK(val != 1, "inner1", "got %d != exp %d\n", val, 1);
88 bpf_map_lookup_elem(map2_fd, &key, &val);
89 CHECK(val != 2, "inner2", "got %d != exp %d\n", val, 2);
90 bpf_map_lookup_elem(map3_fd, &key, &val);
91 CHECK(val != 3, "inner3", "got %d != exp %d\n", val, 3);
92
93 /* inner2 = input, inner1 = input + 1, inner4 = input + 2 */
94 bpf_map_update_elem(outer_arr_fd, &key, &map2_fd, 0);
95 bpf_map_update_elem(outer_hash_fd, &key, &map1_fd, 0);
96 bpf_map_update_elem(outer_arr_dyn_fd, &key, &map4_fd, 0);
97 skel->bss->input = 3;
98 usleep(1);
99 bpf_map_lookup_elem(map1_fd, &key, &val);
100 CHECK(val != 4, "inner1", "got %d != exp %d\n", val, 4);
101 bpf_map_lookup_elem(map2_fd, &key, &val);
102 CHECK(val != 3, "inner2", "got %d != exp %d\n", val, 3);
103 bpf_map_lookup_elem(map4_fd, &key, &val);
104 CHECK(val != 5, "inner4", "got %d != exp %d\n", val, 5);
105
106 /* inner5 = input + 2 */
107 bpf_map_update_elem(outer_arr_dyn_fd, &key, &map5_fd, 0);
108 skel->bss->input = 5;
109 usleep(1);
110 bpf_map_lookup_elem(map5_fd, &key, &val);
111 CHECK(val != 7, "inner5", "got %d != exp %d\n", val, 7);
112
113 for (i = 0; i < 5; i++) {
114 val = i % 2 ? map1_fd : map2_fd;
115 err = bpf_map_update_elem(outer_hash_fd, &key, &val, 0);
116 if (CHECK_FAIL(err)) {
117 printf("failed to update hash_of_maps on iter #%d\n", i);
118 goto cleanup;
119 }
120 err = bpf_map_update_elem(outer_arr_fd, &key, &val, 0);
121 if (CHECK_FAIL(err)) {
122 printf("failed to update array_of_maps on iter #%d\n", i);
123 goto cleanup;
124 }
125 val = i % 2 ? map4_fd : map5_fd;
126 err = bpf_map_update_elem(outer_arr_dyn_fd, &key, &val, 0);
127 if (CHECK_FAIL(err)) {
128 printf("failed to update array_of_maps (dyn) on iter #%d\n", i);
129 goto cleanup;
130 }
131 }
132
133 map1_id = bpf_map_id(skel->maps.inner_map1);
134 map2_id = bpf_map_id(skel->maps.inner_map2);
135 CHECK(map1_id == 0, "map1_id", "failed to get ID 1\n");
136 CHECK(map2_id == 0, "map2_id", "failed to get ID 2\n");
137
138 test_btf_map_in_map__destroy(skel);
139 skel = NULL;
140
141 /* we need to either wait for or force synchronize_rcu(), before
142 * checking for "still exists" condition, otherwise map could still be
143 * resolvable by ID, causing false positives.
144 *
145 * Older kernels (5.8 and earlier) freed map only after two
146 * synchronize_rcu()s, so trigger two, to be entirely sure.
147 */
148 CHECK(kern_sync_rcu(), "sync_rcu", "failed\n");
149 CHECK(kern_sync_rcu(), "sync_rcu", "failed\n");
150
151 fd = bpf_map_get_fd_by_id(map1_id);
152 if (CHECK(fd >= 0, "map1_leak", "inner_map1 leaked!\n")) {
153 close(fd);
154 goto cleanup;
155 }
156 fd = bpf_map_get_fd_by_id(map2_id);
157 if (CHECK(fd >= 0, "map2_leak", "inner_map2 leaked!\n")) {
158 close(fd);
159 goto cleanup;
160 }
161
162cleanup:
163 test_btf_map_in_map__destroy(skel);
164}
165
166static void test_diff_size(void)
167{
168 struct test_btf_map_in_map *skel;
169 int err, inner_map_fd, zero = 0;
170
171 skel = test_btf_map_in_map__open_and_load();
172 if (CHECK(!skel, "skel_open", "failed to open&load skeleton\n"))
173 return;
174
175 inner_map_fd = bpf_map__fd(skel->maps.sockarr_sz2);
176 err = bpf_map_update_elem(bpf_map__fd(skel->maps.outer_sockarr), &zero,
177 &inner_map_fd, 0);
178 CHECK(err, "outer_sockarr inner map size check",
179 "cannot use a different size inner_map\n");
180
181 inner_map_fd = bpf_map__fd(skel->maps.inner_map_sz2);
182 err = bpf_map_update_elem(bpf_map__fd(skel->maps.outer_arr), &zero,
183 &inner_map_fd, 0);
184 CHECK(!err, "outer_arr inner map size check",
185 "incorrectly updated with a different size inner_map\n");
186
187 test_btf_map_in_map__destroy(skel);
188}
189
190void test_btf_map_in_map(void)
191{
192 if (test__start_subtest("lookup_update"))
193 test_lookup_update();
194
195 if (test__start_subtest("diff_size"))
196 test_diff_size();
197}