xref: /linux/tools/testing/selftests/bpf/prog_tests/map_kptr_race.c (revision 57885276cc16a2e2b76282c808a4e84cbecb3aae)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
3 #include <test_progs.h>
4 #include <network_helpers.h>
5 
6 #include "map_kptr_race.skel.h"
7 
8 static int get_map_id(int map_fd)
9 {
10 	struct bpf_map_info info = {};
11 	__u32 len = sizeof(info);
12 
13 	if (!ASSERT_OK(bpf_map_get_info_by_fd(map_fd, &info, &len), "get_map_info"))
14 		return -1;
15 	return info.id;
16 }
17 
18 static int read_refs(struct map_kptr_race *skel)
19 {
20 	LIBBPF_OPTS(bpf_test_run_opts, opts);
21 	int ret;
22 
23 	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.count_ref), &opts);
24 	if (!ASSERT_OK(ret, "count_ref run"))
25 		return -1;
26 	if (!ASSERT_OK(opts.retval, "count_ref retval"))
27 		return -1;
28 	return skel->bss->num_of_refs;
29 }
30 
31 static void test_htab_leak(void)
32 {
33 	LIBBPF_OPTS(bpf_test_run_opts, opts,
34 		.data_in = &pkt_v4,
35 		.data_size_in = sizeof(pkt_v4),
36 		.repeat = 1,
37 	);
38 	struct map_kptr_race *skel, *watcher;
39 	int ret, map_id;
40 
41 	skel = map_kptr_race__open_and_load();
42 	if (!ASSERT_OK_PTR(skel, "open_and_load"))
43 		return;
44 
45 	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_htab_leak), &opts);
46 	if (!ASSERT_OK(ret, "test_htab_leak run"))
47 		goto out_skel;
48 	if (!ASSERT_OK(opts.retval, "test_htab_leak retval"))
49 		goto out_skel;
50 
51 	map_id = get_map_id(bpf_map__fd(skel->maps.race_hash_map));
52 	if (!ASSERT_GE(map_id, 0, "map_id"))
53 		goto out_skel;
54 
55 	watcher = map_kptr_race__open_and_load();
56 	if (!ASSERT_OK_PTR(watcher, "watcher open_and_load"))
57 		goto out_skel;
58 
59 	watcher->bss->target_map_id = map_id;
60 	watcher->links.map_put = bpf_program__attach(watcher->progs.map_put);
61 	if (!ASSERT_OK_PTR(watcher->links.map_put, "attach fentry"))
62 		goto out_watcher;
63 	watcher->links.htab_map_free = bpf_program__attach(watcher->progs.htab_map_free);
64 	if (!ASSERT_OK_PTR(watcher->links.htab_map_free, "attach fexit"))
65 		goto out_watcher;
66 
67 	map_kptr_race__destroy(skel);
68 	skel = NULL;
69 
70 	kern_sync_rcu();
71 
72 	while (!READ_ONCE(watcher->bss->map_freed))
73 		sched_yield();
74 
75 	ASSERT_EQ(watcher->bss->map_freed, 1, "map_freed");
76 	ASSERT_EQ(read_refs(watcher), 2, "htab refcount");
77 
78 out_watcher:
79 	map_kptr_race__destroy(watcher);
80 out_skel:
81 	map_kptr_race__destroy(skel);
82 }
83 
84 static void test_percpu_htab_leak(void)
85 {
86 	LIBBPF_OPTS(bpf_test_run_opts, opts,
87 		.data_in = &pkt_v4,
88 		.data_size_in = sizeof(pkt_v4),
89 		.repeat = 1,
90 	);
91 	struct map_kptr_race *skel, *watcher;
92 	int ret, map_id;
93 
94 	skel = map_kptr_race__open();
95 	if (!ASSERT_OK_PTR(skel, "open"))
96 		return;
97 
98 	skel->rodata->nr_cpus = libbpf_num_possible_cpus();
99 	if (skel->rodata->nr_cpus > 16)
100 		skel->rodata->nr_cpus = 16;
101 
102 	ret = map_kptr_race__load(skel);
103 	if (!ASSERT_OK(ret, "load"))
104 		goto out_skel;
105 
106 	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_percpu_htab_leak), &opts);
107 	if (!ASSERT_OK(ret, "test_percpu_htab_leak run"))
108 		goto out_skel;
109 	if (!ASSERT_OK(opts.retval, "test_percpu_htab_leak retval"))
110 		goto out_skel;
111 
112 	map_id = get_map_id(bpf_map__fd(skel->maps.race_percpu_hash_map));
113 	if (!ASSERT_GE(map_id, 0, "map_id"))
114 		goto out_skel;
115 
116 	watcher = map_kptr_race__open_and_load();
117 	if (!ASSERT_OK_PTR(watcher, "watcher open_and_load"))
118 		goto out_skel;
119 
120 	watcher->bss->target_map_id = map_id;
121 	watcher->links.map_put = bpf_program__attach(watcher->progs.map_put);
122 	if (!ASSERT_OK_PTR(watcher->links.map_put, "attach fentry"))
123 		goto out_watcher;
124 	watcher->links.htab_map_free = bpf_program__attach(watcher->progs.htab_map_free);
125 	if (!ASSERT_OK_PTR(watcher->links.htab_map_free, "attach fexit"))
126 		goto out_watcher;
127 
128 	map_kptr_race__destroy(skel);
129 	skel = NULL;
130 
131 	kern_sync_rcu();
132 
133 	while (!READ_ONCE(watcher->bss->map_freed))
134 		sched_yield();
135 
136 	ASSERT_EQ(watcher->bss->map_freed, 1, "map_freed");
137 	ASSERT_EQ(read_refs(watcher), 2, "percpu_htab refcount");
138 
139 out_watcher:
140 	map_kptr_race__destroy(watcher);
141 out_skel:
142 	map_kptr_race__destroy(skel);
143 }
144 
145 static void test_sk_ls_leak(void)
146 {
147 	struct map_kptr_race *skel, *watcher;
148 	int listen_fd = -1, client_fd = -1, map_id;
149 
150 	skel = map_kptr_race__open_and_load();
151 	if (!ASSERT_OK_PTR(skel, "open_and_load"))
152 		return;
153 
154 	if (!ASSERT_OK(map_kptr_race__attach(skel), "attach"))
155 		goto out_skel;
156 
157 	listen_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0);
158 	if (!ASSERT_GE(listen_fd, 0, "start_server"))
159 		goto out_skel;
160 
161 	client_fd = connect_to_fd(listen_fd, 0);
162 	if (!ASSERT_GE(client_fd, 0, "connect_to_fd"))
163 		goto out_skel;
164 
165 	if (!ASSERT_EQ(skel->bss->sk_ls_leak_done, 1, "sk_ls_leak_done"))
166 		goto out_skel;
167 
168 	close(client_fd);
169 	client_fd = -1;
170 	close(listen_fd);
171 	listen_fd = -1;
172 
173 	map_id = get_map_id(bpf_map__fd(skel->maps.race_sk_ls_map));
174 	if (!ASSERT_GE(map_id, 0, "map_id"))
175 		goto out_skel;
176 
177 	watcher = map_kptr_race__open_and_load();
178 	if (!ASSERT_OK_PTR(watcher, "watcher open_and_load"))
179 		goto out_skel;
180 
181 	watcher->bss->target_map_id = map_id;
182 	watcher->links.map_put = bpf_program__attach(watcher->progs.map_put);
183 	if (!ASSERT_OK_PTR(watcher->links.map_put, "attach fentry"))
184 		goto out_watcher;
185 	watcher->links.sk_map_free = bpf_program__attach(watcher->progs.sk_map_free);
186 	if (!ASSERT_OK_PTR(watcher->links.sk_map_free, "attach fexit"))
187 		goto out_watcher;
188 
189 	map_kptr_race__destroy(skel);
190 	skel = NULL;
191 
192 	kern_sync_rcu();
193 
194 	while (!READ_ONCE(watcher->bss->map_freed))
195 		sched_yield();
196 
197 	ASSERT_EQ(watcher->bss->map_freed, 1, "map_freed");
198 	ASSERT_EQ(read_refs(watcher), 2, "sk_ls refcount");
199 
200 out_watcher:
201 	map_kptr_race__destroy(watcher);
202 out_skel:
203 	if (client_fd >= 0)
204 		close(client_fd);
205 	if (listen_fd >= 0)
206 		close(listen_fd);
207 	map_kptr_race__destroy(skel);
208 }
209 
210 void serial_test_map_kptr_race(void)
211 {
212 	if (test__start_subtest("htab_leak"))
213 		test_htab_leak();
214 	if (test__start_subtest("percpu_htab_leak"))
215 		test_percpu_htab_leak();
216 	if (test__start_subtest("sk_ls_leak"))
217 		test_sk_ls_leak();
218 }
219