1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
3
4 #include <test_progs.h>
5 #include "testing_helpers.h"
6 #include "livepatch_trampoline.skel.h"
7
load_livepatch(void)8 static int load_livepatch(void)
9 {
10 char path[4096];
11
12 /* CI will set KBUILD_OUTPUT */
13 snprintf(path, sizeof(path), "%s/samples/livepatch/livepatch-sample.ko",
14 getenv("KBUILD_OUTPUT") ? : "../../../..");
15
16 return load_module(path, env_verbosity > VERBOSE_NONE);
17 }
18
unload_livepatch(void)19 static void unload_livepatch(void)
20 {
21 /* Disable the livepatch before unloading the module */
22 system("echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled");
23
24 unload_module("livepatch_sample", env_verbosity > VERBOSE_NONE);
25 }
26
read_proc_cmdline(void)27 static void read_proc_cmdline(void)
28 {
29 char buf[4096];
30 int fd, ret;
31
32 fd = open("/proc/cmdline", O_RDONLY);
33 if (!ASSERT_OK_FD(fd, "open /proc/cmdline"))
34 return;
35
36 ret = read(fd, buf, sizeof(buf));
37 if (!ASSERT_GT(ret, 0, "read /proc/cmdline"))
38 goto out;
39
40 ASSERT_OK(strncmp(buf, "this has been live patched", 26), "strncmp");
41
42 out:
43 close(fd);
44 }
45
__test_livepatch_trampoline(bool fexit_first)46 static void __test_livepatch_trampoline(bool fexit_first)
47 {
48 struct livepatch_trampoline *skel = NULL;
49 int err;
50
51 skel = livepatch_trampoline__open_and_load();
52 if (!ASSERT_OK_PTR(skel, "skel_open_and_load"))
53 goto out;
54
55 skel->bss->my_pid = getpid();
56
57 if (!fexit_first) {
58 /* fentry program is loaded first by default */
59 err = livepatch_trampoline__attach(skel);
60 if (!ASSERT_OK(err, "skel_attach"))
61 goto out;
62 } else {
63 /* Manually load fexit program first. */
64 skel->links.fexit_cmdline = bpf_program__attach(skel->progs.fexit_cmdline);
65 if (!ASSERT_OK_PTR(skel->links.fexit_cmdline, "attach_fexit"))
66 goto out;
67
68 skel->links.fentry_cmdline = bpf_program__attach(skel->progs.fentry_cmdline);
69 if (!ASSERT_OK_PTR(skel->links.fentry_cmdline, "attach_fentry"))
70 goto out;
71 }
72
73 read_proc_cmdline();
74
75 ASSERT_EQ(skel->bss->fentry_hit, 1, "fentry_hit");
76 ASSERT_EQ(skel->bss->fexit_hit, 1, "fexit_hit");
77 out:
78 livepatch_trampoline__destroy(skel);
79 }
80
test_livepatch_trampoline(void)81 void test_livepatch_trampoline(void)
82 {
83 int retry_cnt = 0;
84
85 retry:
86 if (load_livepatch()) {
87 if (retry_cnt) {
88 ASSERT_OK(1, "load_livepatch");
89 goto out;
90 }
91 /*
92 * Something else (previous run of the same test?) loaded
93 * the KLP module. Unload the KLP module and retry.
94 */
95 unload_livepatch();
96 retry_cnt++;
97 goto retry;
98 }
99
100 if (test__start_subtest("fentry_first"))
101 __test_livepatch_trampoline(false);
102
103 if (test__start_subtest("fexit_first"))
104 __test_livepatch_trampoline(true);
105 out:
106 unload_livepatch();
107 }
108