1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * test_kprobes.c - simple sanity test for *probes
4 *
5 * Copyright IBM Corp. 2008
6 */
7
8 #define pr_fmt(fmt) "Kprobe smoke test: " fmt
9
10 #include <linux/kernel.h>
11 #include <linux/kprobes.h>
12 #include <linux/random.h>
13
14 #define div_factor 3
15
16 static u32 rand1, preh_val, posth_val;
17 static int errors, handler_errors, num_tests;
18 static u32 (*target)(u32 value);
19 static u32 (*target2)(u32 value);
20
kprobe_target(u32 value)21 static noinline u32 kprobe_target(u32 value)
22 {
23 return (value / div_factor);
24 }
25
kp_pre_handler(struct kprobe * p,struct pt_regs * regs)26 static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
27 {
28 if (preemptible()) {
29 handler_errors++;
30 pr_err("pre-handler is preemptible\n");
31 }
32 preh_val = (rand1 / div_factor);
33 return 0;
34 }
35
kp_post_handler(struct kprobe * p,struct pt_regs * regs,unsigned long flags)36 static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,
37 unsigned long flags)
38 {
39 if (preemptible()) {
40 handler_errors++;
41 pr_err("post-handler is preemptible\n");
42 }
43 if (preh_val != (rand1 / div_factor)) {
44 handler_errors++;
45 pr_err("incorrect value in post_handler\n");
46 }
47 posth_val = preh_val + div_factor;
48 }
49
50 static struct kprobe kp = {
51 .symbol_name = "kprobe_target",
52 .pre_handler = kp_pre_handler,
53 .post_handler = kp_post_handler
54 };
55
test_kprobe(void)56 static int test_kprobe(void)
57 {
58 int ret;
59
60 ret = register_kprobe(&kp);
61 if (ret < 0) {
62 pr_err("register_kprobe returned %d\n", ret);
63 return ret;
64 }
65
66 ret = target(rand1);
67 unregister_kprobe(&kp);
68
69 if (preh_val == 0) {
70 pr_err("kprobe pre_handler not called\n");
71 handler_errors++;
72 }
73
74 if (posth_val == 0) {
75 pr_err("kprobe post_handler not called\n");
76 handler_errors++;
77 }
78
79 return 0;
80 }
81
kprobe_target2(u32 value)82 static noinline u32 kprobe_target2(u32 value)
83 {
84 return (value / div_factor) + 1;
85 }
86
kp_pre_handler2(struct kprobe * p,struct pt_regs * regs)87 static int kp_pre_handler2(struct kprobe *p, struct pt_regs *regs)
88 {
89 preh_val = (rand1 / div_factor) + 1;
90 return 0;
91 }
92
kp_post_handler2(struct kprobe * p,struct pt_regs * regs,unsigned long flags)93 static void kp_post_handler2(struct kprobe *p, struct pt_regs *regs,
94 unsigned long flags)
95 {
96 if (preh_val != (rand1 / div_factor) + 1) {
97 handler_errors++;
98 pr_err("incorrect value in post_handler2\n");
99 }
100 posth_val = preh_val + div_factor;
101 }
102
103 static struct kprobe kp2 = {
104 .symbol_name = "kprobe_target2",
105 .pre_handler = kp_pre_handler2,
106 .post_handler = kp_post_handler2
107 };
108
test_kprobes(void)109 static int test_kprobes(void)
110 {
111 int ret;
112 struct kprobe *kps[2] = {&kp, &kp2};
113
114 /* addr and flags should be cleard for reusing kprobe. */
115 kp.addr = NULL;
116 kp.flags = 0;
117 ret = register_kprobes(kps, 2);
118 if (ret < 0) {
119 pr_err("register_kprobes returned %d\n", ret);
120 return ret;
121 }
122
123 preh_val = 0;
124 posth_val = 0;
125 ret = target(rand1);
126
127 if (preh_val == 0) {
128 pr_err("kprobe pre_handler not called\n");
129 handler_errors++;
130 }
131
132 if (posth_val == 0) {
133 pr_err("kprobe post_handler not called\n");
134 handler_errors++;
135 }
136
137 preh_val = 0;
138 posth_val = 0;
139 ret = target2(rand1);
140
141 if (preh_val == 0) {
142 pr_err("kprobe pre_handler2 not called\n");
143 handler_errors++;
144 }
145
146 if (posth_val == 0) {
147 pr_err("kprobe post_handler2 not called\n");
148 handler_errors++;
149 }
150
151 unregister_kprobes(kps, 2);
152 return 0;
153
154 }
155
156 #ifdef CONFIG_KRETPROBES
157 static u32 krph_val;
158
entry_handler(struct kretprobe_instance * ri,struct pt_regs * regs)159 static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
160 {
161 if (preemptible()) {
162 handler_errors++;
163 pr_err("kretprobe entry handler is preemptible\n");
164 }
165 krph_val = (rand1 / div_factor);
166 return 0;
167 }
168
return_handler(struct kretprobe_instance * ri,struct pt_regs * regs)169 static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
170 {
171 unsigned long ret = regs_return_value(regs);
172
173 if (preemptible()) {
174 handler_errors++;
175 pr_err("kretprobe return handler is preemptible\n");
176 }
177 if (ret != (rand1 / div_factor)) {
178 handler_errors++;
179 pr_err("incorrect value in kretprobe handler\n");
180 }
181 if (krph_val == 0) {
182 handler_errors++;
183 pr_err("call to kretprobe entry handler failed\n");
184 }
185
186 krph_val = rand1;
187 return 0;
188 }
189
190 static struct kretprobe rp = {
191 .handler = return_handler,
192 .entry_handler = entry_handler,
193 .kp.symbol_name = "kprobe_target"
194 };
195
test_kretprobe(void)196 static int test_kretprobe(void)
197 {
198 int ret;
199
200 ret = register_kretprobe(&rp);
201 if (ret < 0) {
202 pr_err("register_kretprobe returned %d\n", ret);
203 return ret;
204 }
205
206 ret = target(rand1);
207 unregister_kretprobe(&rp);
208 if (krph_val != rand1) {
209 pr_err("kretprobe handler not called\n");
210 handler_errors++;
211 }
212
213 return 0;
214 }
215
return_handler2(struct kretprobe_instance * ri,struct pt_regs * regs)216 static int return_handler2(struct kretprobe_instance *ri, struct pt_regs *regs)
217 {
218 unsigned long ret = regs_return_value(regs);
219
220 if (ret != (rand1 / div_factor) + 1) {
221 handler_errors++;
222 pr_err("incorrect value in kretprobe handler2\n");
223 }
224 if (krph_val == 0) {
225 handler_errors++;
226 pr_err("call to kretprobe entry handler failed\n");
227 }
228
229 krph_val = rand1;
230 return 0;
231 }
232
233 static struct kretprobe rp2 = {
234 .handler = return_handler2,
235 .entry_handler = entry_handler,
236 .kp.symbol_name = "kprobe_target2"
237 };
238
test_kretprobes(void)239 static int test_kretprobes(void)
240 {
241 int ret;
242 struct kretprobe *rps[2] = {&rp, &rp2};
243
244 /* addr and flags should be cleard for reusing kprobe. */
245 rp.kp.addr = NULL;
246 rp.kp.flags = 0;
247 ret = register_kretprobes(rps, 2);
248 if (ret < 0) {
249 pr_err("register_kretprobe returned %d\n", ret);
250 return ret;
251 }
252
253 krph_val = 0;
254 ret = target(rand1);
255 if (krph_val != rand1) {
256 pr_err("kretprobe handler not called\n");
257 handler_errors++;
258 }
259
260 krph_val = 0;
261 ret = target2(rand1);
262 if (krph_val != rand1) {
263 pr_err("kretprobe handler2 not called\n");
264 handler_errors++;
265 }
266 unregister_kretprobes(rps, 2);
267 return 0;
268 }
269 #endif /* CONFIG_KRETPROBES */
270
init_test_probes(void)271 int init_test_probes(void)
272 {
273 int ret;
274
275 target = kprobe_target;
276 target2 = kprobe_target2;
277
278 do {
279 rand1 = prandom_u32();
280 } while (rand1 <= div_factor);
281
282 pr_info("started\n");
283 num_tests++;
284 ret = test_kprobe();
285 if (ret < 0)
286 errors++;
287
288 num_tests++;
289 ret = test_kprobes();
290 if (ret < 0)
291 errors++;
292
293 #ifdef CONFIG_KRETPROBES
294 num_tests++;
295 ret = test_kretprobe();
296 if (ret < 0)
297 errors++;
298
299 num_tests++;
300 ret = test_kretprobes();
301 if (ret < 0)
302 errors++;
303 #endif /* CONFIG_KRETPROBES */
304
305 if (errors)
306 pr_err("BUG: %d out of %d tests failed\n", errors, num_tests);
307 else if (handler_errors)
308 pr_err("BUG: %d error(s) running handlers\n", handler_errors);
309 else
310 pr_info("passed successfully\n");
311
312 return 0;
313 }
314