1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * test_fprobe.c - simple sanity test for fprobe
4 */
5
6 #include <linux/kernel.h>
7 #include <linux/fprobe.h>
8 #include <linux/random.h>
9 #include <kunit/test.h>
10
11 #define div_factor 3
12
13 static struct kunit *current_test;
14
15 static u32 rand1, entry_val, exit_val;
16
17 /* Use indirect calls to avoid inlining the target functions */
18 static u32 (*target)(u32 value);
19 static u32 (*target2)(u32 value);
20 static u32 (*target_nest)(u32 value, u32 (*nest)(u32));
21 static unsigned long target_ip;
22 static unsigned long target2_ip;
23 static unsigned long target_nest_ip;
24 static int entry_return_value;
25
fprobe_selftest_target(u32 value)26 static noinline u32 fprobe_selftest_target(u32 value)
27 {
28 return (value / div_factor);
29 }
30
fprobe_selftest_target2(u32 value)31 static noinline u32 fprobe_selftest_target2(u32 value)
32 {
33 return (value / div_factor) + 1;
34 }
35
fprobe_selftest_nest_target(u32 value,u32 (* nest)(u32))36 static noinline u32 fprobe_selftest_nest_target(u32 value, u32 (*nest)(u32))
37 {
38 return nest(value + 2);
39 }
40
fp_entry_handler(struct fprobe * fp,unsigned long ip,unsigned long ret_ip,struct pt_regs * regs,void * data)41 static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
42 unsigned long ret_ip,
43 struct pt_regs *regs, void *data)
44 {
45 KUNIT_EXPECT_FALSE(current_test, preemptible());
46 /* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */
47 if (ip != target_ip)
48 KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
49 entry_val = (rand1 / div_factor);
50 if (fp->entry_data_size) {
51 KUNIT_EXPECT_NOT_NULL(current_test, data);
52 if (data)
53 *(u32 *)data = entry_val;
54 } else
55 KUNIT_EXPECT_NULL(current_test, data);
56
57 return entry_return_value;
58 }
59
fp_exit_handler(struct fprobe * fp,unsigned long ip,unsigned long ret_ip,struct pt_regs * regs,void * data)60 static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
61 unsigned long ret_ip,
62 struct pt_regs *regs, void *data)
63 {
64 unsigned long ret = regs_return_value(regs);
65
66 KUNIT_EXPECT_FALSE(current_test, preemptible());
67 if (ip != target_ip) {
68 KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
69 KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor) + 1);
70 } else
71 KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor));
72 KUNIT_EXPECT_EQ(current_test, entry_val, (rand1 / div_factor));
73 exit_val = entry_val + div_factor;
74 if (fp->entry_data_size) {
75 KUNIT_EXPECT_NOT_NULL(current_test, data);
76 if (data)
77 KUNIT_EXPECT_EQ(current_test, *(u32 *)data, entry_val);
78 } else
79 KUNIT_EXPECT_NULL(current_test, data);
80 }
81
nest_entry_handler(struct fprobe * fp,unsigned long ip,unsigned long ret_ip,struct pt_regs * regs,void * data)82 static notrace int nest_entry_handler(struct fprobe *fp, unsigned long ip,
83 unsigned long ret_ip,
84 struct pt_regs *regs, void *data)
85 {
86 KUNIT_EXPECT_FALSE(current_test, preemptible());
87 return 0;
88 }
89
nest_exit_handler(struct fprobe * fp,unsigned long ip,unsigned long ret_ip,struct pt_regs * regs,void * data)90 static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip,
91 unsigned long ret_ip,
92 struct pt_regs *regs, void *data)
93 {
94 KUNIT_EXPECT_FALSE(current_test, preemptible());
95 KUNIT_EXPECT_EQ(current_test, ip, target_nest_ip);
96 }
97
98 /* Test entry only (no rethook) */
test_fprobe_entry(struct kunit * test)99 static void test_fprobe_entry(struct kunit *test)
100 {
101 struct fprobe fp_entry = {
102 .entry_handler = fp_entry_handler,
103 };
104
105 current_test = test;
106
107 /* Before register, unregister should be failed. */
108 KUNIT_EXPECT_NE(test, 0, unregister_fprobe(&fp_entry));
109 KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp_entry, "fprobe_selftest_target*", NULL));
110
111 entry_val = 0;
112 exit_val = 0;
113 target(rand1);
114 KUNIT_EXPECT_NE(test, 0, entry_val);
115 KUNIT_EXPECT_EQ(test, 0, exit_val);
116
117 entry_val = 0;
118 exit_val = 0;
119 target2(rand1);
120 KUNIT_EXPECT_NE(test, 0, entry_val);
121 KUNIT_EXPECT_EQ(test, 0, exit_val);
122
123 KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp_entry));
124 }
125
test_fprobe(struct kunit * test)126 static void test_fprobe(struct kunit *test)
127 {
128 struct fprobe fp = {
129 .entry_handler = fp_entry_handler,
130 .exit_handler = fp_exit_handler,
131 };
132
133 current_test = test;
134 KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target*", NULL));
135
136 entry_val = 0;
137 exit_val = 0;
138 target(rand1);
139 KUNIT_EXPECT_NE(test, 0, entry_val);
140 KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
141
142 entry_val = 0;
143 exit_val = 0;
144 target2(rand1);
145 KUNIT_EXPECT_NE(test, 0, entry_val);
146 KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
147
148 KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
149 }
150
test_fprobe_syms(struct kunit * test)151 static void test_fprobe_syms(struct kunit *test)
152 {
153 static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_target2"};
154 struct fprobe fp = {
155 .entry_handler = fp_entry_handler,
156 .exit_handler = fp_exit_handler,
157 };
158
159 current_test = test;
160 KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
161
162 entry_val = 0;
163 exit_val = 0;
164 target(rand1);
165 KUNIT_EXPECT_NE(test, 0, entry_val);
166 KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
167
168 entry_val = 0;
169 exit_val = 0;
170 target2(rand1);
171 KUNIT_EXPECT_NE(test, 0, entry_val);
172 KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
173
174 KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
175 }
176
177 /* Test private entry_data */
test_fprobe_data(struct kunit * test)178 static void test_fprobe_data(struct kunit *test)
179 {
180 struct fprobe fp = {
181 .entry_handler = fp_entry_handler,
182 .exit_handler = fp_exit_handler,
183 .entry_data_size = sizeof(u32),
184 };
185
186 current_test = test;
187 KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target", NULL));
188
189 target(rand1);
190
191 KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
192 }
193
194 /* Test nr_maxactive */
test_fprobe_nest(struct kunit * test)195 static void test_fprobe_nest(struct kunit *test)
196 {
197 static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_nest_target"};
198 struct fprobe fp = {
199 .entry_handler = nest_entry_handler,
200 .exit_handler = nest_exit_handler,
201 .nr_maxactive = 1,
202 };
203
204 current_test = test;
205 KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
206
207 target_nest(rand1, target);
208 KUNIT_EXPECT_EQ(test, 1, fp.nmissed);
209
210 KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
211 }
212
test_fprobe_skip(struct kunit * test)213 static void test_fprobe_skip(struct kunit *test)
214 {
215 struct fprobe fp = {
216 .entry_handler = fp_entry_handler,
217 .exit_handler = fp_exit_handler,
218 };
219
220 current_test = test;
221 KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target", NULL));
222
223 entry_return_value = 1;
224 entry_val = 0;
225 exit_val = 0;
226 target(rand1);
227 KUNIT_EXPECT_NE(test, 0, entry_val);
228 KUNIT_EXPECT_EQ(test, 0, exit_val);
229 KUNIT_EXPECT_EQ(test, 0, fp.nmissed);
230 entry_return_value = 0;
231
232 KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
233 }
234
get_ftrace_location(void * func)235 static unsigned long get_ftrace_location(void *func)
236 {
237 unsigned long size, addr = (unsigned long)func;
238
239 if (!kallsyms_lookup_size_offset(addr, &size, NULL) || !size)
240 return 0;
241
242 return ftrace_location_range(addr, addr + size - 1);
243 }
244
fprobe_test_init(struct kunit * test)245 static int fprobe_test_init(struct kunit *test)
246 {
247 rand1 = get_random_u32_above(div_factor);
248 target = fprobe_selftest_target;
249 target2 = fprobe_selftest_target2;
250 target_nest = fprobe_selftest_nest_target;
251 target_ip = get_ftrace_location(target);
252 target2_ip = get_ftrace_location(target2);
253 target_nest_ip = get_ftrace_location(target_nest);
254
255 return 0;
256 }
257
258 static struct kunit_case fprobe_testcases[] = {
259 KUNIT_CASE(test_fprobe_entry),
260 KUNIT_CASE(test_fprobe),
261 KUNIT_CASE(test_fprobe_syms),
262 KUNIT_CASE(test_fprobe_data),
263 KUNIT_CASE(test_fprobe_nest),
264 KUNIT_CASE(test_fprobe_skip),
265 {}
266 };
267
268 static struct kunit_suite fprobe_test_suite = {
269 .name = "fprobe_test",
270 .init = fprobe_test_init,
271 .test_cases = fprobe_testcases,
272 };
273
274 kunit_test_suites(&fprobe_test_suite);
275
276