Root/kernel/test_kprobes.c

1/*
2 * test_kprobes.c - simple sanity test for *probes
3 *
4 * Copyright IBM Corp. 2008
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it would be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
14 * the GNU General Public License for more details.
15 */
16
17#include <linux/kernel.h>
18#include <linux/kprobes.h>
19#include <linux/random.h>
20
21#define div_factor 3
22
23static u32 rand1, preh_val, posth_val, jph_val;
24static int errors, handler_errors, num_tests;
25static u32 (*target)(u32 value);
26static u32 (*target2)(u32 value);
27
28static noinline u32 kprobe_target(u32 value)
29{
30    return (value / div_factor);
31}
32
33static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
34{
35    preh_val = (rand1 / div_factor);
36    return 0;
37}
38
39static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,
40        unsigned long flags)
41{
42    if (preh_val != (rand1 / div_factor)) {
43        handler_errors++;
44        printk(KERN_ERR "Kprobe smoke test failed: "
45                "incorrect value in post_handler\n");
46    }
47    posth_val = preh_val + div_factor;
48}
49
50static struct kprobe kp = {
51    .symbol_name = "kprobe_target",
52    .pre_handler = kp_pre_handler,
53    .post_handler = kp_post_handler
54};
55
56static int test_kprobe(void)
57{
58    int ret;
59
60    ret = register_kprobe(&kp);
61    if (ret < 0) {
62        printk(KERN_ERR "Kprobe smoke test failed: "
63                "register_kprobe returned %d\n", ret);
64        return ret;
65    }
66
67    ret = target(rand1);
68    unregister_kprobe(&kp);
69
70    if (preh_val == 0) {
71        printk(KERN_ERR "Kprobe smoke test failed: "
72                "kprobe pre_handler not called\n");
73        handler_errors++;
74    }
75
76    if (posth_val == 0) {
77        printk(KERN_ERR "Kprobe smoke test failed: "
78                "kprobe post_handler not called\n");
79        handler_errors++;
80    }
81
82    return 0;
83}
84
85static noinline u32 kprobe_target2(u32 value)
86{
87    return (value / div_factor) + 1;
88}
89
90static int kp_pre_handler2(struct kprobe *p, struct pt_regs *regs)
91{
92    preh_val = (rand1 / div_factor) + 1;
93    return 0;
94}
95
96static void kp_post_handler2(struct kprobe *p, struct pt_regs *regs,
97        unsigned long flags)
98{
99    if (preh_val != (rand1 / div_factor) + 1) {
100        handler_errors++;
101        printk(KERN_ERR "Kprobe smoke test failed: "
102                "incorrect value in post_handler2\n");
103    }
104    posth_val = preh_val + div_factor;
105}
106
107static struct kprobe kp2 = {
108    .symbol_name = "kprobe_target2",
109    .pre_handler = kp_pre_handler2,
110    .post_handler = kp_post_handler2
111};
112
113static int test_kprobes(void)
114{
115    int ret;
116    struct kprobe *kps[2] = {&kp, &kp2};
117
118    kp.addr = 0; /* addr should be cleard for reusing kprobe. */
119    ret = register_kprobes(kps, 2);
120    if (ret < 0) {
121        printk(KERN_ERR "Kprobe smoke test failed: "
122                "register_kprobes returned %d\n", ret);
123        return ret;
124    }
125
126    preh_val = 0;
127    posth_val = 0;
128    ret = target(rand1);
129
130    if (preh_val == 0) {
131        printk(KERN_ERR "Kprobe smoke test failed: "
132                "kprobe pre_handler not called\n");
133        handler_errors++;
134    }
135
136    if (posth_val == 0) {
137        printk(KERN_ERR "Kprobe smoke test failed: "
138                "kprobe post_handler not called\n");
139        handler_errors++;
140    }
141
142    preh_val = 0;
143    posth_val = 0;
144    ret = target2(rand1);
145
146    if (preh_val == 0) {
147        printk(KERN_ERR "Kprobe smoke test failed: "
148                "kprobe pre_handler2 not called\n");
149        handler_errors++;
150    }
151
152    if (posth_val == 0) {
153        printk(KERN_ERR "Kprobe smoke test failed: "
154                "kprobe post_handler2 not called\n");
155        handler_errors++;
156    }
157
158    unregister_kprobes(kps, 2);
159    return 0;
160
161}
162
163static u32 j_kprobe_target(u32 value)
164{
165    if (value != rand1) {
166        handler_errors++;
167        printk(KERN_ERR "Kprobe smoke test failed: "
168                "incorrect value in jprobe handler\n");
169    }
170
171    jph_val = rand1;
172    jprobe_return();
173    return 0;
174}
175
176static struct jprobe jp = {
177    .entry = j_kprobe_target,
178    .kp.symbol_name = "kprobe_target"
179};
180
181static int test_jprobe(void)
182{
183    int ret;
184
185    ret = register_jprobe(&jp);
186    if (ret < 0) {
187        printk(KERN_ERR "Kprobe smoke test failed: "
188                "register_jprobe returned %d\n", ret);
189        return ret;
190    }
191
192    ret = target(rand1);
193    unregister_jprobe(&jp);
194    if (jph_val == 0) {
195        printk(KERN_ERR "Kprobe smoke test failed: "
196                "jprobe handler not called\n");
197        handler_errors++;
198    }
199
200    return 0;
201}
202
203static struct jprobe jp2 = {
204    .entry = j_kprobe_target,
205    .kp.symbol_name = "kprobe_target2"
206};
207
208static int test_jprobes(void)
209{
210    int ret;
211    struct jprobe *jps[2] = {&jp, &jp2};
212
213    jp.kp.addr = 0; /* addr should be cleard for reusing kprobe. */
214    ret = register_jprobes(jps, 2);
215    if (ret < 0) {
216        printk(KERN_ERR "Kprobe smoke test failed: "
217                "register_jprobes returned %d\n", ret);
218        return ret;
219    }
220
221    jph_val = 0;
222    ret = target(rand1);
223    if (jph_val == 0) {
224        printk(KERN_ERR "Kprobe smoke test failed: "
225                "jprobe handler not called\n");
226        handler_errors++;
227    }
228
229    jph_val = 0;
230    ret = target2(rand1);
231    if (jph_val == 0) {
232        printk(KERN_ERR "Kprobe smoke test failed: "
233                "jprobe handler2 not called\n");
234        handler_errors++;
235    }
236    unregister_jprobes(jps, 2);
237
238    return 0;
239}
240#ifdef CONFIG_KRETPROBES
241static u32 krph_val;
242
243static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
244{
245    krph_val = (rand1 / div_factor);
246    return 0;
247}
248
249static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
250{
251    unsigned long ret = regs_return_value(regs);
252
253    if (ret != (rand1 / div_factor)) {
254        handler_errors++;
255        printk(KERN_ERR "Kprobe smoke test failed: "
256                "incorrect value in kretprobe handler\n");
257    }
258    if (krph_val == 0) {
259        handler_errors++;
260        printk(KERN_ERR "Kprobe smoke test failed: "
261                "call to kretprobe entry handler failed\n");
262    }
263
264    krph_val = rand1;
265    return 0;
266}
267
268static struct kretprobe rp = {
269    .handler = return_handler,
270    .entry_handler = entry_handler,
271    .kp.symbol_name = "kprobe_target"
272};
273
274static int test_kretprobe(void)
275{
276    int ret;
277
278    ret = register_kretprobe(&rp);
279    if (ret < 0) {
280        printk(KERN_ERR "Kprobe smoke test failed: "
281                "register_kretprobe returned %d\n", ret);
282        return ret;
283    }
284
285    ret = target(rand1);
286    unregister_kretprobe(&rp);
287    if (krph_val != rand1) {
288        printk(KERN_ERR "Kprobe smoke test failed: "
289                "kretprobe handler not called\n");
290        handler_errors++;
291    }
292
293    return 0;
294}
295
296static int return_handler2(struct kretprobe_instance *ri, struct pt_regs *regs)
297{
298    unsigned long ret = regs_return_value(regs);
299
300    if (ret != (rand1 / div_factor) + 1) {
301        handler_errors++;
302        printk(KERN_ERR "Kprobe smoke test failed: "
303                "incorrect value in kretprobe handler2\n");
304    }
305    if (krph_val == 0) {
306        handler_errors++;
307        printk(KERN_ERR "Kprobe smoke test failed: "
308                "call to kretprobe entry handler failed\n");
309    }
310
311    krph_val = rand1;
312    return 0;
313}
314
315static struct kretprobe rp2 = {
316    .handler = return_handler2,
317    .entry_handler = entry_handler,
318    .kp.symbol_name = "kprobe_target2"
319};
320
321static int test_kretprobes(void)
322{
323    int ret;
324    struct kretprobe *rps[2] = {&rp, &rp2};
325
326    rp.kp.addr = 0; /* addr should be cleard for reusing kprobe. */
327    ret = register_kretprobes(rps, 2);
328    if (ret < 0) {
329        printk(KERN_ERR "Kprobe smoke test failed: "
330                "register_kretprobe returned %d\n", ret);
331        return ret;
332    }
333
334    krph_val = 0;
335    ret = target(rand1);
336    if (krph_val != rand1) {
337        printk(KERN_ERR "Kprobe smoke test failed: "
338                "kretprobe handler not called\n");
339        handler_errors++;
340    }
341
342    krph_val = 0;
343    ret = target2(rand1);
344    if (krph_val != rand1) {
345        printk(KERN_ERR "Kprobe smoke test failed: "
346                "kretprobe handler2 not called\n");
347        handler_errors++;
348    }
349    unregister_kretprobes(rps, 2);
350    return 0;
351}
352#endif /* CONFIG_KRETPROBES */
353
354int init_test_probes(void)
355{
356    int ret;
357
358    target = kprobe_target;
359    target2 = kprobe_target2;
360
361    do {
362        rand1 = random32();
363    } while (rand1 <= div_factor);
364
365    printk(KERN_INFO "Kprobe smoke test started\n");
366    num_tests++;
367    ret = test_kprobe();
368    if (ret < 0)
369        errors++;
370
371    num_tests++;
372    ret = test_kprobes();
373    if (ret < 0)
374        errors++;
375
376    num_tests++;
377    ret = test_jprobe();
378    if (ret < 0)
379        errors++;
380
381    num_tests++;
382    ret = test_jprobes();
383    if (ret < 0)
384        errors++;
385
386#ifdef CONFIG_KRETPROBES
387    num_tests++;
388    ret = test_kretprobe();
389    if (ret < 0)
390        errors++;
391
392    num_tests++;
393    ret = test_kretprobes();
394    if (ret < 0)
395        errors++;
396#endif /* CONFIG_KRETPROBES */
397
398    if (errors)
399        printk(KERN_ERR "BUG: Kprobe smoke test: %d out of "
400                "%d tests failed\n", errors, num_tests);
401    else if (handler_errors)
402        printk(KERN_ERR "BUG: Kprobe smoke test: %d error(s) "
403                "running handlers\n", handler_errors);
404    else
405        printk(KERN_INFO "Kprobe smoke test passed successfully\n");
406
407    return 0;
408}
409

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