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authorAnanth N Mavinakayanahalli <ananth@in.ibm.com>2008-01-30 07:32:53 -0500
committerIngo Molnar <mingo@elte.hu>2008-01-30 07:32:53 -0500
commit8c1c9356429741a82ff176d0f3400fb9e06b2a30 (patch)
tree4daa7864163b77943e3d303c32a08672f443685e /kernel/test_kprobes.c
parent3334052a321aca0ffecb54244d666311f98f5487 (diff)
x86: kprobes: add kprobes smoke tests that run on boot
Here is a quick and naive smoke test for kprobes. This is intended to just verify if some unrelated change broke the *probes subsystem. It is self contained, architecture agnostic and isn't of any great use by itself. This needs to be built in the kernel and runs a basic set of tests to verify if kprobes, jprobes and kretprobes run fine on the kernel. In case of an error, it'll print out a message with a "BUG" prefix. This is a start; we intend to add more tests to this bucket over time. Thanks to Jim Keniston and Masami Hiramatsu for comments and suggestions. Tested on x86 (32/64) and powerpc. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/test_kprobes.c')
-rw-r--r--kernel/test_kprobes.c216
1 files changed, 216 insertions, 0 deletions
diff --git a/kernel/test_kprobes.c b/kernel/test_kprobes.c
new file mode 100644
index 000000000000..88cdb109e13c
--- /dev/null
+++ b/kernel/test_kprobes.c
@@ -0,0 +1,216 @@
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;
25
26static noinline u32 kprobe_target(u32 value)
27{
28 /*
29 * gcc ignores noinline on some architectures unless we stuff
30 * sufficient lard into the function. The get_kprobe() here is
31 * just for that.
32 *
33 * NOTE: We aren't concerned about the correctness of get_kprobe()
34 * here; hence, this call is neither under !preempt nor with the
35 * kprobe_mutex held. This is fine(tm)
36 */
37 if (get_kprobe((void *)0xdeadbeef))
38 printk(KERN_INFO "Kprobe smoke test: probe on 0xdeadbeef!\n");
39
40 return (value / div_factor);
41}
42
43static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
44{
45 preh_val = (rand1 / div_factor);
46 return 0;
47}
48
49static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,
50 unsigned long flags)
51{
52 if (preh_val != (rand1 / div_factor)) {
53 handler_errors++;
54 printk(KERN_ERR "Kprobe smoke test failed: "
55 "incorrect value in post_handler\n");
56 }
57 posth_val = preh_val + div_factor;
58}
59
60static struct kprobe kp = {
61 .symbol_name = "kprobe_target",
62 .pre_handler = kp_pre_handler,
63 .post_handler = kp_post_handler
64};
65
66static int test_kprobe(void)
67{
68 int ret;
69
70 ret = register_kprobe(&kp);
71 if (ret < 0) {
72 printk(KERN_ERR "Kprobe smoke test failed: "
73 "register_kprobe returned %d\n", ret);
74 return ret;
75 }
76
77 ret = kprobe_target(rand1);
78 unregister_kprobe(&kp);
79
80 if (preh_val == 0) {
81 printk(KERN_ERR "Kprobe smoke test failed: "
82 "kprobe pre_handler not called\n");
83 handler_errors++;
84 }
85
86 if (posth_val == 0) {
87 printk(KERN_ERR "Kprobe smoke test failed: "
88 "kprobe post_handler not called\n");
89 handler_errors++;
90 }
91
92 return 0;
93}
94
95static u32 j_kprobe_target(u32 value)
96{
97 if (value != rand1) {
98 handler_errors++;
99 printk(KERN_ERR "Kprobe smoke test failed: "
100 "incorrect value in jprobe handler\n");
101 }
102
103 jph_val = rand1;
104 jprobe_return();
105 return 0;
106}
107
108static struct jprobe jp = {
109 .entry = j_kprobe_target,
110 .kp.symbol_name = "kprobe_target"
111};
112
113static int test_jprobe(void)
114{
115 int ret;
116
117 ret = register_jprobe(&jp);
118 if (ret < 0) {
119 printk(KERN_ERR "Kprobe smoke test failed: "
120 "register_jprobe returned %d\n", ret);
121 return ret;
122 }
123
124 ret = kprobe_target(rand1);
125 unregister_jprobe(&jp);
126 if (jph_val == 0) {
127 printk(KERN_ERR "Kprobe smoke test failed: "
128 "jprobe handler not called\n");
129 handler_errors++;
130 }
131
132 return 0;
133}
134
135#ifdef CONFIG_KRETPROBES
136static u32 krph_val;
137
138static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
139{
140 unsigned long ret = regs_return_value(regs);
141
142 if (ret != (rand1 / div_factor)) {
143 handler_errors++;
144 printk(KERN_ERR "Kprobe smoke test failed: "
145 "incorrect value in kretprobe handler\n");
146 }
147
148 krph_val = (rand1 / div_factor);
149 return 0;
150}
151
152static struct kretprobe rp = {
153 .handler = return_handler,
154 .kp.symbol_name = "kprobe_target"
155};
156
157static int test_kretprobe(void)
158{
159 int ret;
160
161 ret = register_kretprobe(&rp);
162 if (ret < 0) {
163 printk(KERN_ERR "Kprobe smoke test failed: "
164 "register_kretprobe returned %d\n", ret);
165 return ret;
166 }
167
168 ret = kprobe_target(rand1);
169 unregister_kretprobe(&rp);
170 if (krph_val == 0) {
171 printk(KERN_ERR "Kprobe smoke test failed: "
172 "kretprobe handler not called\n");
173 handler_errors++;
174 }
175
176 return 0;
177}
178#endif /* CONFIG_KRETPROBES */
179
180int init_test_probes(void)
181{
182 int ret;
183
184 do {
185 rand1 = random32();
186 } while (rand1 <= div_factor);
187
188 printk(KERN_INFO "Kprobe smoke test started\n");
189 num_tests++;
190 ret = test_kprobe();
191 if (ret < 0)
192 errors++;
193
194 num_tests++;
195 ret = test_jprobe();
196 if (ret < 0)
197 errors++;
198
199#ifdef CONFIG_KRETPROBES
200 num_tests++;
201 ret = test_kretprobe();
202 if (ret < 0)
203 errors++;
204#endif /* CONFIG_KRETPROBES */
205
206 if (errors)
207 printk(KERN_ERR "BUG: Kprobe smoke test: %d out of "
208 "%d tests failed\n", errors, num_tests);
209 else if (handler_errors)
210 printk(KERN_ERR "BUG: Kprobe smoke test: %d error(s) "
211 "running handlers\n", handler_errors);
212 else
213 printk(KERN_INFO "Kprobe smoke test passed successfully\n");
214
215 return 0;
216}