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6ff1cb35 AM |
1 | #include <linux/kernel.h> |
2 | #include <linux/init.h> | |
3 | #include <linux/random.h> | |
4 | #include <linux/stat.h> | |
5 | #include <linux/types.h> | |
6 | #include <linux/fs.h> | |
7 | #include <linux/module.h> | |
f4f154fd | 8 | #include <linux/interrupt.h> |
329409ae AM |
9 | #include <linux/unwind.h> |
10 | #include <linux/stacktrace.h> | |
11 | #include <linux/kallsyms.h> | |
6ff1cb35 AM |
12 | #include <linux/fault-inject.h> |
13 | ||
14 | /* | |
15 | * setup_fault_attr() is a helper function for various __setup handlers, so it | |
16 | * returns 0 on error, because that is what __setup handlers do. | |
17 | */ | |
18 | int __init setup_fault_attr(struct fault_attr *attr, char *str) | |
19 | { | |
20 | unsigned long probability; | |
21 | unsigned long interval; | |
22 | int times; | |
23 | int space; | |
24 | ||
25 | /* "<interval>,<probability>,<space>,<times>" */ | |
26 | if (sscanf(str, "%lu,%lu,%d,%d", | |
27 | &interval, &probability, &space, ×) < 4) { | |
28 | printk(KERN_WARNING | |
29 | "FAULT_INJECTION: failed to parse arguments\n"); | |
30 | return 0; | |
31 | } | |
32 | ||
33 | attr->probability = probability; | |
34 | attr->interval = interval; | |
35 | atomic_set(&attr->times, times); | |
36 | atomic_set(&attr->space, space); | |
37 | ||
38 | return 1; | |
39 | } | |
40 | ||
41 | static void fail_dump(struct fault_attr *attr) | |
42 | { | |
43 | if (attr->verbose > 0) | |
44 | printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n"); | |
45 | if (attr->verbose > 1) | |
46 | dump_stack(); | |
47 | } | |
48 | ||
49 | #define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0) | |
50 | ||
f4f154fd AM |
51 | static int fail_task(struct fault_attr *attr, struct task_struct *task) |
52 | { | |
53 | return !in_interrupt() && task->make_it_fail; | |
54 | } | |
55 | ||
329409ae AM |
56 | #ifdef CONFIG_STACK_UNWIND |
57 | ||
58 | static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info, | |
59 | void *arg) | |
60 | { | |
61 | int depth; | |
62 | struct fault_attr *attr = arg; | |
63 | bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); | |
64 | ||
65 | for (depth = 0; depth < attr->stacktrace_depth | |
66 | && unwind(info) == 0 && UNW_PC(info); depth++) { | |
67 | if (arch_unw_user_mode(info)) | |
68 | break; | |
69 | if (attr->reject_start <= UNW_PC(info) && | |
70 | UNW_PC(info) < attr->reject_end) | |
71 | return 0; | |
72 | if (attr->require_start <= UNW_PC(info) && | |
73 | UNW_PC(info) < attr->require_end) | |
74 | found = 1; | |
75 | } | |
76 | return found; | |
77 | } | |
78 | ||
79 | static int fail_stacktrace(struct fault_attr *attr) | |
80 | { | |
81 | struct unwind_frame_info info; | |
82 | ||
83 | return unwind_init_running(&info, fail_stacktrace_callback, attr); | |
84 | } | |
85 | ||
86 | #elif defined(CONFIG_STACKTRACE) | |
87 | ||
88 | #define MAX_STACK_TRACE_DEPTH 32 | |
89 | ||
90 | static int fail_stacktrace(struct fault_attr *attr) | |
91 | { | |
92 | struct stack_trace trace; | |
93 | int depth = attr->stacktrace_depth; | |
94 | unsigned long entries[MAX_STACK_TRACE_DEPTH]; | |
95 | int n; | |
96 | bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); | |
97 | ||
98 | if (depth == 0) | |
99 | return found; | |
100 | ||
101 | trace.nr_entries = 0; | |
102 | trace.entries = entries; | |
103 | trace.max_entries = (depth < MAX_STACK_TRACE_DEPTH) ? | |
104 | depth : MAX_STACK_TRACE_DEPTH; | |
105 | trace.skip = 1; | |
106 | trace.all_contexts = 0; | |
107 | ||
108 | save_stack_trace(&trace, NULL); | |
109 | for (n = 0; n < trace.nr_entries; n++) { | |
110 | if (attr->reject_start <= entries[n] && | |
111 | entries[n] < attr->reject_end) | |
112 | return 0; | |
113 | if (attr->require_start <= entries[n] && | |
114 | entries[n] < attr->require_end) | |
115 | found = 1; | |
116 | } | |
117 | return found; | |
118 | } | |
119 | ||
120 | #else | |
121 | ||
122 | static inline int fail_stacktrace(struct fault_attr *attr) | |
123 | { | |
124 | static int firsttime = 1; | |
125 | ||
126 | if (firsttime) { | |
127 | printk(KERN_WARNING | |
128 | "This architecture does not implement save_stack_trace()\n"); | |
129 | firsttime = 0; | |
130 | } | |
131 | return 0; | |
132 | } | |
133 | ||
134 | #endif | |
135 | ||
6ff1cb35 AM |
136 | /* |
137 | * This code is stolen from failmalloc-1.0 | |
138 | * http://www.nongnu.org/failmalloc/ | |
139 | */ | |
140 | ||
141 | int should_fail(struct fault_attr *attr, ssize_t size) | |
142 | { | |
f4f154fd AM |
143 | if (attr->task_filter && !fail_task(attr, current)) |
144 | return 0; | |
145 | ||
329409ae AM |
146 | if (!fail_stacktrace(attr)) |
147 | return 0; | |
148 | ||
6ff1cb35 AM |
149 | if (atomic_read(&attr->times) == 0) |
150 | return 0; | |
151 | ||
152 | if (atomic_read(&attr->space) > size) { | |
153 | atomic_sub(size, &attr->space); | |
154 | return 0; | |
155 | } | |
156 | ||
157 | if (attr->interval > 1) { | |
158 | attr->count++; | |
159 | if (attr->count % attr->interval) | |
160 | return 0; | |
161 | } | |
162 | ||
163 | if (attr->probability > random32() % 100) | |
164 | goto fail; | |
165 | ||
166 | return 0; | |
167 | ||
168 | fail: | |
169 | fail_dump(attr); | |
170 | ||
171 | if (atomic_read(&attr->times) != -1) | |
172 | atomic_dec_not_zero(&attr->times); | |
173 | ||
174 | return 1; | |
175 | } | |
176 | ||
177 | #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS | |
178 | ||
179 | static void debugfs_ul_set(void *data, u64 val) | |
180 | { | |
181 | *(unsigned long *)data = val; | |
182 | } | |
183 | ||
184 | static u64 debugfs_ul_get(void *data) | |
185 | { | |
186 | return *(unsigned long *)data; | |
187 | } | |
188 | ||
189 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); | |
190 | ||
191 | static struct dentry *debugfs_create_ul(const char *name, mode_t mode, | |
192 | struct dentry *parent, unsigned long *value) | |
193 | { | |
194 | return debugfs_create_file(name, mode, parent, value, &fops_ul); | |
195 | } | |
196 | ||
197 | static void debugfs_atomic_t_set(void *data, u64 val) | |
198 | { | |
199 | atomic_set((atomic_t *)data, val); | |
200 | } | |
201 | ||
202 | static u64 debugfs_atomic_t_get(void *data) | |
203 | { | |
204 | return atomic_read((atomic_t *)data); | |
205 | } | |
206 | ||
207 | DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get, | |
208 | debugfs_atomic_t_set, "%lld\n"); | |
209 | ||
210 | static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode, | |
211 | struct dentry *parent, atomic_t *value) | |
212 | { | |
213 | return debugfs_create_file(name, mode, parent, value, &fops_atomic_t); | |
214 | } | |
215 | ||
216 | void cleanup_fault_attr_dentries(struct fault_attr *attr) | |
217 | { | |
218 | debugfs_remove(attr->dentries.probability_file); | |
219 | attr->dentries.probability_file = NULL; | |
220 | ||
221 | debugfs_remove(attr->dentries.interval_file); | |
222 | attr->dentries.interval_file = NULL; | |
223 | ||
224 | debugfs_remove(attr->dentries.times_file); | |
225 | attr->dentries.times_file = NULL; | |
226 | ||
227 | debugfs_remove(attr->dentries.space_file); | |
228 | attr->dentries.space_file = NULL; | |
229 | ||
230 | debugfs_remove(attr->dentries.verbose_file); | |
231 | attr->dentries.verbose_file = NULL; | |
232 | ||
f4f154fd AM |
233 | debugfs_remove(attr->dentries.task_filter_file); |
234 | attr->dentries.task_filter_file = NULL; | |
235 | ||
329409ae AM |
236 | debugfs_remove(attr->dentries.stacktrace_depth_file); |
237 | attr->dentries.stacktrace_depth_file = NULL; | |
238 | ||
239 | debugfs_remove(attr->dentries.require_start_file); | |
240 | attr->dentries.require_start_file = NULL; | |
241 | ||
242 | debugfs_remove(attr->dentries.require_end_file); | |
243 | attr->dentries.require_end_file = NULL; | |
244 | ||
245 | debugfs_remove(attr->dentries.reject_start_file); | |
246 | attr->dentries.reject_start_file = NULL; | |
247 | ||
248 | debugfs_remove(attr->dentries.reject_end_file); | |
249 | attr->dentries.reject_end_file = NULL; | |
250 | ||
6ff1cb35 AM |
251 | if (attr->dentries.dir) |
252 | WARN_ON(!simple_empty(attr->dentries.dir)); | |
253 | ||
254 | debugfs_remove(attr->dentries.dir); | |
255 | attr->dentries.dir = NULL; | |
256 | } | |
257 | ||
258 | int init_fault_attr_dentries(struct fault_attr *attr, const char *name) | |
259 | { | |
260 | mode_t mode = S_IFREG | S_IRUSR | S_IWUSR; | |
261 | struct dentry *dir; | |
262 | ||
263 | memset(&attr->dentries, 0, sizeof(attr->dentries)); | |
264 | ||
265 | dir = debugfs_create_dir(name, NULL); | |
266 | if (!dir) | |
267 | goto fail; | |
268 | attr->dentries.dir = dir; | |
269 | ||
270 | attr->dentries.probability_file = | |
271 | debugfs_create_ul("probability", mode, dir, &attr->probability); | |
272 | ||
273 | attr->dentries.interval_file = | |
274 | debugfs_create_ul("interval", mode, dir, &attr->interval); | |
275 | ||
276 | attr->dentries.times_file = | |
277 | debugfs_create_atomic_t("times", mode, dir, &attr->times); | |
278 | ||
279 | attr->dentries.space_file = | |
280 | debugfs_create_atomic_t("space", mode, dir, &attr->space); | |
281 | ||
282 | attr->dentries.verbose_file = | |
283 | debugfs_create_ul("verbose", mode, dir, &attr->verbose); | |
284 | ||
f4f154fd AM |
285 | attr->dentries.task_filter_file = debugfs_create_bool("task-filter", |
286 | mode, dir, &attr->task_filter); | |
287 | ||
329409ae AM |
288 | attr->dentries.stacktrace_depth_file = |
289 | debugfs_create_ul("stacktrace-depth", mode, dir, | |
290 | &attr->stacktrace_depth); | |
291 | ||
292 | attr->dentries.require_start_file = | |
293 | debugfs_create_ul("require-start", mode, dir, &attr->require_start); | |
294 | ||
295 | attr->dentries.require_end_file = | |
296 | debugfs_create_ul("require-end", mode, dir, &attr->require_end); | |
297 | ||
298 | attr->dentries.reject_start_file = | |
299 | debugfs_create_ul("reject-start", mode, dir, &attr->reject_start); | |
300 | ||
301 | attr->dentries.reject_end_file = | |
302 | debugfs_create_ul("reject-end", mode, dir, &attr->reject_end); | |
303 | ||
304 | ||
6ff1cb35 AM |
305 | if (!attr->dentries.probability_file || !attr->dentries.interval_file |
306 | || !attr->dentries.times_file || !attr->dentries.space_file | |
329409ae AM |
307 | || !attr->dentries.verbose_file || !attr->dentries.task_filter_file |
308 | || !attr->dentries.stacktrace_depth_file | |
309 | || !attr->dentries.require_start_file | |
310 | || !attr->dentries.require_end_file | |
311 | || !attr->dentries.reject_start_file | |
312 | || !attr->dentries.reject_end_file | |
313 | ) | |
6ff1cb35 AM |
314 | goto fail; |
315 | ||
316 | return 0; | |
317 | fail: | |
318 | cleanup_fault_attr_dentries(attr); | |
319 | return -ENOMEM; | |
320 | } | |
321 | ||
322 | #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ |