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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 | ||
08b3df2d | 51 | static bool fail_task(struct fault_attr *attr, struct task_struct *task) |
f4f154fd AM |
52 | { |
53 | return !in_interrupt() && task->make_it_fail; | |
54 | } | |
55 | ||
a124c28e DM |
56 | #define MAX_STACK_TRACE_DEPTH 32 |
57 | ||
329409ae AM |
58 | #ifdef CONFIG_STACK_UNWIND |
59 | ||
60 | static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info, | |
61 | void *arg) | |
62 | { | |
63 | int depth; | |
64 | struct fault_attr *attr = arg; | |
65 | bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); | |
66 | ||
67 | for (depth = 0; depth < attr->stacktrace_depth | |
68 | && unwind(info) == 0 && UNW_PC(info); depth++) { | |
69 | if (arch_unw_user_mode(info)) | |
70 | break; | |
71 | if (attr->reject_start <= UNW_PC(info) && | |
72 | UNW_PC(info) < attr->reject_end) | |
08b3df2d | 73 | return false; |
329409ae AM |
74 | if (attr->require_start <= UNW_PC(info) && |
75 | UNW_PC(info) < attr->require_end) | |
08b3df2d | 76 | found = true; |
329409ae AM |
77 | } |
78 | return found; | |
79 | } | |
80 | ||
08b3df2d | 81 | static bool fail_stacktrace(struct fault_attr *attr) |
329409ae AM |
82 | { |
83 | struct unwind_frame_info info; | |
84 | ||
85 | return unwind_init_running(&info, fail_stacktrace_callback, attr); | |
86 | } | |
87 | ||
88 | #elif defined(CONFIG_STACKTRACE) | |
89 | ||
08b3df2d | 90 | static bool fail_stacktrace(struct fault_attr *attr) |
329409ae AM |
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; | |
a124c28e | 103 | trace.max_entries = depth; |
329409ae AM |
104 | trace.skip = 1; |
105 | trace.all_contexts = 0; | |
106 | ||
107 | save_stack_trace(&trace, NULL); | |
108 | for (n = 0; n < trace.nr_entries; n++) { | |
109 | if (attr->reject_start <= entries[n] && | |
110 | entries[n] < attr->reject_end) | |
08b3df2d | 111 | return false; |
329409ae AM |
112 | if (attr->require_start <= entries[n] && |
113 | entries[n] < attr->require_end) | |
08b3df2d | 114 | found = true; |
329409ae AM |
115 | } |
116 | return found; | |
117 | } | |
118 | ||
119 | #else | |
120 | ||
08b3df2d | 121 | static inline bool fail_stacktrace(struct fault_attr *attr) |
329409ae | 122 | { |
08b3df2d | 123 | static bool firsttime = true; |
329409ae AM |
124 | |
125 | if (firsttime) { | |
126 | printk(KERN_WARNING | |
127 | "This architecture does not implement save_stack_trace()\n"); | |
08b3df2d | 128 | firsttime = false; |
329409ae | 129 | } |
08b3df2d | 130 | return false; |
329409ae AM |
131 | } |
132 | ||
133 | #endif | |
134 | ||
6ff1cb35 AM |
135 | /* |
136 | * This code is stolen from failmalloc-1.0 | |
137 | * http://www.nongnu.org/failmalloc/ | |
138 | */ | |
139 | ||
08b3df2d | 140 | bool should_fail(struct fault_attr *attr, ssize_t size) |
6ff1cb35 | 141 | { |
f4f154fd | 142 | if (attr->task_filter && !fail_task(attr, current)) |
08b3df2d | 143 | return false; |
f4f154fd | 144 | |
6ff1cb35 | 145 | if (atomic_read(&attr->times) == 0) |
08b3df2d | 146 | return false; |
6ff1cb35 AM |
147 | |
148 | if (atomic_read(&attr->space) > size) { | |
149 | atomic_sub(size, &attr->space); | |
08b3df2d | 150 | return false; |
6ff1cb35 AM |
151 | } |
152 | ||
153 | if (attr->interval > 1) { | |
154 | attr->count++; | |
155 | if (attr->count % attr->interval) | |
08b3df2d | 156 | return false; |
6ff1cb35 AM |
157 | } |
158 | ||
f1729c28 DM |
159 | if (attr->probability <= random32() % 100) |
160 | return false; | |
6ff1cb35 | 161 | |
f1729c28 DM |
162 | if (!fail_stacktrace(attr)) |
163 | return false; | |
6ff1cb35 | 164 | |
6ff1cb35 AM |
165 | fail_dump(attr); |
166 | ||
167 | if (atomic_read(&attr->times) != -1) | |
168 | atomic_dec_not_zero(&attr->times); | |
169 | ||
08b3df2d | 170 | return true; |
6ff1cb35 AM |
171 | } |
172 | ||
173 | #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS | |
174 | ||
175 | static void debugfs_ul_set(void *data, u64 val) | |
176 | { | |
177 | *(unsigned long *)data = val; | |
178 | } | |
179 | ||
a124c28e DM |
180 | static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val) |
181 | { | |
182 | *(unsigned long *)data = | |
183 | val < MAX_STACK_TRACE_DEPTH ? | |
184 | val : MAX_STACK_TRACE_DEPTH; | |
185 | } | |
186 | ||
6ff1cb35 AM |
187 | static u64 debugfs_ul_get(void *data) |
188 | { | |
189 | return *(unsigned long *)data; | |
190 | } | |
191 | ||
192 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); | |
193 | ||
194 | static struct dentry *debugfs_create_ul(const char *name, mode_t mode, | |
195 | struct dentry *parent, unsigned long *value) | |
196 | { | |
197 | return debugfs_create_file(name, mode, parent, value, &fops_ul); | |
198 | } | |
199 | ||
a124c28e DM |
200 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get, |
201 | debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n"); | |
202 | ||
203 | static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH( | |
204 | const char *name, mode_t mode, | |
205 | struct dentry *parent, unsigned long *value) | |
206 | { | |
207 | return debugfs_create_file(name, mode, parent, value, | |
208 | &fops_ul_MAX_STACK_TRACE_DEPTH); | |
209 | } | |
210 | ||
6ff1cb35 AM |
211 | static void debugfs_atomic_t_set(void *data, u64 val) |
212 | { | |
213 | atomic_set((atomic_t *)data, val); | |
214 | } | |
215 | ||
216 | static u64 debugfs_atomic_t_get(void *data) | |
217 | { | |
218 | return atomic_read((atomic_t *)data); | |
219 | } | |
220 | ||
221 | DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get, | |
222 | debugfs_atomic_t_set, "%lld\n"); | |
223 | ||
224 | static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode, | |
225 | struct dentry *parent, atomic_t *value) | |
226 | { | |
227 | return debugfs_create_file(name, mode, parent, value, &fops_atomic_t); | |
228 | } | |
229 | ||
230 | void cleanup_fault_attr_dentries(struct fault_attr *attr) | |
231 | { | |
232 | debugfs_remove(attr->dentries.probability_file); | |
233 | attr->dentries.probability_file = NULL; | |
234 | ||
235 | debugfs_remove(attr->dentries.interval_file); | |
236 | attr->dentries.interval_file = NULL; | |
237 | ||
238 | debugfs_remove(attr->dentries.times_file); | |
239 | attr->dentries.times_file = NULL; | |
240 | ||
241 | debugfs_remove(attr->dentries.space_file); | |
242 | attr->dentries.space_file = NULL; | |
243 | ||
244 | debugfs_remove(attr->dentries.verbose_file); | |
245 | attr->dentries.verbose_file = NULL; | |
246 | ||
f4f154fd AM |
247 | debugfs_remove(attr->dentries.task_filter_file); |
248 | attr->dentries.task_filter_file = NULL; | |
249 | ||
329409ae AM |
250 | debugfs_remove(attr->dentries.stacktrace_depth_file); |
251 | attr->dentries.stacktrace_depth_file = NULL; | |
252 | ||
253 | debugfs_remove(attr->dentries.require_start_file); | |
254 | attr->dentries.require_start_file = NULL; | |
255 | ||
256 | debugfs_remove(attr->dentries.require_end_file); | |
257 | attr->dentries.require_end_file = NULL; | |
258 | ||
259 | debugfs_remove(attr->dentries.reject_start_file); | |
260 | attr->dentries.reject_start_file = NULL; | |
261 | ||
262 | debugfs_remove(attr->dentries.reject_end_file); | |
263 | attr->dentries.reject_end_file = NULL; | |
264 | ||
6ff1cb35 AM |
265 | if (attr->dentries.dir) |
266 | WARN_ON(!simple_empty(attr->dentries.dir)); | |
267 | ||
268 | debugfs_remove(attr->dentries.dir); | |
269 | attr->dentries.dir = NULL; | |
270 | } | |
271 | ||
272 | int init_fault_attr_dentries(struct fault_attr *attr, const char *name) | |
273 | { | |
274 | mode_t mode = S_IFREG | S_IRUSR | S_IWUSR; | |
275 | struct dentry *dir; | |
276 | ||
277 | memset(&attr->dentries, 0, sizeof(attr->dentries)); | |
278 | ||
279 | dir = debugfs_create_dir(name, NULL); | |
280 | if (!dir) | |
281 | goto fail; | |
282 | attr->dentries.dir = dir; | |
283 | ||
284 | attr->dentries.probability_file = | |
285 | debugfs_create_ul("probability", mode, dir, &attr->probability); | |
286 | ||
287 | attr->dentries.interval_file = | |
288 | debugfs_create_ul("interval", mode, dir, &attr->interval); | |
289 | ||
290 | attr->dentries.times_file = | |
291 | debugfs_create_atomic_t("times", mode, dir, &attr->times); | |
292 | ||
293 | attr->dentries.space_file = | |
294 | debugfs_create_atomic_t("space", mode, dir, &attr->space); | |
295 | ||
296 | attr->dentries.verbose_file = | |
297 | debugfs_create_ul("verbose", mode, dir, &attr->verbose); | |
298 | ||
f4f154fd AM |
299 | attr->dentries.task_filter_file = debugfs_create_bool("task-filter", |
300 | mode, dir, &attr->task_filter); | |
301 | ||
329409ae | 302 | attr->dentries.stacktrace_depth_file = |
a124c28e DM |
303 | debugfs_create_ul_MAX_STACK_TRACE_DEPTH( |
304 | "stacktrace-depth", mode, dir, &attr->stacktrace_depth); | |
329409ae AM |
305 | |
306 | attr->dentries.require_start_file = | |
307 | debugfs_create_ul("require-start", mode, dir, &attr->require_start); | |
308 | ||
309 | attr->dentries.require_end_file = | |
310 | debugfs_create_ul("require-end", mode, dir, &attr->require_end); | |
311 | ||
312 | attr->dentries.reject_start_file = | |
313 | debugfs_create_ul("reject-start", mode, dir, &attr->reject_start); | |
314 | ||
315 | attr->dentries.reject_end_file = | |
316 | debugfs_create_ul("reject-end", mode, dir, &attr->reject_end); | |
317 | ||
318 | ||
6ff1cb35 AM |
319 | if (!attr->dentries.probability_file || !attr->dentries.interval_file |
320 | || !attr->dentries.times_file || !attr->dentries.space_file | |
329409ae AM |
321 | || !attr->dentries.verbose_file || !attr->dentries.task_filter_file |
322 | || !attr->dentries.stacktrace_depth_file | |
323 | || !attr->dentries.require_start_file | |
324 | || !attr->dentries.require_end_file | |
325 | || !attr->dentries.reject_start_file | |
326 | || !attr->dentries.reject_end_file | |
327 | ) | |
6ff1cb35 AM |
328 | goto fail; |
329 | ||
330 | return 0; | |
331 | fail: | |
332 | cleanup_fault_attr_dentries(attr); | |
333 | return -ENOMEM; | |
334 | } | |
335 | ||
336 | #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ |