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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 | ||
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) | |
08b3df2d | 71 | return false; |
329409ae AM |
72 | if (attr->require_start <= UNW_PC(info) && |
73 | UNW_PC(info) < attr->require_end) | |
08b3df2d | 74 | found = true; |
329409ae AM |
75 | } |
76 | return found; | |
77 | } | |
78 | ||
08b3df2d | 79 | static bool fail_stacktrace(struct fault_attr *attr) |
329409ae AM |
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 | ||
08b3df2d | 88 | static bool fail_stacktrace(struct fault_attr *attr) |
329409ae AM |
89 | { |
90 | struct stack_trace trace; | |
91 | int depth = attr->stacktrace_depth; | |
92 | unsigned long entries[MAX_STACK_TRACE_DEPTH]; | |
93 | int n; | |
94 | bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); | |
95 | ||
96 | if (depth == 0) | |
97 | return found; | |
98 | ||
99 | trace.nr_entries = 0; | |
100 | trace.entries = entries; | |
101 | trace.max_entries = (depth < MAX_STACK_TRACE_DEPTH) ? | |
102 | depth : MAX_STACK_TRACE_DEPTH; | |
103 | trace.skip = 1; | |
104 | trace.all_contexts = 0; | |
105 | ||
106 | save_stack_trace(&trace, NULL); | |
107 | for (n = 0; n < trace.nr_entries; n++) { | |
108 | if (attr->reject_start <= entries[n] && | |
109 | entries[n] < attr->reject_end) | |
08b3df2d | 110 | return false; |
329409ae AM |
111 | if (attr->require_start <= entries[n] && |
112 | entries[n] < attr->require_end) | |
08b3df2d | 113 | found = true; |
329409ae AM |
114 | } |
115 | return found; | |
116 | } | |
117 | ||
118 | #else | |
119 | ||
08b3df2d | 120 | static inline bool fail_stacktrace(struct fault_attr *attr) |
329409ae | 121 | { |
08b3df2d | 122 | static bool firsttime = true; |
329409ae AM |
123 | |
124 | if (firsttime) { | |
125 | printk(KERN_WARNING | |
126 | "This architecture does not implement save_stack_trace()\n"); | |
08b3df2d | 127 | firsttime = false; |
329409ae | 128 | } |
08b3df2d | 129 | return false; |
329409ae AM |
130 | } |
131 | ||
132 | #endif | |
133 | ||
6ff1cb35 AM |
134 | /* |
135 | * This code is stolen from failmalloc-1.0 | |
136 | * http://www.nongnu.org/failmalloc/ | |
137 | */ | |
138 | ||
08b3df2d | 139 | bool should_fail(struct fault_attr *attr, ssize_t size) |
6ff1cb35 | 140 | { |
f4f154fd | 141 | if (attr->task_filter && !fail_task(attr, current)) |
08b3df2d | 142 | return false; |
f4f154fd | 143 | |
329409ae | 144 | if (!fail_stacktrace(attr)) |
08b3df2d | 145 | return false; |
329409ae | 146 | |
6ff1cb35 | 147 | if (atomic_read(&attr->times) == 0) |
08b3df2d | 148 | return false; |
6ff1cb35 AM |
149 | |
150 | if (atomic_read(&attr->space) > size) { | |
151 | atomic_sub(size, &attr->space); | |
08b3df2d | 152 | return false; |
6ff1cb35 AM |
153 | } |
154 | ||
155 | if (attr->interval > 1) { | |
156 | attr->count++; | |
157 | if (attr->count % attr->interval) | |
08b3df2d | 158 | return false; |
6ff1cb35 AM |
159 | } |
160 | ||
161 | if (attr->probability > random32() % 100) | |
162 | goto fail; | |
163 | ||
08b3df2d | 164 | return false; |
6ff1cb35 AM |
165 | |
166 | fail: | |
167 | fail_dump(attr); | |
168 | ||
169 | if (atomic_read(&attr->times) != -1) | |
170 | atomic_dec_not_zero(&attr->times); | |
171 | ||
08b3df2d | 172 | return true; |
6ff1cb35 AM |
173 | } |
174 | ||
175 | #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS | |
176 | ||
177 | static void debugfs_ul_set(void *data, u64 val) | |
178 | { | |
179 | *(unsigned long *)data = val; | |
180 | } | |
181 | ||
182 | static u64 debugfs_ul_get(void *data) | |
183 | { | |
184 | return *(unsigned long *)data; | |
185 | } | |
186 | ||
187 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); | |
188 | ||
189 | static struct dentry *debugfs_create_ul(const char *name, mode_t mode, | |
190 | struct dentry *parent, unsigned long *value) | |
191 | { | |
192 | return debugfs_create_file(name, mode, parent, value, &fops_ul); | |
193 | } | |
194 | ||
195 | static void debugfs_atomic_t_set(void *data, u64 val) | |
196 | { | |
197 | atomic_set((atomic_t *)data, val); | |
198 | } | |
199 | ||
200 | static u64 debugfs_atomic_t_get(void *data) | |
201 | { | |
202 | return atomic_read((atomic_t *)data); | |
203 | } | |
204 | ||
205 | DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get, | |
206 | debugfs_atomic_t_set, "%lld\n"); | |
207 | ||
208 | static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode, | |
209 | struct dentry *parent, atomic_t *value) | |
210 | { | |
211 | return debugfs_create_file(name, mode, parent, value, &fops_atomic_t); | |
212 | } | |
213 | ||
214 | void cleanup_fault_attr_dentries(struct fault_attr *attr) | |
215 | { | |
216 | debugfs_remove(attr->dentries.probability_file); | |
217 | attr->dentries.probability_file = NULL; | |
218 | ||
219 | debugfs_remove(attr->dentries.interval_file); | |
220 | attr->dentries.interval_file = NULL; | |
221 | ||
222 | debugfs_remove(attr->dentries.times_file); | |
223 | attr->dentries.times_file = NULL; | |
224 | ||
225 | debugfs_remove(attr->dentries.space_file); | |
226 | attr->dentries.space_file = NULL; | |
227 | ||
228 | debugfs_remove(attr->dentries.verbose_file); | |
229 | attr->dentries.verbose_file = NULL; | |
230 | ||
f4f154fd AM |
231 | debugfs_remove(attr->dentries.task_filter_file); |
232 | attr->dentries.task_filter_file = NULL; | |
233 | ||
329409ae AM |
234 | debugfs_remove(attr->dentries.stacktrace_depth_file); |
235 | attr->dentries.stacktrace_depth_file = NULL; | |
236 | ||
237 | debugfs_remove(attr->dentries.require_start_file); | |
238 | attr->dentries.require_start_file = NULL; | |
239 | ||
240 | debugfs_remove(attr->dentries.require_end_file); | |
241 | attr->dentries.require_end_file = NULL; | |
242 | ||
243 | debugfs_remove(attr->dentries.reject_start_file); | |
244 | attr->dentries.reject_start_file = NULL; | |
245 | ||
246 | debugfs_remove(attr->dentries.reject_end_file); | |
247 | attr->dentries.reject_end_file = NULL; | |
248 | ||
6ff1cb35 AM |
249 | if (attr->dentries.dir) |
250 | WARN_ON(!simple_empty(attr->dentries.dir)); | |
251 | ||
252 | debugfs_remove(attr->dentries.dir); | |
253 | attr->dentries.dir = NULL; | |
254 | } | |
255 | ||
256 | int init_fault_attr_dentries(struct fault_attr *attr, const char *name) | |
257 | { | |
258 | mode_t mode = S_IFREG | S_IRUSR | S_IWUSR; | |
259 | struct dentry *dir; | |
260 | ||
261 | memset(&attr->dentries, 0, sizeof(attr->dentries)); | |
262 | ||
263 | dir = debugfs_create_dir(name, NULL); | |
264 | if (!dir) | |
265 | goto fail; | |
266 | attr->dentries.dir = dir; | |
267 | ||
268 | attr->dentries.probability_file = | |
269 | debugfs_create_ul("probability", mode, dir, &attr->probability); | |
270 | ||
271 | attr->dentries.interval_file = | |
272 | debugfs_create_ul("interval", mode, dir, &attr->interval); | |
273 | ||
274 | attr->dentries.times_file = | |
275 | debugfs_create_atomic_t("times", mode, dir, &attr->times); | |
276 | ||
277 | attr->dentries.space_file = | |
278 | debugfs_create_atomic_t("space", mode, dir, &attr->space); | |
279 | ||
280 | attr->dentries.verbose_file = | |
281 | debugfs_create_ul("verbose", mode, dir, &attr->verbose); | |
282 | ||
f4f154fd AM |
283 | attr->dentries.task_filter_file = debugfs_create_bool("task-filter", |
284 | mode, dir, &attr->task_filter); | |
285 | ||
329409ae AM |
286 | attr->dentries.stacktrace_depth_file = |
287 | debugfs_create_ul("stacktrace-depth", mode, dir, | |
288 | &attr->stacktrace_depth); | |
289 | ||
290 | attr->dentries.require_start_file = | |
291 | debugfs_create_ul("require-start", mode, dir, &attr->require_start); | |
292 | ||
293 | attr->dentries.require_end_file = | |
294 | debugfs_create_ul("require-end", mode, dir, &attr->require_end); | |
295 | ||
296 | attr->dentries.reject_start_file = | |
297 | debugfs_create_ul("reject-start", mode, dir, &attr->reject_start); | |
298 | ||
299 | attr->dentries.reject_end_file = | |
300 | debugfs_create_ul("reject-end", mode, dir, &attr->reject_end); | |
301 | ||
302 | ||
6ff1cb35 AM |
303 | if (!attr->dentries.probability_file || !attr->dentries.interval_file |
304 | || !attr->dentries.times_file || !attr->dentries.space_file | |
329409ae AM |
305 | || !attr->dentries.verbose_file || !attr->dentries.task_filter_file |
306 | || !attr->dentries.stacktrace_depth_file | |
307 | || !attr->dentries.require_start_file | |
308 | || !attr->dentries.require_end_file | |
309 | || !attr->dentries.reject_start_file | |
310 | || !attr->dentries.reject_end_file | |
311 | ) | |
6ff1cb35 AM |
312 | goto fail; |
313 | ||
314 | return 0; | |
315 | fail: | |
316 | cleanup_fault_attr_dentries(attr); | |
317 | return -ENOMEM; | |
318 | } | |
319 | ||
320 | #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ |