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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 | ||
1df49008 | 58 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER |
329409ae | 59 | |
08b3df2d | 60 | static bool fail_stacktrace(struct fault_attr *attr) |
329409ae AM |
61 | { |
62 | struct stack_trace trace; | |
63 | int depth = attr->stacktrace_depth; | |
64 | unsigned long entries[MAX_STACK_TRACE_DEPTH]; | |
65 | int n; | |
66 | bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); | |
67 | ||
68 | if (depth == 0) | |
69 | return found; | |
70 | ||
71 | trace.nr_entries = 0; | |
72 | trace.entries = entries; | |
a124c28e | 73 | trace.max_entries = depth; |
329409ae | 74 | trace.skip = 1; |
329409ae | 75 | |
ab1b6f03 | 76 | save_stack_trace(&trace); |
329409ae AM |
77 | for (n = 0; n < trace.nr_entries; n++) { |
78 | if (attr->reject_start <= entries[n] && | |
79 | entries[n] < attr->reject_end) | |
08b3df2d | 80 | return false; |
329409ae AM |
81 | if (attr->require_start <= entries[n] && |
82 | entries[n] < attr->require_end) | |
08b3df2d | 83 | found = true; |
329409ae AM |
84 | } |
85 | return found; | |
86 | } | |
87 | ||
88 | #else | |
89 | ||
08b3df2d | 90 | static inline bool fail_stacktrace(struct fault_attr *attr) |
329409ae | 91 | { |
1df49008 | 92 | return true; |
329409ae AM |
93 | } |
94 | ||
1df49008 | 95 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
329409ae | 96 | |
6ff1cb35 AM |
97 | /* |
98 | * This code is stolen from failmalloc-1.0 | |
99 | * http://www.nongnu.org/failmalloc/ | |
100 | */ | |
101 | ||
08b3df2d | 102 | bool should_fail(struct fault_attr *attr, ssize_t size) |
6ff1cb35 | 103 | { |
f4f154fd | 104 | if (attr->task_filter && !fail_task(attr, current)) |
08b3df2d | 105 | return false; |
f4f154fd | 106 | |
6ff1cb35 | 107 | if (atomic_read(&attr->times) == 0) |
08b3df2d | 108 | return false; |
6ff1cb35 AM |
109 | |
110 | if (atomic_read(&attr->space) > size) { | |
111 | atomic_sub(size, &attr->space); | |
08b3df2d | 112 | return false; |
6ff1cb35 AM |
113 | } |
114 | ||
115 | if (attr->interval > 1) { | |
116 | attr->count++; | |
117 | if (attr->count % attr->interval) | |
08b3df2d | 118 | return false; |
6ff1cb35 AM |
119 | } |
120 | ||
f1729c28 DM |
121 | if (attr->probability <= random32() % 100) |
122 | return false; | |
6ff1cb35 | 123 | |
f1729c28 DM |
124 | if (!fail_stacktrace(attr)) |
125 | return false; | |
6ff1cb35 | 126 | |
6ff1cb35 AM |
127 | fail_dump(attr); |
128 | ||
129 | if (atomic_read(&attr->times) != -1) | |
130 | atomic_dec_not_zero(&attr->times); | |
131 | ||
08b3df2d | 132 | return true; |
6ff1cb35 AM |
133 | } |
134 | ||
135 | #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS | |
136 | ||
137 | static void debugfs_ul_set(void *data, u64 val) | |
138 | { | |
139 | *(unsigned long *)data = val; | |
140 | } | |
141 | ||
6ddb23c7 | 142 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER |
a124c28e DM |
143 | static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val) |
144 | { | |
145 | *(unsigned long *)data = | |
146 | val < MAX_STACK_TRACE_DEPTH ? | |
147 | val : MAX_STACK_TRACE_DEPTH; | |
148 | } | |
6ddb23c7 | 149 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
a124c28e | 150 | |
6ff1cb35 AM |
151 | static u64 debugfs_ul_get(void *data) |
152 | { | |
153 | return *(unsigned long *)data; | |
154 | } | |
155 | ||
156 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); | |
157 | ||
158 | static struct dentry *debugfs_create_ul(const char *name, mode_t mode, | |
159 | struct dentry *parent, unsigned long *value) | |
160 | { | |
161 | return debugfs_create_file(name, mode, parent, value, &fops_ul); | |
162 | } | |
163 | ||
6ddb23c7 | 164 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER |
a124c28e DM |
165 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get, |
166 | debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n"); | |
167 | ||
168 | static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH( | |
169 | const char *name, mode_t mode, | |
170 | struct dentry *parent, unsigned long *value) | |
171 | { | |
172 | return debugfs_create_file(name, mode, parent, value, | |
173 | &fops_ul_MAX_STACK_TRACE_DEPTH); | |
174 | } | |
6ddb23c7 | 175 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
a124c28e | 176 | |
6ff1cb35 AM |
177 | static void debugfs_atomic_t_set(void *data, u64 val) |
178 | { | |
179 | atomic_set((atomic_t *)data, val); | |
180 | } | |
181 | ||
182 | static u64 debugfs_atomic_t_get(void *data) | |
183 | { | |
184 | return atomic_read((atomic_t *)data); | |
185 | } | |
186 | ||
187 | DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get, | |
188 | debugfs_atomic_t_set, "%lld\n"); | |
189 | ||
190 | static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode, | |
191 | struct dentry *parent, atomic_t *value) | |
192 | { | |
193 | return debugfs_create_file(name, mode, parent, value, &fops_atomic_t); | |
194 | } | |
195 | ||
196 | void cleanup_fault_attr_dentries(struct fault_attr *attr) | |
197 | { | |
198 | debugfs_remove(attr->dentries.probability_file); | |
199 | attr->dentries.probability_file = NULL; | |
200 | ||
201 | debugfs_remove(attr->dentries.interval_file); | |
202 | attr->dentries.interval_file = NULL; | |
203 | ||
204 | debugfs_remove(attr->dentries.times_file); | |
205 | attr->dentries.times_file = NULL; | |
206 | ||
207 | debugfs_remove(attr->dentries.space_file); | |
208 | attr->dentries.space_file = NULL; | |
209 | ||
210 | debugfs_remove(attr->dentries.verbose_file); | |
211 | attr->dentries.verbose_file = NULL; | |
212 | ||
f4f154fd AM |
213 | debugfs_remove(attr->dentries.task_filter_file); |
214 | attr->dentries.task_filter_file = NULL; | |
215 | ||
1df49008 AM |
216 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER |
217 | ||
329409ae AM |
218 | debugfs_remove(attr->dentries.stacktrace_depth_file); |
219 | attr->dentries.stacktrace_depth_file = NULL; | |
220 | ||
221 | debugfs_remove(attr->dentries.require_start_file); | |
222 | attr->dentries.require_start_file = NULL; | |
223 | ||
224 | debugfs_remove(attr->dentries.require_end_file); | |
225 | attr->dentries.require_end_file = NULL; | |
226 | ||
227 | debugfs_remove(attr->dentries.reject_start_file); | |
228 | attr->dentries.reject_start_file = NULL; | |
229 | ||
230 | debugfs_remove(attr->dentries.reject_end_file); | |
231 | attr->dentries.reject_end_file = NULL; | |
232 | ||
1df49008 AM |
233 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
234 | ||
6ff1cb35 AM |
235 | if (attr->dentries.dir) |
236 | WARN_ON(!simple_empty(attr->dentries.dir)); | |
237 | ||
238 | debugfs_remove(attr->dentries.dir); | |
239 | attr->dentries.dir = NULL; | |
240 | } | |
241 | ||
242 | int init_fault_attr_dentries(struct fault_attr *attr, const char *name) | |
243 | { | |
244 | mode_t mode = S_IFREG | S_IRUSR | S_IWUSR; | |
245 | struct dentry *dir; | |
246 | ||
247 | memset(&attr->dentries, 0, sizeof(attr->dentries)); | |
248 | ||
249 | dir = debugfs_create_dir(name, NULL); | |
250 | if (!dir) | |
251 | goto fail; | |
252 | attr->dentries.dir = dir; | |
253 | ||
254 | attr->dentries.probability_file = | |
255 | debugfs_create_ul("probability", mode, dir, &attr->probability); | |
256 | ||
257 | attr->dentries.interval_file = | |
258 | debugfs_create_ul("interval", mode, dir, &attr->interval); | |
259 | ||
260 | attr->dentries.times_file = | |
261 | debugfs_create_atomic_t("times", mode, dir, &attr->times); | |
262 | ||
263 | attr->dentries.space_file = | |
264 | debugfs_create_atomic_t("space", mode, dir, &attr->space); | |
265 | ||
266 | attr->dentries.verbose_file = | |
267 | debugfs_create_ul("verbose", mode, dir, &attr->verbose); | |
268 | ||
f4f154fd AM |
269 | attr->dentries.task_filter_file = debugfs_create_bool("task-filter", |
270 | mode, dir, &attr->task_filter); | |
271 | ||
1df49008 AM |
272 | if (!attr->dentries.probability_file || !attr->dentries.interval_file || |
273 | !attr->dentries.times_file || !attr->dentries.space_file || | |
274 | !attr->dentries.verbose_file || !attr->dentries.task_filter_file) | |
275 | goto fail; | |
276 | ||
277 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER | |
278 | ||
329409ae | 279 | attr->dentries.stacktrace_depth_file = |
a124c28e DM |
280 | debugfs_create_ul_MAX_STACK_TRACE_DEPTH( |
281 | "stacktrace-depth", mode, dir, &attr->stacktrace_depth); | |
329409ae AM |
282 | |
283 | attr->dentries.require_start_file = | |
284 | debugfs_create_ul("require-start", mode, dir, &attr->require_start); | |
285 | ||
286 | attr->dentries.require_end_file = | |
287 | debugfs_create_ul("require-end", mode, dir, &attr->require_end); | |
288 | ||
289 | attr->dentries.reject_start_file = | |
290 | debugfs_create_ul("reject-start", mode, dir, &attr->reject_start); | |
291 | ||
292 | attr->dentries.reject_end_file = | |
293 | debugfs_create_ul("reject-end", mode, dir, &attr->reject_end); | |
294 | ||
1df49008 AM |
295 | if (!attr->dentries.stacktrace_depth_file || |
296 | !attr->dentries.require_start_file || | |
297 | !attr->dentries.require_end_file || | |
298 | !attr->dentries.reject_start_file || | |
299 | !attr->dentries.reject_end_file) | |
6ff1cb35 AM |
300 | goto fail; |
301 | ||
1df49008 AM |
302 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
303 | ||
6ff1cb35 AM |
304 | return 0; |
305 | fail: | |
306 | cleanup_fault_attr_dentries(attr); | |
307 | return -ENOMEM; | |
308 | } | |
309 | ||
310 | #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ |