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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 | ||
d1526e2c | 58 | #if defined(CONFIG_STACKTRACE) |
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 AM |
74 | trace.skip = 1; |
75 | trace.all_contexts = 0; | |
76 | ||
77 | save_stack_trace(&trace, NULL); | |
78 | for (n = 0; n < trace.nr_entries; n++) { | |
79 | if (attr->reject_start <= entries[n] && | |
80 | entries[n] < attr->reject_end) | |
08b3df2d | 81 | return false; |
329409ae AM |
82 | if (attr->require_start <= entries[n] && |
83 | entries[n] < attr->require_end) | |
08b3df2d | 84 | found = true; |
329409ae AM |
85 | } |
86 | return found; | |
87 | } | |
88 | ||
89 | #else | |
90 | ||
08b3df2d | 91 | static inline bool fail_stacktrace(struct fault_attr *attr) |
329409ae | 92 | { |
08b3df2d | 93 | static bool firsttime = true; |
329409ae AM |
94 | |
95 | if (firsttime) { | |
96 | printk(KERN_WARNING | |
97 | "This architecture does not implement save_stack_trace()\n"); | |
08b3df2d | 98 | firsttime = false; |
329409ae | 99 | } |
08b3df2d | 100 | return false; |
329409ae AM |
101 | } |
102 | ||
103 | #endif | |
104 | ||
6ff1cb35 AM |
105 | /* |
106 | * This code is stolen from failmalloc-1.0 | |
107 | * http://www.nongnu.org/failmalloc/ | |
108 | */ | |
109 | ||
08b3df2d | 110 | bool should_fail(struct fault_attr *attr, ssize_t size) |
6ff1cb35 | 111 | { |
f4f154fd | 112 | if (attr->task_filter && !fail_task(attr, current)) |
08b3df2d | 113 | return false; |
f4f154fd | 114 | |
6ff1cb35 | 115 | if (atomic_read(&attr->times) == 0) |
08b3df2d | 116 | return false; |
6ff1cb35 AM |
117 | |
118 | if (atomic_read(&attr->space) > size) { | |
119 | atomic_sub(size, &attr->space); | |
08b3df2d | 120 | return false; |
6ff1cb35 AM |
121 | } |
122 | ||
123 | if (attr->interval > 1) { | |
124 | attr->count++; | |
125 | if (attr->count % attr->interval) | |
08b3df2d | 126 | return false; |
6ff1cb35 AM |
127 | } |
128 | ||
f1729c28 DM |
129 | if (attr->probability <= random32() % 100) |
130 | return false; | |
6ff1cb35 | 131 | |
f1729c28 DM |
132 | if (!fail_stacktrace(attr)) |
133 | return false; | |
6ff1cb35 | 134 | |
6ff1cb35 AM |
135 | fail_dump(attr); |
136 | ||
137 | if (atomic_read(&attr->times) != -1) | |
138 | atomic_dec_not_zero(&attr->times); | |
139 | ||
08b3df2d | 140 | return true; |
6ff1cb35 AM |
141 | } |
142 | ||
143 | #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS | |
144 | ||
145 | static void debugfs_ul_set(void *data, u64 val) | |
146 | { | |
147 | *(unsigned long *)data = val; | |
148 | } | |
149 | ||
a124c28e DM |
150 | static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val) |
151 | { | |
152 | *(unsigned long *)data = | |
153 | val < MAX_STACK_TRACE_DEPTH ? | |
154 | val : MAX_STACK_TRACE_DEPTH; | |
155 | } | |
156 | ||
6ff1cb35 AM |
157 | static u64 debugfs_ul_get(void *data) |
158 | { | |
159 | return *(unsigned long *)data; | |
160 | } | |
161 | ||
162 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); | |
163 | ||
164 | static struct dentry *debugfs_create_ul(const char *name, mode_t mode, | |
165 | struct dentry *parent, unsigned long *value) | |
166 | { | |
167 | return debugfs_create_file(name, mode, parent, value, &fops_ul); | |
168 | } | |
169 | ||
a124c28e DM |
170 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get, |
171 | debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n"); | |
172 | ||
173 | static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH( | |
174 | const char *name, mode_t mode, | |
175 | struct dentry *parent, unsigned long *value) | |
176 | { | |
177 | return debugfs_create_file(name, mode, parent, value, | |
178 | &fops_ul_MAX_STACK_TRACE_DEPTH); | |
179 | } | |
180 | ||
6ff1cb35 AM |
181 | static void debugfs_atomic_t_set(void *data, u64 val) |
182 | { | |
183 | atomic_set((atomic_t *)data, val); | |
184 | } | |
185 | ||
186 | static u64 debugfs_atomic_t_get(void *data) | |
187 | { | |
188 | return atomic_read((atomic_t *)data); | |
189 | } | |
190 | ||
191 | DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get, | |
192 | debugfs_atomic_t_set, "%lld\n"); | |
193 | ||
194 | static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode, | |
195 | struct dentry *parent, atomic_t *value) | |
196 | { | |
197 | return debugfs_create_file(name, mode, parent, value, &fops_atomic_t); | |
198 | } | |
199 | ||
200 | void cleanup_fault_attr_dentries(struct fault_attr *attr) | |
201 | { | |
202 | debugfs_remove(attr->dentries.probability_file); | |
203 | attr->dentries.probability_file = NULL; | |
204 | ||
205 | debugfs_remove(attr->dentries.interval_file); | |
206 | attr->dentries.interval_file = NULL; | |
207 | ||
208 | debugfs_remove(attr->dentries.times_file); | |
209 | attr->dentries.times_file = NULL; | |
210 | ||
211 | debugfs_remove(attr->dentries.space_file); | |
212 | attr->dentries.space_file = NULL; | |
213 | ||
214 | debugfs_remove(attr->dentries.verbose_file); | |
215 | attr->dentries.verbose_file = NULL; | |
216 | ||
f4f154fd AM |
217 | debugfs_remove(attr->dentries.task_filter_file); |
218 | attr->dentries.task_filter_file = NULL; | |
219 | ||
329409ae AM |
220 | debugfs_remove(attr->dentries.stacktrace_depth_file); |
221 | attr->dentries.stacktrace_depth_file = NULL; | |
222 | ||
223 | debugfs_remove(attr->dentries.require_start_file); | |
224 | attr->dentries.require_start_file = NULL; | |
225 | ||
226 | debugfs_remove(attr->dentries.require_end_file); | |
227 | attr->dentries.require_end_file = NULL; | |
228 | ||
229 | debugfs_remove(attr->dentries.reject_start_file); | |
230 | attr->dentries.reject_start_file = NULL; | |
231 | ||
232 | debugfs_remove(attr->dentries.reject_end_file); | |
233 | attr->dentries.reject_end_file = NULL; | |
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 | ||
329409ae | 272 | attr->dentries.stacktrace_depth_file = |
a124c28e DM |
273 | debugfs_create_ul_MAX_STACK_TRACE_DEPTH( |
274 | "stacktrace-depth", mode, dir, &attr->stacktrace_depth); | |
329409ae AM |
275 | |
276 | attr->dentries.require_start_file = | |
277 | debugfs_create_ul("require-start", mode, dir, &attr->require_start); | |
278 | ||
279 | attr->dentries.require_end_file = | |
280 | debugfs_create_ul("require-end", mode, dir, &attr->require_end); | |
281 | ||
282 | attr->dentries.reject_start_file = | |
283 | debugfs_create_ul("reject-start", mode, dir, &attr->reject_start); | |
284 | ||
285 | attr->dentries.reject_end_file = | |
286 | debugfs_create_ul("reject-end", mode, dir, &attr->reject_end); | |
287 | ||
288 | ||
6ff1cb35 AM |
289 | if (!attr->dentries.probability_file || !attr->dentries.interval_file |
290 | || !attr->dentries.times_file || !attr->dentries.space_file | |
329409ae AM |
291 | || !attr->dentries.verbose_file || !attr->dentries.task_filter_file |
292 | || !attr->dentries.stacktrace_depth_file | |
293 | || !attr->dentries.require_start_file | |
294 | || !attr->dentries.require_end_file | |
295 | || !attr->dentries.reject_start_file | |
296 | || !attr->dentries.reject_end_file | |
297 | ) | |
6ff1cb35 AM |
298 | goto fail; |
299 | ||
300 | return 0; | |
301 | fail: | |
302 | cleanup_fault_attr_dentries(attr); | |
303 | return -ENOMEM; | |
304 | } | |
305 | ||
306 | #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ |