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Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001#include <linux/kernel.h>
2#include <linux/init.h>
3#include <linux/random.h>
Alexey Dobriyand43c36d2009-10-07 17:09:06 +04004#include <linux/sched.h>
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08005#include <linux/stat.h>
6#include <linux/types.h>
7#include <linux/fs.h>
8#include <linux/module.h>
Akinobu Mitaf4f154f2006-12-08 02:39:47 -08009#include <linux/interrupt.h>
Akinobu Mita329409a2006-12-08 02:39:48 -080010#include <linux/stacktrace.h>
Akinobu Mita6ff1cb32006-12-08 02:39:43 -080011#include <linux/fault-inject.h>
12
13/*
14 * setup_fault_attr() is a helper function for various __setup handlers, so it
15 * returns 0 on error, because that is what __setup handlers do.
16 */
17int __init setup_fault_attr(struct fault_attr *attr, char *str)
18{
19 unsigned long probability;
20 unsigned long interval;
21 int times;
22 int space;
23
24 /* "<interval>,<probability>,<space>,<times>" */
25 if (sscanf(str, "%lu,%lu,%d,%d",
26 &interval, &probability, &space, &times) < 4) {
27 printk(KERN_WARNING
28 "FAULT_INJECTION: failed to parse arguments\n");
29 return 0;
30 }
31
32 attr->probability = probability;
33 attr->interval = interval;
34 atomic_set(&attr->times, times);
35 atomic_set(&attr->space, space);
36
37 return 1;
38}
39
40static void fail_dump(struct fault_attr *attr)
41{
42 if (attr->verbose > 0)
43 printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n");
44 if (attr->verbose > 1)
45 dump_stack();
46}
47
48#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
49
Don Mullis08b3df22006-12-08 02:39:51 -080050static bool fail_task(struct fault_attr *attr, struct task_struct *task)
Akinobu Mitaf4f154f2006-12-08 02:39:47 -080051{
52 return !in_interrupt() && task->make_it_fail;
53}
54
Don Mullisa124c282006-12-08 02:39:52 -080055#define MAX_STACK_TRACE_DEPTH 32
56
Akinobu Mita1df49002007-02-20 13:57:56 -080057#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
Akinobu Mita329409a2006-12-08 02:39:48 -080058
Don Mullis08b3df22006-12-08 02:39:51 -080059static bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -080060{
61 struct stack_trace trace;
62 int depth = attr->stacktrace_depth;
63 unsigned long entries[MAX_STACK_TRACE_DEPTH];
64 int n;
65 bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
66
67 if (depth == 0)
68 return found;
69
70 trace.nr_entries = 0;
71 trace.entries = entries;
Don Mullisa124c282006-12-08 02:39:52 -080072 trace.max_entries = depth;
Akinobu Mita329409a2006-12-08 02:39:48 -080073 trace.skip = 1;
Akinobu Mita329409a2006-12-08 02:39:48 -080074
Christoph Hellwigab1b6f02007-05-08 00:23:29 -070075 save_stack_trace(&trace);
Akinobu Mita329409a2006-12-08 02:39:48 -080076 for (n = 0; n < trace.nr_entries; n++) {
77 if (attr->reject_start <= entries[n] &&
78 entries[n] < attr->reject_end)
Don Mullis08b3df22006-12-08 02:39:51 -080079 return false;
Akinobu Mita329409a2006-12-08 02:39:48 -080080 if (attr->require_start <= entries[n] &&
81 entries[n] < attr->require_end)
Don Mullis08b3df22006-12-08 02:39:51 -080082 found = true;
Akinobu Mita329409a2006-12-08 02:39:48 -080083 }
84 return found;
85}
86
87#else
88
Don Mullis08b3df22006-12-08 02:39:51 -080089static inline bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -080090{
Akinobu Mita1df49002007-02-20 13:57:56 -080091 return true;
Akinobu Mita329409a2006-12-08 02:39:48 -080092}
93
Akinobu Mita1df49002007-02-20 13:57:56 -080094#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
Akinobu Mita329409a2006-12-08 02:39:48 -080095
Akinobu Mita6ff1cb32006-12-08 02:39:43 -080096/*
97 * This code is stolen from failmalloc-1.0
98 * http://www.nongnu.org/failmalloc/
99 */
100
Don Mullis08b3df22006-12-08 02:39:51 -0800101bool should_fail(struct fault_attr *attr, ssize_t size)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800102{
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800103 if (attr->task_filter && !fail_task(attr, current))
Don Mullis08b3df22006-12-08 02:39:51 -0800104 return false;
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800105
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800106 if (atomic_read(&attr->times) == 0)
Don Mullis08b3df22006-12-08 02:39:51 -0800107 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800108
109 if (atomic_read(&attr->space) > size) {
110 atomic_sub(size, &attr->space);
Don Mullis08b3df22006-12-08 02:39:51 -0800111 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800112 }
113
114 if (attr->interval > 1) {
115 attr->count++;
116 if (attr->count % attr->interval)
Don Mullis08b3df22006-12-08 02:39:51 -0800117 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800118 }
119
Don Mullisf1729c22006-12-08 02:39:53 -0800120 if (attr->probability <= random32() % 100)
121 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800122
Don Mullisf1729c22006-12-08 02:39:53 -0800123 if (!fail_stacktrace(attr))
124 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800125
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800126 fail_dump(attr);
127
128 if (atomic_read(&attr->times) != -1)
129 atomic_dec_not_zero(&attr->times);
130
Don Mullis08b3df22006-12-08 02:39:51 -0800131 return true;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800132}
133
134#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
135
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800136static int debugfs_ul_set(void *data, u64 val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800137{
138 *(unsigned long *)data = val;
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800139 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800140}
141
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800142static int debugfs_ul_get(void *data, u64 *val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800143{
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800144 *val = *(unsigned long *)data;
145 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800146}
147
148DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
149
150static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
151 struct dentry *parent, unsigned long *value)
152{
153 return debugfs_create_file(name, mode, parent, value, &fops_ul);
154}
155
Stephen Rothwell6ddb23c2007-07-23 18:43:55 -0700156#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
Don Mullisa124c282006-12-08 02:39:52 -0800157
Akinobu Mita8307fc22011-07-26 16:09:01 -0700158static int debugfs_stacktrace_depth_set(void *data, u64 val)
159{
160 *(unsigned long *)data =
161 min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
162
163 return 0;
164}
165
166DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
167 debugfs_stacktrace_depth_set, "%llu\n");
168
169static struct dentry *debugfs_create_stacktrace_depth(
Don Mullisa124c282006-12-08 02:39:52 -0800170 const char *name, mode_t mode,
171 struct dentry *parent, unsigned long *value)
172{
173 return debugfs_create_file(name, mode, parent, value,
Akinobu Mita8307fc22011-07-26 16:09:01 -0700174 &fops_stacktrace_depth);
Don Mullisa124c282006-12-08 02:39:52 -0800175}
Akinobu Mita8307fc22011-07-26 16:09:01 -0700176
Stephen Rothwell6ddb23c2007-07-23 18:43:55 -0700177#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
Don Mullisa124c282006-12-08 02:39:52 -0800178
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800179static int debugfs_atomic_t_set(void *data, u64 val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800180{
181 atomic_set((atomic_t *)data, val);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800182 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800183}
184
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800185static int debugfs_atomic_t_get(void *data, u64 *val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800186{
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800187 *val = atomic_read((atomic_t *)data);
188 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800189}
190
191DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
192 debugfs_atomic_t_set, "%lld\n");
193
194static 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
200void 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
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800217 debugfs_remove(attr->dentries.task_filter_file);
218 attr->dentries.task_filter_file = NULL;
219
Akinobu Mita1df49002007-02-20 13:57:56 -0800220#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
221
Akinobu Mita329409a2006-12-08 02:39:48 -0800222 debugfs_remove(attr->dentries.stacktrace_depth_file);
223 attr->dentries.stacktrace_depth_file = NULL;
224
225 debugfs_remove(attr->dentries.require_start_file);
226 attr->dentries.require_start_file = NULL;
227
228 debugfs_remove(attr->dentries.require_end_file);
229 attr->dentries.require_end_file = NULL;
230
231 debugfs_remove(attr->dentries.reject_start_file);
232 attr->dentries.reject_start_file = NULL;
233
234 debugfs_remove(attr->dentries.reject_end_file);
235 attr->dentries.reject_end_file = NULL;
236
Akinobu Mita1df49002007-02-20 13:57:56 -0800237#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
238
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800239 if (attr->dentries.dir)
240 WARN_ON(!simple_empty(attr->dentries.dir));
241
242 debugfs_remove(attr->dentries.dir);
243 attr->dentries.dir = NULL;
244}
245
246int init_fault_attr_dentries(struct fault_attr *attr, const char *name)
247{
248 mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
249 struct dentry *dir;
250
251 memset(&attr->dentries, 0, sizeof(attr->dentries));
252
253 dir = debugfs_create_dir(name, NULL);
254 if (!dir)
255 goto fail;
256 attr->dentries.dir = dir;
257
258 attr->dentries.probability_file =
259 debugfs_create_ul("probability", mode, dir, &attr->probability);
260
261 attr->dentries.interval_file =
262 debugfs_create_ul("interval", mode, dir, &attr->interval);
263
264 attr->dentries.times_file =
265 debugfs_create_atomic_t("times", mode, dir, &attr->times);
266
267 attr->dentries.space_file =
268 debugfs_create_atomic_t("space", mode, dir, &attr->space);
269
270 attr->dentries.verbose_file =
271 debugfs_create_ul("verbose", mode, dir, &attr->verbose);
272
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800273 attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
274 mode, dir, &attr->task_filter);
275
Akinobu Mita1df49002007-02-20 13:57:56 -0800276 if (!attr->dentries.probability_file || !attr->dentries.interval_file ||
277 !attr->dentries.times_file || !attr->dentries.space_file ||
278 !attr->dentries.verbose_file || !attr->dentries.task_filter_file)
279 goto fail;
280
281#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
282
Akinobu Mita329409a2006-12-08 02:39:48 -0800283 attr->dentries.stacktrace_depth_file =
Akinobu Mita8307fc22011-07-26 16:09:01 -0700284 debugfs_create_stacktrace_depth(
Don Mullisa124c282006-12-08 02:39:52 -0800285 "stacktrace-depth", mode, dir, &attr->stacktrace_depth);
Akinobu Mita329409a2006-12-08 02:39:48 -0800286
287 attr->dentries.require_start_file =
288 debugfs_create_ul("require-start", mode, dir, &attr->require_start);
289
290 attr->dentries.require_end_file =
291 debugfs_create_ul("require-end", mode, dir, &attr->require_end);
292
293 attr->dentries.reject_start_file =
294 debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
295
296 attr->dentries.reject_end_file =
297 debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
298
Akinobu Mita1df49002007-02-20 13:57:56 -0800299 if (!attr->dentries.stacktrace_depth_file ||
300 !attr->dentries.require_start_file ||
301 !attr->dentries.require_end_file ||
302 !attr->dentries.reject_start_file ||
303 !attr->dentries.reject_end_file)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800304 goto fail;
305
Akinobu Mita1df49002007-02-20 13:57:56 -0800306#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
307
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800308 return 0;
309fail:
310 cleanup_fault_attr_dentries(attr);
311 return -ENOMEM;
312}
313
314#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */