blob: b5a90fc056d3406b838cd71632b91985ce62b09e [file] [log] [blame]
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001#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>
Akinobu Mitaf4f154f2006-12-08 02:39:47 -08008#include <linux/interrupt.h>
Akinobu Mita329409a2006-12-08 02:39:48 -08009#include <linux/unwind.h>
10#include <linux/stacktrace.h>
11#include <linux/kallsyms.h>
Akinobu Mita6ff1cb32006-12-08 02:39:43 -080012#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 */
18int __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, &times) < 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
41static 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
Don Mullis08b3df22006-12-08 02:39:51 -080051static bool fail_task(struct fault_attr *attr, struct task_struct *task)
Akinobu Mitaf4f154f2006-12-08 02:39:47 -080052{
53 return !in_interrupt() && task->make_it_fail;
54}
55
Don Mullisa124c282006-12-08 02:39:52 -080056#define MAX_STACK_TRACE_DEPTH 32
57
Linus Torvaldsd1526e22006-12-15 08:43:13 -080058#if defined(CONFIG_STACKTRACE)
Akinobu Mita329409a2006-12-08 02:39:48 -080059
Don Mullis08b3df22006-12-08 02:39:51 -080060static bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -080061{
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;
Don Mullisa124c282006-12-08 02:39:52 -080073 trace.max_entries = depth;
Akinobu Mita329409a2006-12-08 02:39:48 -080074 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)
Don Mullis08b3df22006-12-08 02:39:51 -080081 return false;
Akinobu Mita329409a2006-12-08 02:39:48 -080082 if (attr->require_start <= entries[n] &&
83 entries[n] < attr->require_end)
Don Mullis08b3df22006-12-08 02:39:51 -080084 found = true;
Akinobu Mita329409a2006-12-08 02:39:48 -080085 }
86 return found;
87}
88
89#else
90
Don Mullis08b3df22006-12-08 02:39:51 -080091static inline bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -080092{
Don Mullis08b3df22006-12-08 02:39:51 -080093 static bool firsttime = true;
Akinobu Mita329409a2006-12-08 02:39:48 -080094
95 if (firsttime) {
96 printk(KERN_WARNING
97 "This architecture does not implement save_stack_trace()\n");
Don Mullis08b3df22006-12-08 02:39:51 -080098 firsttime = false;
Akinobu Mita329409a2006-12-08 02:39:48 -080099 }
Don Mullis08b3df22006-12-08 02:39:51 -0800100 return false;
Akinobu Mita329409a2006-12-08 02:39:48 -0800101}
102
103#endif
104
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800105/*
106 * This code is stolen from failmalloc-1.0
107 * http://www.nongnu.org/failmalloc/
108 */
109
Don Mullis08b3df22006-12-08 02:39:51 -0800110bool should_fail(struct fault_attr *attr, ssize_t size)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800111{
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800112 if (attr->task_filter && !fail_task(attr, current))
Don Mullis08b3df22006-12-08 02:39:51 -0800113 return false;
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800114
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800115 if (atomic_read(&attr->times) == 0)
Don Mullis08b3df22006-12-08 02:39:51 -0800116 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800117
118 if (atomic_read(&attr->space) > size) {
119 atomic_sub(size, &attr->space);
Don Mullis08b3df22006-12-08 02:39:51 -0800120 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800121 }
122
123 if (attr->interval > 1) {
124 attr->count++;
125 if (attr->count % attr->interval)
Don Mullis08b3df22006-12-08 02:39:51 -0800126 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800127 }
128
Don Mullisf1729c282006-12-08 02:39:53 -0800129 if (attr->probability <= random32() % 100)
130 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800131
Don Mullisf1729c282006-12-08 02:39:53 -0800132 if (!fail_stacktrace(attr))
133 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800134
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800135 fail_dump(attr);
136
137 if (atomic_read(&attr->times) != -1)
138 atomic_dec_not_zero(&attr->times);
139
Don Mullis08b3df22006-12-08 02:39:51 -0800140 return true;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800141}
142
143#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
144
145static void debugfs_ul_set(void *data, u64 val)
146{
147 *(unsigned long *)data = val;
148}
149
Don Mullisa124c282006-12-08 02:39:52 -0800150static 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
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800157static u64 debugfs_ul_get(void *data)
158{
159 return *(unsigned long *)data;
160}
161
162DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
163
164static 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
Don Mullisa124c282006-12-08 02:39:52 -0800170DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
171 debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");
172
173static 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
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800181static void debugfs_atomic_t_set(void *data, u64 val)
182{
183 atomic_set((atomic_t *)data, val);
184}
185
186static u64 debugfs_atomic_t_get(void *data)
187{
188 return atomic_read((atomic_t *)data);
189}
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 Mita329409a2006-12-08 02:39:48 -0800220 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
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800235 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
242int 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
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800269 attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
270 mode, dir, &attr->task_filter);
271
Akinobu Mita329409a2006-12-08 02:39:48 -0800272 attr->dentries.stacktrace_depth_file =
Don Mullisa124c282006-12-08 02:39:52 -0800273 debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
274 "stacktrace-depth", mode, dir, &attr->stacktrace_depth);
Akinobu Mita329409a2006-12-08 02:39:48 -0800275
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
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800289 if (!attr->dentries.probability_file || !attr->dentries.interval_file
290 || !attr->dentries.times_file || !attr->dentries.space_file
Akinobu Mita329409a2006-12-08 02:39:48 -0800291 || !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 )
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800298 goto fail;
299
300 return 0;
301fail:
302 cleanup_fault_attr_dentries(attr);
303 return -ENOMEM;
304}
305
306#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */