blob: d143c0faf248f8485f45c6ad655283e9388f8284 [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
Akinobu Mita329409a2006-12-08 02:39:48 -080058#ifdef CONFIG_STACK_UNWIND
59
60static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info,
61 void *arg)
62{
63 int depth;
64 struct fault_attr *attr = arg;
65 bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
66
67 for (depth = 0; depth < attr->stacktrace_depth
68 && unwind(info) == 0 && UNW_PC(info); depth++) {
69 if (arch_unw_user_mode(info))
70 break;
71 if (attr->reject_start <= UNW_PC(info) &&
72 UNW_PC(info) < attr->reject_end)
Don Mullis08b3df22006-12-08 02:39:51 -080073 return false;
Akinobu Mita329409a2006-12-08 02:39:48 -080074 if (attr->require_start <= UNW_PC(info) &&
75 UNW_PC(info) < attr->require_end)
Don Mullis08b3df22006-12-08 02:39:51 -080076 found = true;
Akinobu Mita329409a2006-12-08 02:39:48 -080077 }
78 return found;
79}
80
Don Mullis08b3df22006-12-08 02:39:51 -080081static bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -080082{
83 struct unwind_frame_info info;
84
85 return unwind_init_running(&info, fail_stacktrace_callback, attr);
86}
87
88#elif defined(CONFIG_STACKTRACE)
89
Don Mullis08b3df22006-12-08 02:39:51 -080090static bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -080091{
92 struct stack_trace trace;
93 int depth = attr->stacktrace_depth;
94 unsigned long entries[MAX_STACK_TRACE_DEPTH];
95 int n;
96 bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
97
98 if (depth == 0)
99 return found;
100
101 trace.nr_entries = 0;
102 trace.entries = entries;
Don Mullisa124c282006-12-08 02:39:52 -0800103 trace.max_entries = depth;
Akinobu Mita329409a2006-12-08 02:39:48 -0800104 trace.skip = 1;
105 trace.all_contexts = 0;
106
107 save_stack_trace(&trace, NULL);
108 for (n = 0; n < trace.nr_entries; n++) {
109 if (attr->reject_start <= entries[n] &&
110 entries[n] < attr->reject_end)
Don Mullis08b3df22006-12-08 02:39:51 -0800111 return false;
Akinobu Mita329409a2006-12-08 02:39:48 -0800112 if (attr->require_start <= entries[n] &&
113 entries[n] < attr->require_end)
Don Mullis08b3df22006-12-08 02:39:51 -0800114 found = true;
Akinobu Mita329409a2006-12-08 02:39:48 -0800115 }
116 return found;
117}
118
119#else
120
Don Mullis08b3df22006-12-08 02:39:51 -0800121static inline bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -0800122{
Don Mullis08b3df22006-12-08 02:39:51 -0800123 static bool firsttime = true;
Akinobu Mita329409a2006-12-08 02:39:48 -0800124
125 if (firsttime) {
126 printk(KERN_WARNING
127 "This architecture does not implement save_stack_trace()\n");
Don Mullis08b3df22006-12-08 02:39:51 -0800128 firsttime = false;
Akinobu Mita329409a2006-12-08 02:39:48 -0800129 }
Don Mullis08b3df22006-12-08 02:39:51 -0800130 return false;
Akinobu Mita329409a2006-12-08 02:39:48 -0800131}
132
133#endif
134
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800135/*
136 * This code is stolen from failmalloc-1.0
137 * http://www.nongnu.org/failmalloc/
138 */
139
Don Mullis08b3df22006-12-08 02:39:51 -0800140bool should_fail(struct fault_attr *attr, ssize_t size)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800141{
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800142 if (attr->task_filter && !fail_task(attr, current))
Don Mullis08b3df22006-12-08 02:39:51 -0800143 return false;
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800144
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800145 if (atomic_read(&attr->times) == 0)
Don Mullis08b3df22006-12-08 02:39:51 -0800146 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800147
148 if (atomic_read(&attr->space) > size) {
149 atomic_sub(size, &attr->space);
Don Mullis08b3df22006-12-08 02:39:51 -0800150 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800151 }
152
153 if (attr->interval > 1) {
154 attr->count++;
155 if (attr->count % attr->interval)
Don Mullis08b3df22006-12-08 02:39:51 -0800156 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800157 }
158
Don Mullisf1729c22006-12-08 02:39:53 -0800159 if (attr->probability <= random32() % 100)
160 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800161
Don Mullisf1729c22006-12-08 02:39:53 -0800162 if (!fail_stacktrace(attr))
163 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800164
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800165 fail_dump(attr);
166
167 if (atomic_read(&attr->times) != -1)
168 atomic_dec_not_zero(&attr->times);
169
Don Mullis08b3df22006-12-08 02:39:51 -0800170 return true;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800171}
172
173#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
174
175static void debugfs_ul_set(void *data, u64 val)
176{
177 *(unsigned long *)data = val;
178}
179
Don Mullisa124c282006-12-08 02:39:52 -0800180static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
181{
182 *(unsigned long *)data =
183 val < MAX_STACK_TRACE_DEPTH ?
184 val : MAX_STACK_TRACE_DEPTH;
185}
186
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800187static u64 debugfs_ul_get(void *data)
188{
189 return *(unsigned long *)data;
190}
191
192DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
193
194static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
195 struct dentry *parent, unsigned long *value)
196{
197 return debugfs_create_file(name, mode, parent, value, &fops_ul);
198}
199
Don Mullisa124c282006-12-08 02:39:52 -0800200DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
201 debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");
202
203static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
204 const char *name, mode_t mode,
205 struct dentry *parent, unsigned long *value)
206{
207 return debugfs_create_file(name, mode, parent, value,
208 &fops_ul_MAX_STACK_TRACE_DEPTH);
209}
210
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800211static void debugfs_atomic_t_set(void *data, u64 val)
212{
213 atomic_set((atomic_t *)data, val);
214}
215
216static u64 debugfs_atomic_t_get(void *data)
217{
218 return atomic_read((atomic_t *)data);
219}
220
221DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
222 debugfs_atomic_t_set, "%lld\n");
223
224static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode,
225 struct dentry *parent, atomic_t *value)
226{
227 return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
228}
229
230void cleanup_fault_attr_dentries(struct fault_attr *attr)
231{
232 debugfs_remove(attr->dentries.probability_file);
233 attr->dentries.probability_file = NULL;
234
235 debugfs_remove(attr->dentries.interval_file);
236 attr->dentries.interval_file = NULL;
237
238 debugfs_remove(attr->dentries.times_file);
239 attr->dentries.times_file = NULL;
240
241 debugfs_remove(attr->dentries.space_file);
242 attr->dentries.space_file = NULL;
243
244 debugfs_remove(attr->dentries.verbose_file);
245 attr->dentries.verbose_file = NULL;
246
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800247 debugfs_remove(attr->dentries.task_filter_file);
248 attr->dentries.task_filter_file = NULL;
249
Akinobu Mita329409a2006-12-08 02:39:48 -0800250 debugfs_remove(attr->dentries.stacktrace_depth_file);
251 attr->dentries.stacktrace_depth_file = NULL;
252
253 debugfs_remove(attr->dentries.require_start_file);
254 attr->dentries.require_start_file = NULL;
255
256 debugfs_remove(attr->dentries.require_end_file);
257 attr->dentries.require_end_file = NULL;
258
259 debugfs_remove(attr->dentries.reject_start_file);
260 attr->dentries.reject_start_file = NULL;
261
262 debugfs_remove(attr->dentries.reject_end_file);
263 attr->dentries.reject_end_file = NULL;
264
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800265 if (attr->dentries.dir)
266 WARN_ON(!simple_empty(attr->dentries.dir));
267
268 debugfs_remove(attr->dentries.dir);
269 attr->dentries.dir = NULL;
270}
271
272int init_fault_attr_dentries(struct fault_attr *attr, const char *name)
273{
274 mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
275 struct dentry *dir;
276
277 memset(&attr->dentries, 0, sizeof(attr->dentries));
278
279 dir = debugfs_create_dir(name, NULL);
280 if (!dir)
281 goto fail;
282 attr->dentries.dir = dir;
283
284 attr->dentries.probability_file =
285 debugfs_create_ul("probability", mode, dir, &attr->probability);
286
287 attr->dentries.interval_file =
288 debugfs_create_ul("interval", mode, dir, &attr->interval);
289
290 attr->dentries.times_file =
291 debugfs_create_atomic_t("times", mode, dir, &attr->times);
292
293 attr->dentries.space_file =
294 debugfs_create_atomic_t("space", mode, dir, &attr->space);
295
296 attr->dentries.verbose_file =
297 debugfs_create_ul("verbose", mode, dir, &attr->verbose);
298
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800299 attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
300 mode, dir, &attr->task_filter);
301
Akinobu Mita329409a2006-12-08 02:39:48 -0800302 attr->dentries.stacktrace_depth_file =
Don Mullisa124c282006-12-08 02:39:52 -0800303 debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
304 "stacktrace-depth", mode, dir, &attr->stacktrace_depth);
Akinobu Mita329409a2006-12-08 02:39:48 -0800305
306 attr->dentries.require_start_file =
307 debugfs_create_ul("require-start", mode, dir, &attr->require_start);
308
309 attr->dentries.require_end_file =
310 debugfs_create_ul("require-end", mode, dir, &attr->require_end);
311
312 attr->dentries.reject_start_file =
313 debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
314
315 attr->dentries.reject_end_file =
316 debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
317
318
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800319 if (!attr->dentries.probability_file || !attr->dentries.interval_file
320 || !attr->dentries.times_file || !attr->dentries.space_file
Akinobu Mita329409a2006-12-08 02:39:48 -0800321 || !attr->dentries.verbose_file || !attr->dentries.task_filter_file
322 || !attr->dentries.stacktrace_depth_file
323 || !attr->dentries.require_start_file
324 || !attr->dentries.require_end_file
325 || !attr->dentries.reject_start_file
326 || !attr->dentries.reject_end_file
327 )
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800328 goto fail;
329
330 return 0;
331fail:
332 cleanup_fault_attr_dentries(attr);
333 return -ENOMEM;
334}
335
336#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */