blob: 4f7554025e30e48da1e81b2a090fdf2131f86179 [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>
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 */
Per Forlin6cba00e2011-09-13 23:03:28 +020017int setup_fault_attr(struct fault_attr *attr, char *str)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -080018{
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}
Per Forlin6cba00e2011-09-13 23:03:28 +020039EXPORT_SYMBOL_GPL(setup_fault_attr);
Akinobu Mita6ff1cb32006-12-08 02:39:43 -080040
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 Mita1df49002007-02-20 13:57:56 -080058#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
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;
Akinobu Mita329409a2006-12-08 02:39:48 -080075
Christoph Hellwigab1b6f02007-05-08 00:23:29 -070076 save_stack_trace(&trace);
Akinobu Mita329409a2006-12-08 02:39:48 -080077 for (n = 0; n < trace.nr_entries; n++) {
78 if (attr->reject_start <= entries[n] &&
79 entries[n] < attr->reject_end)
Don Mullis08b3df22006-12-08 02:39:51 -080080 return false;
Akinobu Mita329409a2006-12-08 02:39:48 -080081 if (attr->require_start <= entries[n] &&
82 entries[n] < attr->require_end)
Don Mullis08b3df22006-12-08 02:39:51 -080083 found = true;
Akinobu Mita329409a2006-12-08 02:39:48 -080084 }
85 return found;
86}
87
88#else
89
Don Mullis08b3df22006-12-08 02:39:51 -080090static inline bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -080091{
Akinobu Mita1df49002007-02-20 13:57:56 -080092 return true;
Akinobu Mita329409a2006-12-08 02:39:48 -080093}
94
Akinobu Mita1df49002007-02-20 13:57:56 -080095#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
Akinobu Mita329409a2006-12-08 02:39:48 -080096
Akinobu Mita6ff1cb32006-12-08 02:39:43 -080097/*
98 * This code is stolen from failmalloc-1.0
99 * http://www.nongnu.org/failmalloc/
100 */
101
Don Mullis08b3df22006-12-08 02:39:51 -0800102bool should_fail(struct fault_attr *attr, ssize_t size)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800103{
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800104 if (attr->task_filter && !fail_task(attr, current))
Don Mullis08b3df22006-12-08 02:39:51 -0800105 return false;
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800106
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800107 if (atomic_read(&attr->times) == 0)
Don Mullis08b3df22006-12-08 02:39:51 -0800108 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800109
110 if (atomic_read(&attr->space) > size) {
111 atomic_sub(size, &attr->space);
Don Mullis08b3df22006-12-08 02:39:51 -0800112 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800113 }
114
115 if (attr->interval > 1) {
116 attr->count++;
117 if (attr->count % attr->interval)
Don Mullis08b3df22006-12-08 02:39:51 -0800118 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800119 }
120
Don Mullisf1729c22006-12-08 02:39:53 -0800121 if (attr->probability <= random32() % 100)
122 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800123
Don Mullisf1729c22006-12-08 02:39:53 -0800124 if (!fail_stacktrace(attr))
125 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800126
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800127 fail_dump(attr);
128
129 if (atomic_read(&attr->times) != -1)
130 atomic_dec_not_zero(&attr->times);
131
Don Mullis08b3df22006-12-08 02:39:51 -0800132 return true;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800133}
Per Forlindf87ecb2011-08-19 14:52:36 +0200134EXPORT_SYMBOL_GPL(should_fail);
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800135
136#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
137
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800138static int debugfs_ul_set(void *data, u64 val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800139{
140 *(unsigned long *)data = val;
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800141 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800142}
143
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800144static int debugfs_ul_get(void *data, u64 *val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800145{
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800146 *val = *(unsigned long *)data;
147 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800148}
149
150DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
151
152static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
153 struct dentry *parent, unsigned long *value)
154{
155 return debugfs_create_file(name, mode, parent, value, &fops_ul);
156}
157
Stephen Rothwell6ddb23c2007-07-23 18:43:55 -0700158#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
Don Mullisa124c282006-12-08 02:39:52 -0800159
Akinobu Mita8307fc22011-07-26 16:09:01 -0700160static int debugfs_stacktrace_depth_set(void *data, u64 val)
161{
162 *(unsigned long *)data =
163 min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
164
165 return 0;
166}
167
168DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
169 debugfs_stacktrace_depth_set, "%llu\n");
170
171static struct dentry *debugfs_create_stacktrace_depth(
Don Mullisa124c282006-12-08 02:39:52 -0800172 const char *name, mode_t mode,
173 struct dentry *parent, unsigned long *value)
174{
175 return debugfs_create_file(name, mode, parent, value,
Akinobu Mita8307fc22011-07-26 16:09:01 -0700176 &fops_stacktrace_depth);
Don Mullisa124c282006-12-08 02:39:52 -0800177}
Akinobu Mita8307fc22011-07-26 16:09:01 -0700178
Stephen Rothwell6ddb23c2007-07-23 18:43:55 -0700179#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
Don Mullisa124c282006-12-08 02:39:52 -0800180
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800181static int debugfs_atomic_t_set(void *data, u64 val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800182{
183 atomic_set((atomic_t *)data, val);
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800184 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800185}
186
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800187static int debugfs_atomic_t_get(void *data, u64 *val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800188{
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800189 *val = atomic_read((atomic_t *)data);
190 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800191}
192
193DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
194 debugfs_atomic_t_set, "%lld\n");
195
196static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode,
197 struct dentry *parent, atomic_t *value)
198{
199 return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
200}
201
Akinobu Mitadd48c082011-08-03 16:21:01 -0700202struct dentry *fault_create_debugfs_attr(const char *name,
203 struct dentry *parent, struct fault_attr *attr)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800204{
205 mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
206 struct dentry *dir;
207
Akinobu Mitadd48c082011-08-03 16:21:01 -0700208 dir = debugfs_create_dir(name, parent);
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800209 if (!dir)
Akinobu Mitadd48c082011-08-03 16:21:01 -0700210 return ERR_PTR(-ENOMEM);
Akinobu Mita7f5ddcc2011-07-26 16:09:02 -0700211
212 if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800213 goto fail;
Akinobu Mita7f5ddcc2011-07-26 16:09:02 -0700214 if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
215 goto fail;
216 if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
217 goto fail;
218 if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
219 goto fail;
220 if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
221 goto fail;
222 if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
Akinobu Mita1df49002007-02-20 13:57:56 -0800223 goto fail;
224
225#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
226
Akinobu Mita7f5ddcc2011-07-26 16:09:02 -0700227 if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
228 &attr->stacktrace_depth))
229 goto fail;
230 if (!debugfs_create_ul("require-start", mode, dir,
231 &attr->require_start))
232 goto fail;
233 if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
234 goto fail;
235 if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
236 goto fail;
237 if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800238 goto fail;
239
Akinobu Mita1df49002007-02-20 13:57:56 -0800240#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
241
Akinobu Mitadd48c082011-08-03 16:21:01 -0700242 return dir;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800243fail:
Akinobu Mitadd48c082011-08-03 16:21:01 -0700244 debugfs_remove_recursive(dir);
Akinobu Mita7f5ddcc2011-07-26 16:09:02 -0700245
Akinobu Mitadd48c082011-08-03 16:21:01 -0700246 return ERR_PTR(-ENOMEM);
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800247}
Per Forlindf87ecb2011-08-19 14:52:36 +0200248EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800249
250#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */