blob: cf7b129b0b2b08adcc1aae98f990c384761532dc [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>
Paul Gortmaker8bc3bcc2011-11-16 21:29:17 -05008#include <linux/export.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{
Dmitry Monakhov6adc4a22014-12-12 16:58:00 -080043 if (attr->verbose > 0 && __ratelimit(&attr->ratelimit_state)) {
44 printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure.\n"
45 "name %pd, interval %lu, probability %lu, "
46 "space %d, times %d\n", attr->dname,
Florian Westphalbb387002015-10-22 13:32:27 -070047 attr->interval, attr->probability,
Dmitry Monakhov6adc4a22014-12-12 16:58:00 -080048 atomic_read(&attr->space),
49 atomic_read(&attr->times));
50 if (attr->verbose > 1)
51 dump_stack();
52 }
Akinobu Mita6ff1cb32006-12-08 02:39:43 -080053}
54
55#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
56
Don Mullis08b3df22006-12-08 02:39:51 -080057static bool fail_task(struct fault_attr *attr, struct task_struct *task)
Akinobu Mitaf4f154f2006-12-08 02:39:47 -080058{
Dmitry Vyukovf2ad37d2017-05-08 15:56:51 -070059 return in_task() && task->make_it_fail;
Akinobu Mitaf4f154f2006-12-08 02:39:47 -080060}
61
Don Mullisa124c282006-12-08 02:39:52 -080062#define MAX_STACK_TRACE_DEPTH 32
63
Akinobu Mita1df49002007-02-20 13:57:56 -080064#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
Akinobu Mita329409a2006-12-08 02:39:48 -080065
Don Mullis08b3df22006-12-08 02:39:51 -080066static bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -080067{
68 struct stack_trace trace;
69 int depth = attr->stacktrace_depth;
70 unsigned long entries[MAX_STACK_TRACE_DEPTH];
71 int n;
72 bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
73
74 if (depth == 0)
75 return found;
76
77 trace.nr_entries = 0;
78 trace.entries = entries;
Don Mullisa124c282006-12-08 02:39:52 -080079 trace.max_entries = depth;
Akinobu Mita329409a2006-12-08 02:39:48 -080080 trace.skip = 1;
Akinobu Mita329409a2006-12-08 02:39:48 -080081
Christoph Hellwigab1b6f02007-05-08 00:23:29 -070082 save_stack_trace(&trace);
Akinobu Mita329409a2006-12-08 02:39:48 -080083 for (n = 0; n < trace.nr_entries; n++) {
84 if (attr->reject_start <= entries[n] &&
85 entries[n] < attr->reject_end)
Don Mullis08b3df22006-12-08 02:39:51 -080086 return false;
Akinobu Mita329409a2006-12-08 02:39:48 -080087 if (attr->require_start <= entries[n] &&
88 entries[n] < attr->require_end)
Don Mullis08b3df22006-12-08 02:39:51 -080089 found = true;
Akinobu Mita329409a2006-12-08 02:39:48 -080090 }
91 return found;
92}
93
94#else
95
Don Mullis08b3df22006-12-08 02:39:51 -080096static inline bool fail_stacktrace(struct fault_attr *attr)
Akinobu Mita329409a2006-12-08 02:39:48 -080097{
Akinobu Mita1df49002007-02-20 13:57:56 -080098 return true;
Akinobu Mita329409a2006-12-08 02:39:48 -080099}
100
Akinobu Mita1df49002007-02-20 13:57:56 -0800101#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
Akinobu Mita329409a2006-12-08 02:39:48 -0800102
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800103/*
104 * This code is stolen from failmalloc-1.0
105 * http://www.nongnu.org/failmalloc/
106 */
107
Don Mullis08b3df22006-12-08 02:39:51 -0800108bool should_fail(struct fault_attr *attr, ssize_t size)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800109{
Akinobu Mita1203c8e2017-07-14 14:49:57 -0700110 if (in_task()) {
111 unsigned int fail_nth = READ_ONCE(current->fail_nth);
112
Akinobu Mita9eeb52a2017-08-10 15:23:53 -0700113 if (fail_nth) {
114 if (!WRITE_ONCE(current->fail_nth, fail_nth - 1))
115 goto fail;
Akinobu Mita1203c8e2017-07-14 14:49:57 -0700116
Akinobu Mita9eeb52a2017-08-10 15:23:53 -0700117 return false;
118 }
Dmitry Vyukove41d5812017-07-12 14:34:35 -0700119 }
120
Anton Blanchardf39cdae2012-06-20 12:53:03 -0700121 /* No need to check any other properties if the probability is 0 */
122 if (attr->probability == 0)
123 return false;
124
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800125 if (attr->task_filter && !fail_task(attr, current))
Don Mullis08b3df22006-12-08 02:39:51 -0800126 return false;
Akinobu Mitaf4f154f2006-12-08 02:39:47 -0800127
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800128 if (atomic_read(&attr->times) == 0)
Don Mullis08b3df22006-12-08 02:39:51 -0800129 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800130
131 if (atomic_read(&attr->space) > size) {
132 atomic_sub(size, &attr->space);
Don Mullis08b3df22006-12-08 02:39:51 -0800133 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800134 }
135
136 if (attr->interval > 1) {
137 attr->count++;
138 if (attr->count % attr->interval)
Don Mullis08b3df22006-12-08 02:39:51 -0800139 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800140 }
141
Akinobu Mitaf39fee52013-04-29 16:21:28 -0700142 if (attr->probability <= prandom_u32() % 100)
Don Mullisf1729c282006-12-08 02:39:53 -0800143 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800144
Don Mullisf1729c282006-12-08 02:39:53 -0800145 if (!fail_stacktrace(attr))
146 return false;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800147
Dmitry Vyukove41d5812017-07-12 14:34:35 -0700148fail:
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800149 fail_dump(attr);
150
151 if (atomic_read(&attr->times) != -1)
152 atomic_dec_not_zero(&attr->times);
153
Don Mullis08b3df22006-12-08 02:39:51 -0800154 return true;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800155}
Per Forlindf87ecb2011-08-19 14:52:36 +0200156EXPORT_SYMBOL_GPL(should_fail);
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800157
158#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
159
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800160static int debugfs_ul_set(void *data, u64 val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800161{
162 *(unsigned long *)data = val;
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800163 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800164}
165
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800166static int debugfs_ul_get(void *data, u64 *val)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800167{
Christoph Hellwig8b88b092008-02-08 04:20:26 -0800168 *val = *(unsigned long *)data;
169 return 0;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800170}
171
172DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
173
Al Virof4ae40a2011-07-24 04:33:43 -0400174static struct dentry *debugfs_create_ul(const char *name, umode_t mode,
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800175 struct dentry *parent, unsigned long *value)
176{
177 return debugfs_create_file(name, mode, parent, value, &fops_ul);
178}
179
Stephen Rothwell6ddb23c2007-07-23 18:43:55 -0700180#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
Don Mullisa124c282006-12-08 02:39:52 -0800181
Akinobu Mita8307fc22011-07-26 16:09:01 -0700182static int debugfs_stacktrace_depth_set(void *data, u64 val)
183{
184 *(unsigned long *)data =
185 min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
186
187 return 0;
188}
189
190DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
191 debugfs_stacktrace_depth_set, "%llu\n");
192
193static struct dentry *debugfs_create_stacktrace_depth(
Al Virof4ae40a2011-07-24 04:33:43 -0400194 const char *name, umode_t mode,
Don Mullisa124c282006-12-08 02:39:52 -0800195 struct dentry *parent, unsigned long *value)
196{
197 return debugfs_create_file(name, mode, parent, value,
Akinobu Mita8307fc22011-07-26 16:09:01 -0700198 &fops_stacktrace_depth);
Don Mullisa124c282006-12-08 02:39:52 -0800199}
Akinobu Mita8307fc22011-07-26 16:09:01 -0700200
Stephen Rothwell6ddb23c2007-07-23 18:43:55 -0700201#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
Don Mullisa124c282006-12-08 02:39:52 -0800202
Akinobu Mitadd48c082011-08-03 16:21:01 -0700203struct dentry *fault_create_debugfs_attr(const char *name,
204 struct dentry *parent, struct fault_attr *attr)
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800205{
Al Virof4ae40a2011-07-24 04:33:43 -0400206 umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800207 struct dentry *dir;
208
Akinobu Mitadd48c082011-08-03 16:21:01 -0700209 dir = debugfs_create_dir(name, parent);
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800210 if (!dir)
Akinobu Mitadd48c082011-08-03 16:21:01 -0700211 return ERR_PTR(-ENOMEM);
Akinobu Mita7f5ddcc2011-07-26 16:09:02 -0700212
213 if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800214 goto fail;
Akinobu Mita7f5ddcc2011-07-26 16:09:02 -0700215 if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
216 goto fail;
217 if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
218 goto fail;
219 if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
220 goto fail;
221 if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
222 goto fail;
Dmitry Monakhov6adc4a22014-12-12 16:58:00 -0800223 if (!debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir,
224 &attr->ratelimit_state.interval))
225 goto fail;
226 if (!debugfs_create_u32("verbose_ratelimit_burst", mode, dir,
227 &attr->ratelimit_state.burst))
228 goto fail;
Akinobu Mita7f5ddcc2011-07-26 16:09:02 -0700229 if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
Akinobu Mita1df49002007-02-20 13:57:56 -0800230 goto fail;
231
232#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
233
Akinobu Mita7f5ddcc2011-07-26 16:09:02 -0700234 if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
235 &attr->stacktrace_depth))
236 goto fail;
237 if (!debugfs_create_ul("require-start", mode, dir,
238 &attr->require_start))
239 goto fail;
240 if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
241 goto fail;
242 if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
243 goto fail;
244 if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800245 goto fail;
246
Akinobu Mita1df49002007-02-20 13:57:56 -0800247#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
248
Dmitry Monakhov6adc4a22014-12-12 16:58:00 -0800249 attr->dname = dget(dir);
Akinobu Mitadd48c082011-08-03 16:21:01 -0700250 return dir;
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800251fail:
Akinobu Mitadd48c082011-08-03 16:21:01 -0700252 debugfs_remove_recursive(dir);
Akinobu Mita7f5ddcc2011-07-26 16:09:02 -0700253
Akinobu Mitadd48c082011-08-03 16:21:01 -0700254 return ERR_PTR(-ENOMEM);
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800255}
Per Forlindf87ecb2011-08-19 14:52:36 +0200256EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
Akinobu Mita6ff1cb32006-12-08 02:39:43 -0800257
258#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */