1#include <linux/kernel.h>
  2#include <linux/init.h>
  3#include <linux/random.h>
  4#include <linux/sched.h>
  5#include <linux/stat.h>
  6#include <linux/types.h>
  7#include <linux/fs.h>
  8#include <linux/export.h>
  9#include <linux/interrupt.h>
 10#include <linux/stacktrace.h>
 11#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 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}
 39EXPORT_SYMBOL_GPL(setup_fault_attr);
 40
 41static void fail_dump(struct fault_attr *attr)
 42{
 43	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,
 47		       attr->interval, attr->probability,
 48		       atomic_read(&attr->space),
 49		       atomic_read(&attr->times));
 50		if (attr->verbose > 1)
 51			dump_stack();
 52	}
 53}
 54
 55#define atomic_dec_not_zero(v)		atomic_add_unless((v), -1, 0)
 56
 57static bool fail_task(struct fault_attr *attr, struct task_struct *task)
 58{
 59	return !in_interrupt() && task->make_it_fail;
 60}
 61
 62#define MAX_STACK_TRACE_DEPTH 32
 63
 64#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
 65
 66static bool fail_stacktrace(struct fault_attr *attr)
 67{
 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;
 79	trace.max_entries = depth;
 80	trace.skip = 1;
 81
 82	save_stack_trace(&trace);
 83	for (n = 0; n < trace.nr_entries; n++) {
 84		if (attr->reject_start <= entries[n] &&
 85			       entries[n] < attr->reject_end)
 86			return false;
 87		if (attr->require_start <= entries[n] &&
 88			       entries[n] < attr->require_end)
 89			found = true;
 90	}
 91	return found;
 92}
 93
 94#else
 95
 96static inline bool fail_stacktrace(struct fault_attr *attr)
 97{
 98	return true;
 99}
100
101#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
102
103/*
104 * This code is stolen from failmalloc-1.0
105 * http://www.nongnu.org/failmalloc/
106 */
107
108bool should_fail(struct fault_attr *attr, ssize_t size)
109{
110	/* No need to check any other properties if the probability is 0 */
111	if (attr->probability == 0)
112		return false;
113
114	if (attr->task_filter && !fail_task(attr, current))
115		return false;
116
117	if (atomic_read(&attr->times) == 0)
118		return false;
119
120	if (atomic_read(&attr->space) > size) {
121		atomic_sub(size, &attr->space);
122		return false;
123	}
124
125	if (attr->interval > 1) {
126		attr->count++;
127		if (attr->count % attr->interval)
128			return false;
129	}
130
131	if (attr->probability <= prandom_u32() % 100)
132		return false;
133
134	if (!fail_stacktrace(attr))
135		return false;
136
137	fail_dump(attr);
138
139	if (atomic_read(&attr->times) != -1)
140		atomic_dec_not_zero(&attr->times);
141
142	return true;
143}
144EXPORT_SYMBOL_GPL(should_fail);
145
146#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
147
148static int debugfs_ul_set(void *data, u64 val)
149{
150	*(unsigned long *)data = val;
151	return 0;
152}
153
154static int debugfs_ul_get(void *data, u64 *val)
155{
156	*val = *(unsigned long *)data;
157	return 0;
158}
159
160DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
161
162static struct dentry *debugfs_create_ul(const char *name, umode_t mode,
163				struct dentry *parent, unsigned long *value)
164{
165	return debugfs_create_file(name, mode, parent, value, &fops_ul);
166}
167
168#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
169
170static int debugfs_stacktrace_depth_set(void *data, u64 val)
171{
172	*(unsigned long *)data =
173		min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
174
175	return 0;
176}
177
178DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
179			debugfs_stacktrace_depth_set, "%llu\n");
180
181static struct dentry *debugfs_create_stacktrace_depth(
182	const char *name, umode_t mode,
183	struct dentry *parent, unsigned long *value)
184{
185	return debugfs_create_file(name, mode, parent, value,
186				   &fops_stacktrace_depth);
187}
188
189#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
190
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
191struct dentry *fault_create_debugfs_attr(const char *name,
192			struct dentry *parent, struct fault_attr *attr)
193{
194	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
195	struct dentry *dir;
196
197	dir = debugfs_create_dir(name, parent);
198	if (!dir)
199		return ERR_PTR(-ENOMEM);
200
201	if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
202		goto fail;
203	if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
204		goto fail;
205	if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
206		goto fail;
207	if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
208		goto fail;
209	if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
210		goto fail;
211	if (!debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir,
212				&attr->ratelimit_state.interval))
213		goto fail;
214	if (!debugfs_create_u32("verbose_ratelimit_burst", mode, dir,
215				&attr->ratelimit_state.burst))
216		goto fail;
217	if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
218		goto fail;
219
220#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
221
222	if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
223				&attr->stacktrace_depth))
224		goto fail;
225	if (!debugfs_create_ul("require-start", mode, dir,
226				&attr->require_start))
227		goto fail;
228	if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
229		goto fail;
230	if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
231		goto fail;
232	if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
233		goto fail;
234
235#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
236
237	attr->dname = dget(dir);
238	return dir;
239fail:
240	debugfs_remove_recursive(dir);
241
242	return ERR_PTR(-ENOMEM);
243}
244EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
245
246#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

  1#include <linux/kernel.h>
  2#include <linux/init.h>
  3#include <linux/random.h>
  4#include <linux/sched.h>
  5#include <linux/stat.h>
  6#include <linux/types.h>
  7#include <linux/fs.h>
  8#include <linux/module.h>
  9#include <linux/interrupt.h>
 10#include <linux/stacktrace.h>
 11#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
 50static bool fail_task(struct fault_attr *attr, struct task_struct *task)
 51{
 52	return !in_interrupt() && task->make_it_fail;
 53}
 54
 55#define MAX_STACK_TRACE_DEPTH 32
 56
 57#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
 58
 59static bool fail_stacktrace(struct fault_attr *attr)
 60{
 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;
 72	trace.max_entries = depth;
 73	trace.skip = 1;
 74
 75	save_stack_trace(&trace);
 76	for (n = 0; n < trace.nr_entries; n++) {
 77		if (attr->reject_start <= entries[n] &&
 78			       entries[n] < attr->reject_end)
 79			return false;
 80		if (attr->require_start <= entries[n] &&
 81			       entries[n] < attr->require_end)
 82			found = true;
 83	}
 84	return found;
 85}
 86
 87#else
 88
 89static inline bool fail_stacktrace(struct fault_attr *attr)
 90{
 91	return true;
 92}
 93
 94#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
 95
 96/*
 97 * This code is stolen from failmalloc-1.0
 98 * http://www.nongnu.org/failmalloc/
 99 */
100
101bool should_fail(struct fault_attr *attr, ssize_t size)
102{
 
 
 
 
103	if (attr->task_filter && !fail_task(attr, current))
104		return false;
105
106	if (atomic_read(&attr->times) == 0)
107		return false;
108
109	if (atomic_read(&attr->space) > size) {
110		atomic_sub(size, &attr->space);
111		return false;
112	}
113
114	if (attr->interval > 1) {
115		attr->count++;
116		if (attr->count % attr->interval)
117			return false;
118	}
119
120	if (attr->probability <= random32() % 100)
121		return false;
122
123	if (!fail_stacktrace(attr))
124		return false;
125
126	fail_dump(attr);
127
128	if (atomic_read(&attr->times) != -1)
129		atomic_dec_not_zero(&attr->times);
130
131	return true;
132}
 
133
134#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
135
136static int debugfs_ul_set(void *data, u64 val)
137{
138	*(unsigned long *)data = val;
139	return 0;
140}
141
142static int debugfs_ul_get(void *data, u64 *val)
143{
144	*val = *(unsigned long *)data;
145	return 0;
146}
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
156#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
157
158static 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(
170	const char *name, mode_t mode,
171	struct dentry *parent, unsigned long *value)
172{
173	return debugfs_create_file(name, mode, parent, value,
174				   &fops_stacktrace_depth);
175}
176
177#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
178
179static int debugfs_atomic_t_set(void *data, u64 val)
180{
181	atomic_set((atomic_t *)data, val);
182	return 0;
183}
184
185static int debugfs_atomic_t_get(void *data, u64 *val)
186{
187	*val = atomic_read((atomic_t *)data);
188	return 0;
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
200struct dentry *fault_create_debugfs_attr(const char *name,
201			struct dentry *parent, struct fault_attr *attr)
202{
203	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
204	struct dentry *dir;
205
206	dir = debugfs_create_dir(name, parent);
207	if (!dir)
208		return ERR_PTR(-ENOMEM);
209
210	if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
211		goto fail;
212	if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
213		goto fail;
214	if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
215		goto fail;
216	if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
217		goto fail;
218	if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
219		goto fail;
 
 
 
 
 
 
220	if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
221		goto fail;
222
223#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
224
225	if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
226				&attr->stacktrace_depth))
227		goto fail;
228	if (!debugfs_create_ul("require-start", mode, dir,
229				&attr->require_start))
230		goto fail;
231	if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
232		goto fail;
233	if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
234		goto fail;
235	if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
236		goto fail;
237
238#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
239
 
240	return dir;
241fail:
242	debugfs_remove_recursive(dir);
243
244	return ERR_PTR(-ENOMEM);
245}
 
246
247#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */