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)
 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
 51static bool fail_task(struct fault_attr *attr, struct task_struct *task)
 52{
 53	return !in_interrupt() && task->make_it_fail;
 54}
 55
 56#define MAX_STACK_TRACE_DEPTH 32
 57
 58#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
 59
 60static bool fail_stacktrace(struct fault_attr *attr)
 61{
 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;
 73	trace.max_entries = depth;
 74	trace.skip = 1;
 75
 76	save_stack_trace(&trace);
 77	for (n = 0; n < trace.nr_entries; n++) {
 78		if (attr->reject_start <= entries[n] &&
 79			       entries[n] < attr->reject_end)
 80			return false;
 81		if (attr->require_start <= entries[n] &&
 82			       entries[n] < attr->require_end)
 83			found = true;
 84	}
 85	return found;
 86}
 87
 88#else
 89
 90static inline bool fail_stacktrace(struct fault_attr *attr)
 91{
 92	return true;
 93}
 94
 95#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
 96
 97/*
 98 * This code is stolen from failmalloc-1.0
 99 * http://www.nongnu.org/failmalloc/
100 */
101
102bool should_fail(struct fault_attr *attr, ssize_t size)
103{
104	/* No need to check any other properties if the probability is 0 */
105	if (attr->probability == 0)
106		return false;
107
108	if (attr->task_filter && !fail_task(attr, current))
109		return false;
110
111	if (atomic_read(&attr->times) == 0)
112		return false;
113
114	if (atomic_read(&attr->space) > size) {
115		atomic_sub(size, &attr->space);
116		return false;
117	}
118
119	if (attr->interval > 1) {
120		attr->count++;
121		if (attr->count % attr->interval)
122			return false;
123	}
124
125	if (attr->probability <= prandom_u32() % 100)
126		return false;
127
128	if (!fail_stacktrace(attr))
129		return false;
130
131	fail_dump(attr);
132
133	if (atomic_read(&attr->times) != -1)
134		atomic_dec_not_zero(&attr->times);
135
136	return true;
137}
138EXPORT_SYMBOL_GPL(should_fail);
139
140#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
141
142static int debugfs_ul_set(void *data, u64 val)
143{
144	*(unsigned long *)data = val;
145	return 0;
146}
147
148static int debugfs_ul_get(void *data, u64 *val)
149{
150	*val = *(unsigned long *)data;
151	return 0;
152}
153
154DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
155
156static struct dentry *debugfs_create_ul(const char *name, umode_t mode,
157				struct dentry *parent, unsigned long *value)
158{
159	return debugfs_create_file(name, mode, parent, value, &fops_ul);
160}
161
162#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
163
164static int debugfs_stacktrace_depth_set(void *data, u64 val)
165{
166	*(unsigned long *)data =
167		min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
168
169	return 0;
170}
171
172DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
173			debugfs_stacktrace_depth_set, "%llu\n");
174
175static struct dentry *debugfs_create_stacktrace_depth(
176	const char *name, umode_t mode,
177	struct dentry *parent, unsigned long *value)
178{
179	return debugfs_create_file(name, mode, parent, value,
180				   &fops_stacktrace_depth);
181}
182
183#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
184
185struct dentry *fault_create_debugfs_attr(const char *name,
186			struct dentry *parent, struct fault_attr *attr)
187{
188	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
189	struct dentry *dir;
190
191	dir = debugfs_create_dir(name, parent);
192	if (!dir)
193		return ERR_PTR(-ENOMEM);
194
195	if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
196		goto fail;
197	if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
198		goto fail;
199	if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
200		goto fail;
201	if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
202		goto fail;
203	if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
204		goto fail;
205	if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
206		goto fail;
207
208#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
209
210	if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
211				&attr->stacktrace_depth))
212		goto fail;
213	if (!debugfs_create_ul("require-start", mode, dir,
214				&attr->require_start))
215		goto fail;
216	if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
217		goto fail;
218	if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
219		goto fail;
220	if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
221		goto fail;
222
223#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
224
225	return dir;
226fail:
227	debugfs_remove_recursive(dir);
228
229	return ERR_PTR(-ENOMEM);
230}
231EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
232
233#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/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)
 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
 51static bool fail_task(struct fault_attr *attr, struct task_struct *task)
 52{
 53	return !in_interrupt() && task->make_it_fail;
 54}
 55
 56#define MAX_STACK_TRACE_DEPTH 32
 57
 58#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
 59
 60static bool fail_stacktrace(struct fault_attr *attr)
 61{
 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;
 73	trace.max_entries = depth;
 74	trace.skip = 1;
 75
 76	save_stack_trace(&trace);
 77	for (n = 0; n < trace.nr_entries; n++) {
 78		if (attr->reject_start <= entries[n] &&
 79			       entries[n] < attr->reject_end)
 80			return false;
 81		if (attr->require_start <= entries[n] &&
 82			       entries[n] < attr->require_end)
 83			found = true;
 84	}
 85	return found;
 86}
 87
 88#else
 89
 90static inline bool fail_stacktrace(struct fault_attr *attr)
 91{
 92	return true;
 93}
 94
 95#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
 96
 97/*
 98 * This code is stolen from failmalloc-1.0
 99 * http://www.nongnu.org/failmalloc/
100 */
101
102bool should_fail(struct fault_attr *attr, ssize_t size)
103{
104	/* No need to check any other properties if the probability is 0 */
105	if (attr->probability == 0)
106		return false;
107
108	if (attr->task_filter && !fail_task(attr, current))
109		return false;
110
111	if (atomic_read(&attr->times) == 0)
112		return false;
113
114	if (atomic_read(&attr->space) > size) {
115		atomic_sub(size, &attr->space);
116		return false;
117	}
118
119	if (attr->interval > 1) {
120		attr->count++;
121		if (attr->count % attr->interval)
122			return false;
123	}
124
125	if (attr->probability <= random32() % 100)
126		return false;
127
128	if (!fail_stacktrace(attr))
129		return false;
130
131	fail_dump(attr);
132
133	if (atomic_read(&attr->times) != -1)
134		atomic_dec_not_zero(&attr->times);
135
136	return true;
137}
138EXPORT_SYMBOL_GPL(should_fail);
139
140#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
141
142static int debugfs_ul_set(void *data, u64 val)
143{
144	*(unsigned long *)data = val;
145	return 0;
146}
147
148static int debugfs_ul_get(void *data, u64 *val)
149{
150	*val = *(unsigned long *)data;
151	return 0;
152}
153
154DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
155
156static struct dentry *debugfs_create_ul(const char *name, umode_t mode,
157				struct dentry *parent, unsigned long *value)
158{
159	return debugfs_create_file(name, mode, parent, value, &fops_ul);
160}
161
162#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
163
164static int debugfs_stacktrace_depth_set(void *data, u64 val)
165{
166	*(unsigned long *)data =
167		min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
168
169	return 0;
170}
171
172DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
173			debugfs_stacktrace_depth_set, "%llu\n");
174
175static struct dentry *debugfs_create_stacktrace_depth(
176	const char *name, umode_t mode,
177	struct dentry *parent, unsigned long *value)
178{
179	return debugfs_create_file(name, mode, parent, value,
180				   &fops_stacktrace_depth);
181}
182
183#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
184
185static int debugfs_atomic_t_set(void *data, u64 val)
186{
187	atomic_set((atomic_t *)data, val);
188	return 0;
189}
190
191static int debugfs_atomic_t_get(void *data, u64 *val)
192{
193	*val = atomic_read((atomic_t *)data);
194	return 0;
195}
196
197DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
198			debugfs_atomic_t_set, "%lld\n");
199
200static struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
201				struct dentry *parent, atomic_t *value)
202{
203	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
204}
205
206struct dentry *fault_create_debugfs_attr(const char *name,
207			struct dentry *parent, struct fault_attr *attr)
208{
209	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
210	struct dentry *dir;
211
212	dir = debugfs_create_dir(name, parent);
213	if (!dir)
214		return ERR_PTR(-ENOMEM);
215
216	if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
217		goto fail;
218	if (!debugfs_create_ul("interval", mode, dir, &attr->interval))
219		goto fail;
220	if (!debugfs_create_atomic_t("times", mode, dir, &attr->times))
221		goto fail;
222	if (!debugfs_create_atomic_t("space", mode, dir, &attr->space))
223		goto fail;
224	if (!debugfs_create_ul("verbose", mode, dir, &attr->verbose))
225		goto fail;
226	if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
227		goto fail;
228
229#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
230
231	if (!debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
232				&attr->stacktrace_depth))
233		goto fail;
234	if (!debugfs_create_ul("require-start", mode, dir,
235				&attr->require_start))
236		goto fail;
237	if (!debugfs_create_ul("require-end", mode, dir, &attr->require_end))
238		goto fail;
239	if (!debugfs_create_ul("reject-start", mode, dir, &attr->reject_start))
240		goto fail;
241	if (!debugfs_create_ul("reject-end", mode, dir, &attr->reject_end))
242		goto fail;
243
244#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
245
246	return dir;
247fail:
248	debugfs_remove_recursive(dir);
249
250	return ERR_PTR(-ENOMEM);
251}
252EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
253
254#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */