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 && __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_task() && 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	if (in_task()) {
111		unsigned int fail_nth = READ_ONCE(current->fail_nth);
112
113		if (fail_nth) {
114			if (!WRITE_ONCE(current->fail_nth, fail_nth - 1))
115				goto fail;
116
117			return false;
118		}
119	}
120
121	/* No need to check any other properties if the probability is 0 */
122	if (attr->probability == 0)
123		return false;
124
125	if (attr->task_filter && !fail_task(attr, current))
126		return false;
127
128	if (atomic_read(&attr->times) == 0)
129		return false;
130
131	if (atomic_read(&attr->space) > size) {
132		atomic_sub(size, &attr->space);
133		return false;
134	}
135
136	if (attr->interval > 1) {
137		attr->count++;
138		if (attr->count % attr->interval)
139			return false;
140	}
141
142	if (attr->probability <= prandom_u32() % 100)
143		return false;
144
145	if (!fail_stacktrace(attr))
146		return false;
147
148fail:
149	fail_dump(attr);
150
151	if (atomic_read(&attr->times) != -1)
152		atomic_dec_not_zero(&attr->times);
153
154	return true;
155}
156EXPORT_SYMBOL_GPL(should_fail);
157
158#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
159
160static int debugfs_ul_set(void *data, u64 val)
161{
162	*(unsigned long *)data = val;
163	return 0;
164}
165
166static int debugfs_ul_get(void *data, u64 *val)
167{
168	*val = *(unsigned long *)data;
169	return 0;
170}
171
172DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
173
174static struct dentry *debugfs_create_ul(const char *name, umode_t mode,
175				struct dentry *parent, unsigned long *value)
176{
177	return debugfs_create_file(name, mode, parent, value, &fops_ul);
178}
179
180#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
181
182static 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(
194	const char *name, umode_t mode,
195	struct dentry *parent, unsigned long *value)
196{
197	return debugfs_create_file(name, mode, parent, value,
198				   &fops_stacktrace_depth);
199}
200
201#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
202
203struct dentry *fault_create_debugfs_attr(const char *name,
204			struct dentry *parent, struct fault_attr *attr)
205{
206	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
207	struct dentry *dir;
208
209	dir = debugfs_create_dir(name, parent);
210	if (!dir)
211		return ERR_PTR(-ENOMEM);
212
213	if (!debugfs_create_ul("probability", mode, dir, &attr->probability))
214		goto fail;
215	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;
223	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;
229	if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
230		goto fail;
231
232#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
233
234	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))
245		goto fail;
246
247#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
248
249	attr->dname = dget(dir);
250	return dir;
251fail:
252	debugfs_remove_recursive(dir);
253
254	return ERR_PTR(-ENOMEM);
255}
256EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
257
258#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */