1 #include <linux/kernel.h>
2 #include <linux/init.h>
3 #include <linux/random.h>
4 #include <linux/stat.h>
5 #include <linux/types.h>
7 #include <linux/module.h>
8 #include <linux/interrupt.h>
9 #include <linux/unwind.h>
10 #include <linux/stacktrace.h>
11 #include <linux/kallsyms.h>
12 #include <linux/fault-inject.h>
15 * setup_fault_attr() is a helper function for various __setup handlers, so it
16 * returns 0 on error, because that is what __setup handlers do.
18 int __init setup_fault_attr(struct fault_attr *attr, char *str)
20 unsigned long probability;
21 unsigned long interval;
25 /* "<interval>,<probability>,<space>,<times>" */
26 if (sscanf(str, "%lu,%lu,%d,%d",
27 &interval, &probability, &space, ×) < 4) {
29 "FAULT_INJECTION: failed to parse arguments\n");
33 attr->probability = probability;
34 attr->interval = interval;
35 atomic_set(&attr->times, times);
36 atomic_set(&attr->space, space);
41 static void fail_dump(struct fault_attr *attr)
43 if (attr->verbose > 0)
44 printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n");
45 if (attr->verbose > 1)
49 #define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
51 static bool fail_task(struct fault_attr *attr, struct task_struct *task)
53 return !in_interrupt() && task->make_it_fail;
56 #define MAX_STACK_TRACE_DEPTH 32
58 #if defined(CONFIG_STACKTRACE)
60 static bool fail_stacktrace(struct fault_attr *attr)
62 struct stack_trace trace;
63 int depth = attr->stacktrace_depth;
64 unsigned long entries[MAX_STACK_TRACE_DEPTH];
66 bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
72 trace.entries = entries;
73 trace.max_entries = depth;
75 trace.all_contexts = 0;
77 save_stack_trace(&trace, NULL);
78 for (n = 0; n < trace.nr_entries; n++) {
79 if (attr->reject_start <= entries[n] &&
80 entries[n] < attr->reject_end)
82 if (attr->require_start <= entries[n] &&
83 entries[n] < attr->require_end)
91 static inline bool fail_stacktrace(struct fault_attr *attr)
93 static bool firsttime = true;
97 "This architecture does not implement save_stack_trace()\n");
106 * This code is stolen from failmalloc-1.0
107 * http://www.nongnu.org/failmalloc/
110 bool should_fail(struct fault_attr *attr, ssize_t size)
112 if (attr->task_filter && !fail_task(attr, current))
115 if (atomic_read(&attr->times) == 0)
118 if (atomic_read(&attr->space) > size) {
119 atomic_sub(size, &attr->space);
123 if (attr->interval > 1) {
125 if (attr->count % attr->interval)
129 if (attr->probability <= random32() % 100)
132 if (!fail_stacktrace(attr))
137 if (atomic_read(&attr->times) != -1)
138 atomic_dec_not_zero(&attr->times);
143 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
145 static void debugfs_ul_set(void *data, u64 val)
147 *(unsigned long *)data = val;
150 static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data, u64 val)
152 *(unsigned long *)data =
153 val < MAX_STACK_TRACE_DEPTH ?
154 val : MAX_STACK_TRACE_DEPTH;
157 static u64 debugfs_ul_get(void *data)
159 return *(unsigned long *)data;
162 DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
164 static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
165 struct dentry *parent, unsigned long *value)
167 return debugfs_create_file(name, mode, parent, value, &fops_ul);
170 DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH, debugfs_ul_get,
171 debugfs_ul_set_MAX_STACK_TRACE_DEPTH, "%llu\n");
173 static struct dentry *debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
174 const char *name, mode_t mode,
175 struct dentry *parent, unsigned long *value)
177 return debugfs_create_file(name, mode, parent, value,
178 &fops_ul_MAX_STACK_TRACE_DEPTH);
181 static void debugfs_atomic_t_set(void *data, u64 val)
183 atomic_set((atomic_t *)data, val);
186 static u64 debugfs_atomic_t_get(void *data)
188 return atomic_read((atomic_t *)data);
191 DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
192 debugfs_atomic_t_set, "%lld\n");
194 static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode,
195 struct dentry *parent, atomic_t *value)
197 return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
200 void cleanup_fault_attr_dentries(struct fault_attr *attr)
202 debugfs_remove(attr->dentries.probability_file);
203 attr->dentries.probability_file = NULL;
205 debugfs_remove(attr->dentries.interval_file);
206 attr->dentries.interval_file = NULL;
208 debugfs_remove(attr->dentries.times_file);
209 attr->dentries.times_file = NULL;
211 debugfs_remove(attr->dentries.space_file);
212 attr->dentries.space_file = NULL;
214 debugfs_remove(attr->dentries.verbose_file);
215 attr->dentries.verbose_file = NULL;
217 debugfs_remove(attr->dentries.task_filter_file);
218 attr->dentries.task_filter_file = NULL;
220 debugfs_remove(attr->dentries.stacktrace_depth_file);
221 attr->dentries.stacktrace_depth_file = NULL;
223 debugfs_remove(attr->dentries.require_start_file);
224 attr->dentries.require_start_file = NULL;
226 debugfs_remove(attr->dentries.require_end_file);
227 attr->dentries.require_end_file = NULL;
229 debugfs_remove(attr->dentries.reject_start_file);
230 attr->dentries.reject_start_file = NULL;
232 debugfs_remove(attr->dentries.reject_end_file);
233 attr->dentries.reject_end_file = NULL;
235 if (attr->dentries.dir)
236 WARN_ON(!simple_empty(attr->dentries.dir));
238 debugfs_remove(attr->dentries.dir);
239 attr->dentries.dir = NULL;
242 int init_fault_attr_dentries(struct fault_attr *attr, const char *name)
244 mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
247 memset(&attr->dentries, 0, sizeof(attr->dentries));
249 dir = debugfs_create_dir(name, NULL);
252 attr->dentries.dir = dir;
254 attr->dentries.probability_file =
255 debugfs_create_ul("probability", mode, dir, &attr->probability);
257 attr->dentries.interval_file =
258 debugfs_create_ul("interval", mode, dir, &attr->interval);
260 attr->dentries.times_file =
261 debugfs_create_atomic_t("times", mode, dir, &attr->times);
263 attr->dentries.space_file =
264 debugfs_create_atomic_t("space", mode, dir, &attr->space);
266 attr->dentries.verbose_file =
267 debugfs_create_ul("verbose", mode, dir, &attr->verbose);
269 attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
270 mode, dir, &attr->task_filter);
272 attr->dentries.stacktrace_depth_file =
273 debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
274 "stacktrace-depth", mode, dir, &attr->stacktrace_depth);
276 attr->dentries.require_start_file =
277 debugfs_create_ul("require-start", mode, dir, &attr->require_start);
279 attr->dentries.require_end_file =
280 debugfs_create_ul("require-end", mode, dir, &attr->require_end);
282 attr->dentries.reject_start_file =
283 debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
285 attr->dentries.reject_end_file =
286 debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
289 if (!attr->dentries.probability_file || !attr->dentries.interval_file
290 || !attr->dentries.times_file || !attr->dentries.space_file
291 || !attr->dentries.verbose_file || !attr->dentries.task_filter_file
292 || !attr->dentries.stacktrace_depth_file
293 || !attr->dentries.require_start_file
294 || !attr->dentries.require_end_file
295 || !attr->dentries.reject_start_file
296 || !attr->dentries.reject_end_file
302 cleanup_fault_attr_dentries(attr);
306 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */