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 #ifdef CONFIG_STACK_UNWIND
58 static asmlinkage int fail_stacktrace_callback(struct unwind_frame_info *info,
62 struct fault_attr *attr = arg;
63 bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
65 for (depth = 0; depth < attr->stacktrace_depth
66 && unwind(info) == 0 && UNW_PC(info); depth++) {
67 if (arch_unw_user_mode(info))
69 if (attr->reject_start <= UNW_PC(info) &&
70 UNW_PC(info) < attr->reject_end)
72 if (attr->require_start <= UNW_PC(info) &&
73 UNW_PC(info) < attr->require_end)
79 static bool fail_stacktrace(struct fault_attr *attr)
81 struct unwind_frame_info info;
83 return unwind_init_running(&info, fail_stacktrace_callback, attr);
86 #elif defined(CONFIG_STACKTRACE)
88 static bool fail_stacktrace(struct fault_attr *attr)
90 struct stack_trace trace;
91 int depth = attr->stacktrace_depth;
92 unsigned long entries[MAX_STACK_TRACE_DEPTH];
94 bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
100 trace.entries = entries;
101 trace.max_entries = (depth < MAX_STACK_TRACE_DEPTH) ?
102 depth : MAX_STACK_TRACE_DEPTH;
104 trace.all_contexts = 0;
106 save_stack_trace(&trace, NULL);
107 for (n = 0; n < trace.nr_entries; n++) {
108 if (attr->reject_start <= entries[n] &&
109 entries[n] < attr->reject_end)
111 if (attr->require_start <= entries[n] &&
112 entries[n] < attr->require_end)
120 static inline bool fail_stacktrace(struct fault_attr *attr)
122 static bool firsttime = true;
126 "This architecture does not implement save_stack_trace()\n");
135 * This code is stolen from failmalloc-1.0
136 * http://www.nongnu.org/failmalloc/
139 bool should_fail(struct fault_attr *attr, ssize_t size)
141 if (attr->task_filter && !fail_task(attr, current))
144 if (!fail_stacktrace(attr))
147 if (atomic_read(&attr->times) == 0)
150 if (atomic_read(&attr->space) > size) {
151 atomic_sub(size, &attr->space);
155 if (attr->interval > 1) {
157 if (attr->count % attr->interval)
161 if (attr->probability > random32() % 100)
169 if (atomic_read(&attr->times) != -1)
170 atomic_dec_not_zero(&attr->times);
175 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
177 static void debugfs_ul_set(void *data, u64 val)
179 *(unsigned long *)data = val;
182 static u64 debugfs_ul_get(void *data)
184 return *(unsigned long *)data;
187 DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
189 static struct dentry *debugfs_create_ul(const char *name, mode_t mode,
190 struct dentry *parent, unsigned long *value)
192 return debugfs_create_file(name, mode, parent, value, &fops_ul);
195 static void debugfs_atomic_t_set(void *data, u64 val)
197 atomic_set((atomic_t *)data, val);
200 static u64 debugfs_atomic_t_get(void *data)
202 return atomic_read((atomic_t *)data);
205 DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get,
206 debugfs_atomic_t_set, "%lld\n");
208 static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode,
209 struct dentry *parent, atomic_t *value)
211 return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);
214 void cleanup_fault_attr_dentries(struct fault_attr *attr)
216 debugfs_remove(attr->dentries.probability_file);
217 attr->dentries.probability_file = NULL;
219 debugfs_remove(attr->dentries.interval_file);
220 attr->dentries.interval_file = NULL;
222 debugfs_remove(attr->dentries.times_file);
223 attr->dentries.times_file = NULL;
225 debugfs_remove(attr->dentries.space_file);
226 attr->dentries.space_file = NULL;
228 debugfs_remove(attr->dentries.verbose_file);
229 attr->dentries.verbose_file = NULL;
231 debugfs_remove(attr->dentries.task_filter_file);
232 attr->dentries.task_filter_file = NULL;
234 debugfs_remove(attr->dentries.stacktrace_depth_file);
235 attr->dentries.stacktrace_depth_file = NULL;
237 debugfs_remove(attr->dentries.require_start_file);
238 attr->dentries.require_start_file = NULL;
240 debugfs_remove(attr->dentries.require_end_file);
241 attr->dentries.require_end_file = NULL;
243 debugfs_remove(attr->dentries.reject_start_file);
244 attr->dentries.reject_start_file = NULL;
246 debugfs_remove(attr->dentries.reject_end_file);
247 attr->dentries.reject_end_file = NULL;
249 if (attr->dentries.dir)
250 WARN_ON(!simple_empty(attr->dentries.dir));
252 debugfs_remove(attr->dentries.dir);
253 attr->dentries.dir = NULL;
256 int init_fault_attr_dentries(struct fault_attr *attr, const char *name)
258 mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
261 memset(&attr->dentries, 0, sizeof(attr->dentries));
263 dir = debugfs_create_dir(name, NULL);
266 attr->dentries.dir = dir;
268 attr->dentries.probability_file =
269 debugfs_create_ul("probability", mode, dir, &attr->probability);
271 attr->dentries.interval_file =
272 debugfs_create_ul("interval", mode, dir, &attr->interval);
274 attr->dentries.times_file =
275 debugfs_create_atomic_t("times", mode, dir, &attr->times);
277 attr->dentries.space_file =
278 debugfs_create_atomic_t("space", mode, dir, &attr->space);
280 attr->dentries.verbose_file =
281 debugfs_create_ul("verbose", mode, dir, &attr->verbose);
283 attr->dentries.task_filter_file = debugfs_create_bool("task-filter",
284 mode, dir, &attr->task_filter);
286 attr->dentries.stacktrace_depth_file =
287 debugfs_create_ul("stacktrace-depth", mode, dir,
288 &attr->stacktrace_depth);
290 attr->dentries.require_start_file =
291 debugfs_create_ul("require-start", mode, dir, &attr->require_start);
293 attr->dentries.require_end_file =
294 debugfs_create_ul("require-end", mode, dir, &attr->require_end);
296 attr->dentries.reject_start_file =
297 debugfs_create_ul("reject-start", mode, dir, &attr->reject_start);
299 attr->dentries.reject_end_file =
300 debugfs_create_ul("reject-end", mode, dir, &attr->reject_end);
303 if (!attr->dentries.probability_file || !attr->dentries.interval_file
304 || !attr->dentries.times_file || !attr->dentries.space_file
305 || !attr->dentries.verbose_file || !attr->dentries.task_filter_file
306 || !attr->dentries.stacktrace_depth_file
307 || !attr->dentries.require_start_file
308 || !attr->dentries.require_end_file
309 || !attr->dentries.reject_start_file
310 || !attr->dentries.reject_end_file
316 cleanup_fault_attr_dentries(attr);
320 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */