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 #ifdef CONFIG_STACK_UNWIND
60 static asmlinkage
int fail_stacktrace_callback(struct unwind_frame_info
*info
,
64 struct fault_attr
*attr
= arg
;
65 bool found
= (attr
->require_start
== 0 && attr
->require_end
== ULONG_MAX
);
67 for (depth
= 0; depth
< attr
->stacktrace_depth
68 && unwind(info
) == 0 && UNW_PC(info
); depth
++) {
69 if (arch_unw_user_mode(info
))
71 if (attr
->reject_start
<= UNW_PC(info
) &&
72 UNW_PC(info
) < attr
->reject_end
)
74 if (attr
->require_start
<= UNW_PC(info
) &&
75 UNW_PC(info
) < attr
->require_end
)
81 static bool fail_stacktrace(struct fault_attr
*attr
)
83 struct unwind_frame_info info
;
85 return unwind_init_running(&info
, fail_stacktrace_callback
, attr
);
88 #elif defined(CONFIG_STACKTRACE)
90 static bool fail_stacktrace(struct fault_attr
*attr
)
92 struct stack_trace trace
;
93 int depth
= attr
->stacktrace_depth
;
94 unsigned long entries
[MAX_STACK_TRACE_DEPTH
];
96 bool found
= (attr
->require_start
== 0 && attr
->require_end
== ULONG_MAX
);
101 trace
.nr_entries
= 0;
102 trace
.entries
= entries
;
103 trace
.max_entries
= depth
;
105 trace
.all_contexts
= 0;
107 save_stack_trace(&trace
, NULL
);
108 for (n
= 0; n
< trace
.nr_entries
; n
++) {
109 if (attr
->reject_start
<= entries
[n
] &&
110 entries
[n
] < attr
->reject_end
)
112 if (attr
->require_start
<= entries
[n
] &&
113 entries
[n
] < attr
->require_end
)
121 static inline bool fail_stacktrace(struct fault_attr
*attr
)
123 static bool firsttime
= true;
127 "This architecture does not implement save_stack_trace()\n");
136 * This code is stolen from failmalloc-1.0
137 * http://www.nongnu.org/failmalloc/
140 bool should_fail(struct fault_attr
*attr
, ssize_t size
)
142 if (attr
->task_filter
&& !fail_task(attr
, current
))
145 if (atomic_read(&attr
->times
) == 0)
148 if (atomic_read(&attr
->space
) > size
) {
149 atomic_sub(size
, &attr
->space
);
153 if (attr
->interval
> 1) {
155 if (attr
->count
% attr
->interval
)
159 if (attr
->probability
<= random32() % 100)
162 if (!fail_stacktrace(attr
))
167 if (atomic_read(&attr
->times
) != -1)
168 atomic_dec_not_zero(&attr
->times
);
173 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
175 static void debugfs_ul_set(void *data
, u64 val
)
177 *(unsigned long *)data
= val
;
180 static void debugfs_ul_set_MAX_STACK_TRACE_DEPTH(void *data
, u64 val
)
182 *(unsigned long *)data
=
183 val
< MAX_STACK_TRACE_DEPTH
?
184 val
: MAX_STACK_TRACE_DEPTH
;
187 static u64
debugfs_ul_get(void *data
)
189 return *(unsigned long *)data
;
192 DEFINE_SIMPLE_ATTRIBUTE(fops_ul
, debugfs_ul_get
, debugfs_ul_set
, "%llu\n");
194 static struct dentry
*debugfs_create_ul(const char *name
, mode_t mode
,
195 struct dentry
*parent
, unsigned long *value
)
197 return debugfs_create_file(name
, mode
, parent
, value
, &fops_ul
);
200 DEFINE_SIMPLE_ATTRIBUTE(fops_ul_MAX_STACK_TRACE_DEPTH
, debugfs_ul_get
,
201 debugfs_ul_set_MAX_STACK_TRACE_DEPTH
, "%llu\n");
203 static struct dentry
*debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
204 const char *name
, mode_t mode
,
205 struct dentry
*parent
, unsigned long *value
)
207 return debugfs_create_file(name
, mode
, parent
, value
,
208 &fops_ul_MAX_STACK_TRACE_DEPTH
);
211 static void debugfs_atomic_t_set(void *data
, u64 val
)
213 atomic_set((atomic_t
*)data
, val
);
216 static u64
debugfs_atomic_t_get(void *data
)
218 return atomic_read((atomic_t
*)data
);
221 DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t
, debugfs_atomic_t_get
,
222 debugfs_atomic_t_set
, "%lld\n");
224 static struct dentry
*debugfs_create_atomic_t(const char *name
, mode_t mode
,
225 struct dentry
*parent
, atomic_t
*value
)
227 return debugfs_create_file(name
, mode
, parent
, value
, &fops_atomic_t
);
230 void cleanup_fault_attr_dentries(struct fault_attr
*attr
)
232 debugfs_remove(attr
->dentries
.probability_file
);
233 attr
->dentries
.probability_file
= NULL
;
235 debugfs_remove(attr
->dentries
.interval_file
);
236 attr
->dentries
.interval_file
= NULL
;
238 debugfs_remove(attr
->dentries
.times_file
);
239 attr
->dentries
.times_file
= NULL
;
241 debugfs_remove(attr
->dentries
.space_file
);
242 attr
->dentries
.space_file
= NULL
;
244 debugfs_remove(attr
->dentries
.verbose_file
);
245 attr
->dentries
.verbose_file
= NULL
;
247 debugfs_remove(attr
->dentries
.task_filter_file
);
248 attr
->dentries
.task_filter_file
= NULL
;
250 debugfs_remove(attr
->dentries
.stacktrace_depth_file
);
251 attr
->dentries
.stacktrace_depth_file
= NULL
;
253 debugfs_remove(attr
->dentries
.require_start_file
);
254 attr
->dentries
.require_start_file
= NULL
;
256 debugfs_remove(attr
->dentries
.require_end_file
);
257 attr
->dentries
.require_end_file
= NULL
;
259 debugfs_remove(attr
->dentries
.reject_start_file
);
260 attr
->dentries
.reject_start_file
= NULL
;
262 debugfs_remove(attr
->dentries
.reject_end_file
);
263 attr
->dentries
.reject_end_file
= NULL
;
265 if (attr
->dentries
.dir
)
266 WARN_ON(!simple_empty(attr
->dentries
.dir
));
268 debugfs_remove(attr
->dentries
.dir
);
269 attr
->dentries
.dir
= NULL
;
272 int init_fault_attr_dentries(struct fault_attr
*attr
, const char *name
)
274 mode_t mode
= S_IFREG
| S_IRUSR
| S_IWUSR
;
277 memset(&attr
->dentries
, 0, sizeof(attr
->dentries
));
279 dir
= debugfs_create_dir(name
, NULL
);
282 attr
->dentries
.dir
= dir
;
284 attr
->dentries
.probability_file
=
285 debugfs_create_ul("probability", mode
, dir
, &attr
->probability
);
287 attr
->dentries
.interval_file
=
288 debugfs_create_ul("interval", mode
, dir
, &attr
->interval
);
290 attr
->dentries
.times_file
=
291 debugfs_create_atomic_t("times", mode
, dir
, &attr
->times
);
293 attr
->dentries
.space_file
=
294 debugfs_create_atomic_t("space", mode
, dir
, &attr
->space
);
296 attr
->dentries
.verbose_file
=
297 debugfs_create_ul("verbose", mode
, dir
, &attr
->verbose
);
299 attr
->dentries
.task_filter_file
= debugfs_create_bool("task-filter",
300 mode
, dir
, &attr
->task_filter
);
302 attr
->dentries
.stacktrace_depth_file
=
303 debugfs_create_ul_MAX_STACK_TRACE_DEPTH(
304 "stacktrace-depth", mode
, dir
, &attr
->stacktrace_depth
);
306 attr
->dentries
.require_start_file
=
307 debugfs_create_ul("require-start", mode
, dir
, &attr
->require_start
);
309 attr
->dentries
.require_end_file
=
310 debugfs_create_ul("require-end", mode
, dir
, &attr
->require_end
);
312 attr
->dentries
.reject_start_file
=
313 debugfs_create_ul("reject-start", mode
, dir
, &attr
->reject_start
);
315 attr
->dentries
.reject_end_file
=
316 debugfs_create_ul("reject-end", mode
, dir
, &attr
->reject_end
);
319 if (!attr
->dentries
.probability_file
|| !attr
->dentries
.interval_file
320 || !attr
->dentries
.times_file
|| !attr
->dentries
.space_file
321 || !attr
->dentries
.verbose_file
|| !attr
->dentries
.task_filter_file
322 || !attr
->dentries
.stacktrace_depth_file
323 || !attr
->dentries
.require_start_file
324 || !attr
->dentries
.require_end_file
325 || !attr
->dentries
.reject_start_file
326 || !attr
->dentries
.reject_end_file
332 cleanup_fault_attr_dentries(attr
);
336 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */