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 int 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 int 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 #define MAX_STACK_TRACE_DEPTH 32
90 static int 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
< MAX_STACK_TRACE_DEPTH
) ?
104 depth
: MAX_STACK_TRACE_DEPTH
;
106 trace
.all_contexts
= 0;
108 save_stack_trace(&trace
, NULL
);
109 for (n
= 0; n
< trace
.nr_entries
; n
++) {
110 if (attr
->reject_start
<= entries
[n
] &&
111 entries
[n
] < attr
->reject_end
)
113 if (attr
->require_start
<= entries
[n
] &&
114 entries
[n
] < attr
->require_end
)
122 static inline int fail_stacktrace(struct fault_attr
*attr
)
124 static int firsttime
= 1;
128 "This architecture does not implement save_stack_trace()\n");
137 * This code is stolen from failmalloc-1.0
138 * http://www.nongnu.org/failmalloc/
141 int should_fail(struct fault_attr
*attr
, ssize_t size
)
143 if (attr
->task_filter
&& !fail_task(attr
, current
))
146 if (!fail_stacktrace(attr
))
149 if (atomic_read(&attr
->times
) == 0)
152 if (atomic_read(&attr
->space
) > size
) {
153 atomic_sub(size
, &attr
->space
);
157 if (attr
->interval
> 1) {
159 if (attr
->count
% attr
->interval
)
163 if (attr
->probability
> random32() % 100)
171 if (atomic_read(&attr
->times
) != -1)
172 atomic_dec_not_zero(&attr
->times
);
177 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
179 static void debugfs_ul_set(void *data
, u64 val
)
181 *(unsigned long *)data
= val
;
184 static u64
debugfs_ul_get(void *data
)
186 return *(unsigned long *)data
;
189 DEFINE_SIMPLE_ATTRIBUTE(fops_ul
, debugfs_ul_get
, debugfs_ul_set
, "%llu\n");
191 static struct dentry
*debugfs_create_ul(const char *name
, mode_t mode
,
192 struct dentry
*parent
, unsigned long *value
)
194 return debugfs_create_file(name
, mode
, parent
, value
, &fops_ul
);
197 static void debugfs_atomic_t_set(void *data
, u64 val
)
199 atomic_set((atomic_t
*)data
, val
);
202 static u64
debugfs_atomic_t_get(void *data
)
204 return atomic_read((atomic_t
*)data
);
207 DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t
, debugfs_atomic_t_get
,
208 debugfs_atomic_t_set
, "%lld\n");
210 static struct dentry
*debugfs_create_atomic_t(const char *name
, mode_t mode
,
211 struct dentry
*parent
, atomic_t
*value
)
213 return debugfs_create_file(name
, mode
, parent
, value
, &fops_atomic_t
);
216 void cleanup_fault_attr_dentries(struct fault_attr
*attr
)
218 debugfs_remove(attr
->dentries
.probability_file
);
219 attr
->dentries
.probability_file
= NULL
;
221 debugfs_remove(attr
->dentries
.interval_file
);
222 attr
->dentries
.interval_file
= NULL
;
224 debugfs_remove(attr
->dentries
.times_file
);
225 attr
->dentries
.times_file
= NULL
;
227 debugfs_remove(attr
->dentries
.space_file
);
228 attr
->dentries
.space_file
= NULL
;
230 debugfs_remove(attr
->dentries
.verbose_file
);
231 attr
->dentries
.verbose_file
= NULL
;
233 debugfs_remove(attr
->dentries
.task_filter_file
);
234 attr
->dentries
.task_filter_file
= NULL
;
236 debugfs_remove(attr
->dentries
.stacktrace_depth_file
);
237 attr
->dentries
.stacktrace_depth_file
= NULL
;
239 debugfs_remove(attr
->dentries
.require_start_file
);
240 attr
->dentries
.require_start_file
= NULL
;
242 debugfs_remove(attr
->dentries
.require_end_file
);
243 attr
->dentries
.require_end_file
= NULL
;
245 debugfs_remove(attr
->dentries
.reject_start_file
);
246 attr
->dentries
.reject_start_file
= NULL
;
248 debugfs_remove(attr
->dentries
.reject_end_file
);
249 attr
->dentries
.reject_end_file
= NULL
;
251 if (attr
->dentries
.dir
)
252 WARN_ON(!simple_empty(attr
->dentries
.dir
));
254 debugfs_remove(attr
->dentries
.dir
);
255 attr
->dentries
.dir
= NULL
;
258 int init_fault_attr_dentries(struct fault_attr
*attr
, const char *name
)
260 mode_t mode
= S_IFREG
| S_IRUSR
| S_IWUSR
;
263 memset(&attr
->dentries
, 0, sizeof(attr
->dentries
));
265 dir
= debugfs_create_dir(name
, NULL
);
268 attr
->dentries
.dir
= dir
;
270 attr
->dentries
.probability_file
=
271 debugfs_create_ul("probability", mode
, dir
, &attr
->probability
);
273 attr
->dentries
.interval_file
=
274 debugfs_create_ul("interval", mode
, dir
, &attr
->interval
);
276 attr
->dentries
.times_file
=
277 debugfs_create_atomic_t("times", mode
, dir
, &attr
->times
);
279 attr
->dentries
.space_file
=
280 debugfs_create_atomic_t("space", mode
, dir
, &attr
->space
);
282 attr
->dentries
.verbose_file
=
283 debugfs_create_ul("verbose", mode
, dir
, &attr
->verbose
);
285 attr
->dentries
.task_filter_file
= debugfs_create_bool("task-filter",
286 mode
, dir
, &attr
->task_filter
);
288 attr
->dentries
.stacktrace_depth_file
=
289 debugfs_create_ul("stacktrace-depth", mode
, dir
,
290 &attr
->stacktrace_depth
);
292 attr
->dentries
.require_start_file
=
293 debugfs_create_ul("require-start", mode
, dir
, &attr
->require_start
);
295 attr
->dentries
.require_end_file
=
296 debugfs_create_ul("require-end", mode
, dir
, &attr
->require_end
);
298 attr
->dentries
.reject_start_file
=
299 debugfs_create_ul("reject-start", mode
, dir
, &attr
->reject_start
);
301 attr
->dentries
.reject_end_file
=
302 debugfs_create_ul("reject-end", mode
, dir
, &attr
->reject_end
);
305 if (!attr
->dentries
.probability_file
|| !attr
->dentries
.interval_file
306 || !attr
->dentries
.times_file
|| !attr
->dentries
.space_file
307 || !attr
->dentries
.verbose_file
|| !attr
->dentries
.task_filter_file
308 || !attr
->dentries
.stacktrace_depth_file
309 || !attr
->dentries
.require_start_file
310 || !attr
->dentries
.require_end_file
311 || !attr
->dentries
.reject_start_file
312 || !attr
->dentries
.reject_end_file
318 cleanup_fault_attr_dentries(attr
);
322 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
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