Commit | Line | Data |
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6ff1cb35 AM |
1 | #include <linux/kernel.h> |
2 | #include <linux/init.h> | |
3 | #include <linux/random.h> | |
d43c36dc | 4 | #include <linux/sched.h> |
6ff1cb35 AM |
5 | #include <linux/stat.h> |
6 | #include <linux/types.h> | |
7 | #include <linux/fs.h> | |
8bc3bcc9 | 8 | #include <linux/export.h> |
f4f154fd | 9 | #include <linux/interrupt.h> |
329409ae | 10 | #include <linux/stacktrace.h> |
6ff1cb35 AM |
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 | */ | |
6cba00ea | 17 | int setup_fault_attr(struct fault_attr *attr, char *str) |
6ff1cb35 AM |
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, ×) < 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 | } | |
6cba00ea | 39 | EXPORT_SYMBOL_GPL(setup_fault_attr); |
6ff1cb35 AM |
40 | |
41 | static 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 | ||
08b3df2d | 51 | static bool fail_task(struct fault_attr *attr, struct task_struct *task) |
f4f154fd AM |
52 | { |
53 | return !in_interrupt() && task->make_it_fail; | |
54 | } | |
55 | ||
a124c28e DM |
56 | #define MAX_STACK_TRACE_DEPTH 32 |
57 | ||
1df49008 | 58 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER |
329409ae | 59 | |
08b3df2d | 60 | static bool fail_stacktrace(struct fault_attr *attr) |
329409ae AM |
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; | |
a124c28e | 73 | trace.max_entries = depth; |
329409ae | 74 | trace.skip = 1; |
329409ae | 75 | |
ab1b6f03 | 76 | save_stack_trace(&trace); |
329409ae AM |
77 | for (n = 0; n < trace.nr_entries; n++) { |
78 | if (attr->reject_start <= entries[n] && | |
79 | entries[n] < attr->reject_end) | |
08b3df2d | 80 | return false; |
329409ae AM |
81 | if (attr->require_start <= entries[n] && |
82 | entries[n] < attr->require_end) | |
08b3df2d | 83 | found = true; |
329409ae AM |
84 | } |
85 | return found; | |
86 | } | |
87 | ||
88 | #else | |
89 | ||
08b3df2d | 90 | static inline bool fail_stacktrace(struct fault_attr *attr) |
329409ae | 91 | { |
1df49008 | 92 | return true; |
329409ae AM |
93 | } |
94 | ||
1df49008 | 95 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
329409ae | 96 | |
6ff1cb35 AM |
97 | /* |
98 | * This code is stolen from failmalloc-1.0 | |
99 | * http://www.nongnu.org/failmalloc/ | |
100 | */ | |
101 | ||
08b3df2d | 102 | bool should_fail(struct fault_attr *attr, ssize_t size) |
6ff1cb35 | 103 | { |
f39cdaeb AB |
104 | /* No need to check any other properties if the probability is 0 */ |
105 | if (attr->probability == 0) | |
106 | return false; | |
107 | ||
f4f154fd | 108 | if (attr->task_filter && !fail_task(attr, current)) |
08b3df2d | 109 | return false; |
f4f154fd | 110 | |
6ff1cb35 | 111 | if (atomic_read(&attr->times) == 0) |
08b3df2d | 112 | return false; |
6ff1cb35 AM |
113 | |
114 | if (atomic_read(&attr->space) > size) { | |
115 | atomic_sub(size, &attr->space); | |
08b3df2d | 116 | return false; |
6ff1cb35 AM |
117 | } |
118 | ||
119 | if (attr->interval > 1) { | |
120 | attr->count++; | |
121 | if (attr->count % attr->interval) | |
08b3df2d | 122 | return false; |
6ff1cb35 AM |
123 | } |
124 | ||
f39fee5f | 125 | if (attr->probability <= prandom_u32() % 100) |
f1729c28 | 126 | return false; |
6ff1cb35 | 127 | |
f1729c28 DM |
128 | if (!fail_stacktrace(attr)) |
129 | return false; | |
6ff1cb35 | 130 | |
6ff1cb35 AM |
131 | fail_dump(attr); |
132 | ||
133 | if (atomic_read(&attr->times) != -1) | |
134 | atomic_dec_not_zero(&attr->times); | |
135 | ||
08b3df2d | 136 | return true; |
6ff1cb35 | 137 | } |
df87ecbf | 138 | EXPORT_SYMBOL_GPL(should_fail); |
6ff1cb35 AM |
139 | |
140 | #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS | |
141 | ||
8b88b099 | 142 | static int debugfs_ul_set(void *data, u64 val) |
6ff1cb35 AM |
143 | { |
144 | *(unsigned long *)data = val; | |
8b88b099 | 145 | return 0; |
6ff1cb35 AM |
146 | } |
147 | ||
8b88b099 | 148 | static int debugfs_ul_get(void *data, u64 *val) |
6ff1cb35 | 149 | { |
8b88b099 CH |
150 | *val = *(unsigned long *)data; |
151 | return 0; | |
6ff1cb35 AM |
152 | } |
153 | ||
154 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); | |
155 | ||
f4ae40a6 | 156 | static struct dentry *debugfs_create_ul(const char *name, umode_t mode, |
6ff1cb35 AM |
157 | struct dentry *parent, unsigned long *value) |
158 | { | |
159 | return debugfs_create_file(name, mode, parent, value, &fops_ul); | |
160 | } | |
161 | ||
6ddb23c7 | 162 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER |
a124c28e | 163 | |
8307fc25 AM |
164 | static 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 | ||
172 | DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get, | |
173 | debugfs_stacktrace_depth_set, "%llu\n"); | |
174 | ||
175 | static struct dentry *debugfs_create_stacktrace_depth( | |
f4ae40a6 | 176 | const char *name, umode_t mode, |
a124c28e DM |
177 | struct dentry *parent, unsigned long *value) |
178 | { | |
179 | return debugfs_create_file(name, mode, parent, value, | |
8307fc25 | 180 | &fops_stacktrace_depth); |
a124c28e | 181 | } |
8307fc25 | 182 | |
6ddb23c7 | 183 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
a124c28e | 184 | |
dd48c085 AM |
185 | struct dentry *fault_create_debugfs_attr(const char *name, |
186 | struct dentry *parent, struct fault_attr *attr) | |
6ff1cb35 | 187 | { |
f4ae40a6 | 188 | umode_t mode = S_IFREG | S_IRUSR | S_IWUSR; |
6ff1cb35 AM |
189 | struct dentry *dir; |
190 | ||
dd48c085 | 191 | dir = debugfs_create_dir(name, parent); |
6ff1cb35 | 192 | if (!dir) |
dd48c085 | 193 | return ERR_PTR(-ENOMEM); |
6ff1cb35 | 194 | |
7f5ddcc8 AM |
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)) | |
1df49008 AM |
206 | goto fail; |
207 | ||
208 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER | |
209 | ||
7f5ddcc8 AM |
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)) | |
6ff1cb35 AM |
221 | goto fail; |
222 | ||
1df49008 AM |
223 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
224 | ||
dd48c085 | 225 | return dir; |
6ff1cb35 | 226 | fail: |
dd48c085 | 227 | debugfs_remove_recursive(dir); |
7f5ddcc8 | 228 | |
dd48c085 | 229 | return ERR_PTR(-ENOMEM); |
6ff1cb35 | 230 | } |
df87ecbf | 231 | EXPORT_SYMBOL_GPL(fault_create_debugfs_attr); |
6ff1cb35 AM |
232 | |
233 | #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ |