Commit | Line | Data |
---|---|---|
457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
6ff1cb35 AM |
2 | #include <linux/kernel.h> |
3 | #include <linux/init.h> | |
4 | #include <linux/random.h> | |
d43c36dc | 5 | #include <linux/sched.h> |
6ff1cb35 AM |
6 | #include <linux/stat.h> |
7 | #include <linux/types.h> | |
8 | #include <linux/fs.h> | |
8bc3bcc9 | 9 | #include <linux/export.h> |
f4f154fd | 10 | #include <linux/interrupt.h> |
329409ae | 11 | #include <linux/stacktrace.h> |
6ff1cb35 AM |
12 | #include <linux/fault-inject.h> |
13 | ||
14 | /* | |
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. | |
17 | */ | |
6cba00ea | 18 | int setup_fault_attr(struct fault_attr *attr, char *str) |
6ff1cb35 AM |
19 | { |
20 | unsigned long probability; | |
21 | unsigned long interval; | |
22 | int times; | |
23 | int space; | |
24 | ||
25 | /* "<interval>,<probability>,<space>,<times>" */ | |
26 | if (sscanf(str, "%lu,%lu,%d,%d", | |
27 | &interval, &probability, &space, ×) < 4) { | |
28 | printk(KERN_WARNING | |
29 | "FAULT_INJECTION: failed to parse arguments\n"); | |
30 | return 0; | |
31 | } | |
32 | ||
33 | attr->probability = probability; | |
34 | attr->interval = interval; | |
35 | atomic_set(&attr->times, times); | |
36 | atomic_set(&attr->space, space); | |
37 | ||
38 | return 1; | |
39 | } | |
6cba00ea | 40 | EXPORT_SYMBOL_GPL(setup_fault_attr); |
6ff1cb35 AM |
41 | |
42 | static void fail_dump(struct fault_attr *attr) | |
43 | { | |
6adc4a22 DM |
44 | if (attr->verbose > 0 && __ratelimit(&attr->ratelimit_state)) { |
45 | printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure.\n" | |
46 | "name %pd, interval %lu, probability %lu, " | |
47 | "space %d, times %d\n", attr->dname, | |
bb387002 | 48 | attr->interval, attr->probability, |
6adc4a22 DM |
49 | atomic_read(&attr->space), |
50 | atomic_read(&attr->times)); | |
51 | if (attr->verbose > 1) | |
52 | dump_stack(); | |
53 | } | |
6ff1cb35 AM |
54 | } |
55 | ||
56 | #define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0) | |
57 | ||
08b3df2d | 58 | static bool fail_task(struct fault_attr *attr, struct task_struct *task) |
f4f154fd | 59 | { |
f2ad37da | 60 | return in_task() && task->make_it_fail; |
f4f154fd AM |
61 | } |
62 | ||
a124c28e DM |
63 | #define MAX_STACK_TRACE_DEPTH 32 |
64 | ||
1df49008 | 65 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER |
329409ae | 66 | |
08b3df2d | 67 | static bool fail_stacktrace(struct fault_attr *attr) |
329409ae | 68 | { |
329409ae AM |
69 | int depth = attr->stacktrace_depth; |
70 | unsigned long entries[MAX_STACK_TRACE_DEPTH]; | |
30191250 | 71 | int n, nr_entries; |
329409ae AM |
72 | bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX); |
73 | ||
4acb9e51 | 74 | if (depth == 0 || (found && !attr->reject_start && !attr->reject_end)) |
329409ae AM |
75 | return found; |
76 | ||
30191250 TG |
77 | nr_entries = stack_trace_save(entries, depth, 1); |
78 | for (n = 0; n < nr_entries; n++) { | |
329409ae AM |
79 | if (attr->reject_start <= entries[n] && |
80 | entries[n] < attr->reject_end) | |
08b3df2d | 81 | return false; |
329409ae AM |
82 | if (attr->require_start <= entries[n] && |
83 | entries[n] < attr->require_end) | |
08b3df2d | 84 | found = true; |
329409ae AM |
85 | } |
86 | return found; | |
87 | } | |
88 | ||
89 | #else | |
90 | ||
08b3df2d | 91 | static inline bool fail_stacktrace(struct fault_attr *attr) |
329409ae | 92 | { |
1df49008 | 93 | return true; |
329409ae AM |
94 | } |
95 | ||
1df49008 | 96 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
329409ae | 97 | |
6ff1cb35 AM |
98 | /* |
99 | * This code is stolen from failmalloc-1.0 | |
100 | * http://www.nongnu.org/failmalloc/ | |
101 | */ | |
102 | ||
ea4452de | 103 | bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags) |
6ff1cb35 | 104 | { |
f9eeef59 WY |
105 | bool stack_checked = false; |
106 | ||
1203c8e6 AM |
107 | if (in_task()) { |
108 | unsigned int fail_nth = READ_ONCE(current->fail_nth); | |
109 | ||
9eeb52ae | 110 | if (fail_nth) { |
f9eeef59 WY |
111 | if (!fail_stacktrace(attr)) |
112 | return false; | |
113 | ||
114 | stack_checked = true; | |
9b4fb5ce WD |
115 | fail_nth--; |
116 | WRITE_ONCE(current->fail_nth, fail_nth); | |
117 | if (!fail_nth) | |
9eeb52ae | 118 | goto fail; |
1203c8e6 | 119 | |
9eeb52ae AM |
120 | return false; |
121 | } | |
e41d5818 DV |
122 | } |
123 | ||
f39cdaeb AB |
124 | /* No need to check any other properties if the probability is 0 */ |
125 | if (attr->probability == 0) | |
126 | return false; | |
127 | ||
f4f154fd | 128 | if (attr->task_filter && !fail_task(attr, current)) |
08b3df2d | 129 | return false; |
f4f154fd | 130 | |
6ff1cb35 | 131 | if (atomic_read(&attr->times) == 0) |
08b3df2d | 132 | return false; |
6ff1cb35 | 133 | |
f9eeef59 WY |
134 | if (!stack_checked && !fail_stacktrace(attr)) |
135 | return false; | |
136 | ||
6ff1cb35 AM |
137 | if (atomic_read(&attr->space) > size) { |
138 | atomic_sub(size, &attr->space); | |
08b3df2d | 139 | return false; |
6ff1cb35 AM |
140 | } |
141 | ||
142 | if (attr->interval > 1) { | |
143 | attr->count++; | |
144 | if (attr->count % attr->interval) | |
08b3df2d | 145 | return false; |
6ff1cb35 AM |
146 | } |
147 | ||
8032bf12 | 148 | if (attr->probability <= get_random_u32_below(100)) |
f1729c28 | 149 | return false; |
6ff1cb35 | 150 | |
e41d5818 | 151 | fail: |
ea4452de QZ |
152 | if (!(flags & FAULT_NOWARN)) |
153 | fail_dump(attr); | |
6ff1cb35 AM |
154 | |
155 | if (atomic_read(&attr->times) != -1) | |
156 | atomic_dec_not_zero(&attr->times); | |
157 | ||
08b3df2d | 158 | return true; |
6ff1cb35 | 159 | } |
ea4452de QZ |
160 | |
161 | bool should_fail(struct fault_attr *attr, ssize_t size) | |
162 | { | |
163 | return should_fail_ex(attr, size, 0); | |
164 | } | |
df87ecbf | 165 | EXPORT_SYMBOL_GPL(should_fail); |
6ff1cb35 AM |
166 | |
167 | #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS | |
168 | ||
8b88b099 | 169 | static int debugfs_ul_set(void *data, u64 val) |
6ff1cb35 AM |
170 | { |
171 | *(unsigned long *)data = val; | |
8b88b099 | 172 | return 0; |
6ff1cb35 AM |
173 | } |
174 | ||
8b88b099 | 175 | static int debugfs_ul_get(void *data, u64 *val) |
6ff1cb35 | 176 | { |
8b88b099 CH |
177 | *val = *(unsigned long *)data; |
178 | return 0; | |
6ff1cb35 AM |
179 | } |
180 | ||
181 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); | |
182 | ||
053cf510 GKH |
183 | static void debugfs_create_ul(const char *name, umode_t mode, |
184 | struct dentry *parent, unsigned long *value) | |
6ff1cb35 | 185 | { |
053cf510 | 186 | debugfs_create_file(name, mode, parent, value, &fops_ul); |
6ff1cb35 AM |
187 | } |
188 | ||
6ddb23c7 | 189 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER |
a124c28e | 190 | |
8307fc25 AM |
191 | static int debugfs_stacktrace_depth_set(void *data, u64 val) |
192 | { | |
193 | *(unsigned long *)data = | |
194 | min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH); | |
195 | ||
196 | return 0; | |
197 | } | |
198 | ||
199 | DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get, | |
200 | debugfs_stacktrace_depth_set, "%llu\n"); | |
201 | ||
053cf510 GKH |
202 | static void debugfs_create_stacktrace_depth(const char *name, umode_t mode, |
203 | struct dentry *parent, | |
204 | unsigned long *value) | |
a124c28e | 205 | { |
053cf510 | 206 | debugfs_create_file(name, mode, parent, value, &fops_stacktrace_depth); |
a124c28e | 207 | } |
8307fc25 | 208 | |
6ddb23c7 | 209 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
a124c28e | 210 | |
dd48c085 AM |
211 | struct dentry *fault_create_debugfs_attr(const char *name, |
212 | struct dentry *parent, struct fault_attr *attr) | |
6ff1cb35 | 213 | { |
f4ae40a6 | 214 | umode_t mode = S_IFREG | S_IRUSR | S_IWUSR; |
6ff1cb35 AM |
215 | struct dentry *dir; |
216 | ||
dd48c085 | 217 | dir = debugfs_create_dir(name, parent); |
053cf510 GKH |
218 | if (IS_ERR(dir)) |
219 | return dir; | |
220 | ||
221 | debugfs_create_ul("probability", mode, dir, &attr->probability); | |
222 | debugfs_create_ul("interval", mode, dir, &attr->interval); | |
223 | debugfs_create_atomic_t("times", mode, dir, &attr->times); | |
224 | debugfs_create_atomic_t("space", mode, dir, &attr->space); | |
225 | debugfs_create_ul("verbose", mode, dir, &attr->verbose); | |
226 | debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir, | |
227 | &attr->ratelimit_state.interval); | |
228 | debugfs_create_u32("verbose_ratelimit_burst", mode, dir, | |
229 | &attr->ratelimit_state.burst); | |
230 | debugfs_create_bool("task-filter", mode, dir, &attr->task_filter); | |
1df49008 AM |
231 | |
232 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER | |
053cf510 GKH |
233 | debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir, |
234 | &attr->stacktrace_depth); | |
01999074 WY |
235 | debugfs_create_xul("require-start", mode, dir, &attr->require_start); |
236 | debugfs_create_xul("require-end", mode, dir, &attr->require_end); | |
237 | debugfs_create_xul("reject-start", mode, dir, &attr->reject_start); | |
238 | debugfs_create_xul("reject-end", mode, dir, &attr->reject_end); | |
1df49008 AM |
239 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
240 | ||
6adc4a22 | 241 | attr->dname = dget(dir); |
dd48c085 | 242 | return dir; |
6ff1cb35 | 243 | } |
df87ecbf | 244 | EXPORT_SYMBOL_GPL(fault_create_debugfs_attr); |
6ff1cb35 AM |
245 | |
246 | #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ |