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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 | ||
74 | if (depth == 0) | |
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 | ||
08b3df2d | 103 | bool should_fail(struct fault_attr *attr, ssize_t size) |
6ff1cb35 | 104 | { |
1203c8e6 AM |
105 | if (in_task()) { |
106 | unsigned int fail_nth = READ_ONCE(current->fail_nth); | |
107 | ||
9eeb52ae AM |
108 | if (fail_nth) { |
109 | if (!WRITE_ONCE(current->fail_nth, fail_nth - 1)) | |
110 | goto fail; | |
1203c8e6 | 111 | |
9eeb52ae AM |
112 | return false; |
113 | } | |
e41d5818 DV |
114 | } |
115 | ||
f39cdaeb AB |
116 | /* No need to check any other properties if the probability is 0 */ |
117 | if (attr->probability == 0) | |
118 | return false; | |
119 | ||
f4f154fd | 120 | if (attr->task_filter && !fail_task(attr, current)) |
08b3df2d | 121 | return false; |
f4f154fd | 122 | |
6ff1cb35 | 123 | if (atomic_read(&attr->times) == 0) |
08b3df2d | 124 | return false; |
6ff1cb35 AM |
125 | |
126 | if (atomic_read(&attr->space) > size) { | |
127 | atomic_sub(size, &attr->space); | |
08b3df2d | 128 | return false; |
6ff1cb35 AM |
129 | } |
130 | ||
131 | if (attr->interval > 1) { | |
132 | attr->count++; | |
133 | if (attr->count % attr->interval) | |
08b3df2d | 134 | return false; |
6ff1cb35 AM |
135 | } |
136 | ||
f39fee5f | 137 | if (attr->probability <= prandom_u32() % 100) |
f1729c28 | 138 | return false; |
6ff1cb35 | 139 | |
f1729c28 DM |
140 | if (!fail_stacktrace(attr)) |
141 | return false; | |
6ff1cb35 | 142 | |
e41d5818 | 143 | fail: |
6ff1cb35 AM |
144 | fail_dump(attr); |
145 | ||
146 | if (atomic_read(&attr->times) != -1) | |
147 | atomic_dec_not_zero(&attr->times); | |
148 | ||
08b3df2d | 149 | return true; |
6ff1cb35 | 150 | } |
df87ecbf | 151 | EXPORT_SYMBOL_GPL(should_fail); |
6ff1cb35 AM |
152 | |
153 | #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS | |
154 | ||
8b88b099 | 155 | static int debugfs_ul_set(void *data, u64 val) |
6ff1cb35 AM |
156 | { |
157 | *(unsigned long *)data = val; | |
8b88b099 | 158 | return 0; |
6ff1cb35 AM |
159 | } |
160 | ||
8b88b099 | 161 | static int debugfs_ul_get(void *data, u64 *val) |
6ff1cb35 | 162 | { |
8b88b099 CH |
163 | *val = *(unsigned long *)data; |
164 | return 0; | |
6ff1cb35 AM |
165 | } |
166 | ||
167 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); | |
168 | ||
053cf510 GKH |
169 | static void debugfs_create_ul(const char *name, umode_t mode, |
170 | struct dentry *parent, unsigned long *value) | |
6ff1cb35 | 171 | { |
053cf510 | 172 | debugfs_create_file(name, mode, parent, value, &fops_ul); |
6ff1cb35 AM |
173 | } |
174 | ||
6ddb23c7 | 175 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER |
a124c28e | 176 | |
8307fc25 AM |
177 | static int debugfs_stacktrace_depth_set(void *data, u64 val) |
178 | { | |
179 | *(unsigned long *)data = | |
180 | min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH); | |
181 | ||
182 | return 0; | |
183 | } | |
184 | ||
185 | DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get, | |
186 | debugfs_stacktrace_depth_set, "%llu\n"); | |
187 | ||
053cf510 GKH |
188 | static void debugfs_create_stacktrace_depth(const char *name, umode_t mode, |
189 | struct dentry *parent, | |
190 | unsigned long *value) | |
a124c28e | 191 | { |
053cf510 | 192 | debugfs_create_file(name, mode, parent, value, &fops_stacktrace_depth); |
a124c28e | 193 | } |
8307fc25 | 194 | |
6ddb23c7 | 195 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
a124c28e | 196 | |
dd48c085 AM |
197 | struct dentry *fault_create_debugfs_attr(const char *name, |
198 | struct dentry *parent, struct fault_attr *attr) | |
6ff1cb35 | 199 | { |
f4ae40a6 | 200 | umode_t mode = S_IFREG | S_IRUSR | S_IWUSR; |
6ff1cb35 AM |
201 | struct dentry *dir; |
202 | ||
dd48c085 | 203 | dir = debugfs_create_dir(name, parent); |
053cf510 GKH |
204 | if (IS_ERR(dir)) |
205 | return dir; | |
206 | ||
207 | debugfs_create_ul("probability", mode, dir, &attr->probability); | |
208 | debugfs_create_ul("interval", mode, dir, &attr->interval); | |
209 | debugfs_create_atomic_t("times", mode, dir, &attr->times); | |
210 | debugfs_create_atomic_t("space", mode, dir, &attr->space); | |
211 | debugfs_create_ul("verbose", mode, dir, &attr->verbose); | |
212 | debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir, | |
213 | &attr->ratelimit_state.interval); | |
214 | debugfs_create_u32("verbose_ratelimit_burst", mode, dir, | |
215 | &attr->ratelimit_state.burst); | |
216 | debugfs_create_bool("task-filter", mode, dir, &attr->task_filter); | |
1df49008 AM |
217 | |
218 | #ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER | |
053cf510 GKH |
219 | debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir, |
220 | &attr->stacktrace_depth); | |
221 | debugfs_create_ul("require-start", mode, dir, &attr->require_start); | |
222 | debugfs_create_ul("require-end", mode, dir, &attr->require_end); | |
223 | debugfs_create_ul("reject-start", mode, dir, &attr->reject_start); | |
224 | debugfs_create_ul("reject-end", mode, dir, &attr->reject_end); | |
1df49008 AM |
225 | #endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */ |
226 | ||
6adc4a22 | 227 | attr->dname = dget(dir); |
dd48c085 | 228 | return dir; |
6ff1cb35 | 229 | } |
df87ecbf | 230 | EXPORT_SYMBOL_GPL(fault_create_debugfs_attr); |
6ff1cb35 AM |
231 | |
232 | #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ |