]>
Commit | Line | Data |
---|---|---|
457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
8637c099 IM |
2 | /* |
3 | * kernel/stacktrace.c | |
4 | * | |
5 | * Stack trace management functions | |
6 | * | |
7 | * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <[email protected]> | |
8 | */ | |
214d8ca6 TG |
9 | #include <linux/sched/task_stack.h> |
10 | #include <linux/sched/debug.h> | |
8637c099 | 11 | #include <linux/sched.h> |
9212ddb5 | 12 | #include <linux/kernel.h> |
9984de1a | 13 | #include <linux/export.h> |
8637c099 IM |
14 | #include <linux/kallsyms.h> |
15 | #include <linux/stacktrace.h> | |
16 | ||
e9b98e16 TG |
17 | /** |
18 | * stack_trace_print - Print the entries in the stack trace | |
19 | * @entries: Pointer to storage array | |
20 | * @nr_entries: Number of entries in the storage array | |
21 | * @spaces: Number of leading spaces to print | |
22 | */ | |
a2970421 | 23 | void stack_trace_print(const unsigned long *entries, unsigned int nr_entries, |
e9b98e16 | 24 | int spaces) |
8637c099 | 25 | { |
e9b98e16 | 26 | unsigned int i; |
8637c099 | 27 | |
e9b98e16 | 28 | if (WARN_ON(!entries)) |
bfeeeeb9 JB |
29 | return; |
30 | ||
e9b98e16 TG |
31 | for (i = 0; i < nr_entries; i++) |
32 | printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]); | |
33 | } | |
34 | EXPORT_SYMBOL_GPL(stack_trace_print); | |
35 | ||
e9b98e16 TG |
36 | /** |
37 | * stack_trace_snprint - Print the entries in the stack trace into a buffer | |
38 | * @buf: Pointer to the print buffer | |
39 | * @size: Size of the print buffer | |
40 | * @entries: Pointer to storage array | |
41 | * @nr_entries: Number of entries in the storage array | |
42 | * @spaces: Number of leading spaces to print | |
43 | * | |
44 | * Return: Number of bytes printed. | |
45 | */ | |
a2970421 | 46 | int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries, |
e9b98e16 | 47 | unsigned int nr_entries, int spaces) |
9a92a6ce | 48 | { |
e9b98e16 | 49 | unsigned int generated, i, total = 0; |
9a92a6ce | 50 | |
e9b98e16 | 51 | if (WARN_ON(!entries)) |
9a92a6ce JK |
52 | return 0; |
53 | ||
e9b98e16 | 54 | for (i = 0; i < nr_entries && size; i++) { |
bfeda41d | 55 | generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ', |
e9b98e16 | 56 | (void *)entries[i]); |
9a92a6ce JK |
57 | |
58 | total += generated; | |
9a92a6ce JK |
59 | if (generated >= size) { |
60 | buf += size; | |
61 | size = 0; | |
62 | } else { | |
63 | buf += generated; | |
64 | size -= generated; | |
65 | } | |
66 | } | |
67 | ||
68 | return total; | |
69 | } | |
e9b98e16 TG |
70 | EXPORT_SYMBOL_GPL(stack_trace_snprint); |
71 | ||
214d8ca6 TG |
72 | #ifdef CONFIG_ARCH_STACKWALK |
73 | ||
74 | struct stacktrace_cookie { | |
75 | unsigned long *store; | |
76 | unsigned int size; | |
77 | unsigned int skip; | |
78 | unsigned int len; | |
79 | }; | |
80 | ||
81 | static bool stack_trace_consume_entry(void *cookie, unsigned long addr, | |
82 | bool reliable) | |
83 | { | |
84 | struct stacktrace_cookie *c = cookie; | |
85 | ||
86 | if (c->len >= c->size) | |
87 | return false; | |
88 | ||
89 | if (c->skip > 0) { | |
90 | c->skip--; | |
91 | return true; | |
92 | } | |
93 | c->store[c->len++] = addr; | |
94 | return c->len < c->size; | |
95 | } | |
96 | ||
97 | static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr, | |
98 | bool reliable) | |
99 | { | |
100 | if (in_sched_functions(addr)) | |
101 | return true; | |
102 | return stack_trace_consume_entry(cookie, addr, reliable); | |
103 | } | |
104 | ||
105 | /** | |
106 | * stack_trace_save - Save a stack trace into a storage array | |
107 | * @store: Pointer to storage array | |
108 | * @size: Size of the storage array | |
109 | * @skipnr: Number of entries to skip at the start of the stack trace | |
110 | * | |
111 | * Return: Number of trace entries stored. | |
112 | */ | |
113 | unsigned int stack_trace_save(unsigned long *store, unsigned int size, | |
114 | unsigned int skipnr) | |
115 | { | |
116 | stack_trace_consume_fn consume_entry = stack_trace_consume_entry; | |
117 | struct stacktrace_cookie c = { | |
118 | .store = store, | |
119 | .size = size, | |
120 | .skip = skipnr + 1, | |
121 | }; | |
122 | ||
123 | arch_stack_walk(consume_entry, &c, current, NULL); | |
124 | return c.len; | |
125 | } | |
126 | EXPORT_SYMBOL_GPL(stack_trace_save); | |
127 | ||
128 | /** | |
129 | * stack_trace_save_tsk - Save a task stack trace into a storage array | |
130 | * @task: The task to examine | |
131 | * @store: Pointer to storage array | |
132 | * @size: Size of the storage array | |
133 | * @skipnr: Number of entries to skip at the start of the stack trace | |
134 | * | |
135 | * Return: Number of trace entries stored. | |
136 | */ | |
137 | unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store, | |
138 | unsigned int size, unsigned int skipnr) | |
139 | { | |
140 | stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched; | |
141 | struct stacktrace_cookie c = { | |
142 | .store = store, | |
143 | .size = size, | |
b0c51f15 | 144 | /* skip this function if they are tracing us */ |
4b48512c | 145 | .skip = skipnr + (current == tsk), |
214d8ca6 TG |
146 | }; |
147 | ||
148 | if (!try_get_task_stack(tsk)) | |
149 | return 0; | |
150 | ||
151 | arch_stack_walk(consume_entry, &c, tsk, NULL); | |
152 | put_task_stack(tsk); | |
153 | return c.len; | |
154 | } | |
155 | ||
156 | /** | |
157 | * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array | |
158 | * @regs: Pointer to pt_regs to examine | |
159 | * @store: Pointer to storage array | |
160 | * @size: Size of the storage array | |
161 | * @skipnr: Number of entries to skip at the start of the stack trace | |
162 | * | |
163 | * Return: Number of trace entries stored. | |
164 | */ | |
165 | unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store, | |
166 | unsigned int size, unsigned int skipnr) | |
167 | { | |
168 | stack_trace_consume_fn consume_entry = stack_trace_consume_entry; | |
169 | struct stacktrace_cookie c = { | |
170 | .store = store, | |
171 | .size = size, | |
172 | .skip = skipnr, | |
173 | }; | |
174 | ||
175 | arch_stack_walk(consume_entry, &c, current, regs); | |
176 | return c.len; | |
177 | } | |
178 | ||
179 | #ifdef CONFIG_HAVE_RELIABLE_STACKTRACE | |
180 | /** | |
181 | * stack_trace_save_tsk_reliable - Save task stack with verification | |
182 | * @tsk: Pointer to the task to examine | |
183 | * @store: Pointer to storage array | |
184 | * @size: Size of the storage array | |
185 | * | |
186 | * Return: An error if it detects any unreliable features of the | |
187 | * stack. Otherwise it guarantees that the stack trace is | |
188 | * reliable and returns the number of entries stored. | |
189 | * | |
190 | * If the task is not 'current', the caller *must* ensure the task is inactive. | |
191 | */ | |
192 | int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store, | |
193 | unsigned int size) | |
194 | { | |
195 | stack_trace_consume_fn consume_entry = stack_trace_consume_entry; | |
196 | struct stacktrace_cookie c = { | |
197 | .store = store, | |
198 | .size = size, | |
199 | }; | |
200 | int ret; | |
201 | ||
202 | /* | |
203 | * If the task doesn't have a stack (e.g., a zombie), the stack is | |
204 | * "reliably" empty. | |
205 | */ | |
206 | if (!try_get_task_stack(tsk)) | |
207 | return 0; | |
208 | ||
209 | ret = arch_stack_walk_reliable(consume_entry, &c, tsk); | |
210 | put_task_stack(tsk); | |
7eaf51a2 | 211 | return ret ? ret : c.len; |
214d8ca6 TG |
212 | } |
213 | #endif | |
214 | ||
215 | #ifdef CONFIG_USER_STACKTRACE_SUPPORT | |
216 | /** | |
217 | * stack_trace_save_user - Save a user space stack trace into a storage array | |
218 | * @store: Pointer to storage array | |
219 | * @size: Size of the storage array | |
220 | * | |
221 | * Return: Number of trace entries stored. | |
222 | */ | |
223 | unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) | |
224 | { | |
225 | stack_trace_consume_fn consume_entry = stack_trace_consume_entry; | |
226 | struct stacktrace_cookie c = { | |
227 | .store = store, | |
228 | .size = size, | |
229 | }; | |
cac9b9a4 | 230 | mm_segment_t fs; |
214d8ca6 TG |
231 | |
232 | /* Trace user stack if not a kernel thread */ | |
7e8e6816 | 233 | if (current->flags & PF_KTHREAD) |
214d8ca6 TG |
234 | return 0; |
235 | ||
3d13f313 | 236 | fs = force_uaccess_begin(); |
214d8ca6 | 237 | arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); |
3d13f313 | 238 | force_uaccess_end(fs); |
cac9b9a4 | 239 | |
214d8ca6 TG |
240 | return c.len; |
241 | } | |
242 | #endif | |
243 | ||
244 | #else /* CONFIG_ARCH_STACKWALK */ | |
245 | ||
9212ddb5 | 246 | /* |
af085d90 JP |
247 | * Architectures that do not implement save_stack_trace_*() |
248 | * get these weak aliases and once-per-bootup warnings | |
c624d33f | 249 | * (whenever this facility is utilized - for example by procfs): |
9212ddb5 IM |
250 | */ |
251 | __weak void | |
252 | save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) | |
253 | { | |
254 | WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n"); | |
255 | } | |
c624d33f MH |
256 | |
257 | __weak void | |
258 | save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) | |
259 | { | |
260 | WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n"); | |
261 | } | |
af085d90 | 262 | |
e9b98e16 TG |
263 | /** |
264 | * stack_trace_save - Save a stack trace into a storage array | |
265 | * @store: Pointer to storage array | |
266 | * @size: Size of the storage array | |
267 | * @skipnr: Number of entries to skip at the start of the stack trace | |
268 | * | |
269 | * Return: Number of trace entries stored | |
270 | */ | |
271 | unsigned int stack_trace_save(unsigned long *store, unsigned int size, | |
272 | unsigned int skipnr) | |
273 | { | |
274 | struct stack_trace trace = { | |
275 | .entries = store, | |
276 | .max_entries = size, | |
277 | .skip = skipnr + 1, | |
278 | }; | |
279 | ||
280 | save_stack_trace(&trace); | |
281 | return trace.nr_entries; | |
282 | } | |
283 | EXPORT_SYMBOL_GPL(stack_trace_save); | |
284 | ||
285 | /** | |
286 | * stack_trace_save_tsk - Save a task stack trace into a storage array | |
287 | * @task: The task to examine | |
288 | * @store: Pointer to storage array | |
289 | * @size: Size of the storage array | |
290 | * @skipnr: Number of entries to skip at the start of the stack trace | |
291 | * | |
292 | * Return: Number of trace entries stored | |
293 | */ | |
294 | unsigned int stack_trace_save_tsk(struct task_struct *task, | |
295 | unsigned long *store, unsigned int size, | |
296 | unsigned int skipnr) | |
297 | { | |
298 | struct stack_trace trace = { | |
299 | .entries = store, | |
300 | .max_entries = size, | |
b0c51f15 | 301 | /* skip this function if they are tracing us */ |
4b48512c | 302 | .skip = skipnr + (current == task), |
e9b98e16 TG |
303 | }; |
304 | ||
305 | save_stack_trace_tsk(task, &trace); | |
306 | return trace.nr_entries; | |
307 | } | |
308 | ||
309 | /** | |
310 | * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array | |
311 | * @regs: Pointer to pt_regs to examine | |
312 | * @store: Pointer to storage array | |
313 | * @size: Size of the storage array | |
314 | * @skipnr: Number of entries to skip at the start of the stack trace | |
315 | * | |
316 | * Return: Number of trace entries stored | |
317 | */ | |
318 | unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store, | |
319 | unsigned int size, unsigned int skipnr) | |
320 | { | |
321 | struct stack_trace trace = { | |
322 | .entries = store, | |
323 | .max_entries = size, | |
324 | .skip = skipnr, | |
325 | }; | |
326 | ||
327 | save_stack_trace_regs(regs, &trace); | |
328 | return trace.nr_entries; | |
329 | } | |
330 | ||
331 | #ifdef CONFIG_HAVE_RELIABLE_STACKTRACE | |
332 | /** | |
333 | * stack_trace_save_tsk_reliable - Save task stack with verification | |
334 | * @tsk: Pointer to the task to examine | |
335 | * @store: Pointer to storage array | |
336 | * @size: Size of the storage array | |
337 | * | |
338 | * Return: An error if it detects any unreliable features of the | |
339 | * stack. Otherwise it guarantees that the stack trace is | |
340 | * reliable and returns the number of entries stored. | |
341 | * | |
342 | * If the task is not 'current', the caller *must* ensure the task is inactive. | |
343 | */ | |
344 | int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store, | |
345 | unsigned int size) | |
346 | { | |
347 | struct stack_trace trace = { | |
348 | .entries = store, | |
349 | .max_entries = size, | |
350 | }; | |
351 | int ret = save_stack_trace_tsk_reliable(tsk, &trace); | |
352 | ||
353 | return ret ? ret : trace.nr_entries; | |
354 | } | |
355 | #endif | |
356 | ||
357 | #ifdef CONFIG_USER_STACKTRACE_SUPPORT | |
358 | /** | |
359 | * stack_trace_save_user - Save a user space stack trace into a storage array | |
360 | * @store: Pointer to storage array | |
361 | * @size: Size of the storage array | |
362 | * | |
363 | * Return: Number of trace entries stored | |
364 | */ | |
365 | unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) | |
366 | { | |
367 | struct stack_trace trace = { | |
368 | .entries = store, | |
369 | .max_entries = size, | |
370 | }; | |
371 | ||
372 | save_stack_trace_user(&trace); | |
373 | return trace.nr_entries; | |
374 | } | |
375 | #endif /* CONFIG_USER_STACKTRACE_SUPPORT */ | |
214d8ca6 TG |
376 | |
377 | #endif /* !CONFIG_ARCH_STACKWALK */ |