1 // SPDX-License-Identifier: GPL-2.0-only 1 // SPDX-License-Identifier: GPL-2.0-only
2 /* 2 /*
3 * kernel/stacktrace.c 3 * kernel/stacktrace.c
4 * 4 *
5 * Stack trace management functions 5 * Stack trace management functions
6 * 6 *
7 * Copyright (C) 2006 Red Hat, Inc., Ingo Mol 7 * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
8 */ 8 */
9 #include <linux/sched/task_stack.h> 9 #include <linux/sched/task_stack.h>
10 #include <linux/sched/debug.h> 10 #include <linux/sched/debug.h>
11 #include <linux/sched.h> 11 #include <linux/sched.h>
12 #include <linux/kernel.h> 12 #include <linux/kernel.h>
13 #include <linux/export.h> 13 #include <linux/export.h>
14 #include <linux/kallsyms.h> 14 #include <linux/kallsyms.h>
15 #include <linux/stacktrace.h> 15 #include <linux/stacktrace.h>
16 #include <linux/interrupt.h> 16 #include <linux/interrupt.h>
17 17
18 /** 18 /**
19 * stack_trace_print - Print the entries in th 19 * stack_trace_print - Print the entries in the stack trace
20 * @entries: Pointer to storage array 20 * @entries: Pointer to storage array
21 * @nr_entries: Number of entries in the stora 21 * @nr_entries: Number of entries in the storage array
22 * @spaces: Number of leading spaces to pr 22 * @spaces: Number of leading spaces to print
23 */ 23 */
24 void stack_trace_print(const unsigned long *en 24 void stack_trace_print(const unsigned long *entries, unsigned int nr_entries,
25 int spaces) 25 int spaces)
26 { 26 {
27 unsigned int i; 27 unsigned int i;
28 28
29 if (WARN_ON(!entries)) 29 if (WARN_ON(!entries))
30 return; 30 return;
31 31
32 for (i = 0; i < nr_entries; i++) 32 for (i = 0; i < nr_entries; i++)
33 printk("%*c%pS\n", 1 + spaces, 33 printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);
34 } 34 }
35 EXPORT_SYMBOL_GPL(stack_trace_print); 35 EXPORT_SYMBOL_GPL(stack_trace_print);
36 36
37 /** 37 /**
38 * stack_trace_snprint - Print the entries in 38 * stack_trace_snprint - Print the entries in the stack trace into a buffer
39 * @buf: Pointer to the print buffer 39 * @buf: Pointer to the print buffer
40 * @size: Size of the print buffer 40 * @size: Size of the print buffer
41 * @entries: Pointer to storage array 41 * @entries: Pointer to storage array
42 * @nr_entries: Number of entries in the stora 42 * @nr_entries: Number of entries in the storage array
43 * @spaces: Number of leading spaces to pr 43 * @spaces: Number of leading spaces to print
44 * 44 *
45 * Return: Number of bytes printed. 45 * Return: Number of bytes printed.
46 */ 46 */
47 int stack_trace_snprint(char *buf, size_t size 47 int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,
48 unsigned int nr_entrie 48 unsigned int nr_entries, int spaces)
49 { 49 {
50 unsigned int generated, i, total = 0; 50 unsigned int generated, i, total = 0;
51 51
52 if (WARN_ON(!entries)) 52 if (WARN_ON(!entries))
53 return 0; 53 return 0;
54 54
55 for (i = 0; i < nr_entries && size; i+ 55 for (i = 0; i < nr_entries && size; i++) {
56 generated = snprintf(buf, size 56 generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
57 (void *)e 57 (void *)entries[i]);
58 58
59 total += generated; 59 total += generated;
60 if (generated >= size) { 60 if (generated >= size) {
61 buf += size; 61 buf += size;
62 size = 0; 62 size = 0;
63 } else { 63 } else {
64 buf += generated; 64 buf += generated;
65 size -= generated; 65 size -= generated;
66 } 66 }
67 } 67 }
68 68
69 return total; 69 return total;
70 } 70 }
71 EXPORT_SYMBOL_GPL(stack_trace_snprint); 71 EXPORT_SYMBOL_GPL(stack_trace_snprint);
72 72
73 #ifdef CONFIG_ARCH_STACKWALK 73 #ifdef CONFIG_ARCH_STACKWALK
74 74
75 struct stacktrace_cookie { 75 struct stacktrace_cookie {
76 unsigned long *store; 76 unsigned long *store;
77 unsigned int size; 77 unsigned int size;
78 unsigned int skip; 78 unsigned int skip;
79 unsigned int len; 79 unsigned int len;
80 }; 80 };
81 81
82 static bool stack_trace_consume_entry(void *co 82 static bool stack_trace_consume_entry(void *cookie, unsigned long addr)
83 { 83 {
84 struct stacktrace_cookie *c = cookie; 84 struct stacktrace_cookie *c = cookie;
85 85
86 if (c->len >= c->size) 86 if (c->len >= c->size)
87 return false; 87 return false;
88 88
89 if (c->skip > 0) { 89 if (c->skip > 0) {
90 c->skip--; 90 c->skip--;
91 return true; 91 return true;
92 } 92 }
93 c->store[c->len++] = addr; 93 c->store[c->len++] = addr;
94 return c->len < c->size; 94 return c->len < c->size;
95 } 95 }
96 96
97 static bool stack_trace_consume_entry_nosched( 97 static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr)
98 { 98 {
99 if (in_sched_functions(addr)) 99 if (in_sched_functions(addr))
100 return true; 100 return true;
101 return stack_trace_consume_entry(cooki 101 return stack_trace_consume_entry(cookie, addr);
102 } 102 }
103 103
104 /** 104 /**
105 * stack_trace_save - Save a stack trace into 105 * stack_trace_save - Save a stack trace into a storage array
106 * @store: Pointer to storage array 106 * @store: Pointer to storage array
107 * @size: Size of the storage array 107 * @size: Size of the storage array
108 * @skipnr: Number of entries to skip at t 108 * @skipnr: Number of entries to skip at the start of the stack trace
109 * 109 *
110 * Return: Number of trace entries stored. 110 * Return: Number of trace entries stored.
111 */ 111 */
112 unsigned int stack_trace_save(unsigned long *s 112 unsigned int stack_trace_save(unsigned long *store, unsigned int size,
113 unsigned int ski 113 unsigned int skipnr)
114 { 114 {
115 stack_trace_consume_fn consume_entry = 115 stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
116 struct stacktrace_cookie c = { 116 struct stacktrace_cookie c = {
117 .store = store, 117 .store = store,
118 .size = size, 118 .size = size,
119 .skip = skipnr + 1, 119 .skip = skipnr + 1,
120 }; 120 };
121 121
122 arch_stack_walk(consume_entry, &c, cur 122 arch_stack_walk(consume_entry, &c, current, NULL);
123 return c.len; 123 return c.len;
124 } 124 }
125 EXPORT_SYMBOL_GPL(stack_trace_save); 125 EXPORT_SYMBOL_GPL(stack_trace_save);
126 126
127 /** 127 /**
128 * stack_trace_save_tsk - Save a task stack tr 128 * stack_trace_save_tsk - Save a task stack trace into a storage array
129 * @tsk: The task to examine !! 129 * @task: The task to examine
130 * @store: Pointer to storage array 130 * @store: Pointer to storage array
131 * @size: Size of the storage array 131 * @size: Size of the storage array
132 * @skipnr: Number of entries to skip at t 132 * @skipnr: Number of entries to skip at the start of the stack trace
133 * 133 *
134 * Return: Number of trace entries stored. 134 * Return: Number of trace entries stored.
135 */ 135 */
136 unsigned int stack_trace_save_tsk(struct task_ 136 unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
137 unsigned int 137 unsigned int size, unsigned int skipnr)
138 { 138 {
139 stack_trace_consume_fn consume_entry = 139 stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
140 struct stacktrace_cookie c = { 140 struct stacktrace_cookie c = {
141 .store = store, 141 .store = store,
142 .size = size, 142 .size = size,
143 /* skip this function if they 143 /* skip this function if they are tracing us */
144 .skip = skipnr + (current == 144 .skip = skipnr + (current == tsk),
145 }; 145 };
146 146
147 if (!try_get_task_stack(tsk)) 147 if (!try_get_task_stack(tsk))
148 return 0; 148 return 0;
149 149
150 arch_stack_walk(consume_entry, &c, tsk 150 arch_stack_walk(consume_entry, &c, tsk, NULL);
151 put_task_stack(tsk); 151 put_task_stack(tsk);
152 return c.len; 152 return c.len;
153 } 153 }
154 EXPORT_SYMBOL_GPL(stack_trace_save_tsk); <<
155 154
156 /** 155 /**
157 * stack_trace_save_regs - Save a stack trace 156 * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
158 * @regs: Pointer to pt_regs to examine 157 * @regs: Pointer to pt_regs to examine
159 * @store: Pointer to storage array 158 * @store: Pointer to storage array
160 * @size: Size of the storage array 159 * @size: Size of the storage array
161 * @skipnr: Number of entries to skip at t 160 * @skipnr: Number of entries to skip at the start of the stack trace
162 * 161 *
163 * Return: Number of trace entries stored. 162 * Return: Number of trace entries stored.
164 */ 163 */
165 unsigned int stack_trace_save_regs(struct pt_r 164 unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
166 unsigned in 165 unsigned int size, unsigned int skipnr)
167 { 166 {
168 stack_trace_consume_fn consume_entry = 167 stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
169 struct stacktrace_cookie c = { 168 struct stacktrace_cookie c = {
170 .store = store, 169 .store = store,
171 .size = size, 170 .size = size,
172 .skip = skipnr, 171 .skip = skipnr,
173 }; 172 };
174 173
175 arch_stack_walk(consume_entry, &c, cur 174 arch_stack_walk(consume_entry, &c, current, regs);
176 return c.len; 175 return c.len;
177 } 176 }
178 177
179 #ifdef CONFIG_HAVE_RELIABLE_STACKTRACE 178 #ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
180 /** 179 /**
181 * stack_trace_save_tsk_reliable - Save task s 180 * stack_trace_save_tsk_reliable - Save task stack with verification
182 * @tsk: Pointer to the task to examine 181 * @tsk: Pointer to the task to examine
183 * @store: Pointer to storage array 182 * @store: Pointer to storage array
184 * @size: Size of the storage array 183 * @size: Size of the storage array
185 * 184 *
186 * Return: An error if it detects any unr 185 * Return: An error if it detects any unreliable features of the
187 * stack. Otherwise it guarantees 186 * stack. Otherwise it guarantees that the stack trace is
188 * reliable and returns the numbe 187 * reliable and returns the number of entries stored.
189 * 188 *
190 * If the task is not 'current', the caller *m 189 * If the task is not 'current', the caller *must* ensure the task is inactive.
191 */ 190 */
192 int stack_trace_save_tsk_reliable(struct task_ 191 int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
193 unsigned int 192 unsigned int size)
194 { 193 {
195 stack_trace_consume_fn consume_entry = 194 stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
196 struct stacktrace_cookie c = { 195 struct stacktrace_cookie c = {
197 .store = store, 196 .store = store,
198 .size = size, 197 .size = size,
199 }; 198 };
200 int ret; 199 int ret;
201 200
202 /* 201 /*
203 * If the task doesn't have a stack (e 202 * If the task doesn't have a stack (e.g., a zombie), the stack is
204 * "reliably" empty. 203 * "reliably" empty.
205 */ 204 */
206 if (!try_get_task_stack(tsk)) 205 if (!try_get_task_stack(tsk))
207 return 0; 206 return 0;
208 207
209 ret = arch_stack_walk_reliable(consume 208 ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
210 put_task_stack(tsk); 209 put_task_stack(tsk);
211 return ret ? ret : c.len; 210 return ret ? ret : c.len;
212 } 211 }
213 #endif 212 #endif
214 213
215 #ifdef CONFIG_USER_STACKTRACE_SUPPORT 214 #ifdef CONFIG_USER_STACKTRACE_SUPPORT
216 /** 215 /**
217 * stack_trace_save_user - Save a user space s 216 * stack_trace_save_user - Save a user space stack trace into a storage array
218 * @store: Pointer to storage array 217 * @store: Pointer to storage array
219 * @size: Size of the storage array 218 * @size: Size of the storage array
220 * 219 *
221 * Return: Number of trace entries stored. 220 * Return: Number of trace entries stored.
222 */ 221 */
223 unsigned int stack_trace_save_user(unsigned lo 222 unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
224 { 223 {
225 stack_trace_consume_fn consume_entry = 224 stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
226 struct stacktrace_cookie c = { 225 struct stacktrace_cookie c = {
227 .store = store, 226 .store = store,
228 .size = size, 227 .size = size,
229 }; 228 };
230 229
231 /* Trace user stack if not a kernel th 230 /* Trace user stack if not a kernel thread */
232 if (current->flags & PF_KTHREAD) 231 if (current->flags & PF_KTHREAD)
233 return 0; 232 return 0;
234 233
235 arch_stack_walk_user(consume_entry, &c 234 arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
236 235
237 return c.len; 236 return c.len;
238 } 237 }
239 #endif 238 #endif
240 239
241 #else /* CONFIG_ARCH_STACKWALK */ 240 #else /* CONFIG_ARCH_STACKWALK */
242 241
243 /* 242 /*
244 * Architectures that do not implement save_st 243 * Architectures that do not implement save_stack_trace_*()
245 * get these weak aliases and once-per-bootup 244 * get these weak aliases and once-per-bootup warnings
246 * (whenever this facility is utilized - for e 245 * (whenever this facility is utilized - for example by procfs):
247 */ 246 */
248 __weak void 247 __weak void
249 save_stack_trace_tsk(struct task_struct *tsk, 248 save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
250 { 249 {
251 WARN_ONCE(1, KERN_INFO "save_stack_tra 250 WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
252 } 251 }
253 252
254 __weak void 253 __weak void
255 save_stack_trace_regs(struct pt_regs *regs, st 254 save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
256 { 255 {
257 WARN_ONCE(1, KERN_INFO "save_stack_tra 256 WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
258 } 257 }
259 258
260 /** 259 /**
261 * stack_trace_save - Save a stack trace into 260 * stack_trace_save - Save a stack trace into a storage array
262 * @store: Pointer to storage array 261 * @store: Pointer to storage array
263 * @size: Size of the storage array 262 * @size: Size of the storage array
264 * @skipnr: Number of entries to skip at t 263 * @skipnr: Number of entries to skip at the start of the stack trace
265 * 264 *
266 * Return: Number of trace entries stored 265 * Return: Number of trace entries stored
267 */ 266 */
268 unsigned int stack_trace_save(unsigned long *s 267 unsigned int stack_trace_save(unsigned long *store, unsigned int size,
269 unsigned int ski 268 unsigned int skipnr)
270 { 269 {
271 struct stack_trace trace = { 270 struct stack_trace trace = {
272 .entries = store, 271 .entries = store,
273 .max_entries = size, 272 .max_entries = size,
274 .skip = skipnr + 1, 273 .skip = skipnr + 1,
275 }; 274 };
276 275
277 save_stack_trace(&trace); 276 save_stack_trace(&trace);
278 return trace.nr_entries; 277 return trace.nr_entries;
279 } 278 }
280 EXPORT_SYMBOL_GPL(stack_trace_save); 279 EXPORT_SYMBOL_GPL(stack_trace_save);
281 280
282 /** 281 /**
283 * stack_trace_save_tsk - Save a task stack tr 282 * stack_trace_save_tsk - Save a task stack trace into a storage array
284 * @task: The task to examine 283 * @task: The task to examine
285 * @store: Pointer to storage array 284 * @store: Pointer to storage array
286 * @size: Size of the storage array 285 * @size: Size of the storage array
287 * @skipnr: Number of entries to skip at t 286 * @skipnr: Number of entries to skip at the start of the stack trace
288 * 287 *
289 * Return: Number of trace entries stored 288 * Return: Number of trace entries stored
290 */ 289 */
291 unsigned int stack_trace_save_tsk(struct task_ 290 unsigned int stack_trace_save_tsk(struct task_struct *task,
292 unsigned lon 291 unsigned long *store, unsigned int size,
293 unsigned int 292 unsigned int skipnr)
294 { 293 {
295 struct stack_trace trace = { 294 struct stack_trace trace = {
296 .entries = store, 295 .entries = store,
297 .max_entries = size, 296 .max_entries = size,
298 /* skip this function if they 297 /* skip this function if they are tracing us */
299 .skip = skipnr + (current == 298 .skip = skipnr + (current == task),
300 }; 299 };
301 300
302 save_stack_trace_tsk(task, &trace); 301 save_stack_trace_tsk(task, &trace);
303 return trace.nr_entries; 302 return trace.nr_entries;
304 } 303 }
305 EXPORT_SYMBOL_GPL(stack_trace_save_tsk); <<
306 304
307 /** 305 /**
308 * stack_trace_save_regs - Save a stack trace 306 * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array
309 * @regs: Pointer to pt_regs to examine 307 * @regs: Pointer to pt_regs to examine
310 * @store: Pointer to storage array 308 * @store: Pointer to storage array
311 * @size: Size of the storage array 309 * @size: Size of the storage array
312 * @skipnr: Number of entries to skip at t 310 * @skipnr: Number of entries to skip at the start of the stack trace
313 * 311 *
314 * Return: Number of trace entries stored 312 * Return: Number of trace entries stored
315 */ 313 */
316 unsigned int stack_trace_save_regs(struct pt_r 314 unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
317 unsigned in 315 unsigned int size, unsigned int skipnr)
318 { 316 {
319 struct stack_trace trace = { 317 struct stack_trace trace = {
320 .entries = store, 318 .entries = store,
321 .max_entries = size, 319 .max_entries = size,
322 .skip = skipnr, 320 .skip = skipnr,
323 }; 321 };
324 322
325 save_stack_trace_regs(regs, &trace); 323 save_stack_trace_regs(regs, &trace);
326 return trace.nr_entries; 324 return trace.nr_entries;
327 } 325 }
328 326
329 #ifdef CONFIG_HAVE_RELIABLE_STACKTRACE 327 #ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
330 /** 328 /**
331 * stack_trace_save_tsk_reliable - Save task s 329 * stack_trace_save_tsk_reliable - Save task stack with verification
332 * @tsk: Pointer to the task to examine 330 * @tsk: Pointer to the task to examine
333 * @store: Pointer to storage array 331 * @store: Pointer to storage array
334 * @size: Size of the storage array 332 * @size: Size of the storage array
335 * 333 *
336 * Return: An error if it detects any unr 334 * Return: An error if it detects any unreliable features of the
337 * stack. Otherwise it guarantees 335 * stack. Otherwise it guarantees that the stack trace is
338 * reliable and returns the numbe 336 * reliable and returns the number of entries stored.
339 * 337 *
340 * If the task is not 'current', the caller *m 338 * If the task is not 'current', the caller *must* ensure the task is inactive.
341 */ 339 */
342 int stack_trace_save_tsk_reliable(struct task_ 340 int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
343 unsigned int 341 unsigned int size)
344 { 342 {
345 struct stack_trace trace = { 343 struct stack_trace trace = {
346 .entries = store, 344 .entries = store,
347 .max_entries = size, 345 .max_entries = size,
348 }; 346 };
349 int ret = save_stack_trace_tsk_reliabl 347 int ret = save_stack_trace_tsk_reliable(tsk, &trace);
350 348
351 return ret ? ret : trace.nr_entries; 349 return ret ? ret : trace.nr_entries;
352 } 350 }
353 #endif 351 #endif
354 352
355 #ifdef CONFIG_USER_STACKTRACE_SUPPORT 353 #ifdef CONFIG_USER_STACKTRACE_SUPPORT
356 /** 354 /**
357 * stack_trace_save_user - Save a user space s 355 * stack_trace_save_user - Save a user space stack trace into a storage array
358 * @store: Pointer to storage array 356 * @store: Pointer to storage array
359 * @size: Size of the storage array 357 * @size: Size of the storage array
360 * 358 *
361 * Return: Number of trace entries stored 359 * Return: Number of trace entries stored
362 */ 360 */
363 unsigned int stack_trace_save_user(unsigned lo 361 unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
364 { 362 {
365 struct stack_trace trace = { 363 struct stack_trace trace = {
366 .entries = store, 364 .entries = store,
367 .max_entries = size, 365 .max_entries = size,
368 }; 366 };
369 367
370 save_stack_trace_user(&trace); 368 save_stack_trace_user(&trace);
371 return trace.nr_entries; 369 return trace.nr_entries;
372 } 370 }
373 #endif /* CONFIG_USER_STACKTRACE_SUPPORT */ 371 #endif /* CONFIG_USER_STACKTRACE_SUPPORT */
374 372
375 #endif /* !CONFIG_ARCH_STACKWALK */ 373 #endif /* !CONFIG_ARCH_STACKWALK */
376 374
377 static inline bool in_irqentry_text(unsigned l 375 static inline bool in_irqentry_text(unsigned long ptr)
378 { 376 {
379 return (ptr >= (unsigned long)&__irqen 377 return (ptr >= (unsigned long)&__irqentry_text_start &&
380 ptr < (unsigned long)&__irqent 378 ptr < (unsigned long)&__irqentry_text_end) ||
381 (ptr >= (unsigned long)&__soft 379 (ptr >= (unsigned long)&__softirqentry_text_start &&
382 ptr < (unsigned long)&__softi 380 ptr < (unsigned long)&__softirqentry_text_end);
383 } 381 }
384 382
385 /** 383 /**
386 * filter_irq_stacks - Find first IRQ stack en 384 * filter_irq_stacks - Find first IRQ stack entry in trace
387 * @entries: Pointer to stack trace array 385 * @entries: Pointer to stack trace array
388 * @nr_entries: Number of entries in the stora 386 * @nr_entries: Number of entries in the storage array
389 * 387 *
390 * Return: Number of trace entries until IRQ s 388 * Return: Number of trace entries until IRQ stack starts.
391 */ 389 */
392 unsigned int filter_irq_stacks(unsigned long * 390 unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries)
393 { 391 {
394 unsigned int i; 392 unsigned int i;
395 393
396 for (i = 0; i < nr_entries; i++) { 394 for (i = 0; i < nr_entries; i++) {
397 if (in_irqentry_text(entries[i 395 if (in_irqentry_text(entries[i])) {
398 /* Include the irqentr 396 /* Include the irqentry function into the stack. */
399 return i + 1; 397 return i + 1;
400 } 398 }
401 } 399 }
402 return nr_entries; 400 return nr_entries;
403 } 401 }
404 EXPORT_SYMBOL_GPL(filter_irq_stacks); 402 EXPORT_SYMBOL_GPL(filter_irq_stacks);
405 403
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