1 // SPDX-License-Identifier: GPL-2.0
2 /* Include in trace.c */
3
4 #include <uapi/linux/sched/types.h>
5 #include <linux/stringify.h>
6 #include <linux/kthread.h>
7 #include <linux/delay.h>
8 #include <linux/slab.h>
9
trace_valid_entry(struct trace_entry * entry)10 static inline int trace_valid_entry(struct trace_entry *entry)
11 {
12 switch (entry->type) {
13 case TRACE_FN:
14 case TRACE_CTX:
15 case TRACE_WAKE:
16 case TRACE_STACK:
17 case TRACE_PRINT:
18 case TRACE_BRANCH:
19 case TRACE_GRAPH_ENT:
20 case TRACE_GRAPH_RET:
21 return 1;
22 }
23 return 0;
24 }
25
trace_test_buffer_cpu(struct array_buffer * buf,int cpu)26 static int trace_test_buffer_cpu(struct array_buffer *buf, int cpu)
27 {
28 struct ring_buffer_event *event;
29 struct trace_entry *entry;
30 unsigned int loops = 0;
31
32 while ((event = ring_buffer_consume(buf->buffer, cpu, NULL, NULL))) {
33 entry = ring_buffer_event_data(event);
34
35 /*
36 * The ring buffer is a size of trace_buf_size, if
37 * we loop more than the size, there's something wrong
38 * with the ring buffer.
39 */
40 if (loops++ > trace_buf_size) {
41 printk(KERN_CONT ".. bad ring buffer ");
42 goto failed;
43 }
44 if (!trace_valid_entry(entry)) {
45 printk(KERN_CONT ".. invalid entry %d ",
46 entry->type);
47 goto failed;
48 }
49 }
50 return 0;
51
52 failed:
53 /* disable tracing */
54 tracing_disabled = 1;
55 printk(KERN_CONT ".. corrupted trace buffer .. ");
56 return -1;
57 }
58
59 /*
60 * Test the trace buffer to see if all the elements
61 * are still sane.
62 */
trace_test_buffer(struct array_buffer * buf,unsigned long * count)63 static int __maybe_unused trace_test_buffer(struct array_buffer *buf, unsigned long *count)
64 {
65 unsigned long flags, cnt = 0;
66 int cpu, ret = 0;
67
68 /* Don't allow flipping of max traces now */
69 local_irq_save(flags);
70 arch_spin_lock(&buf->tr->max_lock);
71
72 cnt = ring_buffer_entries(buf->buffer);
73
74 /*
75 * The trace_test_buffer_cpu runs a while loop to consume all data.
76 * If the calling tracer is broken, and is constantly filling
77 * the buffer, this will run forever, and hard lock the box.
78 * We disable the ring buffer while we do this test to prevent
79 * a hard lock up.
80 */
81 tracing_off();
82 for_each_possible_cpu(cpu) {
83 ret = trace_test_buffer_cpu(buf, cpu);
84 if (ret)
85 break;
86 }
87 tracing_on();
88 arch_spin_unlock(&buf->tr->max_lock);
89 local_irq_restore(flags);
90
91 if (count)
92 *count = cnt;
93
94 return ret;
95 }
96
warn_failed_init_tracer(struct tracer * trace,int init_ret)97 static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
98 {
99 printk(KERN_WARNING "Failed to init %s tracer, init returned %d\n",
100 trace->name, init_ret);
101 }
102 #ifdef CONFIG_FUNCTION_TRACER
103
104 #ifdef CONFIG_DYNAMIC_FTRACE
105
106 static int trace_selftest_test_probe1_cnt;
trace_selftest_test_probe1_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct ftrace_regs * fregs)107 static void trace_selftest_test_probe1_func(unsigned long ip,
108 unsigned long pip,
109 struct ftrace_ops *op,
110 struct ftrace_regs *fregs)
111 {
112 trace_selftest_test_probe1_cnt++;
113 }
114
115 static int trace_selftest_test_probe2_cnt;
trace_selftest_test_probe2_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct ftrace_regs * fregs)116 static void trace_selftest_test_probe2_func(unsigned long ip,
117 unsigned long pip,
118 struct ftrace_ops *op,
119 struct ftrace_regs *fregs)
120 {
121 trace_selftest_test_probe2_cnt++;
122 }
123
124 static int trace_selftest_test_probe3_cnt;
trace_selftest_test_probe3_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct ftrace_regs * fregs)125 static void trace_selftest_test_probe3_func(unsigned long ip,
126 unsigned long pip,
127 struct ftrace_ops *op,
128 struct ftrace_regs *fregs)
129 {
130 trace_selftest_test_probe3_cnt++;
131 }
132
133 static int trace_selftest_test_global_cnt;
trace_selftest_test_global_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct ftrace_regs * fregs)134 static void trace_selftest_test_global_func(unsigned long ip,
135 unsigned long pip,
136 struct ftrace_ops *op,
137 struct ftrace_regs *fregs)
138 {
139 trace_selftest_test_global_cnt++;
140 }
141
142 static int trace_selftest_test_dyn_cnt;
trace_selftest_test_dyn_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct ftrace_regs * fregs)143 static void trace_selftest_test_dyn_func(unsigned long ip,
144 unsigned long pip,
145 struct ftrace_ops *op,
146 struct ftrace_regs *fregs)
147 {
148 trace_selftest_test_dyn_cnt++;
149 }
150
151 static struct ftrace_ops test_probe1 = {
152 .func = trace_selftest_test_probe1_func,
153 };
154
155 static struct ftrace_ops test_probe2 = {
156 .func = trace_selftest_test_probe2_func,
157 };
158
159 static struct ftrace_ops test_probe3 = {
160 .func = trace_selftest_test_probe3_func,
161 };
162
print_counts(void)163 static void print_counts(void)
164 {
165 printk("(%d %d %d %d %d) ",
166 trace_selftest_test_probe1_cnt,
167 trace_selftest_test_probe2_cnt,
168 trace_selftest_test_probe3_cnt,
169 trace_selftest_test_global_cnt,
170 trace_selftest_test_dyn_cnt);
171 }
172
reset_counts(void)173 static void reset_counts(void)
174 {
175 trace_selftest_test_probe1_cnt = 0;
176 trace_selftest_test_probe2_cnt = 0;
177 trace_selftest_test_probe3_cnt = 0;
178 trace_selftest_test_global_cnt = 0;
179 trace_selftest_test_dyn_cnt = 0;
180 }
181
trace_selftest_ops(struct trace_array * tr,int cnt)182 static int trace_selftest_ops(struct trace_array *tr, int cnt)
183 {
184 int save_ftrace_enabled = ftrace_enabled;
185 struct ftrace_ops *dyn_ops;
186 char *func1_name;
187 char *func2_name;
188 int len1;
189 int len2;
190 int ret = -1;
191
192 printk(KERN_CONT "PASSED\n");
193 pr_info("Testing dynamic ftrace ops #%d: ", cnt);
194
195 ftrace_enabled = 1;
196 reset_counts();
197
198 /* Handle PPC64 '.' name */
199 func1_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
200 func2_name = "*" __stringify(DYN_FTRACE_TEST_NAME2);
201 len1 = strlen(func1_name);
202 len2 = strlen(func2_name);
203
204 /*
205 * Probe 1 will trace function 1.
206 * Probe 2 will trace function 2.
207 * Probe 3 will trace functions 1 and 2.
208 */
209 ftrace_set_filter(&test_probe1, func1_name, len1, 1);
210 ftrace_set_filter(&test_probe2, func2_name, len2, 1);
211 ftrace_set_filter(&test_probe3, func1_name, len1, 1);
212 ftrace_set_filter(&test_probe3, func2_name, len2, 0);
213
214 register_ftrace_function(&test_probe1);
215 register_ftrace_function(&test_probe2);
216 register_ftrace_function(&test_probe3);
217 /* First time we are running with main function */
218 if (cnt > 1) {
219 ftrace_init_array_ops(tr, trace_selftest_test_global_func);
220 register_ftrace_function(tr->ops);
221 }
222
223 DYN_FTRACE_TEST_NAME();
224
225 print_counts();
226
227 if (trace_selftest_test_probe1_cnt != 1)
228 goto out;
229 if (trace_selftest_test_probe2_cnt != 0)
230 goto out;
231 if (trace_selftest_test_probe3_cnt != 1)
232 goto out;
233 if (cnt > 1) {
234 if (trace_selftest_test_global_cnt == 0)
235 goto out;
236 }
237
238 DYN_FTRACE_TEST_NAME2();
239
240 print_counts();
241
242 if (trace_selftest_test_probe1_cnt != 1)
243 goto out;
244 if (trace_selftest_test_probe2_cnt != 1)
245 goto out;
246 if (trace_selftest_test_probe3_cnt != 2)
247 goto out;
248
249 /* Add a dynamic probe */
250 dyn_ops = kzalloc(sizeof(*dyn_ops), GFP_KERNEL);
251 if (!dyn_ops) {
252 printk("MEMORY ERROR ");
253 goto out;
254 }
255
256 dyn_ops->func = trace_selftest_test_dyn_func;
257
258 register_ftrace_function(dyn_ops);
259
260 trace_selftest_test_global_cnt = 0;
261
262 DYN_FTRACE_TEST_NAME();
263
264 print_counts();
265
266 if (trace_selftest_test_probe1_cnt != 2)
267 goto out_free;
268 if (trace_selftest_test_probe2_cnt != 1)
269 goto out_free;
270 if (trace_selftest_test_probe3_cnt != 3)
271 goto out_free;
272 if (cnt > 1) {
273 if (trace_selftest_test_global_cnt == 0)
274 goto out_free;
275 }
276 if (trace_selftest_test_dyn_cnt == 0)
277 goto out_free;
278
279 DYN_FTRACE_TEST_NAME2();
280
281 print_counts();
282
283 if (trace_selftest_test_probe1_cnt != 2)
284 goto out_free;
285 if (trace_selftest_test_probe2_cnt != 2)
286 goto out_free;
287 if (trace_selftest_test_probe3_cnt != 4)
288 goto out_free;
289
290 /* Remove trace function from probe 3 */
291 func1_name = "!" __stringify(DYN_FTRACE_TEST_NAME);
292 len1 = strlen(func1_name);
293
294 ftrace_set_filter(&test_probe3, func1_name, len1, 0);
295
296 DYN_FTRACE_TEST_NAME();
297
298 print_counts();
299
300 if (trace_selftest_test_probe1_cnt != 3)
301 goto out_free;
302 if (trace_selftest_test_probe2_cnt != 2)
303 goto out_free;
304 if (trace_selftest_test_probe3_cnt != 4)
305 goto out_free;
306 if (cnt > 1) {
307 if (trace_selftest_test_global_cnt == 0)
308 goto out_free;
309 }
310 if (trace_selftest_test_dyn_cnt == 0)
311 goto out_free;
312
313 DYN_FTRACE_TEST_NAME2();
314
315 print_counts();
316
317 if (trace_selftest_test_probe1_cnt != 3)
318 goto out_free;
319 if (trace_selftest_test_probe2_cnt != 3)
320 goto out_free;
321 if (trace_selftest_test_probe3_cnt != 5)
322 goto out_free;
323
324 ret = 0;
325 out_free:
326 unregister_ftrace_function(dyn_ops);
327 kfree(dyn_ops);
328
329 out:
330 /* Purposely unregister in the same order */
331 unregister_ftrace_function(&test_probe1);
332 unregister_ftrace_function(&test_probe2);
333 unregister_ftrace_function(&test_probe3);
334 if (cnt > 1)
335 unregister_ftrace_function(tr->ops);
336 ftrace_reset_array_ops(tr);
337
338 /* Make sure everything is off */
339 reset_counts();
340 DYN_FTRACE_TEST_NAME();
341 DYN_FTRACE_TEST_NAME();
342
343 if (trace_selftest_test_probe1_cnt ||
344 trace_selftest_test_probe2_cnt ||
345 trace_selftest_test_probe3_cnt ||
346 trace_selftest_test_global_cnt ||
347 trace_selftest_test_dyn_cnt)
348 ret = -1;
349
350 ftrace_enabled = save_ftrace_enabled;
351
352 return ret;
353 }
354
355 /* Test dynamic code modification and ftrace filters */
trace_selftest_startup_dynamic_tracing(struct tracer * trace,struct trace_array * tr,int (* func)(void))356 static int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
357 struct trace_array *tr,
358 int (*func)(void))
359 {
360 int save_ftrace_enabled = ftrace_enabled;
361 unsigned long count;
362 char *func_name;
363 int ret;
364
365 /* The ftrace test PASSED */
366 printk(KERN_CONT "PASSED\n");
367 pr_info("Testing dynamic ftrace: ");
368
369 /* enable tracing, and record the filter function */
370 ftrace_enabled = 1;
371
372 /* passed in by parameter to fool gcc from optimizing */
373 func();
374
375 /*
376 * Some archs *cough*PowerPC*cough* add characters to the
377 * start of the function names. We simply put a '*' to
378 * accommodate them.
379 */
380 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
381
382 /* filter only on our function */
383 ftrace_set_global_filter(func_name, strlen(func_name), 1);
384
385 /* enable tracing */
386 ret = tracer_init(trace, tr);
387 if (ret) {
388 warn_failed_init_tracer(trace, ret);
389 goto out;
390 }
391
392 /* Sleep for a 1/10 of a second */
393 msleep(100);
394
395 /* we should have nothing in the buffer */
396 ret = trace_test_buffer(&tr->array_buffer, &count);
397 if (ret)
398 goto out;
399
400 if (count) {
401 ret = -1;
402 printk(KERN_CONT ".. filter did not filter .. ");
403 goto out;
404 }
405
406 /* call our function again */
407 func();
408
409 /* sleep again */
410 msleep(100);
411
412 /* stop the tracing. */
413 tracing_stop();
414 ftrace_enabled = 0;
415
416 /* check the trace buffer */
417 ret = trace_test_buffer(&tr->array_buffer, &count);
418
419 ftrace_enabled = 1;
420 tracing_start();
421
422 /* we should only have one item */
423 if (!ret && count != 1) {
424 trace->reset(tr);
425 printk(KERN_CONT ".. filter failed count=%ld ..", count);
426 ret = -1;
427 goto out;
428 }
429
430 /* Test the ops with global tracing running */
431 ret = trace_selftest_ops(tr, 1);
432 trace->reset(tr);
433
434 out:
435 ftrace_enabled = save_ftrace_enabled;
436
437 /* Enable tracing on all functions again */
438 ftrace_set_global_filter(NULL, 0, 1);
439
440 /* Test the ops with global tracing off */
441 if (!ret)
442 ret = trace_selftest_ops(tr, 2);
443
444 return ret;
445 }
446
447 static int trace_selftest_recursion_cnt;
trace_selftest_test_recursion_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct ftrace_regs * fregs)448 static void trace_selftest_test_recursion_func(unsigned long ip,
449 unsigned long pip,
450 struct ftrace_ops *op,
451 struct ftrace_regs *fregs)
452 {
453 /*
454 * This function is registered without the recursion safe flag.
455 * The ftrace infrastructure should provide the recursion
456 * protection. If not, this will crash the kernel!
457 */
458 if (trace_selftest_recursion_cnt++ > 10)
459 return;
460 DYN_FTRACE_TEST_NAME();
461 }
462
trace_selftest_test_recursion_safe_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct ftrace_regs * fregs)463 static void trace_selftest_test_recursion_safe_func(unsigned long ip,
464 unsigned long pip,
465 struct ftrace_ops *op,
466 struct ftrace_regs *fregs)
467 {
468 /*
469 * We said we would provide our own recursion. By calling
470 * this function again, we should recurse back into this function
471 * and count again. But this only happens if the arch supports
472 * all of ftrace features and nothing else is using the function
473 * tracing utility.
474 */
475 if (trace_selftest_recursion_cnt++)
476 return;
477 DYN_FTRACE_TEST_NAME();
478 }
479
480 static struct ftrace_ops test_rec_probe = {
481 .func = trace_selftest_test_recursion_func,
482 .flags = FTRACE_OPS_FL_RECURSION,
483 };
484
485 static struct ftrace_ops test_recsafe_probe = {
486 .func = trace_selftest_test_recursion_safe_func,
487 };
488
489 static int
trace_selftest_function_recursion(void)490 trace_selftest_function_recursion(void)
491 {
492 int save_ftrace_enabled = ftrace_enabled;
493 char *func_name;
494 int len;
495 int ret;
496
497 /* The previous test PASSED */
498 pr_cont("PASSED\n");
499 pr_info("Testing ftrace recursion: ");
500
501
502 /* enable tracing, and record the filter function */
503 ftrace_enabled = 1;
504
505 /* Handle PPC64 '.' name */
506 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
507 len = strlen(func_name);
508
509 ret = ftrace_set_filter(&test_rec_probe, func_name, len, 1);
510 if (ret) {
511 pr_cont("*Could not set filter* ");
512 goto out;
513 }
514
515 ret = register_ftrace_function(&test_rec_probe);
516 if (ret) {
517 pr_cont("*could not register callback* ");
518 goto out;
519 }
520
521 DYN_FTRACE_TEST_NAME();
522
523 unregister_ftrace_function(&test_rec_probe);
524
525 ret = -1;
526 /*
527 * Recursion allows for transitions between context,
528 * and may call the callback twice.
529 */
530 if (trace_selftest_recursion_cnt != 1 &&
531 trace_selftest_recursion_cnt != 2) {
532 pr_cont("*callback not called once (or twice) (%d)* ",
533 trace_selftest_recursion_cnt);
534 goto out;
535 }
536
537 trace_selftest_recursion_cnt = 1;
538
539 pr_cont("PASSED\n");
540 pr_info("Testing ftrace recursion safe: ");
541
542 ret = ftrace_set_filter(&test_recsafe_probe, func_name, len, 1);
543 if (ret) {
544 pr_cont("*Could not set filter* ");
545 goto out;
546 }
547
548 ret = register_ftrace_function(&test_recsafe_probe);
549 if (ret) {
550 pr_cont("*could not register callback* ");
551 goto out;
552 }
553
554 DYN_FTRACE_TEST_NAME();
555
556 unregister_ftrace_function(&test_recsafe_probe);
557
558 ret = -1;
559 if (trace_selftest_recursion_cnt != 2) {
560 pr_cont("*callback not called expected 2 times (%d)* ",
561 trace_selftest_recursion_cnt);
562 goto out;
563 }
564
565 ret = 0;
566 out:
567 ftrace_enabled = save_ftrace_enabled;
568
569 return ret;
570 }
571 #else
572 # define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; })
573 # define trace_selftest_function_recursion() ({ 0; })
574 #endif /* CONFIG_DYNAMIC_FTRACE */
575
576 static enum {
577 TRACE_SELFTEST_REGS_START,
578 TRACE_SELFTEST_REGS_FOUND,
579 TRACE_SELFTEST_REGS_NOT_FOUND,
580 } trace_selftest_regs_stat;
581
trace_selftest_test_regs_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct ftrace_regs * fregs)582 static void trace_selftest_test_regs_func(unsigned long ip,
583 unsigned long pip,
584 struct ftrace_ops *op,
585 struct ftrace_regs *fregs)
586 {
587 struct pt_regs *regs = ftrace_get_regs(fregs);
588
589 if (regs)
590 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND;
591 else
592 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND;
593 }
594
595 static struct ftrace_ops test_regs_probe = {
596 .func = trace_selftest_test_regs_func,
597 .flags = FTRACE_OPS_FL_SAVE_REGS,
598 };
599
600 static int
trace_selftest_function_regs(void)601 trace_selftest_function_regs(void)
602 {
603 int save_ftrace_enabled = ftrace_enabled;
604 char *func_name;
605 int len;
606 int ret;
607 int supported = 0;
608
609 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
610 supported = 1;
611 #endif
612
613 /* The previous test PASSED */
614 pr_cont("PASSED\n");
615 pr_info("Testing ftrace regs%s: ",
616 !supported ? "(no arch support)" : "");
617
618 /* enable tracing, and record the filter function */
619 ftrace_enabled = 1;
620
621 /* Handle PPC64 '.' name */
622 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
623 len = strlen(func_name);
624
625 ret = ftrace_set_filter(&test_regs_probe, func_name, len, 1);
626 /*
627 * If DYNAMIC_FTRACE is not set, then we just trace all functions.
628 * This test really doesn't care.
629 */
630 if (ret && ret != -ENODEV) {
631 pr_cont("*Could not set filter* ");
632 goto out;
633 }
634
635 ret = register_ftrace_function(&test_regs_probe);
636 /*
637 * Now if the arch does not support passing regs, then this should
638 * have failed.
639 */
640 if (!supported) {
641 if (!ret) {
642 pr_cont("*registered save-regs without arch support* ");
643 goto out;
644 }
645 test_regs_probe.flags |= FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED;
646 ret = register_ftrace_function(&test_regs_probe);
647 }
648 if (ret) {
649 pr_cont("*could not register callback* ");
650 goto out;
651 }
652
653
654 DYN_FTRACE_TEST_NAME();
655
656 unregister_ftrace_function(&test_regs_probe);
657
658 ret = -1;
659
660 switch (trace_selftest_regs_stat) {
661 case TRACE_SELFTEST_REGS_START:
662 pr_cont("*callback never called* ");
663 goto out;
664
665 case TRACE_SELFTEST_REGS_FOUND:
666 if (supported)
667 break;
668 pr_cont("*callback received regs without arch support* ");
669 goto out;
670
671 case TRACE_SELFTEST_REGS_NOT_FOUND:
672 if (!supported)
673 break;
674 pr_cont("*callback received NULL regs* ");
675 goto out;
676 }
677
678 ret = 0;
679 out:
680 ftrace_enabled = save_ftrace_enabled;
681
682 return ret;
683 }
684
685 /*
686 * Simple verification test of ftrace function tracer.
687 * Enable ftrace, sleep 1/10 second, and then read the trace
688 * buffer to see if all is in order.
689 */
690 __init int
trace_selftest_startup_function(struct tracer * trace,struct trace_array * tr)691 trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
692 {
693 int save_ftrace_enabled = ftrace_enabled;
694 unsigned long count;
695 int ret;
696
697 #ifdef CONFIG_DYNAMIC_FTRACE
698 if (ftrace_filter_param) {
699 printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
700 return 0;
701 }
702 #endif
703
704 /* make sure msleep has been recorded */
705 msleep(1);
706
707 /* start the tracing */
708 ftrace_enabled = 1;
709
710 ret = tracer_init(trace, tr);
711 if (ret) {
712 warn_failed_init_tracer(trace, ret);
713 goto out;
714 }
715
716 /* Sleep for a 1/10 of a second */
717 msleep(100);
718 /* stop the tracing. */
719 tracing_stop();
720 ftrace_enabled = 0;
721
722 /* check the trace buffer */
723 ret = trace_test_buffer(&tr->array_buffer, &count);
724
725 ftrace_enabled = 1;
726 trace->reset(tr);
727 tracing_start();
728
729 if (!ret && !count) {
730 printk(KERN_CONT ".. no entries found ..");
731 ret = -1;
732 goto out;
733 }
734
735 ret = trace_selftest_startup_dynamic_tracing(trace, tr,
736 DYN_FTRACE_TEST_NAME);
737 if (ret)
738 goto out;
739
740 ret = trace_selftest_function_recursion();
741 if (ret)
742 goto out;
743
744 ret = trace_selftest_function_regs();
745 out:
746 ftrace_enabled = save_ftrace_enabled;
747
748 /* kill ftrace totally if we failed */
749 if (ret)
750 ftrace_kill();
751
752 return ret;
753 }
754 #endif /* CONFIG_FUNCTION_TRACER */
755
756
757 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
758
759 /* Maximum number of functions to trace before diagnosing a hang */
760 #define GRAPH_MAX_FUNC_TEST 100000000
761
762 static unsigned int graph_hang_thresh;
763
764 /* Wrap the real function entry probe to avoid possible hanging */
trace_graph_entry_watchdog(struct ftrace_graph_ent * trace)765 static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
766 {
767 /* This is harmlessly racy, we want to approximately detect a hang */
768 if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) {
769 ftrace_graph_stop();
770 printk(KERN_WARNING "BUG: Function graph tracer hang!\n");
771 if (ftrace_dump_on_oops) {
772 ftrace_dump(DUMP_ALL);
773 /* ftrace_dump() disables tracing */
774 tracing_on();
775 }
776 return 0;
777 }
778
779 return trace_graph_entry(trace);
780 }
781
782 static struct fgraph_ops fgraph_ops __initdata = {
783 .entryfunc = &trace_graph_entry_watchdog,
784 .retfunc = &trace_graph_return,
785 };
786
787 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
788 static struct ftrace_ops direct;
789 #endif
790
791 /*
792 * Pretty much the same than for the function tracer from which the selftest
793 * has been borrowed.
794 */
795 __init int
trace_selftest_startup_function_graph(struct tracer * trace,struct trace_array * tr)796 trace_selftest_startup_function_graph(struct tracer *trace,
797 struct trace_array *tr)
798 {
799 int ret;
800 unsigned long count;
801 char *func_name __maybe_unused;
802
803 #ifdef CONFIG_DYNAMIC_FTRACE
804 if (ftrace_filter_param) {
805 printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
806 return 0;
807 }
808 #endif
809
810 /*
811 * Simulate the init() callback but we attach a watchdog callback
812 * to detect and recover from possible hangs
813 */
814 tracing_reset_online_cpus(&tr->array_buffer);
815 set_graph_array(tr);
816 ret = register_ftrace_graph(&fgraph_ops);
817 if (ret) {
818 warn_failed_init_tracer(trace, ret);
819 goto out;
820 }
821 tracing_start_cmdline_record();
822
823 /* Sleep for a 1/10 of a second */
824 msleep(100);
825
826 /* Have we just recovered from a hang? */
827 if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) {
828 disable_tracing_selftest("recovering from a hang");
829 ret = -1;
830 goto out;
831 }
832
833 tracing_stop();
834
835 /* check the trace buffer */
836 ret = trace_test_buffer(&tr->array_buffer, &count);
837
838 /* Need to also simulate the tr->reset to remove this fgraph_ops */
839 tracing_stop_cmdline_record();
840 unregister_ftrace_graph(&fgraph_ops);
841
842 tracing_start();
843
844 if (!ret && !count) {
845 printk(KERN_CONT ".. no entries found ..");
846 ret = -1;
847 goto out;
848 }
849
850 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
851 /*
852 * These tests can take some time to run. Make sure on non PREEMPT
853 * kernels, we do not trigger the softlockup detector.
854 */
855 cond_resched();
856
857 tracing_reset_online_cpus(&tr->array_buffer);
858 set_graph_array(tr);
859
860 /*
861 * Some archs *cough*PowerPC*cough* add characters to the
862 * start of the function names. We simply put a '*' to
863 * accommodate them.
864 */
865 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
866 ftrace_set_global_filter(func_name, strlen(func_name), 1);
867
868 /*
869 * Register direct function together with graph tracer
870 * and make sure we get graph trace.
871 */
872 ftrace_set_filter_ip(&direct, (unsigned long)DYN_FTRACE_TEST_NAME, 0, 0);
873 ret = register_ftrace_direct(&direct,
874 (unsigned long)ftrace_stub_direct_tramp);
875 if (ret)
876 goto out;
877
878 cond_resched();
879
880 ret = register_ftrace_graph(&fgraph_ops);
881 if (ret) {
882 warn_failed_init_tracer(trace, ret);
883 goto out;
884 }
885
886 DYN_FTRACE_TEST_NAME();
887
888 count = 0;
889
890 tracing_stop();
891 /* check the trace buffer */
892 ret = trace_test_buffer(&tr->array_buffer, &count);
893
894 unregister_ftrace_graph(&fgraph_ops);
895
896 ret = unregister_ftrace_direct(&direct,
897 (unsigned long)ftrace_stub_direct_tramp,
898 true);
899 if (ret)
900 goto out;
901
902 cond_resched();
903
904 tracing_start();
905
906 if (!ret && !count) {
907 ret = -1;
908 goto out;
909 }
910
911 /* Enable tracing on all functions again */
912 ftrace_set_global_filter(NULL, 0, 1);
913 #endif
914
915 /* Don't test dynamic tracing, the function tracer already did */
916 out:
917 /* Stop it if we failed */
918 if (ret)
919 ftrace_graph_stop();
920
921 return ret;
922 }
923 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
924
925
926 #ifdef CONFIG_IRQSOFF_TRACER
927 int
trace_selftest_startup_irqsoff(struct tracer * trace,struct trace_array * tr)928 trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
929 {
930 unsigned long save_max = tr->max_latency;
931 unsigned long count;
932 int ret;
933
934 /* start the tracing */
935 ret = tracer_init(trace, tr);
936 if (ret) {
937 warn_failed_init_tracer(trace, ret);
938 return ret;
939 }
940
941 /* reset the max latency */
942 tr->max_latency = 0;
943 /* disable interrupts for a bit */
944 local_irq_disable();
945 udelay(100);
946 local_irq_enable();
947
948 /*
949 * Stop the tracer to avoid a warning subsequent
950 * to buffer flipping failure because tracing_stop()
951 * disables the tr and max buffers, making flipping impossible
952 * in case of parallels max irqs off latencies.
953 */
954 trace->stop(tr);
955 /* stop the tracing. */
956 tracing_stop();
957 /* check both trace buffers */
958 ret = trace_test_buffer(&tr->array_buffer, NULL);
959 if (!ret)
960 ret = trace_test_buffer(&tr->max_buffer, &count);
961 trace->reset(tr);
962 tracing_start();
963
964 if (!ret && !count) {
965 printk(KERN_CONT ".. no entries found ..");
966 ret = -1;
967 }
968
969 tr->max_latency = save_max;
970
971 return ret;
972 }
973 #endif /* CONFIG_IRQSOFF_TRACER */
974
975 #ifdef CONFIG_PREEMPT_TRACER
976 int
trace_selftest_startup_preemptoff(struct tracer * trace,struct trace_array * tr)977 trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
978 {
979 unsigned long save_max = tr->max_latency;
980 unsigned long count;
981 int ret;
982
983 /*
984 * Now that the big kernel lock is no longer preemptible,
985 * and this is called with the BKL held, it will always
986 * fail. If preemption is already disabled, simply
987 * pass the test. When the BKL is removed, or becomes
988 * preemptible again, we will once again test this,
989 * so keep it in.
990 */
991 if (preempt_count()) {
992 printk(KERN_CONT "can not test ... force ");
993 return 0;
994 }
995
996 /* start the tracing */
997 ret = tracer_init(trace, tr);
998 if (ret) {
999 warn_failed_init_tracer(trace, ret);
1000 return ret;
1001 }
1002
1003 /* reset the max latency */
1004 tr->max_latency = 0;
1005 /* disable preemption for a bit */
1006 preempt_disable();
1007 udelay(100);
1008 preempt_enable();
1009
1010 /*
1011 * Stop the tracer to avoid a warning subsequent
1012 * to buffer flipping failure because tracing_stop()
1013 * disables the tr and max buffers, making flipping impossible
1014 * in case of parallels max preempt off latencies.
1015 */
1016 trace->stop(tr);
1017 /* stop the tracing. */
1018 tracing_stop();
1019 /* check both trace buffers */
1020 ret = trace_test_buffer(&tr->array_buffer, NULL);
1021 if (!ret)
1022 ret = trace_test_buffer(&tr->max_buffer, &count);
1023 trace->reset(tr);
1024 tracing_start();
1025
1026 if (!ret && !count) {
1027 printk(KERN_CONT ".. no entries found ..");
1028 ret = -1;
1029 }
1030
1031 tr->max_latency = save_max;
1032
1033 return ret;
1034 }
1035 #endif /* CONFIG_PREEMPT_TRACER */
1036
1037 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
1038 int
trace_selftest_startup_preemptirqsoff(struct tracer * trace,struct trace_array * tr)1039 trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
1040 {
1041 unsigned long save_max = tr->max_latency;
1042 unsigned long count;
1043 int ret;
1044
1045 /*
1046 * Now that the big kernel lock is no longer preemptible,
1047 * and this is called with the BKL held, it will always
1048 * fail. If preemption is already disabled, simply
1049 * pass the test. When the BKL is removed, or becomes
1050 * preemptible again, we will once again test this,
1051 * so keep it in.
1052 */
1053 if (preempt_count()) {
1054 printk(KERN_CONT "can not test ... force ");
1055 return 0;
1056 }
1057
1058 /* start the tracing */
1059 ret = tracer_init(trace, tr);
1060 if (ret) {
1061 warn_failed_init_tracer(trace, ret);
1062 goto out_no_start;
1063 }
1064
1065 /* reset the max latency */
1066 tr->max_latency = 0;
1067
1068 /* disable preemption and interrupts for a bit */
1069 preempt_disable();
1070 local_irq_disable();
1071 udelay(100);
1072 preempt_enable();
1073 /* reverse the order of preempt vs irqs */
1074 local_irq_enable();
1075
1076 /*
1077 * Stop the tracer to avoid a warning subsequent
1078 * to buffer flipping failure because tracing_stop()
1079 * disables the tr and max buffers, making flipping impossible
1080 * in case of parallels max irqs/preempt off latencies.
1081 */
1082 trace->stop(tr);
1083 /* stop the tracing. */
1084 tracing_stop();
1085 /* check both trace buffers */
1086 ret = trace_test_buffer(&tr->array_buffer, NULL);
1087 if (ret)
1088 goto out;
1089
1090 ret = trace_test_buffer(&tr->max_buffer, &count);
1091 if (ret)
1092 goto out;
1093
1094 if (!ret && !count) {
1095 printk(KERN_CONT ".. no entries found ..");
1096 ret = -1;
1097 goto out;
1098 }
1099
1100 /* do the test by disabling interrupts first this time */
1101 tr->max_latency = 0;
1102 tracing_start();
1103 trace->start(tr);
1104
1105 preempt_disable();
1106 local_irq_disable();
1107 udelay(100);
1108 preempt_enable();
1109 /* reverse the order of preempt vs irqs */
1110 local_irq_enable();
1111
1112 trace->stop(tr);
1113 /* stop the tracing. */
1114 tracing_stop();
1115 /* check both trace buffers */
1116 ret = trace_test_buffer(&tr->array_buffer, NULL);
1117 if (ret)
1118 goto out;
1119
1120 ret = trace_test_buffer(&tr->max_buffer, &count);
1121
1122 if (!ret && !count) {
1123 printk(KERN_CONT ".. no entries found ..");
1124 ret = -1;
1125 goto out;
1126 }
1127
1128 out:
1129 tracing_start();
1130 out_no_start:
1131 trace->reset(tr);
1132 tr->max_latency = save_max;
1133
1134 return ret;
1135 }
1136 #endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
1137
1138 #ifdef CONFIG_NOP_TRACER
1139 int
trace_selftest_startup_nop(struct tracer * trace,struct trace_array * tr)1140 trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
1141 {
1142 /* What could possibly go wrong? */
1143 return 0;
1144 }
1145 #endif
1146
1147 #ifdef CONFIG_SCHED_TRACER
1148
1149 struct wakeup_test_data {
1150 struct completion is_ready;
1151 int go;
1152 };
1153
trace_wakeup_test_thread(void * data)1154 static int trace_wakeup_test_thread(void *data)
1155 {
1156 /* Make this a -deadline thread */
1157 static const struct sched_attr attr = {
1158 .sched_policy = SCHED_DEADLINE,
1159 .sched_runtime = 100000ULL,
1160 .sched_deadline = 10000000ULL,
1161 .sched_period = 10000000ULL
1162 };
1163 struct wakeup_test_data *x = data;
1164
1165 sched_setattr(current, &attr);
1166
1167 /* Make it know we have a new prio */
1168 complete(&x->is_ready);
1169
1170 /* now go to sleep and let the test wake us up */
1171 set_current_state(TASK_INTERRUPTIBLE);
1172 while (!x->go) {
1173 schedule();
1174 set_current_state(TASK_INTERRUPTIBLE);
1175 }
1176
1177 complete(&x->is_ready);
1178
1179 set_current_state(TASK_INTERRUPTIBLE);
1180
1181 /* we are awake, now wait to disappear */
1182 while (!kthread_should_stop()) {
1183 schedule();
1184 set_current_state(TASK_INTERRUPTIBLE);
1185 }
1186
1187 __set_current_state(TASK_RUNNING);
1188
1189 return 0;
1190 }
1191 int
trace_selftest_startup_wakeup(struct tracer * trace,struct trace_array * tr)1192 trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
1193 {
1194 unsigned long save_max = tr->max_latency;
1195 struct task_struct *p;
1196 struct wakeup_test_data data;
1197 unsigned long count;
1198 int ret;
1199
1200 memset(&data, 0, sizeof(data));
1201
1202 init_completion(&data.is_ready);
1203
1204 /* create a -deadline thread */
1205 p = kthread_run(trace_wakeup_test_thread, &data, "ftrace-test");
1206 if (IS_ERR(p)) {
1207 printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
1208 return -1;
1209 }
1210
1211 /* make sure the thread is running at -deadline policy */
1212 wait_for_completion(&data.is_ready);
1213
1214 /* start the tracing */
1215 ret = tracer_init(trace, tr);
1216 if (ret) {
1217 warn_failed_init_tracer(trace, ret);
1218 return ret;
1219 }
1220
1221 /* reset the max latency */
1222 tr->max_latency = 0;
1223
1224 while (p->on_rq) {
1225 /*
1226 * Sleep to make sure the -deadline thread is asleep too.
1227 * On virtual machines we can't rely on timings,
1228 * but we want to make sure this test still works.
1229 */
1230 msleep(100);
1231 }
1232
1233 init_completion(&data.is_ready);
1234
1235 data.go = 1;
1236 /* memory barrier is in the wake_up_process() */
1237
1238 wake_up_process(p);
1239
1240 /* Wait for the task to wake up */
1241 wait_for_completion(&data.is_ready);
1242
1243 /* stop the tracing. */
1244 tracing_stop();
1245 /* check both trace buffers */
1246 ret = trace_test_buffer(&tr->array_buffer, NULL);
1247 if (!ret)
1248 ret = trace_test_buffer(&tr->max_buffer, &count);
1249
1250
1251 trace->reset(tr);
1252 tracing_start();
1253
1254 tr->max_latency = save_max;
1255
1256 /* kill the thread */
1257 kthread_stop(p);
1258
1259 if (!ret && !count) {
1260 printk(KERN_CONT ".. no entries found ..");
1261 ret = -1;
1262 }
1263
1264 return ret;
1265 }
1266 #endif /* CONFIG_SCHED_TRACER */
1267
1268 #ifdef CONFIG_BRANCH_TRACER
1269 int
trace_selftest_startup_branch(struct tracer * trace,struct trace_array * tr)1270 trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
1271 {
1272 unsigned long count;
1273 int ret;
1274
1275 /* start the tracing */
1276 ret = tracer_init(trace, tr);
1277 if (ret) {
1278 warn_failed_init_tracer(trace, ret);
1279 return ret;
1280 }
1281
1282 /* Sleep for a 1/10 of a second */
1283 msleep(100);
1284 /* stop the tracing. */
1285 tracing_stop();
1286 /* check the trace buffer */
1287 ret = trace_test_buffer(&tr->array_buffer, &count);
1288 trace->reset(tr);
1289 tracing_start();
1290
1291 if (!ret && !count) {
1292 printk(KERN_CONT ".. no entries found ..");
1293 ret = -1;
1294 }
1295
1296 return ret;
1297 }
1298 #endif /* CONFIG_BRANCH_TRACER */
1299
1300