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