kernel/trace/trace_selftest.c

   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
  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
  26 static 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  */
  63 static 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
  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;
 107 static 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
 115 static int trace_selftest_test_probe2_cnt;
 116 static 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
 124 static int trace_selftest_test_probe3_cnt;
 125 static 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
 133 static int trace_selftest_test_global_cnt;
 134 static 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
 142 static int trace_selftest_test_dyn_cnt;
 143 static 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
 151 static struct ftrace_ops test_probe1 = {
 152         .func                   = trace_selftest_test_probe1_func,
 153         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 154 };
 155
 156 static struct ftrace_ops test_probe2 = {
 157         .func                   = trace_selftest_test_probe2_func,
 158         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 159 };
 160
 161 static struct ftrace_ops test_probe3 = {
 162         .func                   = trace_selftest_test_probe3_func,
 163         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 164 };
 165
 166 static 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
 176 static 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
 185 static 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 */
 325 static 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
 416 static int trace_selftest_recursion_cnt;
 417 static 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
 432 static 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
 449 static struct ftrace_ops test_rec_probe = {
 450         .func                   = trace_selftest_test_recursion_func,
 451 };
 452
 453 static struct ftrace_ops test_recsafe_probe = {
 454         .func                   = trace_selftest_test_recursion_safe_func,
 455         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 456 };
 457
 458 static int
 459 trace_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;
 530 out:
 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
 540 static enum {
 541         TRACE_SELFTEST_REGS_START,
 542         TRACE_SELFTEST_REGS_FOUND,
 543         TRACE_SELFTEST_REGS_NOT_FOUND,
 544 } trace_selftest_regs_stat;
 545
 546 static 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
 557 static 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
 562 static int
 563 trace_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;
 641 out:
 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
 653 trace_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
 724 static unsigned int graph_hang_thresh;
 725
 726 /* Wrap the real function entry probe to avoid possible hanging */
 727 static 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
 749 trace_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
 802 out:
 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
 813 int
 814 trace_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
 862 int
 863 trace_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)
 924 int
 925 trace_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
1014 out:
1015         tracing_start();
1016 out_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
1025 int
1026 trace_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
1035 struct wakeup_test_data {
1036         struct completion       is_ready;
1037         int                     go;
1038 };
1039
1040 static 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 }
1077 int
1078 trace_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
1155 int
1156 trace_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