kernel/trace/trace_selftest.c

   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
   8 static 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
  24 static 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  */
  61 static 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
  95 static 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
 104 static int trace_selftest_test_probe1_cnt;
 105 static void trace_selftest_test_probe1_func(unsigned long ip,
 106                                             unsigned long pip,
 107                                             struct ftrace_ops *op,
 108                                             struct pt_regs *pt_regs)
 109 {
 110         trace_selftest_test_probe1_cnt++;
 111 }
 112
 113 static int trace_selftest_test_probe2_cnt;
 114 static void trace_selftest_test_probe2_func(unsigned long ip,
 115                                             unsigned long pip,
 116                                             struct ftrace_ops *op,
 117                                             struct pt_regs *pt_regs)
 118 {
 119         trace_selftest_test_probe2_cnt++;
 120 }
 121
 122 static int trace_selftest_test_probe3_cnt;
 123 static void trace_selftest_test_probe3_func(unsigned long ip,
 124                                             unsigned long pip,
 125                                             struct ftrace_ops *op,
 126                                             struct pt_regs *pt_regs)
 127 {
 128         trace_selftest_test_probe3_cnt++;
 129 }
 130
 131 static int trace_selftest_test_global_cnt;
 132 static void trace_selftest_test_global_func(unsigned long ip,
 133                                             unsigned long pip,
 134                                             struct ftrace_ops *op,
 135                                             struct pt_regs *pt_regs)
 136 {
 137         trace_selftest_test_global_cnt++;
 138 }
 139
 140 static int trace_selftest_test_dyn_cnt;
 141 static void trace_selftest_test_dyn_func(unsigned long ip,
 142                                          unsigned long pip,
 143                                          struct ftrace_ops *op,
 144                                          struct pt_regs *pt_regs)
 145 {
 146         trace_selftest_test_dyn_cnt++;
 147 }
 148
 149 static struct ftrace_ops test_probe1 = {
 150         .func                   = trace_selftest_test_probe1_func,
 151         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 152 };
 153
 154 static struct ftrace_ops test_probe2 = {
 155         .func                   = trace_selftest_test_probe2_func,
 156         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 157 };
 158
 159 static struct ftrace_ops test_probe3 = {
 160         .func                   = trace_selftest_test_probe3_func,
 161         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 162 };
 163
 164 static struct ftrace_ops test_global = {
 165         .func           = trace_selftest_test_global_func,
 166         .flags          = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,
 167 };
 168
 169 static void print_counts(void)
 170 {
 171         printk("(%d %d %d %d %d) ",
 172                trace_selftest_test_probe1_cnt,
 173                trace_selftest_test_probe2_cnt,
 174                trace_selftest_test_probe3_cnt,
 175                trace_selftest_test_global_cnt,
 176                trace_selftest_test_dyn_cnt);
 177 }
 178
 179 static void reset_counts(void)
 180 {
 181         trace_selftest_test_probe1_cnt = 0;
 182         trace_selftest_test_probe2_cnt = 0;
 183         trace_selftest_test_probe3_cnt = 0;
 184         trace_selftest_test_global_cnt = 0;
 185         trace_selftest_test_dyn_cnt = 0;
 186 }
 187
 188 static int trace_selftest_ops(int cnt)
 189 {
 190         int save_ftrace_enabled = ftrace_enabled;
 191         struct ftrace_ops *dyn_ops;
 192         char *func1_name;
 193         char *func2_name;
 194         int len1;
 195         int len2;
 196         int ret = -1;
 197
 198         printk(KERN_CONT "PASSED\n");
 199         pr_info("Testing dynamic ftrace ops #%d: ", cnt);
 200
 201         ftrace_enabled = 1;
 202         reset_counts();
 203
 204         /* Handle PPC64 '.' name */
 205         func1_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
 206         func2_name = "*" __stringify(DYN_FTRACE_TEST_NAME2);
 207         len1 = strlen(func1_name);
 208         len2 = strlen(func2_name);
 209
 210         /*
 211          * Probe 1 will trace function 1.
 212          * Probe 2 will trace function 2.
 213          * Probe 3 will trace functions 1 and 2.
 214          */
 215         ftrace_set_filter(&test_probe1, func1_name, len1, 1);
 216         ftrace_set_filter(&test_probe2, func2_name, len2, 1);
 217         ftrace_set_filter(&test_probe3, func1_name, len1, 1);
 218         ftrace_set_filter(&test_probe3, func2_name, len2, 0);
 219
 220         register_ftrace_function(&test_probe1);
 221         register_ftrace_function(&test_probe2);
 222         register_ftrace_function(&test_probe3);
 223         register_ftrace_function(&test_global);
 224
 225         DYN_FTRACE_TEST_NAME();
 226
 227         print_counts();
 228
 229         if (trace_selftest_test_probe1_cnt != 1)
 230                 goto out;
 231         if (trace_selftest_test_probe2_cnt != 0)
 232                 goto out;
 233         if (trace_selftest_test_probe3_cnt != 1)
 234                 goto out;
 235         if (trace_selftest_test_global_cnt == 0)
 236                 goto out;
 237
 238         DYN_FTRACE_TEST_NAME2();
 239
 240         print_counts();
 241
 242         if (trace_selftest_test_probe1_cnt != 1)
 243                 goto out;
 244         if (trace_selftest_test_probe2_cnt != 1)
 245                 goto out;
 246         if (trace_selftest_test_probe3_cnt != 2)
 247                 goto out;
 248
 249         /* Add a dynamic probe */
 250         dyn_ops = kzalloc(sizeof(*dyn_ops), GFP_KERNEL);
 251         if (!dyn_ops) {
 252                 printk("MEMORY ERROR ");
 253                 goto out;
 254         }
 255
 256         dyn_ops->func = trace_selftest_test_dyn_func;
 257
 258         register_ftrace_function(dyn_ops);
 259
 260         trace_selftest_test_global_cnt = 0;
 261
 262         DYN_FTRACE_TEST_NAME();
 263
 264         print_counts();
 265
 266         if (trace_selftest_test_probe1_cnt != 2)
 267                 goto out_free;
 268         if (trace_selftest_test_probe2_cnt != 1)
 269                 goto out_free;
 270         if (trace_selftest_test_probe3_cnt != 3)
 271                 goto out_free;
 272         if (trace_selftest_test_global_cnt == 0)
 273                 goto out;
 274         if (trace_selftest_test_dyn_cnt == 0)
 275                 goto out_free;
 276
 277         DYN_FTRACE_TEST_NAME2();
 278
 279         print_counts();
 280
 281         if (trace_selftest_test_probe1_cnt != 2)
 282                 goto out_free;
 283         if (trace_selftest_test_probe2_cnt != 2)
 284                 goto out_free;
 285         if (trace_selftest_test_probe3_cnt != 4)
 286                 goto out_free;
 287
 288         ret = 0;
 289  out_free:
 290         unregister_ftrace_function(dyn_ops);
 291         kfree(dyn_ops);
 292
 293  out:
 294         /* Purposely unregister in the same order */
 295         unregister_ftrace_function(&test_probe1);
 296         unregister_ftrace_function(&test_probe2);
 297         unregister_ftrace_function(&test_probe3);
 298         unregister_ftrace_function(&test_global);
 299
 300         /* Make sure everything is off */
 301         reset_counts();
 302         DYN_FTRACE_TEST_NAME();
 303         DYN_FTRACE_TEST_NAME();
 304
 305         if (trace_selftest_test_probe1_cnt ||
 306             trace_selftest_test_probe2_cnt ||
 307             trace_selftest_test_probe3_cnt ||
 308             trace_selftest_test_global_cnt ||
 309             trace_selftest_test_dyn_cnt)
 310                 ret = -1;
 311
 312         ftrace_enabled = save_ftrace_enabled;
 313
 314         return ret;
 315 }
 316
 317 /* Test dynamic code modification and ftrace filters */
 318 int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
 319                                            struct trace_array *tr,
 320                                            int (*func)(void))
 321 {
 322         int save_ftrace_enabled = ftrace_enabled;
 323         unsigned long count;
 324         char *func_name;
 325         int ret;
 326
 327         /* The ftrace test PASSED */
 328         printk(KERN_CONT "PASSED\n");
 329         pr_info("Testing dynamic ftrace: ");
 330
 331         /* enable tracing, and record the filter function */
 332         ftrace_enabled = 1;
 333
 334         /* passed in by parameter to fool gcc from optimizing */
 335         func();
 336
 337         /*
 338          * Some archs *cough*PowerPC*cough* add characters to the
 339          * start of the function names. We simply put a '*' to
 340          * accommodate them.
 341          */
 342         func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
 343
 344         /* filter only on our function */
 345         ftrace_set_global_filter(func_name, strlen(func_name), 1);
 346
 347         /* enable tracing */
 348         ret = tracer_init(trace, tr);
 349         if (ret) {
 350                 warn_failed_init_tracer(trace, ret);
 351                 goto out;
 352         }
 353
 354         /* Sleep for a 1/10 of a second */
 355         msleep(100);
 356
 357         /* we should have nothing in the buffer */
 358         ret = trace_test_buffer(tr, &count);
 359         if (ret)
 360                 goto out;
 361
 362         if (count) {
 363                 ret = -1;
 364                 printk(KERN_CONT ".. filter did not filter .. ");
 365                 goto out;
 366         }
 367
 368         /* call our function again */
 369         func();
 370
 371         /* sleep again */
 372         msleep(100);
 373
 374         /* stop the tracing. */
 375         tracing_stop();
 376         ftrace_enabled = 0;
 377
 378         /* check the trace buffer */
 379         ret = trace_test_buffer(tr, &count);
 380         tracing_start();
 381
 382         /* we should only have one item */
 383         if (!ret && count != 1) {
 384                 trace->reset(tr);
 385                 printk(KERN_CONT ".. filter failed count=%ld ..", count);
 386                 ret = -1;
 387                 goto out;
 388         }
 389
 390         /* Test the ops with global tracing running */
 391         ret = trace_selftest_ops(1);
 392         trace->reset(tr);
 393
 394  out:
 395         ftrace_enabled = save_ftrace_enabled;
 396
 397         /* Enable tracing on all functions again */
 398         ftrace_set_global_filter(NULL, 0, 1);
 399
 400         /* Test the ops with global tracing off */
 401         if (!ret)
 402                 ret = trace_selftest_ops(2);
 403
 404         return ret;
 405 }
 406
 407 static int trace_selftest_recursion_cnt;
 408 static void trace_selftest_test_recursion_func(unsigned long ip,
 409                                                unsigned long pip,
 410                                                struct ftrace_ops *op,
 411                                                struct pt_regs *pt_regs)
 412 {
 413         /*
 414          * This function is registered without the recursion safe flag.
 415          * The ftrace infrastructure should provide the recursion
 416          * protection. If not, this will crash the kernel!
 417          */
 418         trace_selftest_recursion_cnt++;
 419         DYN_FTRACE_TEST_NAME();
 420 }
 421
 422 static void trace_selftest_test_recursion_safe_func(unsigned long ip,
 423                                                     unsigned long pip,
 424                                                     struct ftrace_ops *op,
 425                                                     struct pt_regs *pt_regs)
 426 {
 427         /*
 428          * We said we would provide our own recursion. By calling
 429          * this function again, we should recurse back into this function
 430          * and count again. But this only happens if the arch supports
 431          * all of ftrace features and nothing else is using the function
 432          * tracing utility.
 433          */
 434         if (trace_selftest_recursion_cnt++)
 435                 return;
 436         DYN_FTRACE_TEST_NAME();
 437 }
 438
 439 static struct ftrace_ops test_rec_probe = {
 440         .func                   = trace_selftest_test_recursion_func,
 441 };
 442
 443 static struct ftrace_ops test_recsafe_probe = {
 444         .func                   = trace_selftest_test_recursion_safe_func,
 445         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 446 };
 447
 448 static int
 449 trace_selftest_function_recursion(void)
 450 {
 451         int save_ftrace_enabled = ftrace_enabled;
 452         char *func_name;
 453         int len;
 454         int ret;
 455         int cnt;
 456
 457         /* The previous test PASSED */
 458         pr_cont("PASSED\n");
 459         pr_info("Testing ftrace recursion: ");
 460
 461
 462         /* enable tracing, and record the filter function */
 463         ftrace_enabled = 1;
 464
 465         /* Handle PPC64 '.' name */
 466         func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
 467         len = strlen(func_name);
 468
 469         ret = ftrace_set_filter(&test_rec_probe, func_name, len, 1);
 470         if (ret) {
 471                 pr_cont("*Could not set filter* ");
 472                 goto out;
 473         }
 474
 475         ret = register_ftrace_function(&test_rec_probe);
 476         if (ret) {
 477                 pr_cont("*could not register callback* ");
 478                 goto out;
 479         }
 480
 481         DYN_FTRACE_TEST_NAME();
 482
 483         unregister_ftrace_function(&test_rec_probe);
 484
 485         ret = -1;
 486         if (trace_selftest_recursion_cnt != 1) {
 487                 pr_cont("*callback not called once (%d)* ",
 488                         trace_selftest_recursion_cnt);
 489                 goto out;
 490         }
 491
 492         trace_selftest_recursion_cnt = 1;
 493
 494         pr_cont("PASSED\n");
 495         pr_info("Testing ftrace recursion safe: ");
 496
 497         ret = ftrace_set_filter(&test_recsafe_probe, func_name, len, 1);
 498         if (ret) {
 499                 pr_cont("*Could not set filter* ");
 500                 goto out;
 501         }
 502
 503         ret = register_ftrace_function(&test_recsafe_probe);
 504         if (ret) {
 505                 pr_cont("*could not register callback* ");
 506                 goto out;
 507         }
 508
 509         DYN_FTRACE_TEST_NAME();
 510
 511         unregister_ftrace_function(&test_recsafe_probe);
 512
 513         /*
 514          * If arch supports all ftrace features, and no other task
 515          * was on the list, we should be fine.
 516          */
 517         if (!ftrace_nr_registered_ops() && !FTRACE_FORCE_LIST_FUNC)
 518                 cnt = 2; /* Should have recursed */
 519         else
 520                 cnt = 1;
 521
 522         ret = -1;
 523         if (trace_selftest_recursion_cnt != cnt) {
 524                 pr_cont("*callback not called expected %d times (%d)* ",
 525                         cnt, 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 ARCH_SUPPORTS_FTRACE_SAVE_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 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         /* make sure msleep has been recorded */
 660         msleep(1);
 661
 662         /* start the tracing */
 663         ftrace_enabled = 1;
 664
 665         ret = tracer_init(trace, tr);
 666         if (ret) {
 667                 warn_failed_init_tracer(trace, ret);
 668                 goto out;
 669         }
 670
 671         /* Sleep for a 1/10 of a second */
 672         msleep(100);
 673         /* stop the tracing. */
 674         tracing_stop();
 675         ftrace_enabled = 0;
 676
 677         /* check the trace buffer */
 678         ret = trace_test_buffer(tr, &count);
 679         trace->reset(tr);
 680         tracing_start();
 681
 682         if (!ret && !count) {
 683                 printk(KERN_CONT ".. no entries found ..");
 684                 ret = -1;
 685                 goto out;
 686         }
 687
 688         ret = trace_selftest_startup_dynamic_tracing(trace, tr,
 689                                                      DYN_FTRACE_TEST_NAME);
 690         if (ret)
 691                 goto out;
 692
 693         ret = trace_selftest_function_recursion();
 694         if (ret)
 695                 goto out;
 696
 697         ret = trace_selftest_function_regs();
 698  out:
 699         ftrace_enabled = save_ftrace_enabled;
 700
 701         /* kill ftrace totally if we failed */
 702         if (ret)
 703                 ftrace_kill();
 704
 705         return ret;
 706 }
 707 #endif /* CONFIG_FUNCTION_TRACER */
 708
 709
 710 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 711
 712 /* Maximum number of functions to trace before diagnosing a hang */
 713 #define GRAPH_MAX_FUNC_TEST     100000000
 714
 715 static void
 716 __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode);
 717 static unsigned int graph_hang_thresh;
 718
 719 /* Wrap the real function entry probe to avoid possible hanging */
 720 static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
 721 {
 722         /* This is harmlessly racy, we want to approximately detect a hang */
 723         if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) {
 724                 ftrace_graph_stop();
 725                 printk(KERN_WARNING "BUG: Function graph tracer hang!\n");
 726                 if (ftrace_dump_on_oops)
 727                         __ftrace_dump(false, DUMP_ALL);
 728                 return 0;
 729         }
 730
 731         return trace_graph_entry(trace);
 732 }
 733
 734 /*
 735  * Pretty much the same than for the function tracer from which the selftest
 736  * has been borrowed.
 737  */
 738 int
 739 trace_selftest_startup_function_graph(struct tracer *trace,
 740                                         struct trace_array *tr)
 741 {
 742         int ret;
 743         unsigned long count;
 744
 745         /*
 746          * Simulate the init() callback but we attach a watchdog callback
 747          * to detect and recover from possible hangs
 748          */
 749         tracing_reset_online_cpus(tr);
 750         set_graph_array(tr);
 751         ret = register_ftrace_graph(&trace_graph_return,
 752                                     &trace_graph_entry_watchdog);
 753         if (ret) {
 754                 warn_failed_init_tracer(trace, ret);
 755                 goto out;
 756         }
 757         tracing_start_cmdline_record();
 758
 759         /* Sleep for a 1/10 of a second */
 760         msleep(100);
 761
 762         /* Have we just recovered from a hang? */
 763         if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) {
 764                 tracing_selftest_disabled = true;
 765                 ret = -1;
 766                 goto out;
 767         }
 768
 769         tracing_stop();
 770
 771         /* check the trace buffer */
 772         ret = trace_test_buffer(tr, &count);
 773
 774         trace->reset(tr);
 775         tracing_start();
 776
 777         if (!ret && !count) {
 778                 printk(KERN_CONT ".. no entries found ..");
 779                 ret = -1;
 780                 goto out;
 781         }
 782
 783         /* Don't test dynamic tracing, the function tracer already did */
 784
 785 out:
 786         /* Stop it if we failed */
 787         if (ret)
 788                 ftrace_graph_stop();
 789
 790         return ret;
 791 }
 792 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 793
 794
 795 #ifdef CONFIG_IRQSOFF_TRACER
 796 int
 797 trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
 798 {
 799         unsigned long save_max = tracing_max_latency;
 800         unsigned long count;
 801         int ret;
 802
 803         /* start the tracing */
 804         ret = tracer_init(trace, tr);
 805         if (ret) {
 806                 warn_failed_init_tracer(trace, ret);
 807                 return ret;
 808         }
 809
 810         /* reset the max latency */
 811         tracing_max_latency = 0;
 812         /* disable interrupts for a bit */
 813         local_irq_disable();
 814         udelay(100);
 815         local_irq_enable();
 816
 817         /*
 818          * Stop the tracer to avoid a warning subsequent
 819          * to buffer flipping failure because tracing_stop()
 820          * disables the tr and max buffers, making flipping impossible
 821          * in case of parallels max irqs off latencies.
 822          */
 823         trace->stop(tr);
 824         /* stop the tracing. */
 825         tracing_stop();
 826         /* check both trace buffers */
 827         ret = trace_test_buffer(tr, NULL);
 828         if (!ret)
 829                 ret = trace_test_buffer(&max_tr, &count);
 830         trace->reset(tr);
 831         tracing_start();
 832
 833         if (!ret && !count) {
 834                 printk(KERN_CONT ".. no entries found ..");
 835                 ret = -1;
 836         }
 837
 838         tracing_max_latency = save_max;
 839
 840         return ret;
 841 }
 842 #endif /* CONFIG_IRQSOFF_TRACER */
 843
 844 #ifdef CONFIG_PREEMPT_TRACER
 845 int
 846 trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
 847 {
 848         unsigned long save_max = tracing_max_latency;
 849         unsigned long count;
 850         int ret;
 851
 852         /*
 853          * Now that the big kernel lock is no longer preemptable,
 854          * and this is called with the BKL held, it will always
 855          * fail. If preemption is already disabled, simply
 856          * pass the test. When the BKL is removed, or becomes
 857          * preemptible again, we will once again test this,
 858          * so keep it in.
 859          */
 860         if (preempt_count()) {
 861                 printk(KERN_CONT "can not test ... force ");
 862                 return 0;
 863         }
 864
 865         /* start the tracing */
 866         ret = tracer_init(trace, tr);
 867         if (ret) {
 868                 warn_failed_init_tracer(trace, ret);
 869                 return ret;
 870         }
 871
 872         /* reset the max latency */
 873         tracing_max_latency = 0;
 874         /* disable preemption for a bit */
 875         preempt_disable();
 876         udelay(100);
 877         preempt_enable();
 878
 879         /*
 880          * Stop the tracer to avoid a warning subsequent
 881          * to buffer flipping failure because tracing_stop()
 882          * disables the tr and max buffers, making flipping impossible
 883          * in case of parallels max preempt off latencies.
 884          */
 885         trace->stop(tr);
 886         /* stop the tracing. */
 887         tracing_stop();
 888         /* check both trace buffers */
 889         ret = trace_test_buffer(tr, NULL);
 890         if (!ret)
 891                 ret = trace_test_buffer(&max_tr, &count);
 892         trace->reset(tr);
 893         tracing_start();
 894
 895         if (!ret && !count) {
 896                 printk(KERN_CONT ".. no entries found ..");
 897                 ret = -1;
 898         }
 899
 900         tracing_max_latency = save_max;
 901
 902         return ret;
 903 }
 904 #endif /* CONFIG_PREEMPT_TRACER */
 905
 906 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 907 int
 908 trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
 909 {
 910         unsigned long save_max = tracing_max_latency;
 911         unsigned long count;
 912         int ret;
 913
 914         /*
 915          * Now that the big kernel lock is no longer preemptable,
 916          * and this is called with the BKL held, it will always
 917          * fail. If preemption is already disabled, simply
 918          * pass the test. When the BKL is removed, or becomes
 919          * preemptible again, we will once again test this,
 920          * so keep it in.
 921          */
 922         if (preempt_count()) {
 923                 printk(KERN_CONT "can not test ... force ");
 924                 return 0;
 925         }
 926
 927         /* start the tracing */
 928         ret = tracer_init(trace, tr);
 929         if (ret) {
 930                 warn_failed_init_tracer(trace, ret);
 931                 goto out_no_start;
 932         }
 933
 934         /* reset the max latency */
 935         tracing_max_latency = 0;
 936
 937         /* disable preemption and interrupts for a bit */
 938         preempt_disable();
 939         local_irq_disable();
 940         udelay(100);
 941         preempt_enable();
 942         /* reverse the order of preempt vs irqs */
 943         local_irq_enable();
 944
 945         /*
 946          * Stop the tracer to avoid a warning subsequent
 947          * to buffer flipping failure because tracing_stop()
 948          * disables the tr and max buffers, making flipping impossible
 949          * in case of parallels max irqs/preempt off latencies.
 950          */
 951         trace->stop(tr);
 952         /* stop the tracing. */
 953         tracing_stop();
 954         /* check both trace buffers */
 955         ret = trace_test_buffer(tr, NULL);
 956         if (ret)
 957                 goto out;
 958
 959         ret = trace_test_buffer(&max_tr, &count);
 960         if (ret)
 961                 goto out;
 962
 963         if (!ret && !count) {
 964                 printk(KERN_CONT ".. no entries found ..");
 965                 ret = -1;
 966                 goto out;
 967         }
 968
 969         /* do the test by disabling interrupts first this time */
 970         tracing_max_latency = 0;
 971         tracing_start();
 972         trace->start(tr);
 973
 974         preempt_disable();
 975         local_irq_disable();
 976         udelay(100);
 977         preempt_enable();
 978         /* reverse the order of preempt vs irqs */
 979         local_irq_enable();
 980
 981         trace->stop(tr);
 982         /* stop the tracing. */
 983         tracing_stop();
 984         /* check both trace buffers */
 985         ret = trace_test_buffer(tr, NULL);
 986         if (ret)
 987                 goto out;
 988
 989         ret = trace_test_buffer(&max_tr, &count);
 990
 991         if (!ret && !count) {
 992                 printk(KERN_CONT ".. no entries found ..");
 993                 ret = -1;
 994                 goto out;
 995         }
 996
 997 out:
 998         tracing_start();
 999 out_no_start:
1000         trace->reset(tr);
1001         tracing_max_latency = save_max;
1002
1003         return ret;
1004 }
1005 #endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
1006
1007 #ifdef CONFIG_NOP_TRACER
1008 int
1009 trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
1010 {
1011         /* What could possibly go wrong? */
1012         return 0;
1013 }
1014 #endif
1015
1016 #ifdef CONFIG_SCHED_TRACER
1017 static int trace_wakeup_test_thread(void *data)
1018 {
1019         /* Make this a RT thread, doesn't need to be too high */
1020         static const struct sched_param param = { .sched_priority = 5 };
1021         struct completion *x = data;
1022
1023         sched_setscheduler(current, SCHED_FIFO, &param);
1024
1025         /* Make it know we have a new prio */
1026         complete(x);
1027
1028         /* now go to sleep and let the test wake us up */
1029         set_current_state(TASK_INTERRUPTIBLE);
1030         schedule();
1031
1032         complete(x);
1033
1034         /* we are awake, now wait to disappear */
1035         while (!kthread_should_stop()) {
1036                 /*
1037                  * This is an RT task, do short sleeps to let
1038                  * others run.
1039                  */
1040                 msleep(100);
1041         }
1042
1043         return 0;
1044 }
1045
1046 int
1047 trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
1048 {
1049         unsigned long save_max = tracing_max_latency;
1050         struct task_struct *p;
1051         struct completion isrt;
1052         unsigned long count;
1053         int ret;
1054
1055         init_completion(&isrt);
1056
1057         /* create a high prio thread */
1058         p = kthread_run(trace_wakeup_test_thread, &isrt, "ftrace-test");
1059         if (IS_ERR(p)) {
1060                 printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
1061                 return -1;
1062         }
1063
1064         /* make sure the thread is running at an RT prio */
1065         wait_for_completion(&isrt);
1066
1067         /* start the tracing */
1068         ret = tracer_init(trace, tr);
1069         if (ret) {
1070                 warn_failed_init_tracer(trace, ret);
1071                 return ret;
1072         }
1073
1074         /* reset the max latency */
1075         tracing_max_latency = 0;
1076
1077         while (p->on_rq) {
1078                 /*
1079                  * Sleep to make sure the RT thread is asleep too.
1080                  * On virtual machines we can't rely on timings,
1081                  * but we want to make sure this test still works.
1082                  */
1083                 msleep(100);
1084         }
1085
1086         init_completion(&isrt);
1087
1088         wake_up_process(p);
1089
1090         /* Wait for the task to wake up */
1091         wait_for_completion(&isrt);
1092
1093         /* stop the tracing. */
1094         tracing_stop();
1095         /* check both trace buffers */
1096         ret = trace_test_buffer(tr, NULL);
1097         printk("ret = %d\n", ret);
1098         if (!ret)
1099                 ret = trace_test_buffer(&max_tr, &count);
1100
1101
1102         trace->reset(tr);
1103         tracing_start();
1104
1105         tracing_max_latency = save_max;
1106
1107         /* kill the thread */
1108         kthread_stop(p);
1109
1110         if (!ret && !count) {
1111                 printk(KERN_CONT ".. no entries found ..");
1112                 ret = -1;
1113         }
1114
1115         return ret;
1116 }
1117 #endif /* CONFIG_SCHED_TRACER */
1118
1119 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
1120 int
1121 trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr)
1122 {
1123         unsigned long count;
1124         int ret;
1125
1126         /* start the tracing */
1127         ret = tracer_init(trace, tr);
1128         if (ret) {
1129                 warn_failed_init_tracer(trace, ret);
1130                 return ret;
1131         }
1132
1133         /* Sleep for a 1/10 of a second */
1134         msleep(100);
1135         /* stop the tracing. */
1136         tracing_stop();
1137         /* check the trace buffer */
1138         ret = trace_test_buffer(tr, &count);
1139         trace->reset(tr);
1140         tracing_start();
1141
1142         if (!ret && !count) {
1143                 printk(KERN_CONT ".. no entries found ..");
1144                 ret = -1;
1145         }
1146
1147         return ret;
1148 }
1149 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
1150
1151 #ifdef CONFIG_BRANCH_TRACER
1152 int
1153 trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
1154 {
1155         unsigned long count;
1156         int ret;
1157
1158         /* start the tracing */
1159         ret = tracer_init(trace, tr);
1160         if (ret) {
1161                 warn_failed_init_tracer(trace, ret);
1162                 return ret;
1163         }
1164
1165         /* Sleep for a 1/10 of a second */
1166         msleep(100);
1167         /* stop the tracing. */
1168         tracing_stop();
1169         /* check the trace buffer */
1170         ret = trace_test_buffer(tr, &count);
1171         trace->reset(tr);
1172         tracing_start();
1173
1174         if (!ret && !count) {
1175                 printk(KERN_CONT ".. no entries found ..");
1176                 ret = -1;
1177         }
1178
1179         return ret;
1180 }
1181 #endif /* CONFIG_BRANCH_TRACER */
1182