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         if (trace_selftest_recursion_cnt++ > 10)
 419                 return;
 420         DYN_FTRACE_TEST_NAME();
 421 }
 422
 423 static void trace_selftest_test_recursion_safe_func(unsigned long ip,
 424                                                     unsigned long pip,
 425                                                     struct ftrace_ops *op,
 426                                                     struct pt_regs *pt_regs)
 427 {
 428         /*
 429          * We said we would provide our own recursion. By calling
 430          * this function again, we should recurse back into this function
 431          * and count again. But this only happens if the arch supports
 432          * all of ftrace features and nothing else is using the function
 433          * tracing utility.
 434          */
 435         if (trace_selftest_recursion_cnt++)
 436                 return;
 437         DYN_FTRACE_TEST_NAME();
 438 }
 439
 440 static struct ftrace_ops test_rec_probe = {
 441         .func                   = trace_selftest_test_recursion_func,
 442 };
 443
 444 static struct ftrace_ops test_recsafe_probe = {
 445         .func                   = trace_selftest_test_recursion_safe_func,
 446         .flags                  = FTRACE_OPS_FL_RECURSION_SAFE,
 447 };
 448
 449 static int
 450 trace_selftest_function_recursion(void)
 451 {
 452         int save_ftrace_enabled = ftrace_enabled;
 453         char *func_name;
 454         int len;
 455         int ret;
 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         ret = -1;
 514         if (trace_selftest_recursion_cnt != 2) {
 515                 pr_cont("*callback not called expected 2 times (%d)* ",
 516                         trace_selftest_recursion_cnt);
 517                 goto out;
 518         }
 519
 520         ret = 0;
 521 out:
 522         ftrace_enabled = save_ftrace_enabled;
 523
 524         return ret;
 525 }
 526 #else
 527 # define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; })
 528 # define trace_selftest_function_recursion() ({ 0; })
 529 #endif /* CONFIG_DYNAMIC_FTRACE */
 530
 531 static enum {
 532         TRACE_SELFTEST_REGS_START,
 533         TRACE_SELFTEST_REGS_FOUND,
 534         TRACE_SELFTEST_REGS_NOT_FOUND,
 535 } trace_selftest_regs_stat;
 536
 537 static void trace_selftest_test_regs_func(unsigned long ip,
 538                                           unsigned long pip,
 539                                           struct ftrace_ops *op,
 540                                           struct pt_regs *pt_regs)
 541 {
 542         if (pt_regs)
 543                 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND;
 544         else
 545                 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND;
 546 }
 547
 548 static struct ftrace_ops test_regs_probe = {
 549         .func           = trace_selftest_test_regs_func,
 550         .flags          = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_SAVE_REGS,
 551 };
 552
 553 static int
 554 trace_selftest_function_regs(void)
 555 {
 556         int save_ftrace_enabled = ftrace_enabled;
 557         char *func_name;
 558         int len;
 559         int ret;
 560         int supported = 0;
 561
 562 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 563         supported = 1;
 564 #endif
 565
 566         /* The previous test PASSED */
 567         pr_cont("PASSED\n");
 568         pr_info("Testing ftrace regs%s: ",
 569                 !supported ? "(no arch support)" : "");
 570
 571         /* enable tracing, and record the filter function */
 572         ftrace_enabled = 1;
 573
 574         /* Handle PPC64 '.' name */
 575         func_name = "*" __stringify(DYN_FTRACE_TEST_NAME);
 576         len = strlen(func_name);
 577
 578         ret = ftrace_set_filter(&test_regs_probe, func_name, len, 1);
 579         /*
 580          * If DYNAMIC_FTRACE is not set, then we just trace all functions.
 581          * This test really doesn't care.
 582          */
 583         if (ret && ret != -ENODEV) {
 584                 pr_cont("*Could not set filter* ");
 585                 goto out;
 586         }
 587
 588         ret = register_ftrace_function(&test_regs_probe);
 589         /*
 590          * Now if the arch does not support passing regs, then this should
 591          * have failed.
 592          */
 593         if (!supported) {
 594                 if (!ret) {
 595                         pr_cont("*registered save-regs without arch support* ");
 596                         goto out;
 597                 }
 598                 test_regs_probe.flags |= FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED;
 599                 ret = register_ftrace_function(&test_regs_probe);
 600         }
 601         if (ret) {
 602                 pr_cont("*could not register callback* ");
 603                 goto out;
 604         }
 605
 606
 607         DYN_FTRACE_TEST_NAME();
 608
 609         unregister_ftrace_function(&test_regs_probe);
 610
 611         ret = -1;
 612
 613         switch (trace_selftest_regs_stat) {
 614         case TRACE_SELFTEST_REGS_START:
 615                 pr_cont("*callback never called* ");
 616                 goto out;
 617
 618         case TRACE_SELFTEST_REGS_FOUND:
 619                 if (supported)
 620                         break;
 621                 pr_cont("*callback received regs without arch support* ");
 622                 goto out;
 623
 624         case TRACE_SELFTEST_REGS_NOT_FOUND:
 625                 if (!supported)
 626                         break;
 627                 pr_cont("*callback received NULL regs* ");
 628                 goto out;
 629         }
 630
 631         ret = 0;
 632 out:
 633         ftrace_enabled = save_ftrace_enabled;
 634
 635         return ret;
 636 }
 637
 638 /*
 639  * Simple verification test of ftrace function tracer.
 640  * Enable ftrace, sleep 1/10 second, and then read the trace
 641  * buffer to see if all is in order.
 642  */
 643 int
 644 trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
 645 {
 646         int save_ftrace_enabled = ftrace_enabled;
 647         unsigned long count;
 648         int ret;
 649
 650         /* make sure msleep has been recorded */
 651         msleep(1);
 652
 653         /* start the tracing */
 654         ftrace_enabled = 1;
 655
 656         ret = tracer_init(trace, tr);
 657         if (ret) {
 658                 warn_failed_init_tracer(trace, ret);
 659                 goto out;
 660         }
 661
 662         /* Sleep for a 1/10 of a second */
 663         msleep(100);
 664         /* stop the tracing. */
 665         tracing_stop();
 666         ftrace_enabled = 0;
 667
 668         /* check the trace buffer */
 669         ret = trace_test_buffer(tr, &count);
 670         trace->reset(tr);
 671         tracing_start();
 672
 673         if (!ret && !count) {
 674                 printk(KERN_CONT ".. no entries found ..");
 675                 ret = -1;
 676                 goto out;
 677         }
 678
 679         ret = trace_selftest_startup_dynamic_tracing(trace, tr,
 680                                                      DYN_FTRACE_TEST_NAME);
 681         if (ret)
 682                 goto out;
 683
 684         ret = trace_selftest_function_recursion();
 685         if (ret)
 686                 goto out;
 687
 688         ret = trace_selftest_function_regs();
 689  out:
 690         ftrace_enabled = save_ftrace_enabled;
 691
 692         /* kill ftrace totally if we failed */
 693         if (ret)
 694                 ftrace_kill();
 695
 696         return ret;
 697 }
 698 #endif /* CONFIG_FUNCTION_TRACER */
 699
 700
 701 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 702
 703 /* Maximum number of functions to trace before diagnosing a hang */
 704 #define GRAPH_MAX_FUNC_TEST     100000000
 705
 706 static void
 707 __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode);
 708 static unsigned int graph_hang_thresh;
 709
 710 /* Wrap the real function entry probe to avoid possible hanging */
 711 static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
 712 {
 713         /* This is harmlessly racy, we want to approximately detect a hang */
 714         if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) {
 715                 ftrace_graph_stop();
 716                 printk(KERN_WARNING "BUG: Function graph tracer hang!\n");
 717                 if (ftrace_dump_on_oops)
 718                         __ftrace_dump(false, DUMP_ALL);
 719                 return 0;
 720         }
 721
 722         return trace_graph_entry(trace);
 723 }
 724
 725 /*
 726  * Pretty much the same than for the function tracer from which the selftest
 727  * has been borrowed.
 728  */
 729 int
 730 trace_selftest_startup_function_graph(struct tracer *trace,
 731                                         struct trace_array *tr)
 732 {
 733         int ret;
 734         unsigned long count;
 735
 736         /*
 737          * Simulate the init() callback but we attach a watchdog callback
 738          * to detect and recover from possible hangs
 739          */
 740         tracing_reset_online_cpus(tr);
 741         set_graph_array(tr);
 742         ret = register_ftrace_graph(&trace_graph_return,
 743                                     &trace_graph_entry_watchdog);
 744         if (ret) {
 745                 warn_failed_init_tracer(trace, ret);
 746                 goto out;
 747         }
 748         tracing_start_cmdline_record();
 749
 750         /* Sleep for a 1/10 of a second */
 751         msleep(100);
 752
 753         /* Have we just recovered from a hang? */
 754         if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) {
 755                 tracing_selftest_disabled = true;
 756                 ret = -1;
 757                 goto out;
 758         }
 759
 760         tracing_stop();
 761
 762         /* check the trace buffer */
 763         ret = trace_test_buffer(tr, &count);
 764
 765         trace->reset(tr);
 766         tracing_start();
 767
 768         if (!ret && !count) {
 769                 printk(KERN_CONT ".. no entries found ..");
 770                 ret = -1;
 771                 goto out;
 772         }
 773
 774         /* Don't test dynamic tracing, the function tracer already did */
 775
 776 out:
 777         /* Stop it if we failed */
 778         if (ret)
 779                 ftrace_graph_stop();
 780
 781         return ret;
 782 }
 783 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 784
 785
 786 #ifdef CONFIG_IRQSOFF_TRACER
 787 int
 788 trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
 789 {
 790         unsigned long save_max = tracing_max_latency;
 791         unsigned long count;
 792         int ret;
 793
 794         /* start the tracing */
 795         ret = tracer_init(trace, tr);
 796         if (ret) {
 797                 warn_failed_init_tracer(trace, ret);
 798                 return ret;
 799         }
 800
 801         /* reset the max latency */
 802         tracing_max_latency = 0;
 803         /* disable interrupts for a bit */
 804         local_irq_disable();
 805         udelay(100);
 806         local_irq_enable();
 807
 808         /*
 809          * Stop the tracer to avoid a warning subsequent
 810          * to buffer flipping failure because tracing_stop()
 811          * disables the tr and max buffers, making flipping impossible
 812          * in case of parallels max irqs off latencies.
 813          */
 814         trace->stop(tr);
 815         /* stop the tracing. */
 816         tracing_stop();
 817         /* check both trace buffers */
 818         ret = trace_test_buffer(tr, NULL);
 819         if (!ret)
 820                 ret = trace_test_buffer(&max_tr, &count);
 821         trace->reset(tr);
 822         tracing_start();
 823
 824         if (!ret && !count) {
 825                 printk(KERN_CONT ".. no entries found ..");
 826                 ret = -1;
 827         }
 828
 829         tracing_max_latency = save_max;
 830
 831         return ret;
 832 }
 833 #endif /* CONFIG_IRQSOFF_TRACER */
 834
 835 #ifdef CONFIG_PREEMPT_TRACER
 836 int
 837 trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
 838 {
 839         unsigned long save_max = tracing_max_latency;
 840         unsigned long count;
 841         int ret;
 842
 843         /*
 844          * Now that the big kernel lock is no longer preemptable,
 845          * and this is called with the BKL held, it will always
 846          * fail. If preemption is already disabled, simply
 847          * pass the test. When the BKL is removed, or becomes
 848          * preemptible again, we will once again test this,
 849          * so keep it in.
 850          */
 851         if (preempt_count()) {
 852                 printk(KERN_CONT "can not test ... force ");
 853                 return 0;
 854         }
 855
 856         /* start the tracing */
 857         ret = tracer_init(trace, tr);
 858         if (ret) {
 859                 warn_failed_init_tracer(trace, ret);
 860                 return ret;
 861         }
 862
 863         /* reset the max latency */
 864         tracing_max_latency = 0;
 865         /* disable preemption for a bit */
 866         preempt_disable();
 867         udelay(100);
 868         preempt_enable();
 869
 870         /*
 871          * Stop the tracer to avoid a warning subsequent
 872          * to buffer flipping failure because tracing_stop()
 873          * disables the tr and max buffers, making flipping impossible
 874          * in case of parallels max preempt off latencies.
 875          */
 876         trace->stop(tr);
 877         /* stop the tracing. */
 878         tracing_stop();
 879         /* check both trace buffers */
 880         ret = trace_test_buffer(tr, NULL);
 881         if (!ret)
 882                 ret = trace_test_buffer(&max_tr, &count);
 883         trace->reset(tr);
 884         tracing_start();
 885
 886         if (!ret && !count) {
 887                 printk(KERN_CONT ".. no entries found ..");
 888                 ret = -1;
 889         }
 890
 891         tracing_max_latency = save_max;
 892
 893         return ret;
 894 }
 895 #endif /* CONFIG_PREEMPT_TRACER */
 896
 897 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 898 int
 899 trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
 900 {
 901         unsigned long save_max = tracing_max_latency;
 902         unsigned long count;
 903         int ret;
 904
 905         /*
 906          * Now that the big kernel lock is no longer preemptable,
 907          * and this is called with the BKL held, it will always
 908          * fail. If preemption is already disabled, simply
 909          * pass the test. When the BKL is removed, or becomes
 910          * preemptible again, we will once again test this,
 911          * so keep it in.
 912          */
 913         if (preempt_count()) {
 914                 printk(KERN_CONT "can not test ... force ");
 915                 return 0;
 916         }
 917
 918         /* start the tracing */
 919         ret = tracer_init(trace, tr);
 920         if (ret) {
 921                 warn_failed_init_tracer(trace, ret);
 922                 goto out_no_start;
 923         }
 924
 925         /* reset the max latency */
 926         tracing_max_latency = 0;
 927
 928         /* disable preemption and interrupts for a bit */
 929         preempt_disable();
 930         local_irq_disable();
 931         udelay(100);
 932         preempt_enable();
 933         /* reverse the order of preempt vs irqs */
 934         local_irq_enable();
 935
 936         /*
 937          * Stop the tracer to avoid a warning subsequent
 938          * to buffer flipping failure because tracing_stop()
 939          * disables the tr and max buffers, making flipping impossible
 940          * in case of parallels max irqs/preempt off latencies.
 941          */
 942         trace->stop(tr);
 943         /* stop the tracing. */
 944         tracing_stop();
 945         /* check both trace buffers */
 946         ret = trace_test_buffer(tr, NULL);
 947         if (ret)
 948                 goto out;
 949
 950         ret = trace_test_buffer(&max_tr, &count);
 951         if (ret)
 952                 goto out;
 953
 954         if (!ret && !count) {
 955                 printk(KERN_CONT ".. no entries found ..");
 956                 ret = -1;
 957                 goto out;
 958         }
 959
 960         /* do the test by disabling interrupts first this time */
 961         tracing_max_latency = 0;
 962         tracing_start();
 963         trace->start(tr);
 964
 965         preempt_disable();
 966         local_irq_disable();
 967         udelay(100);
 968         preempt_enable();
 969         /* reverse the order of preempt vs irqs */
 970         local_irq_enable();
 971
 972         trace->stop(tr);
 973         /* stop the tracing. */
 974         tracing_stop();
 975         /* check both trace buffers */
 976         ret = trace_test_buffer(tr, NULL);
 977         if (ret)
 978                 goto out;
 979
 980         ret = trace_test_buffer(&max_tr, &count);
 981
 982         if (!ret && !count) {
 983                 printk(KERN_CONT ".. no entries found ..");
 984                 ret = -1;
 985                 goto out;
 986         }
 987
 988 out:
 989         tracing_start();
 990 out_no_start:
 991         trace->reset(tr);
 992         tracing_max_latency = save_max;
 993
 994         return ret;
 995 }
 996 #endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
 997
 998 #ifdef CONFIG_NOP_TRACER
 999 int
1000 trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
1001 {
1002         /* What could possibly go wrong? */
1003         return 0;
1004 }
1005 #endif
1006
1007 #ifdef CONFIG_SCHED_TRACER
1008 static int trace_wakeup_test_thread(void *data)
1009 {
1010         /* Make this a RT thread, doesn't need to be too high */
1011         static const struct sched_param param = { .sched_priority = 5 };
1012         struct completion *x = data;
1013
1014         sched_setscheduler(current, SCHED_FIFO, &param);
1015
1016         /* Make it know we have a new prio */
1017         complete(x);
1018
1019         /* now go to sleep and let the test wake us up */
1020         set_current_state(TASK_INTERRUPTIBLE);
1021         schedule();
1022
1023         complete(x);
1024
1025         /* we are awake, now wait to disappear */
1026         while (!kthread_should_stop()) {
1027                 /*
1028                  * This is an RT task, do short sleeps to let
1029                  * others run.
1030                  */
1031                 msleep(100);
1032         }
1033
1034         return 0;
1035 }
1036
1037 int
1038 trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
1039 {
1040         unsigned long save_max = tracing_max_latency;
1041         struct task_struct *p;
1042         struct completion isrt;
1043         unsigned long count;
1044         int ret;
1045
1046         init_completion(&isrt);
1047
1048         /* create a high prio thread */
1049         p = kthread_run(trace_wakeup_test_thread, &isrt, "ftrace-test");
1050         if (IS_ERR(p)) {
1051                 printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
1052                 return -1;
1053         }
1054
1055         /* make sure the thread is running at an RT prio */
1056         wait_for_completion(&isrt);
1057
1058         /* start the tracing */
1059         ret = tracer_init(trace, tr);
1060         if (ret) {
1061                 warn_failed_init_tracer(trace, ret);
1062                 return ret;
1063         }
1064
1065         /* reset the max latency */
1066         tracing_max_latency = 0;
1067
1068         while (p->on_rq) {
1069                 /*
1070                  * Sleep to make sure the RT thread is asleep too.
1071                  * On virtual machines we can't rely on timings,
1072                  * but we want to make sure this test still works.
1073                  */
1074                 msleep(100);
1075         }
1076
1077         init_completion(&isrt);
1078
1079         wake_up_process(p);
1080
1081         /* Wait for the task to wake up */
1082         wait_for_completion(&isrt);
1083
1084         /* stop the tracing. */
1085         tracing_stop();
1086         /* check both trace buffers */
1087         ret = trace_test_buffer(tr, NULL);
1088         printk("ret = %d\n", ret);
1089         if (!ret)
1090                 ret = trace_test_buffer(&max_tr, &count);
1091
1092
1093         trace->reset(tr);
1094         tracing_start();
1095
1096         tracing_max_latency = save_max;
1097
1098         /* kill the thread */
1099         kthread_stop(p);
1100
1101         if (!ret && !count) {
1102                 printk(KERN_CONT ".. no entries found ..");
1103                 ret = -1;
1104         }
1105
1106         return ret;
1107 }
1108 #endif /* CONFIG_SCHED_TRACER */
1109
1110 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
1111 int
1112 trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr)
1113 {
1114         unsigned long count;
1115         int ret;
1116
1117         /* start the tracing */
1118         ret = tracer_init(trace, tr);
1119         if (ret) {
1120                 warn_failed_init_tracer(trace, ret);
1121                 return ret;
1122         }
1123
1124         /* Sleep for a 1/10 of a second */
1125         msleep(100);
1126         /* stop the tracing. */
1127         tracing_stop();
1128         /* check the trace buffer */
1129         ret = trace_test_buffer(tr, &count);
1130         trace->reset(tr);
1131         tracing_start();
1132
1133         if (!ret && !count) {
1134                 printk(KERN_CONT ".. no entries found ..");
1135                 ret = -1;
1136         }
1137
1138         return ret;
1139 }
1140 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
1141
1142 #ifdef CONFIG_BRANCH_TRACER
1143 int
1144 trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
1145 {
1146         unsigned long count;
1147         int ret;
1148
1149         /* start the tracing */
1150         ret = tracer_init(trace, tr);
1151         if (ret) {
1152                 warn_failed_init_tracer(trace, ret);
1153                 return ret;
1154         }
1155
1156         /* Sleep for a 1/10 of a second */
1157         msleep(100);
1158         /* stop the tracing. */
1159         tracing_stop();
1160         /* check the trace buffer */
1161         ret = trace_test_buffer(tr, &count);
1162         trace->reset(tr);
1163         tracing_start();
1164
1165         if (!ret && !count) {
1166                 printk(KERN_CONT ".. no entries found ..");
1167                 ret = -1;
1168         }
1169
1170         return ret;
1171 }
1172 #endif /* CONFIG_BRANCH_TRACER */
1173