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_buffer *buf, 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(buf->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_buffer *buf, 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(buf->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(buf, 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->trace_buffer, &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->trace_buffer, &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->trace_buffer, &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 unsigned int graph_hang_thresh;
 707
 708 /* Wrap the real function entry probe to avoid possible hanging */
 709 static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
 710 {
 711         /* This is harmlessly racy, we want to approximately detect a hang */
 712         if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) {
 713                 ftrace_graph_stop();
 714                 printk(KERN_WARNING "BUG: Function graph tracer hang!\n");
 715                 if (ftrace_dump_on_oops) {
 716                         ftrace_dump(DUMP_ALL);
 717                         /* ftrace_dump() disables tracing */
 718                         tracing_on();
 719                 }
 720                 return 0;
 721         }
 722
 723         return trace_graph_entry(trace);
 724 }
 725
 726 /*
 727  * Pretty much the same than for the function tracer from which the selftest
 728  * has been borrowed.
 729  */
 730 int
 731 trace_selftest_startup_function_graph(struct tracer *trace,
 732                                         struct trace_array *tr)
 733 {
 734         int ret;
 735         unsigned long count;
 736
 737         /*
 738          * Simulate the init() callback but we attach a watchdog callback
 739          * to detect and recover from possible hangs
 740          */
 741         tracing_reset_online_cpus(&tr->trace_buffer);
 742         set_graph_array(tr);
 743         ret = register_ftrace_graph(&trace_graph_return,
 744                                     &trace_graph_entry_watchdog);
 745         if (ret) {
 746                 warn_failed_init_tracer(trace, ret);
 747                 goto out;
 748         }
 749         tracing_start_cmdline_record();
 750
 751         /* Sleep for a 1/10 of a second */
 752         msleep(100);
 753
 754         /* Have we just recovered from a hang? */
 755         if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) {
 756                 tracing_selftest_disabled = true;
 757                 ret = -1;
 758                 goto out;
 759         }
 760
 761         tracing_stop();
 762
 763         /* check the trace buffer */
 764         ret = trace_test_buffer(&tr->trace_buffer, &count);
 765
 766         trace->reset(tr);
 767         tracing_start();
 768
 769         if (!ret && !count) {
 770                 printk(KERN_CONT ".. no entries found ..");
 771                 ret = -1;
 772                 goto out;
 773         }
 774
 775         /* Don't test dynamic tracing, the function tracer already did */
 776
 777 out:
 778         /* Stop it if we failed */
 779         if (ret)
 780                 ftrace_graph_stop();
 781
 782         return ret;
 783 }
 784 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 785
 786
 787 #ifdef CONFIG_IRQSOFF_TRACER
 788 int
 789 trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
 790 {
 791         unsigned long save_max = tracing_max_latency;
 792         unsigned long count;
 793         int ret;
 794
 795         /* start the tracing */
 796         ret = tracer_init(trace, tr);
 797         if (ret) {
 798                 warn_failed_init_tracer(trace, ret);
 799                 return ret;
 800         }
 801
 802         /* reset the max latency */
 803         tracing_max_latency = 0;
 804         /* disable interrupts for a bit */
 805         local_irq_disable();
 806         udelay(100);
 807         local_irq_enable();
 808
 809         /*
 810          * Stop the tracer to avoid a warning subsequent
 811          * to buffer flipping failure because tracing_stop()
 812          * disables the tr and max buffers, making flipping impossible
 813          * in case of parallels max irqs off latencies.
 814          */
 815         trace->stop(tr);
 816         /* stop the tracing. */
 817         tracing_stop();
 818         /* check both trace buffers */
 819         ret = trace_test_buffer(&tr->trace_buffer, NULL);
 820         if (!ret)
 821                 ret = trace_test_buffer(&tr->max_buffer, &count);
 822         trace->reset(tr);
 823         tracing_start();
 824
 825         if (!ret && !count) {
 826                 printk(KERN_CONT ".. no entries found ..");
 827                 ret = -1;
 828         }
 829
 830         tracing_max_latency = save_max;
 831
 832         return ret;
 833 }
 834 #endif /* CONFIG_IRQSOFF_TRACER */
 835
 836 #ifdef CONFIG_PREEMPT_TRACER
 837 int
 838 trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
 839 {
 840         unsigned long save_max = tracing_max_latency;
 841         unsigned long count;
 842         int ret;
 843
 844         /*
 845          * Now that the big kernel lock is no longer preemptable,
 846          * and this is called with the BKL held, it will always
 847          * fail. If preemption is already disabled, simply
 848          * pass the test. When the BKL is removed, or becomes
 849          * preemptible again, we will once again test this,
 850          * so keep it in.
 851          */
 852         if (preempt_count()) {
 853                 printk(KERN_CONT "can not test ... force ");
 854                 return 0;
 855         }
 856
 857         /* start the tracing */
 858         ret = tracer_init(trace, tr);
 859         if (ret) {
 860                 warn_failed_init_tracer(trace, ret);
 861                 return ret;
 862         }
 863
 864         /* reset the max latency */
 865         tracing_max_latency = 0;
 866         /* disable preemption for a bit */
 867         preempt_disable();
 868         udelay(100);
 869         preempt_enable();
 870
 871         /*
 872          * Stop the tracer to avoid a warning subsequent
 873          * to buffer flipping failure because tracing_stop()
 874          * disables the tr and max buffers, making flipping impossible
 875          * in case of parallels max preempt off latencies.
 876          */
 877         trace->stop(tr);
 878         /* stop the tracing. */
 879         tracing_stop();
 880         /* check both trace buffers */
 881         ret = trace_test_buffer(&tr->trace_buffer, NULL);
 882         if (!ret)
 883                 ret = trace_test_buffer(&tr->max_buffer, &count);
 884         trace->reset(tr);
 885         tracing_start();
 886
 887         if (!ret && !count) {
 888                 printk(KERN_CONT ".. no entries found ..");
 889                 ret = -1;
 890         }
 891
 892         tracing_max_latency = save_max;
 893
 894         return ret;
 895 }
 896 #endif /* CONFIG_PREEMPT_TRACER */
 897
 898 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER)
 899 int
 900 trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr)
 901 {
 902         unsigned long save_max = tracing_max_latency;
 903         unsigned long count;
 904         int ret;
 905
 906         /*
 907          * Now that the big kernel lock is no longer preemptable,
 908          * and this is called with the BKL held, it will always
 909          * fail. If preemption is already disabled, simply
 910          * pass the test. When the BKL is removed, or becomes
 911          * preemptible again, we will once again test this,
 912          * so keep it in.
 913          */
 914         if (preempt_count()) {
 915                 printk(KERN_CONT "can not test ... force ");
 916                 return 0;
 917         }
 918
 919         /* start the tracing */
 920         ret = tracer_init(trace, tr);
 921         if (ret) {
 922                 warn_failed_init_tracer(trace, ret);
 923                 goto out_no_start;
 924         }
 925
 926         /* reset the max latency */
 927         tracing_max_latency = 0;
 928
 929         /* disable preemption and interrupts for a bit */
 930         preempt_disable();
 931         local_irq_disable();
 932         udelay(100);
 933         preempt_enable();
 934         /* reverse the order of preempt vs irqs */
 935         local_irq_enable();
 936
 937         /*
 938          * Stop the tracer to avoid a warning subsequent
 939          * to buffer flipping failure because tracing_stop()
 940          * disables the tr and max buffers, making flipping impossible
 941          * in case of parallels max irqs/preempt off latencies.
 942          */
 943         trace->stop(tr);
 944         /* stop the tracing. */
 945         tracing_stop();
 946         /* check both trace buffers */
 947         ret = trace_test_buffer(&tr->trace_buffer, NULL);
 948         if (ret)
 949                 goto out;
 950
 951         ret = trace_test_buffer(&tr->max_buffer, &count);
 952         if (ret)
 953                 goto out;
 954
 955         if (!ret && !count) {
 956                 printk(KERN_CONT ".. no entries found ..");
 957                 ret = -1;
 958                 goto out;
 959         }
 960
 961         /* do the test by disabling interrupts first this time */
 962         tracing_max_latency = 0;
 963         tracing_start();
 964         trace->start(tr);
 965
 966         preempt_disable();
 967         local_irq_disable();
 968         udelay(100);
 969         preempt_enable();
 970         /* reverse the order of preempt vs irqs */
 971         local_irq_enable();
 972
 973         trace->stop(tr);
 974         /* stop the tracing. */
 975         tracing_stop();
 976         /* check both trace buffers */
 977         ret = trace_test_buffer(&tr->trace_buffer, NULL);
 978         if (ret)
 979                 goto out;
 980
 981         ret = trace_test_buffer(&tr->max_buffer, &count);
 982
 983         if (!ret && !count) {
 984                 printk(KERN_CONT ".. no entries found ..");
 985                 ret = -1;
 986                 goto out;
 987         }
 988
 989 out:
 990         tracing_start();
 991 out_no_start:
 992         trace->reset(tr);
 993         tracing_max_latency = save_max;
 994
 995         return ret;
 996 }
 997 #endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */
 998
 999 #ifdef CONFIG_NOP_TRACER
1000 int
1001 trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr)
1002 {
1003         /* What could possibly go wrong? */
1004         return 0;
1005 }
1006 #endif
1007
1008 #ifdef CONFIG_SCHED_TRACER
1009 static int trace_wakeup_test_thread(void *data)
1010 {
1011         /* Make this a RT thread, doesn't need to be too high */
1012         static const struct sched_param param = { .sched_priority = 5 };
1013         struct completion *x = data;
1014
1015         sched_setscheduler(current, SCHED_FIFO, &param);
1016
1017         /* Make it know we have a new prio */
1018         complete(x);
1019
1020         /* now go to sleep and let the test wake us up */
1021         set_current_state(TASK_INTERRUPTIBLE);
1022         schedule();
1023
1024         complete(x);
1025
1026         /* we are awake, now wait to disappear */
1027         while (!kthread_should_stop()) {
1028                 /*
1029                  * This is an RT task, do short sleeps to let
1030                  * others run.
1031                  */
1032                 msleep(100);
1033         }
1034
1035         return 0;
1036 }
1037
1038 int
1039 trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
1040 {
1041         unsigned long save_max = tracing_max_latency;
1042         struct task_struct *p;
1043         struct completion isrt;
1044         unsigned long count;
1045         int ret;
1046
1047         init_completion(&isrt);
1048
1049         /* create a high prio thread */
1050         p = kthread_run(trace_wakeup_test_thread, &isrt, "ftrace-test");
1051         if (IS_ERR(p)) {
1052                 printk(KERN_CONT "Failed to create ftrace wakeup test thread ");
1053                 return -1;
1054         }
1055
1056         /* make sure the thread is running at an RT prio */
1057         wait_for_completion(&isrt);
1058
1059         /* start the tracing */
1060         ret = tracer_init(trace, tr);
1061         if (ret) {
1062                 warn_failed_init_tracer(trace, ret);
1063                 return ret;
1064         }
1065
1066         /* reset the max latency */
1067         tracing_max_latency = 0;
1068
1069         while (p->on_rq) {
1070                 /*
1071                  * Sleep to make sure the RT thread is asleep too.
1072                  * On virtual machines we can't rely on timings,
1073                  * but we want to make sure this test still works.
1074                  */
1075                 msleep(100);
1076         }
1077
1078         init_completion(&isrt);
1079
1080         wake_up_process(p);
1081
1082         /* Wait for the task to wake up */
1083         wait_for_completion(&isrt);
1084
1085         /* stop the tracing. */
1086         tracing_stop();
1087         /* check both trace buffers */
1088         ret = trace_test_buffer(&tr->trace_buffer, NULL);
1089         printk("ret = %d\n", ret);
1090         if (!ret)
1091                 ret = trace_test_buffer(&tr->max_buffer, &count);
1092
1093
1094         trace->reset(tr);
1095         tracing_start();
1096
1097         tracing_max_latency = save_max;
1098
1099         /* kill the thread */
1100         kthread_stop(p);
1101
1102         if (!ret && !count) {
1103                 printk(KERN_CONT ".. no entries found ..");
1104                 ret = -1;
1105         }
1106
1107         return ret;
1108 }
1109 #endif /* CONFIG_SCHED_TRACER */
1110
1111 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
1112 int
1113 trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr)
1114 {
1115         unsigned long count;
1116         int ret;
1117
1118         /* start the tracing */
1119         ret = tracer_init(trace, tr);
1120         if (ret) {
1121                 warn_failed_init_tracer(trace, ret);
1122                 return ret;
1123         }
1124
1125         /* Sleep for a 1/10 of a second */
1126         msleep(100);
1127         /* stop the tracing. */
1128         tracing_stop();
1129         /* check the trace buffer */
1130         ret = trace_test_buffer(&tr->trace_buffer, &count);
1131         trace->reset(tr);
1132         tracing_start();
1133
1134         if (!ret && !count) {
1135                 printk(KERN_CONT ".. no entries found ..");
1136                 ret = -1;
1137         }
1138
1139         return ret;
1140 }
1141 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
1142
1143 #ifdef CONFIG_BRANCH_TRACER
1144 int
1145 trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
1146 {
1147         unsigned long count;
1148         int ret;
1149
1150         /* start the tracing */
1151         ret = tracer_init(trace, tr);
1152         if (ret) {
1153                 warn_failed_init_tracer(trace, ret);
1154                 return ret;
1155         }
1156
1157         /* Sleep for a 1/10 of a second */
1158         msleep(100);
1159         /* stop the tracing. */
1160         tracing_stop();
1161         /* check the trace buffer */
1162         ret = trace_test_buffer(tr, &count);
1163         trace->reset(tr);
1164         tracing_start();
1165
1166         if (!ret && !count) {
1167                 printk(KERN_CONT ".. no entries found ..");
1168                 ret = -1;
1169         }
1170
1171         return ret;
1172 }
1173 #endif /* CONFIG_BRANCH_TRACER */
1174