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 trace_valid_entry(struct trace_entry * entry)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 trace_test_buffer_cpu(struct trace_buffer * buf,int cpu)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 */ trace_test_buffer(struct trace_buffer * buf,unsigned long * count)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(&buf->tr->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(&buf->tr->max_lock); 87 local_irq_restore(flags); 88 89 if (count) 90 *count = cnt; 91 92 return ret; 93 } 94 warn_failed_init_tracer(struct tracer * trace,int init_ret)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; trace_selftest_test_probe1_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct pt_regs * pt_regs)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; trace_selftest_test_probe2_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct pt_regs * pt_regs)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; trace_selftest_test_probe3_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct pt_regs * pt_regs)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; trace_selftest_test_global_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct pt_regs * pt_regs)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; trace_selftest_test_dyn_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct pt_regs * pt_regs)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 print_counts(void)164 static void print_counts(void) 165 { 166 printk("(%d %d %d %d %d) ", 167 trace_selftest_test_probe1_cnt, 168 trace_selftest_test_probe2_cnt, 169 trace_selftest_test_probe3_cnt, 170 trace_selftest_test_global_cnt, 171 trace_selftest_test_dyn_cnt); 172 } 173 reset_counts(void)174 static void reset_counts(void) 175 { 176 trace_selftest_test_probe1_cnt = 0; 177 trace_selftest_test_probe2_cnt = 0; 178 trace_selftest_test_probe3_cnt = 0; 179 trace_selftest_test_global_cnt = 0; 180 trace_selftest_test_dyn_cnt = 0; 181 } 182 trace_selftest_ops(struct trace_array * tr,int cnt)183 static int trace_selftest_ops(struct trace_array *tr, int cnt) 184 { 185 int save_ftrace_enabled = ftrace_enabled; 186 struct ftrace_ops *dyn_ops; 187 char *func1_name; 188 char *func2_name; 189 int len1; 190 int len2; 191 int ret = -1; 192 193 printk(KERN_CONT "PASSED\n"); 194 pr_info("Testing dynamic ftrace ops #%d: ", cnt); 195 196 ftrace_enabled = 1; 197 reset_counts(); 198 199 /* Handle PPC64 '.' name */ 200 func1_name = "*" __stringify(DYN_FTRACE_TEST_NAME); 201 func2_name = "*" __stringify(DYN_FTRACE_TEST_NAME2); 202 len1 = strlen(func1_name); 203 len2 = strlen(func2_name); 204 205 /* 206 * Probe 1 will trace function 1. 207 * Probe 2 will trace function 2. 208 * Probe 3 will trace functions 1 and 2. 209 */ 210 ftrace_set_filter(&test_probe1, func1_name, len1, 1); 211 ftrace_set_filter(&test_probe2, func2_name, len2, 1); 212 ftrace_set_filter(&test_probe3, func1_name, len1, 1); 213 ftrace_set_filter(&test_probe3, func2_name, len2, 0); 214 215 register_ftrace_function(&test_probe1); 216 register_ftrace_function(&test_probe2); 217 register_ftrace_function(&test_probe3); 218 /* First time we are running with main function */ 219 if (cnt > 1) { 220 ftrace_init_array_ops(tr, trace_selftest_test_global_func); 221 register_ftrace_function(tr->ops); 222 } 223 224 DYN_FTRACE_TEST_NAME(); 225 226 print_counts(); 227 228 if (trace_selftest_test_probe1_cnt != 1) 229 goto out; 230 if (trace_selftest_test_probe2_cnt != 0) 231 goto out; 232 if (trace_selftest_test_probe3_cnt != 1) 233 goto out; 234 if (cnt > 1) { 235 if (trace_selftest_test_global_cnt == 0) 236 goto out; 237 } 238 239 DYN_FTRACE_TEST_NAME2(); 240 241 print_counts(); 242 243 if (trace_selftest_test_probe1_cnt != 1) 244 goto out; 245 if (trace_selftest_test_probe2_cnt != 1) 246 goto out; 247 if (trace_selftest_test_probe3_cnt != 2) 248 goto out; 249 250 /* Add a dynamic probe */ 251 dyn_ops = kzalloc(sizeof(*dyn_ops), GFP_KERNEL); 252 if (!dyn_ops) { 253 printk("MEMORY ERROR "); 254 goto out; 255 } 256 257 dyn_ops->func = trace_selftest_test_dyn_func; 258 259 register_ftrace_function(dyn_ops); 260 261 trace_selftest_test_global_cnt = 0; 262 263 DYN_FTRACE_TEST_NAME(); 264 265 print_counts(); 266 267 if (trace_selftest_test_probe1_cnt != 2) 268 goto out_free; 269 if (trace_selftest_test_probe2_cnt != 1) 270 goto out_free; 271 if (trace_selftest_test_probe3_cnt != 3) 272 goto out_free; 273 if (cnt > 1) { 274 if (trace_selftest_test_global_cnt == 0) 275 goto out_free; 276 } 277 if (trace_selftest_test_dyn_cnt == 0) 278 goto out_free; 279 280 DYN_FTRACE_TEST_NAME2(); 281 282 print_counts(); 283 284 if (trace_selftest_test_probe1_cnt != 2) 285 goto out_free; 286 if (trace_selftest_test_probe2_cnt != 2) 287 goto out_free; 288 if (trace_selftest_test_probe3_cnt != 4) 289 goto out_free; 290 291 ret = 0; 292 out_free: 293 unregister_ftrace_function(dyn_ops); 294 kfree(dyn_ops); 295 296 out: 297 /* Purposely unregister in the same order */ 298 unregister_ftrace_function(&test_probe1); 299 unregister_ftrace_function(&test_probe2); 300 unregister_ftrace_function(&test_probe3); 301 if (cnt > 1) 302 unregister_ftrace_function(tr->ops); 303 ftrace_reset_array_ops(tr); 304 305 /* Make sure everything is off */ 306 reset_counts(); 307 DYN_FTRACE_TEST_NAME(); 308 DYN_FTRACE_TEST_NAME(); 309 310 if (trace_selftest_test_probe1_cnt || 311 trace_selftest_test_probe2_cnt || 312 trace_selftest_test_probe3_cnt || 313 trace_selftest_test_global_cnt || 314 trace_selftest_test_dyn_cnt) 315 ret = -1; 316 317 ftrace_enabled = save_ftrace_enabled; 318 319 return ret; 320 } 321 322 /* Test dynamic code modification and ftrace filters */ trace_selftest_startup_dynamic_tracing(struct tracer * trace,struct trace_array * tr,int (* func)(void))323 static int trace_selftest_startup_dynamic_tracing(struct tracer *trace, 324 struct trace_array *tr, 325 int (*func)(void)) 326 { 327 int save_ftrace_enabled = ftrace_enabled; 328 unsigned long count; 329 char *func_name; 330 int ret; 331 332 /* The ftrace test PASSED */ 333 printk(KERN_CONT "PASSED\n"); 334 pr_info("Testing dynamic ftrace: "); 335 336 /* enable tracing, and record the filter function */ 337 ftrace_enabled = 1; 338 339 /* passed in by parameter to fool gcc from optimizing */ 340 func(); 341 342 /* 343 * Some archs *cough*PowerPC*cough* add characters to the 344 * start of the function names. We simply put a '*' to 345 * accommodate them. 346 */ 347 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME); 348 349 /* filter only on our function */ 350 ftrace_set_global_filter(func_name, strlen(func_name), 1); 351 352 /* enable tracing */ 353 ret = tracer_init(trace, tr); 354 if (ret) { 355 warn_failed_init_tracer(trace, ret); 356 goto out; 357 } 358 359 /* Sleep for a 1/10 of a second */ 360 msleep(100); 361 362 /* we should have nothing in the buffer */ 363 ret = trace_test_buffer(&tr->trace_buffer, &count); 364 if (ret) 365 goto out; 366 367 if (count) { 368 ret = -1; 369 printk(KERN_CONT ".. filter did not filter .. "); 370 goto out; 371 } 372 373 /* call our function again */ 374 func(); 375 376 /* sleep again */ 377 msleep(100); 378 379 /* stop the tracing. */ 380 tracing_stop(); 381 ftrace_enabled = 0; 382 383 /* check the trace buffer */ 384 ret = trace_test_buffer(&tr->trace_buffer, &count); 385 386 ftrace_enabled = 1; 387 tracing_start(); 388 389 /* we should only have one item */ 390 if (!ret && count != 1) { 391 trace->reset(tr); 392 printk(KERN_CONT ".. filter failed count=%ld ..", count); 393 ret = -1; 394 goto out; 395 } 396 397 /* Test the ops with global tracing running */ 398 ret = trace_selftest_ops(tr, 1); 399 trace->reset(tr); 400 401 out: 402 ftrace_enabled = save_ftrace_enabled; 403 404 /* Enable tracing on all functions again */ 405 ftrace_set_global_filter(NULL, 0, 1); 406 407 /* Test the ops with global tracing off */ 408 if (!ret) 409 ret = trace_selftest_ops(tr, 2); 410 411 return ret; 412 } 413 414 static int trace_selftest_recursion_cnt; trace_selftest_test_recursion_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct pt_regs * pt_regs)415 static void trace_selftest_test_recursion_func(unsigned long ip, 416 unsigned long pip, 417 struct ftrace_ops *op, 418 struct pt_regs *pt_regs) 419 { 420 /* 421 * This function is registered without the recursion safe flag. 422 * The ftrace infrastructure should provide the recursion 423 * protection. If not, this will crash the kernel! 424 */ 425 if (trace_selftest_recursion_cnt++ > 10) 426 return; 427 DYN_FTRACE_TEST_NAME(); 428 } 429 trace_selftest_test_recursion_safe_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct pt_regs * pt_regs)430 static void trace_selftest_test_recursion_safe_func(unsigned long ip, 431 unsigned long pip, 432 struct ftrace_ops *op, 433 struct pt_regs *pt_regs) 434 { 435 /* 436 * We said we would provide our own recursion. By calling 437 * this function again, we should recurse back into this function 438 * and count again. But this only happens if the arch supports 439 * all of ftrace features and nothing else is using the function 440 * tracing utility. 441 */ 442 if (trace_selftest_recursion_cnt++) 443 return; 444 DYN_FTRACE_TEST_NAME(); 445 } 446 447 static struct ftrace_ops test_rec_probe = { 448 .func = trace_selftest_test_recursion_func, 449 }; 450 451 static struct ftrace_ops test_recsafe_probe = { 452 .func = trace_selftest_test_recursion_safe_func, 453 .flags = FTRACE_OPS_FL_RECURSION_SAFE, 454 }; 455 456 static int trace_selftest_function_recursion(void)457 trace_selftest_function_recursion(void) 458 { 459 int save_ftrace_enabled = ftrace_enabled; 460 char *func_name; 461 int len; 462 int ret; 463 464 /* The previous test PASSED */ 465 pr_cont("PASSED\n"); 466 pr_info("Testing ftrace recursion: "); 467 468 469 /* enable tracing, and record the filter function */ 470 ftrace_enabled = 1; 471 472 /* Handle PPC64 '.' name */ 473 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME); 474 len = strlen(func_name); 475 476 ret = ftrace_set_filter(&test_rec_probe, func_name, len, 1); 477 if (ret) { 478 pr_cont("*Could not set filter* "); 479 goto out; 480 } 481 482 ret = register_ftrace_function(&test_rec_probe); 483 if (ret) { 484 pr_cont("*could not register callback* "); 485 goto out; 486 } 487 488 DYN_FTRACE_TEST_NAME(); 489 490 unregister_ftrace_function(&test_rec_probe); 491 492 ret = -1; 493 if (trace_selftest_recursion_cnt != 1) { 494 pr_cont("*callback not called once (%d)* ", 495 trace_selftest_recursion_cnt); 496 goto out; 497 } 498 499 trace_selftest_recursion_cnt = 1; 500 501 pr_cont("PASSED\n"); 502 pr_info("Testing ftrace recursion safe: "); 503 504 ret = ftrace_set_filter(&test_recsafe_probe, func_name, len, 1); 505 if (ret) { 506 pr_cont("*Could not set filter* "); 507 goto out; 508 } 509 510 ret = register_ftrace_function(&test_recsafe_probe); 511 if (ret) { 512 pr_cont("*could not register callback* "); 513 goto out; 514 } 515 516 DYN_FTRACE_TEST_NAME(); 517 518 unregister_ftrace_function(&test_recsafe_probe); 519 520 ret = -1; 521 if (trace_selftest_recursion_cnt != 2) { 522 pr_cont("*callback not called expected 2 times (%d)* ", 523 trace_selftest_recursion_cnt); 524 goto out; 525 } 526 527 ret = 0; 528 out: 529 ftrace_enabled = save_ftrace_enabled; 530 531 return ret; 532 } 533 #else 534 # define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; }) 535 # define trace_selftest_function_recursion() ({ 0; }) 536 #endif /* CONFIG_DYNAMIC_FTRACE */ 537 538 static enum { 539 TRACE_SELFTEST_REGS_START, 540 TRACE_SELFTEST_REGS_FOUND, 541 TRACE_SELFTEST_REGS_NOT_FOUND, 542 } trace_selftest_regs_stat; 543 trace_selftest_test_regs_func(unsigned long ip,unsigned long pip,struct ftrace_ops * op,struct pt_regs * pt_regs)544 static void trace_selftest_test_regs_func(unsigned long ip, 545 unsigned long pip, 546 struct ftrace_ops *op, 547 struct pt_regs *pt_regs) 548 { 549 if (pt_regs) 550 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_FOUND; 551 else 552 trace_selftest_regs_stat = TRACE_SELFTEST_REGS_NOT_FOUND; 553 } 554 555 static struct ftrace_ops test_regs_probe = { 556 .func = trace_selftest_test_regs_func, 557 .flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_SAVE_REGS, 558 }; 559 560 static int trace_selftest_function_regs(void)561 trace_selftest_function_regs(void) 562 { 563 int save_ftrace_enabled = ftrace_enabled; 564 char *func_name; 565 int len; 566 int ret; 567 int supported = 0; 568 569 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS 570 supported = 1; 571 #endif 572 573 /* The previous test PASSED */ 574 pr_cont("PASSED\n"); 575 pr_info("Testing ftrace regs%s: ", 576 !supported ? "(no arch support)" : ""); 577 578 /* enable tracing, and record the filter function */ 579 ftrace_enabled = 1; 580 581 /* Handle PPC64 '.' name */ 582 func_name = "*" __stringify(DYN_FTRACE_TEST_NAME); 583 len = strlen(func_name); 584 585 ret = ftrace_set_filter(&test_regs_probe, func_name, len, 1); 586 /* 587 * If DYNAMIC_FTRACE is not set, then we just trace all functions. 588 * This test really doesn't care. 589 */ 590 if (ret && ret != -ENODEV) { 591 pr_cont("*Could not set filter* "); 592 goto out; 593 } 594 595 ret = register_ftrace_function(&test_regs_probe); 596 /* 597 * Now if the arch does not support passing regs, then this should 598 * have failed. 599 */ 600 if (!supported) { 601 if (!ret) { 602 pr_cont("*registered save-regs without arch support* "); 603 goto out; 604 } 605 test_regs_probe.flags |= FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED; 606 ret = register_ftrace_function(&test_regs_probe); 607 } 608 if (ret) { 609 pr_cont("*could not register callback* "); 610 goto out; 611 } 612 613 614 DYN_FTRACE_TEST_NAME(); 615 616 unregister_ftrace_function(&test_regs_probe); 617 618 ret = -1; 619 620 switch (trace_selftest_regs_stat) { 621 case TRACE_SELFTEST_REGS_START: 622 pr_cont("*callback never called* "); 623 goto out; 624 625 case TRACE_SELFTEST_REGS_FOUND: 626 if (supported) 627 break; 628 pr_cont("*callback received regs without arch support* "); 629 goto out; 630 631 case TRACE_SELFTEST_REGS_NOT_FOUND: 632 if (!supported) 633 break; 634 pr_cont("*callback received NULL regs* "); 635 goto out; 636 } 637 638 ret = 0; 639 out: 640 ftrace_enabled = save_ftrace_enabled; 641 642 return ret; 643 } 644 645 /* 646 * Simple verification test of ftrace function tracer. 647 * Enable ftrace, sleep 1/10 second, and then read the trace 648 * buffer to see if all is in order. 649 */ 650 __init int trace_selftest_startup_function(struct tracer * trace,struct trace_array * tr)651 trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr) 652 { 653 int save_ftrace_enabled = ftrace_enabled; 654 unsigned long count; 655 int ret; 656 657 #ifdef CONFIG_DYNAMIC_FTRACE 658 if (ftrace_filter_param) { 659 printk(KERN_CONT " ... kernel command line filter set: force PASS ... "); 660 return 0; 661 } 662 #endif 663 664 /* make sure msleep has been recorded */ 665 msleep(1); 666 667 /* start the tracing */ 668 ftrace_enabled = 1; 669 670 ret = tracer_init(trace, tr); 671 if (ret) { 672 warn_failed_init_tracer(trace, ret); 673 goto out; 674 } 675 676 /* Sleep for a 1/10 of a second */ 677 msleep(100); 678 /* stop the tracing. */ 679 tracing_stop(); 680 ftrace_enabled = 0; 681 682 /* check the trace buffer */ 683 ret = trace_test_buffer(&tr->trace_buffer, &count); 684 685 ftrace_enabled = 1; 686 trace->reset(tr); 687 tracing_start(); 688 689 if (!ret && !count) { 690 printk(KERN_CONT ".. no entries found .."); 691 ret = -1; 692 goto out; 693 } 694 695 ret = trace_selftest_startup_dynamic_tracing(trace, tr, 696 DYN_FTRACE_TEST_NAME); 697 if (ret) 698 goto out; 699 700 ret = trace_selftest_function_recursion(); 701 if (ret) 702 goto out; 703 704 ret = trace_selftest_function_regs(); 705 out: 706 ftrace_enabled = save_ftrace_enabled; 707 708 /* kill ftrace totally if we failed */ 709 if (ret) 710 ftrace_kill(); 711 712 return ret; 713 } 714 #endif /* CONFIG_FUNCTION_TRACER */ 715 716 717 #ifdef CONFIG_FUNCTION_GRAPH_TRACER 718 719 /* Maximum number of functions to trace before diagnosing a hang */ 720 #define GRAPH_MAX_FUNC_TEST 100000000 721 722 static unsigned int graph_hang_thresh; 723 724 /* Wrap the real function entry probe to avoid possible hanging */ trace_graph_entry_watchdog(struct ftrace_graph_ent * trace)725 static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace) 726 { 727 /* This is harmlessly racy, we want to approximately detect a hang */ 728 if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) { 729 ftrace_graph_stop(); 730 printk(KERN_WARNING "BUG: Function graph tracer hang!\n"); 731 if (ftrace_dump_on_oops) { 732 ftrace_dump(DUMP_ALL); 733 /* ftrace_dump() disables tracing */ 734 tracing_on(); 735 } 736 return 0; 737 } 738 739 return trace_graph_entry(trace); 740 } 741 742 /* 743 * Pretty much the same than for the function tracer from which the selftest 744 * has been borrowed. 745 */ 746 __init int trace_selftest_startup_function_graph(struct tracer * trace,struct trace_array * tr)747 trace_selftest_startup_function_graph(struct tracer *trace, 748 struct trace_array *tr) 749 { 750 int ret; 751 unsigned long count; 752 753 #ifdef CONFIG_DYNAMIC_FTRACE 754 if (ftrace_filter_param) { 755 printk(KERN_CONT " ... kernel command line filter set: force PASS ... "); 756 return 0; 757 } 758 #endif 759 760 /* 761 * Simulate the init() callback but we attach a watchdog callback 762 * to detect and recover from possible hangs 763 */ 764 tracing_reset_online_cpus(&tr->trace_buffer); 765 set_graph_array(tr); 766 ret = register_ftrace_graph(&trace_graph_return, 767 &trace_graph_entry_watchdog); 768 if (ret) { 769 warn_failed_init_tracer(trace, ret); 770 goto out; 771 } 772 tracing_start_cmdline_record(); 773 774 /* Sleep for a 1/10 of a second */ 775 msleep(100); 776 777 /* Have we just recovered from a hang? */ 778 if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) { 779 tracing_selftest_disabled = true; 780 ret = -1; 781 goto out; 782 } 783 784 tracing_stop(); 785 786 /* check the trace buffer */ 787 ret = trace_test_buffer(&tr->trace_buffer, &count); 788 789 trace->reset(tr); 790 tracing_start(); 791 792 if (!ret && !count) { 793 printk(KERN_CONT ".. no entries found .."); 794 ret = -1; 795 goto out; 796 } 797 798 /* Don't test dynamic tracing, the function tracer already did */ 799 800 out: 801 /* Stop it if we failed */ 802 if (ret) 803 ftrace_graph_stop(); 804 805 return ret; 806 } 807 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ 808 809 810 #ifdef CONFIG_IRQSOFF_TRACER 811 int trace_selftest_startup_irqsoff(struct tracer * trace,struct trace_array * tr)812 trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr) 813 { 814 unsigned long save_max = tr->max_latency; 815 unsigned long count; 816 int ret; 817 818 /* start the tracing */ 819 ret = tracer_init(trace, tr); 820 if (ret) { 821 warn_failed_init_tracer(trace, ret); 822 return ret; 823 } 824 825 /* reset the max latency */ 826 tr->max_latency = 0; 827 /* disable interrupts for a bit */ 828 local_irq_disable(); 829 udelay(100); 830 local_irq_enable(); 831 832 /* 833 * Stop the tracer to avoid a warning subsequent 834 * to buffer flipping failure because tracing_stop() 835 * disables the tr and max buffers, making flipping impossible 836 * in case of parallels max irqs off latencies. 837 */ 838 trace->stop(tr); 839 /* stop the tracing. */ 840 tracing_stop(); 841 /* check both trace buffers */ 842 ret = trace_test_buffer(&tr->trace_buffer, NULL); 843 if (!ret) 844 ret = trace_test_buffer(&tr->max_buffer, &count); 845 trace->reset(tr); 846 tracing_start(); 847 848 if (!ret && !count) { 849 printk(KERN_CONT ".. no entries found .."); 850 ret = -1; 851 } 852 853 tr->max_latency = save_max; 854 855 return ret; 856 } 857 #endif /* CONFIG_IRQSOFF_TRACER */ 858 859 #ifdef CONFIG_PREEMPT_TRACER 860 int trace_selftest_startup_preemptoff(struct tracer * trace,struct trace_array * tr)861 trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) 862 { 863 unsigned long save_max = tr->max_latency; 864 unsigned long count; 865 int ret; 866 867 /* 868 * Now that the big kernel lock is no longer preemptable, 869 * and this is called with the BKL held, it will always 870 * fail. If preemption is already disabled, simply 871 * pass the test. When the BKL is removed, or becomes 872 * preemptible again, we will once again test this, 873 * so keep it in. 874 */ 875 if (preempt_count()) { 876 printk(KERN_CONT "can not test ... force "); 877 return 0; 878 } 879 880 /* start the tracing */ 881 ret = tracer_init(trace, tr); 882 if (ret) { 883 warn_failed_init_tracer(trace, ret); 884 return ret; 885 } 886 887 /* reset the max latency */ 888 tr->max_latency = 0; 889 /* disable preemption for a bit */ 890 preempt_disable(); 891 udelay(100); 892 preempt_enable(); 893 894 /* 895 * Stop the tracer to avoid a warning subsequent 896 * to buffer flipping failure because tracing_stop() 897 * disables the tr and max buffers, making flipping impossible 898 * in case of parallels max preempt off latencies. 899 */ 900 trace->stop(tr); 901 /* stop the tracing. */ 902 tracing_stop(); 903 /* check both trace buffers */ 904 ret = trace_test_buffer(&tr->trace_buffer, NULL); 905 if (!ret) 906 ret = trace_test_buffer(&tr->max_buffer, &count); 907 trace->reset(tr); 908 tracing_start(); 909 910 if (!ret && !count) { 911 printk(KERN_CONT ".. no entries found .."); 912 ret = -1; 913 } 914 915 tr->max_latency = save_max; 916 917 return ret; 918 } 919 #endif /* CONFIG_PREEMPT_TRACER */ 920 921 #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) 922 int trace_selftest_startup_preemptirqsoff(struct tracer * trace,struct trace_array * tr)923 trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr) 924 { 925 unsigned long save_max = tr->max_latency; 926 unsigned long count; 927 int ret; 928 929 /* 930 * Now that the big kernel lock is no longer preemptable, 931 * and this is called with the BKL held, it will always 932 * fail. If preemption is already disabled, simply 933 * pass the test. When the BKL is removed, or becomes 934 * preemptible again, we will once again test this, 935 * so keep it in. 936 */ 937 if (preempt_count()) { 938 printk(KERN_CONT "can not test ... force "); 939 return 0; 940 } 941 942 /* start the tracing */ 943 ret = tracer_init(trace, tr); 944 if (ret) { 945 warn_failed_init_tracer(trace, ret); 946 goto out_no_start; 947 } 948 949 /* reset the max latency */ 950 tr->max_latency = 0; 951 952 /* disable preemption and interrupts for a bit */ 953 preempt_disable(); 954 local_irq_disable(); 955 udelay(100); 956 preempt_enable(); 957 /* reverse the order of preempt vs irqs */ 958 local_irq_enable(); 959 960 /* 961 * Stop the tracer to avoid a warning subsequent 962 * to buffer flipping failure because tracing_stop() 963 * disables the tr and max buffers, making flipping impossible 964 * in case of parallels max irqs/preempt off latencies. 965 */ 966 trace->stop(tr); 967 /* stop the tracing. */ 968 tracing_stop(); 969 /* check both trace buffers */ 970 ret = trace_test_buffer(&tr->trace_buffer, NULL); 971 if (ret) 972 goto out; 973 974 ret = trace_test_buffer(&tr->max_buffer, &count); 975 if (ret) 976 goto out; 977 978 if (!ret && !count) { 979 printk(KERN_CONT ".. no entries found .."); 980 ret = -1; 981 goto out; 982 } 983 984 /* do the test by disabling interrupts first this time */ 985 tr->max_latency = 0; 986 tracing_start(); 987 trace->start(tr); 988 989 preempt_disable(); 990 local_irq_disable(); 991 udelay(100); 992 preempt_enable(); 993 /* reverse the order of preempt vs irqs */ 994 local_irq_enable(); 995 996 trace->stop(tr); 997 /* stop the tracing. */ 998 tracing_stop(); 999 /* check both trace buffers */ 1000 ret = trace_test_buffer(&tr->trace_buffer, NULL); 1001 if (ret) 1002 goto out; 1003 1004 ret = trace_test_buffer(&tr->max_buffer, &count); 1005 1006 if (!ret && !count) { 1007 printk(KERN_CONT ".. no entries found .."); 1008 ret = -1; 1009 goto out; 1010 } 1011 1012 out: 1013 tracing_start(); 1014 out_no_start: 1015 trace->reset(tr); 1016 tr->max_latency = save_max; 1017 1018 return ret; 1019 } 1020 #endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */ 1021 1022 #ifdef CONFIG_NOP_TRACER 1023 int trace_selftest_startup_nop(struct tracer * trace,struct trace_array * tr)1024 trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr) 1025 { 1026 /* What could possibly go wrong? */ 1027 return 0; 1028 } 1029 #endif 1030 1031 #ifdef CONFIG_SCHED_TRACER 1032 1033 struct wakeup_test_data { 1034 struct completion is_ready; 1035 int go; 1036 }; 1037 trace_wakeup_test_thread(void * data)1038 static int trace_wakeup_test_thread(void *data) 1039 { 1040 /* Make this a -deadline thread */ 1041 static const struct sched_attr attr = { 1042 .sched_policy = SCHED_DEADLINE, 1043 .sched_runtime = 100000ULL, 1044 .sched_deadline = 10000000ULL, 1045 .sched_period = 10000000ULL 1046 }; 1047 struct wakeup_test_data *x = data; 1048 1049 sched_setattr(current, &attr); 1050 1051 /* Make it know we have a new prio */ 1052 complete(&x->is_ready); 1053 1054 /* now go to sleep and let the test wake us up */ 1055 set_current_state(TASK_INTERRUPTIBLE); 1056 while (!x->go) { 1057 schedule(); 1058 set_current_state(TASK_INTERRUPTIBLE); 1059 } 1060 1061 complete(&x->is_ready); 1062 1063 set_current_state(TASK_INTERRUPTIBLE); 1064 1065 /* we are awake, now wait to disappear */ 1066 while (!kthread_should_stop()) { 1067 schedule(); 1068 set_current_state(TASK_INTERRUPTIBLE); 1069 } 1070 1071 __set_current_state(TASK_RUNNING); 1072 1073 return 0; 1074 } 1075 int trace_selftest_startup_wakeup(struct tracer * trace,struct trace_array * tr)1076 trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) 1077 { 1078 unsigned long save_max = tr->max_latency; 1079 struct task_struct *p; 1080 struct wakeup_test_data data; 1081 unsigned long count; 1082 int ret; 1083 1084 memset(&data, 0, sizeof(data)); 1085 1086 init_completion(&data.is_ready); 1087 1088 /* create a -deadline thread */ 1089 p = kthread_run(trace_wakeup_test_thread, &data, "ftrace-test"); 1090 if (IS_ERR(p)) { 1091 printk(KERN_CONT "Failed to create ftrace wakeup test thread "); 1092 return -1; 1093 } 1094 1095 /* make sure the thread is running at -deadline policy */ 1096 wait_for_completion(&data.is_ready); 1097 1098 /* start the tracing */ 1099 ret = tracer_init(trace, tr); 1100 if (ret) { 1101 warn_failed_init_tracer(trace, ret); 1102 return ret; 1103 } 1104 1105 /* reset the max latency */ 1106 tr->max_latency = 0; 1107 1108 while (p->on_rq) { 1109 /* 1110 * Sleep to make sure the -deadline thread is asleep too. 1111 * On virtual machines we can't rely on timings, 1112 * but we want to make sure this test still works. 1113 */ 1114 msleep(100); 1115 } 1116 1117 init_completion(&data.is_ready); 1118 1119 data.go = 1; 1120 /* memory barrier is in the wake_up_process() */ 1121 1122 wake_up_process(p); 1123 1124 /* Wait for the task to wake up */ 1125 wait_for_completion(&data.is_ready); 1126 1127 /* stop the tracing. */ 1128 tracing_stop(); 1129 /* check both trace buffers */ 1130 ret = trace_test_buffer(&tr->trace_buffer, NULL); 1131 if (!ret) 1132 ret = trace_test_buffer(&tr->max_buffer, &count); 1133 1134 1135 trace->reset(tr); 1136 tracing_start(); 1137 1138 tr->max_latency = save_max; 1139 1140 /* kill the thread */ 1141 kthread_stop(p); 1142 1143 if (!ret && !count) { 1144 printk(KERN_CONT ".. no entries found .."); 1145 ret = -1; 1146 } 1147 1148 return ret; 1149 } 1150 #endif /* CONFIG_SCHED_TRACER */ 1151 1152 #ifdef CONFIG_CONTEXT_SWITCH_TRACER 1153 int trace_selftest_startup_sched_switch(struct tracer * trace,struct trace_array * tr)1154 trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr) 1155 { 1156 unsigned long count; 1157 int ret; 1158 1159 /* start the tracing */ 1160 ret = tracer_init(trace, tr); 1161 if (ret) { 1162 warn_failed_init_tracer(trace, ret); 1163 return ret; 1164 } 1165 1166 /* Sleep for a 1/10 of a second */ 1167 msleep(100); 1168 /* stop the tracing. */ 1169 tracing_stop(); 1170 /* check the trace buffer */ 1171 ret = trace_test_buffer(&tr->trace_buffer, &count); 1172 trace->reset(tr); 1173 tracing_start(); 1174 1175 if (!ret && !count) { 1176 printk(KERN_CONT ".. no entries found .."); 1177 ret = -1; 1178 } 1179 1180 return ret; 1181 } 1182 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */ 1183 1184 #ifdef CONFIG_BRANCH_TRACER 1185 int trace_selftest_startup_branch(struct tracer * trace,struct trace_array * tr)1186 trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr) 1187 { 1188 unsigned long count; 1189 int ret; 1190 1191 /* start the tracing */ 1192 ret = tracer_init(trace, tr); 1193 if (ret) { 1194 warn_failed_init_tracer(trace, ret); 1195 return ret; 1196 } 1197 1198 /* Sleep for a 1/10 of a second */ 1199 msleep(100); 1200 /* stop the tracing. */ 1201 tracing_stop(); 1202 /* check the trace buffer */ 1203 ret = trace_test_buffer(&tr->trace_buffer, &count); 1204 trace->reset(tr); 1205 tracing_start(); 1206 1207 if (!ret && !count) { 1208 printk(KERN_CONT ".. no entries found .."); 1209 ret = -1; 1210 } 1211 1212 return ret; 1213 } 1214 #endif /* CONFIG_BRANCH_TRACER */ 1215 1216