yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 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 | { |
| 108 | trace_selftest_test_probe1_cnt++; |
| 109 | } |
| 110 | |
| 111 | static int trace_selftest_test_probe2_cnt; |
| 112 | static void trace_selftest_test_probe2_func(unsigned long ip, |
| 113 | unsigned long pip) |
| 114 | { |
| 115 | trace_selftest_test_probe2_cnt++; |
| 116 | } |
| 117 | |
| 118 | static int trace_selftest_test_probe3_cnt; |
| 119 | static void trace_selftest_test_probe3_func(unsigned long ip, |
| 120 | unsigned long pip) |
| 121 | { |
| 122 | trace_selftest_test_probe3_cnt++; |
| 123 | } |
| 124 | |
| 125 | static int trace_selftest_test_global_cnt; |
| 126 | static void trace_selftest_test_global_func(unsigned long ip, |
| 127 | unsigned long pip) |
| 128 | { |
| 129 | trace_selftest_test_global_cnt++; |
| 130 | } |
| 131 | |
| 132 | static int trace_selftest_test_dyn_cnt; |
| 133 | static void trace_selftest_test_dyn_func(unsigned long ip, |
| 134 | unsigned long pip) |
| 135 | { |
| 136 | trace_selftest_test_dyn_cnt++; |
| 137 | } |
| 138 | |
| 139 | static struct ftrace_ops test_probe1 = { |
| 140 | .func = trace_selftest_test_probe1_func, |
| 141 | }; |
| 142 | |
| 143 | static struct ftrace_ops test_probe2 = { |
| 144 | .func = trace_selftest_test_probe2_func, |
| 145 | }; |
| 146 | |
| 147 | static struct ftrace_ops test_probe3 = { |
| 148 | .func = trace_selftest_test_probe3_func, |
| 149 | }; |
| 150 | |
| 151 | static struct ftrace_ops test_global = { |
| 152 | .func = trace_selftest_test_global_func, |
| 153 | .flags = FTRACE_OPS_FL_GLOBAL, |
| 154 | }; |
| 155 | |
| 156 | static void print_counts(void) |
| 157 | { |
| 158 | printk("(%d %d %d %d %d) ", |
| 159 | trace_selftest_test_probe1_cnt, |
| 160 | trace_selftest_test_probe2_cnt, |
| 161 | trace_selftest_test_probe3_cnt, |
| 162 | trace_selftest_test_global_cnt, |
| 163 | trace_selftest_test_dyn_cnt); |
| 164 | } |
| 165 | |
| 166 | static void reset_counts(void) |
| 167 | { |
| 168 | trace_selftest_test_probe1_cnt = 0; |
| 169 | trace_selftest_test_probe2_cnt = 0; |
| 170 | trace_selftest_test_probe3_cnt = 0; |
| 171 | trace_selftest_test_global_cnt = 0; |
| 172 | trace_selftest_test_dyn_cnt = 0; |
| 173 | } |
| 174 | |
| 175 | static int trace_selftest_ops(int cnt) |
| 176 | { |
| 177 | int save_ftrace_enabled = ftrace_enabled; |
| 178 | struct ftrace_ops *dyn_ops; |
| 179 | char *func1_name; |
| 180 | char *func2_name; |
| 181 | int len1; |
| 182 | int len2; |
| 183 | int ret = -1; |
| 184 | |
| 185 | printk(KERN_CONT "PASSED\n"); |
| 186 | pr_info("Testing dynamic ftrace ops #%d: ", cnt); |
| 187 | |
| 188 | ftrace_enabled = 1; |
| 189 | reset_counts(); |
| 190 | |
| 191 | /* Handle PPC64 '.' name */ |
| 192 | func1_name = "*" __stringify(DYN_FTRACE_TEST_NAME); |
| 193 | func2_name = "*" __stringify(DYN_FTRACE_TEST_NAME2); |
| 194 | len1 = strlen(func1_name); |
| 195 | len2 = strlen(func2_name); |
| 196 | |
| 197 | /* |
| 198 | * Probe 1 will trace function 1. |
| 199 | * Probe 2 will trace function 2. |
| 200 | * Probe 3 will trace functions 1 and 2. |
| 201 | */ |
| 202 | ftrace_set_filter(&test_probe1, func1_name, len1, 1); |
| 203 | ftrace_set_filter(&test_probe2, func2_name, len2, 1); |
| 204 | ftrace_set_filter(&test_probe3, func1_name, len1, 1); |
| 205 | ftrace_set_filter(&test_probe3, func2_name, len2, 0); |
| 206 | |
| 207 | register_ftrace_function(&test_probe1); |
| 208 | register_ftrace_function(&test_probe2); |
| 209 | register_ftrace_function(&test_probe3); |
| 210 | register_ftrace_function(&test_global); |
| 211 | |
| 212 | DYN_FTRACE_TEST_NAME(); |
| 213 | |
| 214 | print_counts(); |
| 215 | |
| 216 | if (trace_selftest_test_probe1_cnt != 1) |
| 217 | goto out; |
| 218 | if (trace_selftest_test_probe2_cnt != 0) |
| 219 | goto out; |
| 220 | if (trace_selftest_test_probe3_cnt != 1) |
| 221 | goto out; |
| 222 | if (trace_selftest_test_global_cnt == 0) |
| 223 | goto out; |
| 224 | |
| 225 | DYN_FTRACE_TEST_NAME2(); |
| 226 | |
| 227 | print_counts(); |
| 228 | |
| 229 | if (trace_selftest_test_probe1_cnt != 1) |
| 230 | goto out; |
| 231 | if (trace_selftest_test_probe2_cnt != 1) |
| 232 | goto out; |
| 233 | if (trace_selftest_test_probe3_cnt != 2) |
| 234 | goto out; |
| 235 | |
| 236 | /* Add a dynamic probe */ |
| 237 | dyn_ops = kzalloc(sizeof(*dyn_ops), GFP_KERNEL); |
| 238 | if (!dyn_ops) { |
| 239 | printk("MEMORY ERROR "); |
| 240 | goto out; |
| 241 | } |
| 242 | |
| 243 | dyn_ops->func = trace_selftest_test_dyn_func; |
| 244 | |
| 245 | register_ftrace_function(dyn_ops); |
| 246 | |
| 247 | trace_selftest_test_global_cnt = 0; |
| 248 | |
| 249 | DYN_FTRACE_TEST_NAME(); |
| 250 | |
| 251 | print_counts(); |
| 252 | |
| 253 | if (trace_selftest_test_probe1_cnt != 2) |
| 254 | goto out_free; |
| 255 | if (trace_selftest_test_probe2_cnt != 1) |
| 256 | goto out_free; |
| 257 | if (trace_selftest_test_probe3_cnt != 3) |
| 258 | goto out_free; |
| 259 | if (trace_selftest_test_global_cnt == 0) |
| 260 | goto out; |
| 261 | if (trace_selftest_test_dyn_cnt == 0) |
| 262 | goto out_free; |
| 263 | |
| 264 | DYN_FTRACE_TEST_NAME2(); |
| 265 | |
| 266 | print_counts(); |
| 267 | |
| 268 | if (trace_selftest_test_probe1_cnt != 2) |
| 269 | goto out_free; |
| 270 | if (trace_selftest_test_probe2_cnt != 2) |
| 271 | goto out_free; |
| 272 | if (trace_selftest_test_probe3_cnt != 4) |
| 273 | goto out_free; |
| 274 | |
| 275 | ret = 0; |
| 276 | out_free: |
| 277 | unregister_ftrace_function(dyn_ops); |
| 278 | kfree(dyn_ops); |
| 279 | |
| 280 | out: |
| 281 | /* Purposely unregister in the same order */ |
| 282 | unregister_ftrace_function(&test_probe1); |
| 283 | unregister_ftrace_function(&test_probe2); |
| 284 | unregister_ftrace_function(&test_probe3); |
| 285 | unregister_ftrace_function(&test_global); |
| 286 | |
| 287 | /* Make sure everything is off */ |
| 288 | reset_counts(); |
| 289 | DYN_FTRACE_TEST_NAME(); |
| 290 | DYN_FTRACE_TEST_NAME(); |
| 291 | |
| 292 | if (trace_selftest_test_probe1_cnt || |
| 293 | trace_selftest_test_probe2_cnt || |
| 294 | trace_selftest_test_probe3_cnt || |
| 295 | trace_selftest_test_global_cnt || |
| 296 | trace_selftest_test_dyn_cnt) |
| 297 | ret = -1; |
| 298 | |
| 299 | ftrace_enabled = save_ftrace_enabled; |
| 300 | |
| 301 | return ret; |
| 302 | } |
| 303 | |
| 304 | /* Test dynamic code modification and ftrace filters */ |
| 305 | int trace_selftest_startup_dynamic_tracing(struct tracer *trace, |
| 306 | struct trace_array *tr, |
| 307 | int (*func)(void)) |
| 308 | { |
| 309 | int save_ftrace_enabled = ftrace_enabled; |
| 310 | int save_tracer_enabled = tracer_enabled; |
| 311 | unsigned long count; |
| 312 | char *func_name; |
| 313 | int ret; |
| 314 | |
| 315 | /* The ftrace test PASSED */ |
| 316 | printk(KERN_CONT "PASSED\n"); |
| 317 | pr_info("Testing dynamic ftrace: "); |
| 318 | |
| 319 | /* enable tracing, and record the filter function */ |
| 320 | ftrace_enabled = 1; |
| 321 | tracer_enabled = 1; |
| 322 | |
| 323 | /* passed in by parameter to fool gcc from optimizing */ |
| 324 | func(); |
| 325 | |
| 326 | /* |
| 327 | * Some archs *cough*PowerPC*cough* add characters to the |
| 328 | * start of the function names. We simply put a '*' to |
| 329 | * accommodate them. |
| 330 | */ |
| 331 | func_name = "*" __stringify(DYN_FTRACE_TEST_NAME); |
| 332 | |
| 333 | /* filter only on our function */ |
| 334 | ftrace_set_global_filter(func_name, strlen(func_name), 1); |
| 335 | |
| 336 | /* enable tracing */ |
| 337 | ret = tracer_init(trace, tr); |
| 338 | if (ret) { |
| 339 | warn_failed_init_tracer(trace, ret); |
| 340 | goto out; |
| 341 | } |
| 342 | |
| 343 | /* Sleep for a 1/10 of a second */ |
| 344 | msleep(100); |
| 345 | |
| 346 | /* we should have nothing in the buffer */ |
| 347 | ret = trace_test_buffer(tr, &count); |
| 348 | if (ret) |
| 349 | goto out; |
| 350 | |
| 351 | if (count) { |
| 352 | ret = -1; |
| 353 | printk(KERN_CONT ".. filter did not filter .. "); |
| 354 | goto out; |
| 355 | } |
| 356 | |
| 357 | /* call our function again */ |
| 358 | func(); |
| 359 | |
| 360 | /* sleep again */ |
| 361 | msleep(100); |
| 362 | |
| 363 | /* stop the tracing. */ |
| 364 | tracing_stop(); |
| 365 | ftrace_enabled = 0; |
| 366 | |
| 367 | /* check the trace buffer */ |
| 368 | ret = trace_test_buffer(tr, &count); |
| 369 | tracing_start(); |
| 370 | |
| 371 | /* we should only have one item */ |
| 372 | if (!ret && count != 1) { |
| 373 | trace->reset(tr); |
| 374 | printk(KERN_CONT ".. filter failed count=%ld ..", count); |
| 375 | ret = -1; |
| 376 | goto out; |
| 377 | } |
| 378 | |
| 379 | /* Test the ops with global tracing running */ |
| 380 | ret = trace_selftest_ops(1); |
| 381 | trace->reset(tr); |
| 382 | |
| 383 | out: |
| 384 | ftrace_enabled = save_ftrace_enabled; |
| 385 | tracer_enabled = save_tracer_enabled; |
| 386 | |
| 387 | /* Enable tracing on all functions again */ |
| 388 | ftrace_set_global_filter(NULL, 0, 1); |
| 389 | |
| 390 | /* Test the ops with global tracing off */ |
| 391 | if (!ret) |
| 392 | ret = trace_selftest_ops(2); |
| 393 | |
| 394 | return ret; |
| 395 | } |
| 396 | #else |
| 397 | # define trace_selftest_startup_dynamic_tracing(trace, tr, func) ({ 0; }) |
| 398 | #endif /* CONFIG_DYNAMIC_FTRACE */ |
| 399 | |
| 400 | /* |
| 401 | * Simple verification test of ftrace function tracer. |
| 402 | * Enable ftrace, sleep 1/10 second, and then read the trace |
| 403 | * buffer to see if all is in order. |
| 404 | */ |
| 405 | int |
| 406 | trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr) |
| 407 | { |
| 408 | int save_ftrace_enabled = ftrace_enabled; |
| 409 | int save_tracer_enabled = tracer_enabled; |
| 410 | unsigned long count; |
| 411 | int ret; |
| 412 | |
| 413 | /* make sure msleep has been recorded */ |
| 414 | msleep(1); |
| 415 | |
| 416 | /* start the tracing */ |
| 417 | ftrace_enabled = 1; |
| 418 | tracer_enabled = 1; |
| 419 | |
| 420 | ret = tracer_init(trace, tr); |
| 421 | if (ret) { |
| 422 | warn_failed_init_tracer(trace, ret); |
| 423 | goto out; |
| 424 | } |
| 425 | |
| 426 | /* Sleep for a 1/10 of a second */ |
| 427 | msleep(100); |
| 428 | /* stop the tracing. */ |
| 429 | tracing_stop(); |
| 430 | ftrace_enabled = 0; |
| 431 | |
| 432 | /* check the trace buffer */ |
| 433 | ret = trace_test_buffer(tr, &count); |
| 434 | trace->reset(tr); |
| 435 | tracing_start(); |
| 436 | |
| 437 | if (!ret && !count) { |
| 438 | printk(KERN_CONT ".. no entries found .."); |
| 439 | ret = -1; |
| 440 | goto out; |
| 441 | } |
| 442 | |
| 443 | ret = trace_selftest_startup_dynamic_tracing(trace, tr, |
| 444 | DYN_FTRACE_TEST_NAME); |
| 445 | |
| 446 | out: |
| 447 | ftrace_enabled = save_ftrace_enabled; |
| 448 | tracer_enabled = save_tracer_enabled; |
| 449 | |
| 450 | /* kill ftrace totally if we failed */ |
| 451 | if (ret) |
| 452 | ftrace_kill(); |
| 453 | |
| 454 | return ret; |
| 455 | } |
| 456 | #endif /* CONFIG_FUNCTION_TRACER */ |
| 457 | |
| 458 | |
| 459 | #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| 460 | |
| 461 | /* Maximum number of functions to trace before diagnosing a hang */ |
| 462 | #define GRAPH_MAX_FUNC_TEST 100000000 |
| 463 | |
| 464 | static unsigned int graph_hang_thresh; |
| 465 | |
| 466 | /* Wrap the real function entry probe to avoid possible hanging */ |
| 467 | static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace) |
| 468 | { |
| 469 | /* This is harmlessly racy, we want to approximately detect a hang */ |
| 470 | if (unlikely(++graph_hang_thresh > GRAPH_MAX_FUNC_TEST)) { |
| 471 | ftrace_graph_stop(); |
| 472 | printk(KERN_WARNING "BUG: Function graph tracer hang!\n"); |
| 473 | if (ftrace_dump_on_oops) { |
| 474 | ftrace_dump(DUMP_ALL); |
| 475 | /* ftrace_dump() disables tracing */ |
| 476 | tracing_on(); |
| 477 | } |
| 478 | return 0; |
| 479 | } |
| 480 | |
| 481 | return trace_graph_entry(trace); |
| 482 | } |
| 483 | |
| 484 | /* |
| 485 | * Pretty much the same than for the function tracer from which the selftest |
| 486 | * has been borrowed. |
| 487 | */ |
| 488 | int |
| 489 | trace_selftest_startup_function_graph(struct tracer *trace, |
| 490 | struct trace_array *tr) |
| 491 | { |
| 492 | int ret; |
| 493 | unsigned long count; |
| 494 | |
| 495 | /* |
| 496 | * Simulate the init() callback but we attach a watchdog callback |
| 497 | * to detect and recover from possible hangs |
| 498 | */ |
| 499 | tracing_reset_online_cpus(tr); |
| 500 | set_graph_array(tr); |
| 501 | ret = register_ftrace_graph(&trace_graph_return, |
| 502 | &trace_graph_entry_watchdog); |
| 503 | if (ret) { |
| 504 | warn_failed_init_tracer(trace, ret); |
| 505 | goto out; |
| 506 | } |
| 507 | tracing_start_cmdline_record(); |
| 508 | |
| 509 | /* Sleep for a 1/10 of a second */ |
| 510 | msleep(100); |
| 511 | |
| 512 | /* Have we just recovered from a hang? */ |
| 513 | if (graph_hang_thresh > GRAPH_MAX_FUNC_TEST) { |
| 514 | tracing_selftest_disabled = true; |
| 515 | ret = -1; |
| 516 | goto out; |
| 517 | } |
| 518 | |
| 519 | tracing_stop(); |
| 520 | |
| 521 | /* check the trace buffer */ |
| 522 | ret = trace_test_buffer(tr, &count); |
| 523 | |
| 524 | trace->reset(tr); |
| 525 | tracing_start(); |
| 526 | |
| 527 | if (!ret && !count) { |
| 528 | printk(KERN_CONT ".. no entries found .."); |
| 529 | ret = -1; |
| 530 | goto out; |
| 531 | } |
| 532 | |
| 533 | /* Don't test dynamic tracing, the function tracer already did */ |
| 534 | |
| 535 | out: |
| 536 | /* Stop it if we failed */ |
| 537 | if (ret) |
| 538 | ftrace_graph_stop(); |
| 539 | |
| 540 | return ret; |
| 541 | } |
| 542 | #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
| 543 | |
| 544 | |
| 545 | #ifdef CONFIG_IRQSOFF_TRACER |
| 546 | int |
| 547 | trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr) |
| 548 | { |
| 549 | unsigned long save_max = tracing_max_latency; |
| 550 | unsigned long count; |
| 551 | int ret; |
| 552 | |
| 553 | /* start the tracing */ |
| 554 | ret = tracer_init(trace, tr); |
| 555 | if (ret) { |
| 556 | warn_failed_init_tracer(trace, ret); |
| 557 | return ret; |
| 558 | } |
| 559 | |
| 560 | /* reset the max latency */ |
| 561 | tracing_max_latency = 0; |
| 562 | /* disable interrupts for a bit */ |
| 563 | local_irq_disable(); |
| 564 | udelay(100); |
| 565 | local_irq_enable(); |
| 566 | |
| 567 | /* |
| 568 | * Stop the tracer to avoid a warning subsequent |
| 569 | * to buffer flipping failure because tracing_stop() |
| 570 | * disables the tr and max buffers, making flipping impossible |
| 571 | * in case of parallels max irqs off latencies. |
| 572 | */ |
| 573 | trace->stop(tr); |
| 574 | /* stop the tracing. */ |
| 575 | tracing_stop(); |
| 576 | /* check both trace buffers */ |
| 577 | ret = trace_test_buffer(tr, NULL); |
| 578 | if (!ret) |
| 579 | ret = trace_test_buffer(&max_tr, &count); |
| 580 | trace->reset(tr); |
| 581 | tracing_start(); |
| 582 | |
| 583 | if (!ret && !count) { |
| 584 | printk(KERN_CONT ".. no entries found .."); |
| 585 | ret = -1; |
| 586 | } |
| 587 | |
| 588 | tracing_max_latency = save_max; |
| 589 | |
| 590 | return ret; |
| 591 | } |
| 592 | #endif /* CONFIG_IRQSOFF_TRACER */ |
| 593 | |
| 594 | #ifdef CONFIG_PREEMPT_TRACER |
| 595 | int |
| 596 | trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr) |
| 597 | { |
| 598 | unsigned long save_max = tracing_max_latency; |
| 599 | unsigned long count; |
| 600 | int ret; |
| 601 | |
| 602 | /* |
| 603 | * Now that the big kernel lock is no longer preemptable, |
| 604 | * and this is called with the BKL held, it will always |
| 605 | * fail. If preemption is already disabled, simply |
| 606 | * pass the test. When the BKL is removed, or becomes |
| 607 | * preemptible again, we will once again test this, |
| 608 | * so keep it in. |
| 609 | */ |
| 610 | if (preempt_count()) { |
| 611 | printk(KERN_CONT "can not test ... force "); |
| 612 | return 0; |
| 613 | } |
| 614 | |
| 615 | /* start the tracing */ |
| 616 | ret = tracer_init(trace, tr); |
| 617 | if (ret) { |
| 618 | warn_failed_init_tracer(trace, ret); |
| 619 | return ret; |
| 620 | } |
| 621 | |
| 622 | /* reset the max latency */ |
| 623 | tracing_max_latency = 0; |
| 624 | /* disable preemption for a bit */ |
| 625 | preempt_disable(); |
| 626 | udelay(100); |
| 627 | preempt_enable(); |
| 628 | |
| 629 | /* |
| 630 | * Stop the tracer to avoid a warning subsequent |
| 631 | * to buffer flipping failure because tracing_stop() |
| 632 | * disables the tr and max buffers, making flipping impossible |
| 633 | * in case of parallels max preempt off latencies. |
| 634 | */ |
| 635 | trace->stop(tr); |
| 636 | /* stop the tracing. */ |
| 637 | tracing_stop(); |
| 638 | /* check both trace buffers */ |
| 639 | ret = trace_test_buffer(tr, NULL); |
| 640 | if (!ret) |
| 641 | ret = trace_test_buffer(&max_tr, &count); |
| 642 | trace->reset(tr); |
| 643 | tracing_start(); |
| 644 | |
| 645 | if (!ret && !count) { |
| 646 | printk(KERN_CONT ".. no entries found .."); |
| 647 | ret = -1; |
| 648 | } |
| 649 | |
| 650 | tracing_max_latency = save_max; |
| 651 | |
| 652 | return ret; |
| 653 | } |
| 654 | #endif /* CONFIG_PREEMPT_TRACER */ |
| 655 | |
| 656 | #if defined(CONFIG_IRQSOFF_TRACER) && defined(CONFIG_PREEMPT_TRACER) |
| 657 | int |
| 658 | trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *tr) |
| 659 | { |
| 660 | unsigned long save_max = tracing_max_latency; |
| 661 | unsigned long count; |
| 662 | int ret; |
| 663 | |
| 664 | /* |
| 665 | * Now that the big kernel lock is no longer preemptable, |
| 666 | * and this is called with the BKL held, it will always |
| 667 | * fail. If preemption is already disabled, simply |
| 668 | * pass the test. When the BKL is removed, or becomes |
| 669 | * preemptible again, we will once again test this, |
| 670 | * so keep it in. |
| 671 | */ |
| 672 | if (preempt_count()) { |
| 673 | printk(KERN_CONT "can not test ... force "); |
| 674 | return 0; |
| 675 | } |
| 676 | |
| 677 | /* start the tracing */ |
| 678 | ret = tracer_init(trace, tr); |
| 679 | if (ret) { |
| 680 | warn_failed_init_tracer(trace, ret); |
| 681 | goto out_no_start; |
| 682 | } |
| 683 | |
| 684 | /* reset the max latency */ |
| 685 | tracing_max_latency = 0; |
| 686 | |
| 687 | /* disable preemption and interrupts for a bit */ |
| 688 | preempt_disable(); |
| 689 | local_irq_disable(); |
| 690 | udelay(100); |
| 691 | preempt_enable(); |
| 692 | /* reverse the order of preempt vs irqs */ |
| 693 | local_irq_enable(); |
| 694 | |
| 695 | /* |
| 696 | * Stop the tracer to avoid a warning subsequent |
| 697 | * to buffer flipping failure because tracing_stop() |
| 698 | * disables the tr and max buffers, making flipping impossible |
| 699 | * in case of parallels max irqs/preempt off latencies. |
| 700 | */ |
| 701 | trace->stop(tr); |
| 702 | /* stop the tracing. */ |
| 703 | tracing_stop(); |
| 704 | /* check both trace buffers */ |
| 705 | ret = trace_test_buffer(tr, NULL); |
| 706 | if (ret) |
| 707 | goto out; |
| 708 | |
| 709 | ret = trace_test_buffer(&max_tr, &count); |
| 710 | if (ret) |
| 711 | goto out; |
| 712 | |
| 713 | if (!ret && !count) { |
| 714 | printk(KERN_CONT ".. no entries found .."); |
| 715 | ret = -1; |
| 716 | goto out; |
| 717 | } |
| 718 | |
| 719 | /* do the test by disabling interrupts first this time */ |
| 720 | tracing_max_latency = 0; |
| 721 | tracing_start(); |
| 722 | trace->start(tr); |
| 723 | |
| 724 | preempt_disable(); |
| 725 | local_irq_disable(); |
| 726 | udelay(100); |
| 727 | preempt_enable(); |
| 728 | /* reverse the order of preempt vs irqs */ |
| 729 | local_irq_enable(); |
| 730 | |
| 731 | trace->stop(tr); |
| 732 | /* stop the tracing. */ |
| 733 | tracing_stop(); |
| 734 | /* check both trace buffers */ |
| 735 | ret = trace_test_buffer(tr, NULL); |
| 736 | if (ret) |
| 737 | goto out; |
| 738 | |
| 739 | ret = trace_test_buffer(&max_tr, &count); |
| 740 | |
| 741 | if (!ret && !count) { |
| 742 | printk(KERN_CONT ".. no entries found .."); |
| 743 | ret = -1; |
| 744 | goto out; |
| 745 | } |
| 746 | |
| 747 | out: |
| 748 | tracing_start(); |
| 749 | out_no_start: |
| 750 | trace->reset(tr); |
| 751 | tracing_max_latency = save_max; |
| 752 | |
| 753 | return ret; |
| 754 | } |
| 755 | #endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */ |
| 756 | |
| 757 | #ifdef CONFIG_NOP_TRACER |
| 758 | int |
| 759 | trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr) |
| 760 | { |
| 761 | /* What could possibly go wrong? */ |
| 762 | return 0; |
| 763 | } |
| 764 | #endif |
| 765 | |
| 766 | #ifdef CONFIG_SCHED_TRACER |
| 767 | static int trace_wakeup_test_thread(void *data) |
| 768 | { |
| 769 | /* Make this a RT thread, doesn't need to be too high */ |
| 770 | static const struct sched_param param = { .sched_priority = 5 }; |
| 771 | struct completion *x = data; |
| 772 | |
| 773 | sched_setscheduler(current, SCHED_FIFO, ¶m); |
| 774 | |
| 775 | /* Make it know we have a new prio */ |
| 776 | complete(x); |
| 777 | |
| 778 | /* now go to sleep and let the test wake us up */ |
| 779 | set_current_state(TASK_INTERRUPTIBLE); |
| 780 | schedule(); |
| 781 | |
| 782 | /* we are awake, now wait to disappear */ |
| 783 | while (!kthread_should_stop()) { |
| 784 | /* |
| 785 | * This is an RT task, do short sleeps to let |
| 786 | * others run. |
| 787 | */ |
| 788 | msleep(100); |
| 789 | } |
| 790 | |
| 791 | return 0; |
| 792 | } |
| 793 | |
| 794 | int |
| 795 | trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) |
| 796 | { |
| 797 | unsigned long save_max = tracing_max_latency; |
| 798 | struct task_struct *p; |
| 799 | struct completion isrt; |
| 800 | unsigned long count; |
| 801 | int ret; |
| 802 | |
| 803 | init_completion(&isrt); |
| 804 | |
| 805 | /* create a high prio thread */ |
| 806 | p = kthread_run(trace_wakeup_test_thread, &isrt, "ftrace-test"); |
| 807 | if (IS_ERR(p)) { |
| 808 | printk(KERN_CONT "Failed to create ftrace wakeup test thread "); |
| 809 | return -1; |
| 810 | } |
| 811 | |
| 812 | /* make sure the thread is running at an RT prio */ |
| 813 | wait_for_completion(&isrt); |
| 814 | |
| 815 | /* start the tracing */ |
| 816 | ret = tracer_init(trace, tr); |
| 817 | if (ret) { |
| 818 | warn_failed_init_tracer(trace, ret); |
| 819 | return ret; |
| 820 | } |
| 821 | |
| 822 | /* reset the max latency */ |
| 823 | tracing_max_latency = 0; |
| 824 | |
| 825 | /* sleep to let the RT thread sleep too */ |
| 826 | msleep(100); |
| 827 | |
| 828 | /* |
| 829 | * Yes this is slightly racy. It is possible that for some |
| 830 | * strange reason that the RT thread we created, did not |
| 831 | * call schedule for 100ms after doing the completion, |
| 832 | * and we do a wakeup on a task that already is awake. |
| 833 | * But that is extremely unlikely, and the worst thing that |
| 834 | * happens in such a case, is that we disable tracing. |
| 835 | * Honestly, if this race does happen something is horrible |
| 836 | * wrong with the system. |
| 837 | */ |
| 838 | |
| 839 | wake_up_process(p); |
| 840 | |
| 841 | /* give a little time to let the thread wake up */ |
| 842 | msleep(100); |
| 843 | |
| 844 | /* stop the tracing. */ |
| 845 | tracing_stop(); |
| 846 | /* check both trace buffers */ |
| 847 | ret = trace_test_buffer(tr, NULL); |
| 848 | if (!ret) |
| 849 | ret = trace_test_buffer(&max_tr, &count); |
| 850 | |
| 851 | |
| 852 | trace->reset(tr); |
| 853 | tracing_start(); |
| 854 | |
| 855 | tracing_max_latency = save_max; |
| 856 | |
| 857 | /* kill the thread */ |
| 858 | kthread_stop(p); |
| 859 | |
| 860 | if (!ret && !count) { |
| 861 | printk(KERN_CONT ".. no entries found .."); |
| 862 | ret = -1; |
| 863 | } |
| 864 | |
| 865 | return ret; |
| 866 | } |
| 867 | #endif /* CONFIG_SCHED_TRACER */ |
| 868 | |
| 869 | #ifdef CONFIG_CONTEXT_SWITCH_TRACER |
| 870 | int |
| 871 | trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr) |
| 872 | { |
| 873 | unsigned long count; |
| 874 | int ret; |
| 875 | |
| 876 | /* start the tracing */ |
| 877 | ret = tracer_init(trace, tr); |
| 878 | if (ret) { |
| 879 | warn_failed_init_tracer(trace, ret); |
| 880 | return ret; |
| 881 | } |
| 882 | |
| 883 | /* Sleep for a 1/10 of a second */ |
| 884 | msleep(100); |
| 885 | /* stop the tracing. */ |
| 886 | tracing_stop(); |
| 887 | /* check the trace buffer */ |
| 888 | ret = trace_test_buffer(tr, &count); |
| 889 | trace->reset(tr); |
| 890 | tracing_start(); |
| 891 | |
| 892 | if (!ret && !count) { |
| 893 | printk(KERN_CONT ".. no entries found .."); |
| 894 | ret = -1; |
| 895 | } |
| 896 | |
| 897 | return ret; |
| 898 | } |
| 899 | #endif /* CONFIG_CONTEXT_SWITCH_TRACER */ |
| 900 | |
| 901 | #ifdef CONFIG_BRANCH_TRACER |
| 902 | int |
| 903 | trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr) |
| 904 | { |
| 905 | unsigned long count; |
| 906 | int ret; |
| 907 | |
| 908 | /* start the tracing */ |
| 909 | ret = tracer_init(trace, tr); |
| 910 | if (ret) { |
| 911 | warn_failed_init_tracer(trace, ret); |
| 912 | return ret; |
| 913 | } |
| 914 | |
| 915 | /* Sleep for a 1/10 of a second */ |
| 916 | msleep(100); |
| 917 | /* stop the tracing. */ |
| 918 | tracing_stop(); |
| 919 | /* check the trace buffer */ |
| 920 | ret = trace_test_buffer(tr, &count); |
| 921 | trace->reset(tr); |
| 922 | tracing_start(); |
| 923 | |
| 924 | if (!ret && !count) { |
| 925 | printk(KERN_CONT ".. no entries found .."); |
| 926 | ret = -1; |
| 927 | } |
| 928 | |
| 929 | return ret; |
| 930 | } |
| 931 | #endif /* CONFIG_BRANCH_TRACER */ |
| 932 | |