1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Kprobes-based tracing events 4 * 5 * Created by Masami Hiramatsu <mhiramat@redhat.com> 6 * 7 */ 8 #define pr_fmt(fmt) "trace_kprobe: " fmt 9 10 #include <linux/bpf-cgroup.h> 11 #include <linux/cleanup.h> 12 #include <linux/error-injection.h> 13 #include <linux/module.h> 14 #include <linux/rculist.h> 15 #include <linux/security.h> 16 #include <linux/uaccess.h> 17 18 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */ 19 20 #include "trace_dynevent.h" 21 #include "trace_kprobe_selftest.h" 22 #include "trace_probe.h" 23 #include "trace_probe_kernel.h" 24 #include "trace_probe_tmpl.h" 25 26 #define KPROBE_EVENT_SYSTEM "kprobes" 27 #define KRETPROBE_MAXACTIVE_MAX 4096 28 29 /* Kprobe early definition from command line */ 30 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata; 31 32 static int __init set_kprobe_boot_events(char *str) 33 { 34 strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE); 35 disable_tracing_selftest("running kprobe events"); 36 37 return 1; 38 } 39 __setup("kprobe_event=", set_kprobe_boot_events); 40 41 static int trace_kprobe_create(const char *raw_command); 42 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev); 43 static int trace_kprobe_release(struct dyn_event *ev); 44 static bool trace_kprobe_is_busy(struct dyn_event *ev); 45 static bool trace_kprobe_match(const char *system, const char *event, 46 int argc, const char **argv, struct dyn_event *ev); 47 48 static struct dyn_event_operations trace_kprobe_ops = { 49 .create = trace_kprobe_create, 50 .show = trace_kprobe_show, 51 .is_busy = trace_kprobe_is_busy, 52 .free = trace_kprobe_release, 53 .match = trace_kprobe_match, 54 }; 55 56 /* 57 * Kprobe event core functions 58 */ 59 struct trace_kprobe { 60 struct dyn_event devent; 61 struct kretprobe rp; /* Use rp.kp for kprobe use */ 62 unsigned long __percpu *nhit; 63 const char *symbol; /* symbol name */ 64 struct trace_probe tp; 65 }; 66 67 static bool is_trace_kprobe(struct dyn_event *ev) 68 { 69 return ev->ops == &trace_kprobe_ops; 70 } 71 72 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev) 73 { 74 return container_of(ev, struct trace_kprobe, devent); 75 } 76 77 /** 78 * for_each_trace_kprobe - iterate over the trace_kprobe list 79 * @pos: the struct trace_kprobe * for each entry 80 * @dpos: the struct dyn_event * to use as a loop cursor 81 */ 82 #define for_each_trace_kprobe(pos, dpos) \ 83 for_each_dyn_event(dpos) \ 84 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos))) 85 86 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk) 87 { 88 return tk->rp.handler != NULL; 89 } 90 91 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk) 92 { 93 return tk->symbol ? tk->symbol : "unknown"; 94 } 95 96 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk) 97 { 98 return tk->rp.kp.offset; 99 } 100 101 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk) 102 { 103 return kprobe_gone(&tk->rp.kp); 104 } 105 106 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, 107 struct module *mod) 108 { 109 int len = strlen(module_name(mod)); 110 const char *name = trace_kprobe_symbol(tk); 111 112 return strncmp(module_name(mod), name, len) == 0 && name[len] == ':'; 113 } 114 115 #ifdef CONFIG_MODULES 116 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) 117 { 118 char *p; 119 bool ret; 120 121 if (!tk->symbol) 122 return false; 123 p = strchr(tk->symbol, ':'); 124 if (!p) 125 return true; 126 *p = '\0'; 127 scoped_guard(rcu) 128 ret = !!find_module(tk->symbol); 129 *p = ':'; 130 131 return ret; 132 } 133 #else 134 static inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) 135 { 136 return false; 137 } 138 #endif 139 140 static bool trace_kprobe_is_busy(struct dyn_event *ev) 141 { 142 struct trace_kprobe *tk = to_trace_kprobe(ev); 143 144 return trace_probe_is_enabled(&tk->tp); 145 } 146 147 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk, 148 int argc, const char **argv) 149 { 150 char buf[MAX_ARGSTR_LEN + 1]; 151 152 if (!argc) 153 return true; 154 155 if (!tk->symbol) 156 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr); 157 else if (tk->rp.kp.offset) 158 snprintf(buf, sizeof(buf), "%s+%u", 159 trace_kprobe_symbol(tk), tk->rp.kp.offset); 160 else 161 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk)); 162 if (strcmp(buf, argv[0])) 163 return false; 164 argc--; argv++; 165 166 return trace_probe_match_command_args(&tk->tp, argc, argv); 167 } 168 169 static bool trace_kprobe_match(const char *system, const char *event, 170 int argc, const char **argv, struct dyn_event *ev) 171 { 172 struct trace_kprobe *tk = to_trace_kprobe(ev); 173 174 return (event[0] == '\0' || 175 strcmp(trace_probe_name(&tk->tp), event) == 0) && 176 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) && 177 trace_kprobe_match_command_head(tk, argc, argv); 178 } 179 180 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) 181 { 182 unsigned long nhit = 0; 183 int cpu; 184 185 for_each_possible_cpu(cpu) 186 nhit += *per_cpu_ptr(tk->nhit, cpu); 187 188 return nhit; 189 } 190 191 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk) 192 { 193 return !(list_empty(&tk->rp.kp.list) && 194 hlist_unhashed(&tk->rp.kp.hlist)); 195 } 196 197 /* Return 0 if it fails to find the symbol address */ 198 static nokprobe_inline 199 unsigned long trace_kprobe_address(struct trace_kprobe *tk) 200 { 201 unsigned long addr; 202 203 if (tk->symbol) { 204 addr = (unsigned long) 205 kallsyms_lookup_name(trace_kprobe_symbol(tk)); 206 if (addr) 207 addr += tk->rp.kp.offset; 208 } else { 209 addr = (unsigned long)tk->rp.kp.addr; 210 } 211 return addr; 212 } 213 214 static nokprobe_inline struct trace_kprobe * 215 trace_kprobe_primary_from_call(struct trace_event_call *call) 216 { 217 struct trace_probe *tp; 218 219 tp = trace_probe_primary_from_call(call); 220 if (WARN_ON_ONCE(!tp)) 221 return NULL; 222 223 return container_of(tp, struct trace_kprobe, tp); 224 } 225 226 bool trace_kprobe_on_func_entry(struct trace_event_call *call) 227 { 228 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 229 230 return tk ? (kprobe_on_func_entry(tk->rp.kp.addr, 231 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name, 232 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false; 233 } 234 235 bool trace_kprobe_error_injectable(struct trace_event_call *call) 236 { 237 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 238 239 return tk ? within_error_injection_list(trace_kprobe_address(tk)) : 240 false; 241 } 242 243 static int register_kprobe_event(struct trace_kprobe *tk); 244 static int unregister_kprobe_event(struct trace_kprobe *tk); 245 246 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); 247 static int kretprobe_dispatcher(struct kretprobe_instance *ri, 248 struct pt_regs *regs); 249 250 static void free_trace_kprobe(struct trace_kprobe *tk) 251 { 252 if (tk) { 253 trace_probe_cleanup(&tk->tp); 254 kfree(tk->symbol); 255 free_percpu(tk->nhit); 256 kfree(tk); 257 } 258 } 259 260 DEFINE_FREE(free_trace_kprobe, struct trace_kprobe *, 261 if (!IS_ERR_OR_NULL(_T)) free_trace_kprobe(_T)) 262 263 /* 264 * Allocate new trace_probe and initialize it (including kprobes). 265 */ 266 static struct trace_kprobe *alloc_trace_kprobe(const char *group, 267 const char *event, 268 void *addr, 269 const char *symbol, 270 unsigned long offs, 271 int maxactive, 272 int nargs, bool is_return) 273 { 274 struct trace_kprobe *tk __free(free_trace_kprobe) = NULL; 275 int ret = -ENOMEM; 276 277 tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL); 278 if (!tk) 279 return ERR_PTR(ret); 280 281 tk->nhit = alloc_percpu(unsigned long); 282 if (!tk->nhit) 283 return ERR_PTR(ret); 284 285 if (symbol) { 286 tk->symbol = kstrdup(symbol, GFP_KERNEL); 287 if (!tk->symbol) 288 return ERR_PTR(ret); 289 tk->rp.kp.symbol_name = tk->symbol; 290 tk->rp.kp.offset = offs; 291 } else 292 tk->rp.kp.addr = addr; 293 294 if (is_return) 295 tk->rp.handler = kretprobe_dispatcher; 296 else 297 tk->rp.kp.pre_handler = kprobe_dispatcher; 298 299 tk->rp.maxactive = maxactive; 300 INIT_HLIST_NODE(&tk->rp.kp.hlist); 301 INIT_LIST_HEAD(&tk->rp.kp.list); 302 303 ret = trace_probe_init(&tk->tp, event, group, false, nargs); 304 if (ret < 0) 305 return ERR_PTR(ret); 306 307 dyn_event_init(&tk->devent, &trace_kprobe_ops); 308 return_ptr(tk); 309 } 310 311 static struct trace_kprobe *find_trace_kprobe(const char *event, 312 const char *group) 313 { 314 struct dyn_event *pos; 315 struct trace_kprobe *tk; 316 317 for_each_trace_kprobe(tk, pos) 318 if (strcmp(trace_probe_name(&tk->tp), event) == 0 && 319 strcmp(trace_probe_group_name(&tk->tp), group) == 0) 320 return tk; 321 return NULL; 322 } 323 324 static inline int __enable_trace_kprobe(struct trace_kprobe *tk) 325 { 326 int ret = 0; 327 328 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) { 329 if (trace_kprobe_is_return(tk)) 330 ret = enable_kretprobe(&tk->rp); 331 else 332 ret = enable_kprobe(&tk->rp.kp); 333 } 334 335 return ret; 336 } 337 338 static void __disable_trace_kprobe(struct trace_probe *tp) 339 { 340 struct trace_kprobe *tk; 341 342 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) { 343 if (!trace_kprobe_is_registered(tk)) 344 continue; 345 if (trace_kprobe_is_return(tk)) 346 disable_kretprobe(&tk->rp); 347 else 348 disable_kprobe(&tk->rp.kp); 349 } 350 } 351 352 /* 353 * Enable trace_probe 354 * if the file is NULL, enable "perf" handler, or enable "trace" handler. 355 */ 356 static int enable_trace_kprobe(struct trace_event_call *call, 357 struct trace_event_file *file) 358 { 359 struct trace_probe *tp; 360 struct trace_kprobe *tk; 361 bool enabled; 362 int ret = 0; 363 364 tp = trace_probe_primary_from_call(call); 365 if (WARN_ON_ONCE(!tp)) 366 return -ENODEV; 367 enabled = trace_probe_is_enabled(tp); 368 369 /* This also changes "enabled" state */ 370 if (file) { 371 ret = trace_probe_add_file(tp, file); 372 if (ret) 373 return ret; 374 } else 375 trace_probe_set_flag(tp, TP_FLAG_PROFILE); 376 377 if (enabled) 378 return 0; 379 380 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) { 381 if (trace_kprobe_has_gone(tk)) 382 continue; 383 ret = __enable_trace_kprobe(tk); 384 if (ret) 385 break; 386 enabled = true; 387 } 388 389 if (ret) { 390 /* Failed to enable one of them. Roll back all */ 391 if (enabled) 392 __disable_trace_kprobe(tp); 393 if (file) 394 trace_probe_remove_file(tp, file); 395 else 396 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 397 } 398 399 return ret; 400 } 401 402 /* 403 * Disable trace_probe 404 * if the file is NULL, disable "perf" handler, or disable "trace" handler. 405 */ 406 static int disable_trace_kprobe(struct trace_event_call *call, 407 struct trace_event_file *file) 408 { 409 struct trace_probe *tp; 410 411 tp = trace_probe_primary_from_call(call); 412 if (WARN_ON_ONCE(!tp)) 413 return -ENODEV; 414 415 if (file) { 416 if (!trace_probe_get_file_link(tp, file)) 417 return -ENOENT; 418 if (!trace_probe_has_single_file(tp)) 419 goto out; 420 trace_probe_clear_flag(tp, TP_FLAG_TRACE); 421 } else 422 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 423 424 if (!trace_probe_is_enabled(tp)) 425 __disable_trace_kprobe(tp); 426 427 out: 428 if (file) 429 /* 430 * Synchronization is done in below function. For perf event, 431 * file == NULL and perf_trace_event_unreg() calls 432 * tracepoint_synchronize_unregister() to ensure synchronize 433 * event. We don't need to care about it. 434 */ 435 trace_probe_remove_file(tp, file); 436 437 return 0; 438 } 439 440 #if defined(CONFIG_DYNAMIC_FTRACE) && \ 441 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) 442 static bool __within_notrace_func(unsigned long addr) 443 { 444 unsigned long offset, size; 445 446 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) 447 return false; 448 449 /* Get the entry address of the target function */ 450 addr -= offset; 451 452 /* 453 * Since ftrace_location_range() does inclusive range check, we need 454 * to subtract 1 byte from the end address. 455 */ 456 return !ftrace_location_range(addr, addr + size - 1); 457 } 458 459 static bool within_notrace_func(struct trace_kprobe *tk) 460 { 461 unsigned long addr = trace_kprobe_address(tk); 462 char symname[KSYM_NAME_LEN], *p; 463 464 if (!__within_notrace_func(addr)) 465 return false; 466 467 /* Check if the address is on a suffixed-symbol */ 468 if (!lookup_symbol_name(addr, symname)) { 469 p = strchr(symname, '.'); 470 if (!p) 471 return true; 472 *p = '\0'; 473 addr = (unsigned long)kprobe_lookup_name(symname, 0); 474 if (addr) 475 return __within_notrace_func(addr); 476 } 477 478 return true; 479 } 480 #else 481 #define within_notrace_func(tk) (false) 482 #endif 483 484 /* Internal register function - just handle k*probes and flags */ 485 static int __register_trace_kprobe(struct trace_kprobe *tk) 486 { 487 int i, ret; 488 489 ret = security_locked_down(LOCKDOWN_KPROBES); 490 if (ret) 491 return ret; 492 493 if (trace_kprobe_is_registered(tk)) 494 return -EINVAL; 495 496 if (within_notrace_func(tk)) { 497 pr_warn("Could not probe notrace function %ps\n", 498 (void *)trace_kprobe_address(tk)); 499 return -EINVAL; 500 } 501 502 for (i = 0; i < tk->tp.nr_args; i++) { 503 ret = traceprobe_update_arg(&tk->tp.args[i]); 504 if (ret) 505 return ret; 506 } 507 508 /* Set/clear disabled flag according to tp->flag */ 509 if (trace_probe_is_enabled(&tk->tp)) 510 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; 511 else 512 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; 513 514 if (trace_kprobe_is_return(tk)) 515 ret = register_kretprobe(&tk->rp); 516 else 517 ret = register_kprobe(&tk->rp.kp); 518 519 return ret; 520 } 521 522 /* Internal unregister function - just handle k*probes and flags */ 523 static void __unregister_trace_kprobe(struct trace_kprobe *tk) 524 { 525 if (trace_kprobe_is_registered(tk)) { 526 if (trace_kprobe_is_return(tk)) 527 unregister_kretprobe(&tk->rp); 528 else 529 unregister_kprobe(&tk->rp.kp); 530 /* Cleanup kprobe for reuse and mark it unregistered */ 531 INIT_HLIST_NODE(&tk->rp.kp.hlist); 532 INIT_LIST_HEAD(&tk->rp.kp.list); 533 if (tk->rp.kp.symbol_name) 534 tk->rp.kp.addr = NULL; 535 } 536 } 537 538 /* Unregister a trace_probe and probe_event */ 539 static int unregister_trace_kprobe(struct trace_kprobe *tk) 540 { 541 /* If other probes are on the event, just unregister kprobe */ 542 if (trace_probe_has_sibling(&tk->tp)) 543 goto unreg; 544 545 /* Enabled event can not be unregistered */ 546 if (trace_probe_is_enabled(&tk->tp)) 547 return -EBUSY; 548 549 /* If there's a reference to the dynamic event */ 550 if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp))) 551 return -EBUSY; 552 553 /* Will fail if probe is being used by ftrace or perf */ 554 if (unregister_kprobe_event(tk)) 555 return -EBUSY; 556 557 unreg: 558 __unregister_trace_kprobe(tk); 559 dyn_event_remove(&tk->devent); 560 trace_probe_unlink(&tk->tp); 561 562 return 0; 563 } 564 565 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig, 566 struct trace_kprobe *comp) 567 { 568 struct trace_probe_event *tpe = orig->tp.event; 569 int i; 570 571 list_for_each_entry(orig, &tpe->probes, tp.list) { 572 if (strcmp(trace_kprobe_symbol(orig), 573 trace_kprobe_symbol(comp)) || 574 trace_kprobe_offset(orig) != trace_kprobe_offset(comp)) 575 continue; 576 577 /* 578 * trace_probe_compare_arg_type() ensured that nr_args and 579 * each argument name and type are same. Let's compare comm. 580 */ 581 for (i = 0; i < orig->tp.nr_args; i++) { 582 if (strcmp(orig->tp.args[i].comm, 583 comp->tp.args[i].comm)) 584 break; 585 } 586 587 if (i == orig->tp.nr_args) 588 return true; 589 } 590 591 return false; 592 } 593 594 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to) 595 { 596 int ret; 597 598 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp); 599 if (ret) { 600 /* Note that argument starts index = 2 */ 601 trace_probe_log_set_index(ret + 1); 602 trace_probe_log_err(0, DIFF_ARG_TYPE); 603 return -EEXIST; 604 } 605 if (trace_kprobe_has_same_kprobe(to, tk)) { 606 trace_probe_log_set_index(0); 607 trace_probe_log_err(0, SAME_PROBE); 608 return -EEXIST; 609 } 610 611 /* Append to existing event */ 612 ret = trace_probe_append(&tk->tp, &to->tp); 613 if (ret) 614 return ret; 615 616 /* Register k*probe */ 617 ret = __register_trace_kprobe(tk); 618 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 619 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 620 ret = 0; 621 } 622 623 if (ret) 624 trace_probe_unlink(&tk->tp); 625 else 626 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp)); 627 628 return ret; 629 } 630 631 /* Register a trace_probe and probe_event */ 632 static int register_trace_kprobe(struct trace_kprobe *tk) 633 { 634 struct trace_kprobe *old_tk; 635 int ret; 636 637 guard(mutex)(&event_mutex); 638 639 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp), 640 trace_probe_group_name(&tk->tp)); 641 if (old_tk) { 642 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) { 643 trace_probe_log_set_index(0); 644 trace_probe_log_err(0, DIFF_PROBE_TYPE); 645 return -EEXIST; 646 } 647 return append_trace_kprobe(tk, old_tk); 648 } 649 650 /* Register new event */ 651 ret = register_kprobe_event(tk); 652 if (ret) { 653 if (ret == -EEXIST) { 654 trace_probe_log_set_index(0); 655 trace_probe_log_err(0, EVENT_EXIST); 656 } else 657 pr_warn("Failed to register probe event(%d)\n", ret); 658 return ret; 659 } 660 661 /* Register k*probe */ 662 ret = __register_trace_kprobe(tk); 663 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 664 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 665 ret = 0; 666 } 667 668 if (ret < 0) 669 unregister_kprobe_event(tk); 670 else 671 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp)); 672 673 return ret; 674 } 675 676 #ifdef CONFIG_MODULES 677 static int validate_module_probe_symbol(const char *modname, const char *symbol); 678 679 static int register_module_trace_kprobe(struct module *mod, struct trace_kprobe *tk) 680 { 681 const char *p; 682 int ret = 0; 683 684 p = strchr(trace_kprobe_symbol(tk), ':'); 685 if (p) 686 ret = validate_module_probe_symbol(module_name(mod), p + 1); 687 if (!ret) 688 ret = __register_trace_kprobe(tk); 689 return ret; 690 } 691 692 /* Module notifier call back, checking event on the module */ 693 static int trace_kprobe_module_callback(struct notifier_block *nb, 694 unsigned long val, void *data) 695 { 696 struct module *mod = data; 697 struct dyn_event *pos; 698 struct trace_kprobe *tk; 699 int ret; 700 701 if (val != MODULE_STATE_COMING) 702 return NOTIFY_DONE; 703 704 /* Update probes on coming module */ 705 guard(mutex)(&event_mutex); 706 for_each_trace_kprobe(tk, pos) { 707 if (trace_kprobe_within_module(tk, mod)) { 708 /* Don't need to check busy - this should have gone. */ 709 __unregister_trace_kprobe(tk); 710 ret = register_module_trace_kprobe(mod, tk); 711 if (ret) 712 pr_warn("Failed to re-register probe %s on %s: %d\n", 713 trace_probe_name(&tk->tp), 714 module_name(mod), ret); 715 } 716 } 717 718 return NOTIFY_DONE; 719 } 720 721 static struct notifier_block trace_kprobe_module_nb = { 722 .notifier_call = trace_kprobe_module_callback, 723 .priority = 2 /* Invoked after kprobe and jump_label module callback */ 724 }; 725 static int trace_kprobe_register_module_notifier(void) 726 { 727 return register_module_notifier(&trace_kprobe_module_nb); 728 } 729 #else 730 static int trace_kprobe_register_module_notifier(void) 731 { 732 return 0; 733 } 734 #endif /* CONFIG_MODULES */ 735 736 static int count_symbols(void *data, unsigned long unused) 737 { 738 unsigned int *count = data; 739 740 (*count)++; 741 742 return 0; 743 } 744 745 struct sym_count_ctx { 746 unsigned int count; 747 const char *name; 748 }; 749 750 static int count_mod_symbols(void *data, const char *name, unsigned long unused) 751 { 752 struct sym_count_ctx *ctx = data; 753 754 if (strcmp(name, ctx->name) == 0) 755 ctx->count++; 756 757 return 0; 758 } 759 760 static unsigned int number_of_same_symbols(const char *mod, const char *func_name) 761 { 762 struct sym_count_ctx ctx = { .count = 0, .name = func_name }; 763 764 if (!mod) 765 kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count); 766 767 module_kallsyms_on_each_symbol(mod, count_mod_symbols, &ctx); 768 769 return ctx.count; 770 } 771 772 static int validate_module_probe_symbol(const char *modname, const char *symbol) 773 { 774 unsigned int count = number_of_same_symbols(modname, symbol); 775 776 if (count > 1) { 777 /* 778 * Users should use ADDR to remove the ambiguity of 779 * using KSYM only. 780 */ 781 return -EADDRNOTAVAIL; 782 } else if (count == 0) { 783 /* 784 * We can return ENOENT earlier than when register the 785 * kprobe. 786 */ 787 return -ENOENT; 788 } 789 return 0; 790 } 791 792 #ifdef CONFIG_MODULES 793 /* Return NULL if the module is not loaded or under unloading. */ 794 static struct module *try_module_get_by_name(const char *name) 795 { 796 struct module *mod; 797 798 guard(rcu)(); 799 mod = find_module(name); 800 if (mod && !try_module_get(mod)) 801 mod = NULL; 802 return mod; 803 } 804 #else 805 #define try_module_get_by_name(name) (NULL) 806 #endif 807 808 static int validate_probe_symbol(char *symbol) 809 { 810 struct module *mod = NULL; 811 char *modname = NULL, *p; 812 int ret = 0; 813 814 p = strchr(symbol, ':'); 815 if (p) { 816 modname = symbol; 817 symbol = p + 1; 818 *p = '\0'; 819 mod = try_module_get_by_name(modname); 820 if (!mod) 821 goto out; 822 } 823 824 ret = validate_module_probe_symbol(modname, symbol); 825 out: 826 if (p) 827 *p = ':'; 828 if (mod) 829 module_put(mod); 830 return ret; 831 } 832 833 static int trace_kprobe_entry_handler(struct kretprobe_instance *ri, 834 struct pt_regs *regs); 835 836 static int trace_kprobe_create_internal(int argc, const char *argv[], 837 struct traceprobe_parse_context *ctx) 838 { 839 /* 840 * Argument syntax: 841 * - Add kprobe: 842 * p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] 843 * - Add kretprobe: 844 * r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS] 845 * Or 846 * p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS] 847 * 848 * Fetch args: 849 * $retval : fetch return value 850 * $stack : fetch stack address 851 * $stackN : fetch Nth of stack (N:0-) 852 * $comm : fetch current task comm 853 * @ADDR : fetch memory at ADDR (ADDR should be in kernel) 854 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) 855 * %REG : fetch register REG 856 * Dereferencing memory fetch: 857 * +|-offs(ARG) : fetch memory at ARG +|- offs address. 858 * Alias name of args: 859 * NAME=FETCHARG : set NAME as alias of FETCHARG. 860 * Type of args: 861 * FETCHARG:TYPE : use TYPE instead of unsigned long. 862 */ 863 struct trace_kprobe *tk __free(free_trace_kprobe) = NULL; 864 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM; 865 const char **new_argv __free(kfree) = NULL; 866 int i, len, new_argc = 0, ret = 0; 867 char *symbol __free(kfree) = NULL; 868 char *ebuf __free(kfree) = NULL; 869 char *gbuf __free(kfree) = NULL; 870 char *abuf __free(kfree) = NULL; 871 char *dbuf __free(kfree) = NULL; 872 enum probe_print_type ptype; 873 bool is_return = false; 874 int maxactive = 0; 875 void *addr = NULL; 876 char *tmp = NULL; 877 long offset = 0; 878 879 switch (argv[0][0]) { 880 case 'r': 881 is_return = true; 882 break; 883 case 'p': 884 break; 885 default: 886 return -ECANCELED; 887 } 888 if (argc < 2) 889 return -ECANCELED; 890 891 event = strchr(&argv[0][1], ':'); 892 if (event) 893 event++; 894 895 if (isdigit(argv[0][1])) { 896 char *buf __free(kfree) = NULL; 897 898 if (!is_return) { 899 trace_probe_log_err(1, BAD_MAXACT_TYPE); 900 return -EINVAL; 901 } 902 if (event) 903 len = event - &argv[0][1] - 1; 904 else 905 len = strlen(&argv[0][1]); 906 if (len > MAX_EVENT_NAME_LEN - 1) { 907 trace_probe_log_err(1, BAD_MAXACT); 908 return -EINVAL; 909 } 910 buf = kmemdup(&argv[0][1], len + 1, GFP_KERNEL); 911 buf[len] = '\0'; 912 ret = kstrtouint(buf, 0, &maxactive); 913 if (ret || !maxactive) { 914 trace_probe_log_err(1, BAD_MAXACT); 915 return -EINVAL; 916 } 917 /* kretprobes instances are iterated over via a list. The 918 * maximum should stay reasonable. 919 */ 920 if (maxactive > KRETPROBE_MAXACTIVE_MAX) { 921 trace_probe_log_err(1, MAXACT_TOO_BIG); 922 return -EINVAL; 923 } 924 } 925 926 /* try to parse an address. if that fails, try to read the 927 * input as a symbol. */ 928 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { 929 trace_probe_log_set_index(1); 930 /* Check whether uprobe event specified */ 931 if (strchr(argv[1], '/') && strchr(argv[1], ':')) 932 return -ECANCELED; 933 934 /* a symbol specified */ 935 symbol = kstrdup(argv[1], GFP_KERNEL); 936 if (!symbol) 937 return -ENOMEM; 938 939 tmp = strchr(symbol, '%'); 940 if (tmp) { 941 if (!strcmp(tmp, "%return")) { 942 *tmp = '\0'; 943 is_return = true; 944 } else { 945 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX); 946 return -EINVAL; 947 } 948 } 949 950 /* TODO: support .init module functions */ 951 ret = traceprobe_split_symbol_offset(symbol, &offset); 952 if (ret || offset < 0 || offset > UINT_MAX) { 953 trace_probe_log_err(0, BAD_PROBE_ADDR); 954 return -EINVAL; 955 } 956 ret = validate_probe_symbol(symbol); 957 if (ret) { 958 if (ret == -EADDRNOTAVAIL) 959 trace_probe_log_err(0, NON_UNIQ_SYMBOL); 960 else 961 trace_probe_log_err(0, BAD_PROBE_ADDR); 962 return -EINVAL; 963 } 964 if (is_return) 965 ctx->flags |= TPARG_FL_RETURN; 966 ret = kprobe_on_func_entry(NULL, symbol, offset); 967 if (ret == 0 && !is_return) 968 ctx->flags |= TPARG_FL_FENTRY; 969 /* Defer the ENOENT case until register kprobe */ 970 if (ret == -EINVAL && is_return) { 971 trace_probe_log_err(0, BAD_RETPROBE); 972 return -EINVAL; 973 } 974 } 975 976 trace_probe_log_set_index(0); 977 if (event) { 978 gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL); 979 if (!gbuf) 980 return -ENOMEM; 981 ret = traceprobe_parse_event_name(&event, &group, gbuf, 982 event - argv[0]); 983 if (ret) 984 return ret; 985 } 986 987 if (!event) { 988 /* Make a new event name */ 989 ebuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL); 990 if (!ebuf) 991 return -ENOMEM; 992 if (symbol) 993 snprintf(ebuf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", 994 is_return ? 'r' : 'p', symbol, offset); 995 else 996 snprintf(ebuf, MAX_EVENT_NAME_LEN, "%c_0x%p", 997 is_return ? 'r' : 'p', addr); 998 sanitize_event_name(ebuf); 999 event = ebuf; 1000 } 1001 1002 abuf = kmalloc(MAX_BTF_ARGS_LEN, GFP_KERNEL); 1003 if (!abuf) 1004 return -ENOMEM; 1005 argc -= 2; argv += 2; 1006 ctx->funcname = symbol; 1007 new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc, 1008 abuf, MAX_BTF_ARGS_LEN, ctx); 1009 if (IS_ERR(new_argv)) { 1010 ret = PTR_ERR(new_argv); 1011 new_argv = NULL; 1012 return ret; 1013 } 1014 if (new_argv) { 1015 argc = new_argc; 1016 argv = new_argv; 1017 } 1018 if (argc > MAX_TRACE_ARGS) { 1019 trace_probe_log_set_index(2); 1020 trace_probe_log_err(0, TOO_MANY_ARGS); 1021 return -E2BIG; 1022 } 1023 1024 ret = traceprobe_expand_dentry_args(argc, argv, &dbuf); 1025 if (ret) 1026 return ret; 1027 1028 /* setup a probe */ 1029 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, 1030 argc, is_return); 1031 if (IS_ERR(tk)) { 1032 ret = PTR_ERR(tk); 1033 /* This must return -ENOMEM, else there is a bug */ 1034 WARN_ON_ONCE(ret != -ENOMEM); 1035 return ret; /* We know tk is not allocated */ 1036 } 1037 1038 /* parse arguments */ 1039 for (i = 0; i < argc; i++) { 1040 trace_probe_log_set_index(i + 2); 1041 ctx->offset = 0; 1042 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], ctx); 1043 if (ret) 1044 return ret; /* This can be -ENOMEM */ 1045 } 1046 /* entry handler for kretprobe */ 1047 if (is_return && tk->tp.entry_arg) { 1048 tk->rp.entry_handler = trace_kprobe_entry_handler; 1049 tk->rp.data_size = traceprobe_get_entry_data_size(&tk->tp); 1050 } 1051 1052 ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; 1053 ret = traceprobe_set_print_fmt(&tk->tp, ptype); 1054 if (ret < 0) 1055 return ret; 1056 1057 ret = register_trace_kprobe(tk); 1058 if (ret) { 1059 trace_probe_log_set_index(1); 1060 if (ret == -EILSEQ) 1061 trace_probe_log_err(0, BAD_INSN_BNDRY); 1062 else if (ret == -ENOENT) 1063 trace_probe_log_err(0, BAD_PROBE_ADDR); 1064 else if (ret != -ENOMEM && ret != -EEXIST) 1065 trace_probe_log_err(0, FAIL_REG_PROBE); 1066 return ret; 1067 } 1068 /* 1069 * Here, 'tk' has been registered to the list successfully, 1070 * so we don't need to free it. 1071 */ 1072 tk = NULL; 1073 1074 return 0; 1075 } 1076 1077 static int trace_kprobe_create_cb(int argc, const char *argv[]) 1078 { 1079 struct traceprobe_parse_context *ctx __free(traceprobe_parse_context) = NULL; 1080 int ret; 1081 1082 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); 1083 if (!ctx) 1084 return -ENOMEM; 1085 ctx->flags = TPARG_FL_KERNEL; 1086 1087 trace_probe_log_init("trace_kprobe", argc, argv); 1088 1089 ret = trace_kprobe_create_internal(argc, argv, ctx); 1090 1091 trace_probe_log_clear(); 1092 return ret; 1093 } 1094 1095 static int trace_kprobe_create(const char *raw_command) 1096 { 1097 return trace_probe_create(raw_command, trace_kprobe_create_cb); 1098 } 1099 1100 static int create_or_delete_trace_kprobe(const char *raw_command) 1101 { 1102 int ret; 1103 1104 if (raw_command[0] == '-') 1105 return dyn_event_release(raw_command, &trace_kprobe_ops); 1106 1107 ret = dyn_event_create(raw_command, &trace_kprobe_ops); 1108 return ret == -ECANCELED ? -EINVAL : ret; 1109 } 1110 1111 static int trace_kprobe_run_command(struct dynevent_cmd *cmd) 1112 { 1113 return create_or_delete_trace_kprobe(cmd->seq.buffer); 1114 } 1115 1116 /** 1117 * kprobe_event_cmd_init - Initialize a kprobe event command object 1118 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1119 * @buf: A pointer to the buffer used to build the command 1120 * @maxlen: The length of the buffer passed in @buf 1121 * 1122 * Initialize a synthetic event command object. Use this before 1123 * calling any of the other kprobe_event functions. 1124 */ 1125 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) 1126 { 1127 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE, 1128 trace_kprobe_run_command); 1129 } 1130 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init); 1131 1132 /** 1133 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list 1134 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1135 * @kretprobe: Is this a return probe? 1136 * @name: The name of the kprobe event 1137 * @loc: The location of the kprobe event 1138 * @...: Variable number of arg (pairs), one pair for each field 1139 * 1140 * NOTE: Users normally won't want to call this function directly, but 1141 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically 1142 * adds a NULL to the end of the arg list. If this function is used 1143 * directly, make sure the last arg in the variable arg list is NULL. 1144 * 1145 * Generate a kprobe event command to be executed by 1146 * kprobe_event_gen_cmd_end(). This function can be used to generate the 1147 * complete command or only the first part of it; in the latter case, 1148 * kprobe_event_add_fields() can be used to add more fields following this. 1149 * 1150 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This 1151 * returns -EINVAL if @loc == NULL. 1152 * 1153 * Return: 0 if successful, error otherwise. 1154 */ 1155 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, 1156 const char *name, const char *loc, ...) 1157 { 1158 char buf[MAX_EVENT_NAME_LEN]; 1159 struct dynevent_arg arg; 1160 va_list args; 1161 int ret; 1162 1163 if (cmd->type != DYNEVENT_TYPE_KPROBE) 1164 return -EINVAL; 1165 1166 if (!loc) 1167 return -EINVAL; 1168 1169 if (kretprobe) 1170 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name); 1171 else 1172 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name); 1173 1174 ret = dynevent_str_add(cmd, buf); 1175 if (ret) 1176 return ret; 1177 1178 dynevent_arg_init(&arg, 0); 1179 arg.str = loc; 1180 ret = dynevent_arg_add(cmd, &arg, NULL); 1181 if (ret) 1182 return ret; 1183 1184 va_start(args, loc); 1185 for (;;) { 1186 const char *field; 1187 1188 field = va_arg(args, const char *); 1189 if (!field) 1190 break; 1191 1192 if (++cmd->n_fields > MAX_TRACE_ARGS) { 1193 ret = -EINVAL; 1194 break; 1195 } 1196 1197 arg.str = field; 1198 ret = dynevent_arg_add(cmd, &arg, NULL); 1199 if (ret) 1200 break; 1201 } 1202 va_end(args); 1203 1204 return ret; 1205 } 1206 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start); 1207 1208 /** 1209 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list 1210 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1211 * @...: Variable number of arg (pairs), one pair for each field 1212 * 1213 * NOTE: Users normally won't want to call this function directly, but 1214 * rather use the kprobe_event_add_fields() wrapper, which 1215 * automatically adds a NULL to the end of the arg list. If this 1216 * function is used directly, make sure the last arg in the variable 1217 * arg list is NULL. 1218 * 1219 * Add probe fields to an existing kprobe command using a variable 1220 * list of args. Fields are added in the same order they're listed. 1221 * 1222 * Return: 0 if successful, error otherwise. 1223 */ 1224 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...) 1225 { 1226 struct dynevent_arg arg; 1227 va_list args; 1228 int ret = 0; 1229 1230 if (cmd->type != DYNEVENT_TYPE_KPROBE) 1231 return -EINVAL; 1232 1233 dynevent_arg_init(&arg, 0); 1234 1235 va_start(args, cmd); 1236 for (;;) { 1237 const char *field; 1238 1239 field = va_arg(args, const char *); 1240 if (!field) 1241 break; 1242 1243 if (++cmd->n_fields > MAX_TRACE_ARGS) { 1244 ret = -EINVAL; 1245 break; 1246 } 1247 1248 arg.str = field; 1249 ret = dynevent_arg_add(cmd, &arg, NULL); 1250 if (ret) 1251 break; 1252 } 1253 va_end(args); 1254 1255 return ret; 1256 } 1257 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields); 1258 1259 /** 1260 * kprobe_event_delete - Delete a kprobe event 1261 * @name: The name of the kprobe event to delete 1262 * 1263 * Delete a kprobe event with the give @name from kernel code rather 1264 * than directly from the command line. 1265 * 1266 * Return: 0 if successful, error otherwise. 1267 */ 1268 int kprobe_event_delete(const char *name) 1269 { 1270 char buf[MAX_EVENT_NAME_LEN]; 1271 1272 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name); 1273 1274 return create_or_delete_trace_kprobe(buf); 1275 } 1276 EXPORT_SYMBOL_GPL(kprobe_event_delete); 1277 1278 static int trace_kprobe_release(struct dyn_event *ev) 1279 { 1280 struct trace_kprobe *tk = to_trace_kprobe(ev); 1281 int ret = unregister_trace_kprobe(tk); 1282 1283 if (!ret) 1284 free_trace_kprobe(tk); 1285 return ret; 1286 } 1287 1288 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) 1289 { 1290 struct trace_kprobe *tk = to_trace_kprobe(ev); 1291 int i; 1292 1293 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 1294 if (trace_kprobe_is_return(tk) && tk->rp.maxactive) 1295 seq_printf(m, "%d", tk->rp.maxactive); 1296 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), 1297 trace_probe_name(&tk->tp)); 1298 1299 if (!tk->symbol) 1300 seq_printf(m, " 0x%p", tk->rp.kp.addr); 1301 else if (tk->rp.kp.offset) 1302 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 1303 tk->rp.kp.offset); 1304 else 1305 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 1306 1307 for (i = 0; i < tk->tp.nr_args; i++) 1308 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 1309 seq_putc(m, '\n'); 1310 1311 return 0; 1312 } 1313 1314 static int probes_seq_show(struct seq_file *m, void *v) 1315 { 1316 struct dyn_event *ev = v; 1317 1318 if (!is_trace_kprobe(ev)) 1319 return 0; 1320 1321 return trace_kprobe_show(m, ev); 1322 } 1323 1324 static const struct seq_operations probes_seq_op = { 1325 .start = dyn_event_seq_start, 1326 .next = dyn_event_seq_next, 1327 .stop = dyn_event_seq_stop, 1328 .show = probes_seq_show 1329 }; 1330 1331 static int probes_open(struct inode *inode, struct file *file) 1332 { 1333 int ret; 1334 1335 ret = security_locked_down(LOCKDOWN_TRACEFS); 1336 if (ret) 1337 return ret; 1338 1339 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 1340 ret = dyn_events_release_all(&trace_kprobe_ops); 1341 if (ret < 0) 1342 return ret; 1343 } 1344 1345 return seq_open(file, &probes_seq_op); 1346 } 1347 1348 static ssize_t probes_write(struct file *file, const char __user *buffer, 1349 size_t count, loff_t *ppos) 1350 { 1351 return trace_parse_run_command(file, buffer, count, ppos, 1352 create_or_delete_trace_kprobe); 1353 } 1354 1355 static const struct file_operations kprobe_events_ops = { 1356 .owner = THIS_MODULE, 1357 .open = probes_open, 1358 .read = seq_read, 1359 .llseek = seq_lseek, 1360 .release = seq_release, 1361 .write = probes_write, 1362 }; 1363 1364 static unsigned long trace_kprobe_missed(struct trace_kprobe *tk) 1365 { 1366 return trace_kprobe_is_return(tk) ? 1367 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed; 1368 } 1369 1370 /* Probes profiling interfaces */ 1371 static int probes_profile_seq_show(struct seq_file *m, void *v) 1372 { 1373 struct dyn_event *ev = v; 1374 struct trace_kprobe *tk; 1375 unsigned long nmissed; 1376 1377 if (!is_trace_kprobe(ev)) 1378 return 0; 1379 1380 tk = to_trace_kprobe(ev); 1381 nmissed = trace_kprobe_missed(tk); 1382 seq_printf(m, " %-44s %15lu %15lu\n", 1383 trace_probe_name(&tk->tp), 1384 trace_kprobe_nhit(tk), 1385 nmissed); 1386 1387 return 0; 1388 } 1389 1390 static const struct seq_operations profile_seq_op = { 1391 .start = dyn_event_seq_start, 1392 .next = dyn_event_seq_next, 1393 .stop = dyn_event_seq_stop, 1394 .show = probes_profile_seq_show 1395 }; 1396 1397 static int profile_open(struct inode *inode, struct file *file) 1398 { 1399 int ret; 1400 1401 ret = security_locked_down(LOCKDOWN_TRACEFS); 1402 if (ret) 1403 return ret; 1404 1405 return seq_open(file, &profile_seq_op); 1406 } 1407 1408 static const struct file_operations kprobe_profile_ops = { 1409 .owner = THIS_MODULE, 1410 .open = profile_open, 1411 .read = seq_read, 1412 .llseek = seq_lseek, 1413 .release = seq_release, 1414 }; 1415 1416 /* Note that we don't verify it, since the code does not come from user space */ 1417 static int 1418 process_fetch_insn(struct fetch_insn *code, void *rec, void *edata, 1419 void *dest, void *base) 1420 { 1421 struct pt_regs *regs = rec; 1422 unsigned long val; 1423 int ret; 1424 1425 retry: 1426 /* 1st stage: get value from context */ 1427 switch (code->op) { 1428 case FETCH_OP_REG: 1429 val = regs_get_register(regs, code->param); 1430 break; 1431 case FETCH_OP_STACK: 1432 val = regs_get_kernel_stack_nth(regs, code->param); 1433 break; 1434 case FETCH_OP_STACKP: 1435 val = kernel_stack_pointer(regs); 1436 break; 1437 case FETCH_OP_RETVAL: 1438 val = regs_return_value(regs); 1439 break; 1440 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 1441 case FETCH_OP_ARG: 1442 val = regs_get_kernel_argument(regs, code->param); 1443 break; 1444 case FETCH_OP_EDATA: 1445 val = *(unsigned long *)((unsigned long)edata + code->offset); 1446 break; 1447 #endif 1448 case FETCH_NOP_SYMBOL: /* Ignore a place holder */ 1449 code++; 1450 goto retry; 1451 default: 1452 ret = process_common_fetch_insn(code, &val); 1453 if (ret < 0) 1454 return ret; 1455 } 1456 code++; 1457 1458 return process_fetch_insn_bottom(code, val, dest, base); 1459 } 1460 NOKPROBE_SYMBOL(process_fetch_insn) 1461 1462 /* Kprobe handler */ 1463 static nokprobe_inline void 1464 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 1465 struct trace_event_file *trace_file) 1466 { 1467 struct kprobe_trace_entry_head *entry; 1468 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1469 struct trace_event_buffer fbuffer; 1470 int dsize; 1471 1472 WARN_ON(call != trace_file->event_call); 1473 1474 if (trace_trigger_soft_disabled(trace_file)) 1475 return; 1476 1477 dsize = __get_data_size(&tk->tp, regs, NULL); 1478 1479 entry = trace_event_buffer_reserve(&fbuffer, trace_file, 1480 sizeof(*entry) + tk->tp.size + dsize); 1481 if (!entry) 1482 return; 1483 1484 fbuffer.regs = regs; 1485 entry->ip = (unsigned long)tk->rp.kp.addr; 1486 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize); 1487 1488 trace_event_buffer_commit(&fbuffer); 1489 } 1490 1491 static void 1492 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 1493 { 1494 struct event_file_link *link; 1495 1496 trace_probe_for_each_link_rcu(link, &tk->tp) 1497 __kprobe_trace_func(tk, regs, link->file); 1498 } 1499 NOKPROBE_SYMBOL(kprobe_trace_func); 1500 1501 /* Kretprobe handler */ 1502 1503 static int trace_kprobe_entry_handler(struct kretprobe_instance *ri, 1504 struct pt_regs *regs) 1505 { 1506 struct kretprobe *rp = get_kretprobe(ri); 1507 struct trace_kprobe *tk; 1508 1509 /* 1510 * There is a small chance that get_kretprobe(ri) returns NULL when 1511 * the kretprobe is unregister on another CPU between kretprobe's 1512 * trampoline_handler and this function. 1513 */ 1514 if (unlikely(!rp)) 1515 return -ENOENT; 1516 1517 tk = container_of(rp, struct trace_kprobe, rp); 1518 1519 /* store argument values into ri->data as entry data */ 1520 if (tk->tp.entry_arg) 1521 store_trace_entry_data(ri->data, &tk->tp, regs); 1522 1523 return 0; 1524 } 1525 1526 1527 static nokprobe_inline void 1528 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1529 struct pt_regs *regs, 1530 struct trace_event_file *trace_file) 1531 { 1532 struct kretprobe_trace_entry_head *entry; 1533 struct trace_event_buffer fbuffer; 1534 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1535 int dsize; 1536 1537 WARN_ON(call != trace_file->event_call); 1538 1539 if (trace_trigger_soft_disabled(trace_file)) 1540 return; 1541 1542 dsize = __get_data_size(&tk->tp, regs, ri->data); 1543 1544 entry = trace_event_buffer_reserve(&fbuffer, trace_file, 1545 sizeof(*entry) + tk->tp.size + dsize); 1546 if (!entry) 1547 return; 1548 1549 fbuffer.regs = regs; 1550 entry->func = (unsigned long)tk->rp.kp.addr; 1551 entry->ret_ip = get_kretprobe_retaddr(ri); 1552 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize); 1553 1554 trace_event_buffer_commit(&fbuffer); 1555 } 1556 1557 static void 1558 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1559 struct pt_regs *regs) 1560 { 1561 struct event_file_link *link; 1562 1563 trace_probe_for_each_link_rcu(link, &tk->tp) 1564 __kretprobe_trace_func(tk, ri, regs, link->file); 1565 } 1566 NOKPROBE_SYMBOL(kretprobe_trace_func); 1567 1568 /* Event entry printers */ 1569 static enum print_line_t 1570 print_kprobe_event(struct trace_iterator *iter, int flags, 1571 struct trace_event *event) 1572 { 1573 struct kprobe_trace_entry_head *field; 1574 struct trace_seq *s = &iter->seq; 1575 struct trace_probe *tp; 1576 1577 field = (struct kprobe_trace_entry_head *)iter->ent; 1578 tp = trace_probe_primary_from_call( 1579 container_of(event, struct trace_event_call, event)); 1580 if (WARN_ON_ONCE(!tp)) 1581 goto out; 1582 1583 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1584 1585 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) 1586 goto out; 1587 1588 trace_seq_putc(s, ')'); 1589 1590 if (trace_probe_print_args(s, tp->args, tp->nr_args, 1591 (u8 *)&field[1], field) < 0) 1592 goto out; 1593 1594 trace_seq_putc(s, '\n'); 1595 out: 1596 return trace_handle_return(s); 1597 } 1598 1599 static enum print_line_t 1600 print_kretprobe_event(struct trace_iterator *iter, int flags, 1601 struct trace_event *event) 1602 { 1603 struct kretprobe_trace_entry_head *field; 1604 struct trace_seq *s = &iter->seq; 1605 struct trace_probe *tp; 1606 1607 field = (struct kretprobe_trace_entry_head *)iter->ent; 1608 tp = trace_probe_primary_from_call( 1609 container_of(event, struct trace_event_call, event)); 1610 if (WARN_ON_ONCE(!tp)) 1611 goto out; 1612 1613 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1614 1615 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) 1616 goto out; 1617 1618 trace_seq_puts(s, " <- "); 1619 1620 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) 1621 goto out; 1622 1623 trace_seq_putc(s, ')'); 1624 1625 if (trace_probe_print_args(s, tp->args, tp->nr_args, 1626 (u8 *)&field[1], field) < 0) 1627 goto out; 1628 1629 trace_seq_putc(s, '\n'); 1630 1631 out: 1632 return trace_handle_return(s); 1633 } 1634 1635 1636 static int kprobe_event_define_fields(struct trace_event_call *event_call) 1637 { 1638 int ret; 1639 struct kprobe_trace_entry_head field; 1640 struct trace_probe *tp; 1641 1642 tp = trace_probe_primary_from_call(event_call); 1643 if (WARN_ON_ONCE(!tp)) 1644 return -ENOENT; 1645 1646 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1647 1648 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1649 } 1650 1651 static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1652 { 1653 int ret; 1654 struct kretprobe_trace_entry_head field; 1655 struct trace_probe *tp; 1656 1657 tp = trace_probe_primary_from_call(event_call); 1658 if (WARN_ON_ONCE(!tp)) 1659 return -ENOENT; 1660 1661 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1662 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1663 1664 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1665 } 1666 1667 #ifdef CONFIG_PERF_EVENTS 1668 1669 /* Kprobe profile handler */ 1670 static int 1671 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1672 { 1673 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1674 struct kprobe_trace_entry_head *entry; 1675 struct hlist_head *head; 1676 int size, __size, dsize; 1677 int rctx; 1678 1679 if (bpf_prog_array_valid(call)) { 1680 unsigned long orig_ip = instruction_pointer(regs); 1681 int ret; 1682 1683 ret = trace_call_bpf(call, regs); 1684 1685 /* 1686 * We need to check and see if we modified the pc of the 1687 * pt_regs, and if so return 1 so that we don't do the 1688 * single stepping. 1689 */ 1690 if (orig_ip != instruction_pointer(regs)) 1691 return 1; 1692 if (!ret) 1693 return 0; 1694 } 1695 1696 head = this_cpu_ptr(call->perf_events); 1697 if (hlist_empty(head)) 1698 return 0; 1699 1700 dsize = __get_data_size(&tk->tp, regs, NULL); 1701 __size = sizeof(*entry) + tk->tp.size + dsize; 1702 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1703 size -= sizeof(u32); 1704 1705 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1706 if (!entry) 1707 return 0; 1708 1709 entry->ip = (unsigned long)tk->rp.kp.addr; 1710 memset(&entry[1], 0, dsize); 1711 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize); 1712 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1713 head, NULL); 1714 return 0; 1715 } 1716 NOKPROBE_SYMBOL(kprobe_perf_func); 1717 1718 /* Kretprobe profile handler */ 1719 static void 1720 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1721 struct pt_regs *regs) 1722 { 1723 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1724 struct kretprobe_trace_entry_head *entry; 1725 struct hlist_head *head; 1726 int size, __size, dsize; 1727 int rctx; 1728 1729 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1730 return; 1731 1732 head = this_cpu_ptr(call->perf_events); 1733 if (hlist_empty(head)) 1734 return; 1735 1736 dsize = __get_data_size(&tk->tp, regs, ri->data); 1737 __size = sizeof(*entry) + tk->tp.size + dsize; 1738 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1739 size -= sizeof(u32); 1740 1741 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1742 if (!entry) 1743 return; 1744 1745 entry->func = (unsigned long)tk->rp.kp.addr; 1746 entry->ret_ip = get_kretprobe_retaddr(ri); 1747 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize); 1748 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1749 head, NULL); 1750 } 1751 NOKPROBE_SYMBOL(kretprobe_perf_func); 1752 1753 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, 1754 const char **symbol, u64 *probe_offset, 1755 u64 *probe_addr, unsigned long *missed, 1756 bool perf_type_tracepoint) 1757 { 1758 const char *pevent = trace_event_name(event->tp_event); 1759 const char *group = event->tp_event->class->system; 1760 struct trace_kprobe *tk; 1761 1762 if (perf_type_tracepoint) 1763 tk = find_trace_kprobe(pevent, group); 1764 else 1765 tk = trace_kprobe_primary_from_call(event->tp_event); 1766 if (!tk) 1767 return -EINVAL; 1768 1769 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE 1770 : BPF_FD_TYPE_KPROBE; 1771 *probe_offset = tk->rp.kp.offset; 1772 *probe_addr = kallsyms_show_value(current_cred()) ? 1773 (unsigned long)tk->rp.kp.addr : 0; 1774 *symbol = tk->symbol; 1775 if (missed) 1776 *missed = trace_kprobe_missed(tk); 1777 return 0; 1778 } 1779 #endif /* CONFIG_PERF_EVENTS */ 1780 1781 /* 1782 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1783 * 1784 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1785 * lockless, but we can't race with this __init function. 1786 */ 1787 static int kprobe_register(struct trace_event_call *event, 1788 enum trace_reg type, void *data) 1789 { 1790 struct trace_event_file *file = data; 1791 1792 switch (type) { 1793 case TRACE_REG_REGISTER: 1794 return enable_trace_kprobe(event, file); 1795 case TRACE_REG_UNREGISTER: 1796 return disable_trace_kprobe(event, file); 1797 1798 #ifdef CONFIG_PERF_EVENTS 1799 case TRACE_REG_PERF_REGISTER: 1800 return enable_trace_kprobe(event, NULL); 1801 case TRACE_REG_PERF_UNREGISTER: 1802 return disable_trace_kprobe(event, NULL); 1803 case TRACE_REG_PERF_OPEN: 1804 case TRACE_REG_PERF_CLOSE: 1805 case TRACE_REG_PERF_ADD: 1806 case TRACE_REG_PERF_DEL: 1807 return 0; 1808 #endif 1809 } 1810 return 0; 1811 } 1812 1813 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1814 { 1815 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1816 int ret = 0; 1817 1818 raw_cpu_inc(*tk->nhit); 1819 1820 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1821 kprobe_trace_func(tk, regs); 1822 #ifdef CONFIG_PERF_EVENTS 1823 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1824 ret = kprobe_perf_func(tk, regs); 1825 #endif 1826 return ret; 1827 } 1828 NOKPROBE_SYMBOL(kprobe_dispatcher); 1829 1830 static int 1831 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1832 { 1833 struct kretprobe *rp = get_kretprobe(ri); 1834 struct trace_kprobe *tk; 1835 1836 /* 1837 * There is a small chance that get_kretprobe(ri) returns NULL when 1838 * the kretprobe is unregister on another CPU between kretprobe's 1839 * trampoline_handler and this function. 1840 */ 1841 if (unlikely(!rp)) 1842 return 0; 1843 1844 tk = container_of(rp, struct trace_kprobe, rp); 1845 raw_cpu_inc(*tk->nhit); 1846 1847 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1848 kretprobe_trace_func(tk, ri, regs); 1849 #ifdef CONFIG_PERF_EVENTS 1850 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1851 kretprobe_perf_func(tk, ri, regs); 1852 #endif 1853 return 0; /* We don't tweak kernel, so just return 0 */ 1854 } 1855 NOKPROBE_SYMBOL(kretprobe_dispatcher); 1856 1857 static struct trace_event_functions kretprobe_funcs = { 1858 .trace = print_kretprobe_event 1859 }; 1860 1861 static struct trace_event_functions kprobe_funcs = { 1862 .trace = print_kprobe_event 1863 }; 1864 1865 static struct trace_event_fields kretprobe_fields_array[] = { 1866 { .type = TRACE_FUNCTION_TYPE, 1867 .define_fields = kretprobe_event_define_fields }, 1868 {} 1869 }; 1870 1871 static struct trace_event_fields kprobe_fields_array[] = { 1872 { .type = TRACE_FUNCTION_TYPE, 1873 .define_fields = kprobe_event_define_fields }, 1874 {} 1875 }; 1876 1877 static inline void init_trace_event_call(struct trace_kprobe *tk) 1878 { 1879 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1880 1881 if (trace_kprobe_is_return(tk)) { 1882 call->event.funcs = &kretprobe_funcs; 1883 call->class->fields_array = kretprobe_fields_array; 1884 } else { 1885 call->event.funcs = &kprobe_funcs; 1886 call->class->fields_array = kprobe_fields_array; 1887 } 1888 1889 call->flags = TRACE_EVENT_FL_KPROBE; 1890 call->class->reg = kprobe_register; 1891 } 1892 1893 static int register_kprobe_event(struct trace_kprobe *tk) 1894 { 1895 init_trace_event_call(tk); 1896 1897 return trace_probe_register_event_call(&tk->tp); 1898 } 1899 1900 static int unregister_kprobe_event(struct trace_kprobe *tk) 1901 { 1902 return trace_probe_unregister_event_call(&tk->tp); 1903 } 1904 1905 #ifdef CONFIG_PERF_EVENTS 1906 1907 /* create a trace_kprobe, but don't add it to global lists */ 1908 struct trace_event_call * 1909 create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 1910 bool is_return) 1911 { 1912 enum probe_print_type ptype; 1913 struct trace_kprobe *tk __free(free_trace_kprobe) = NULL; 1914 int ret; 1915 char *event; 1916 1917 if (func) { 1918 ret = validate_probe_symbol(func); 1919 if (ret) 1920 return ERR_PTR(ret); 1921 } 1922 1923 /* 1924 * local trace_kprobes are not added to dyn_event, so they are never 1925 * searched in find_trace_kprobe(). Therefore, there is no concern of 1926 * duplicated name here. 1927 */ 1928 event = func ? func : "DUMMY_EVENT"; 1929 1930 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, 1931 offs, 0 /* maxactive */, 0 /* nargs */, 1932 is_return); 1933 1934 if (IS_ERR(tk)) { 1935 pr_info("Failed to allocate trace_probe.(%d)\n", 1936 (int)PTR_ERR(tk)); 1937 return ERR_CAST(tk); 1938 } 1939 1940 init_trace_event_call(tk); 1941 1942 ptype = trace_kprobe_is_return(tk) ? 1943 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; 1944 if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) 1945 return ERR_PTR(-ENOMEM); 1946 1947 ret = __register_trace_kprobe(tk); 1948 if (ret < 0) 1949 return ERR_PTR(ret); 1950 1951 return trace_probe_event_call(&(no_free_ptr(tk)->tp)); 1952 } 1953 1954 void destroy_local_trace_kprobe(struct trace_event_call *event_call) 1955 { 1956 struct trace_kprobe *tk; 1957 1958 tk = trace_kprobe_primary_from_call(event_call); 1959 if (unlikely(!tk)) 1960 return; 1961 1962 if (trace_probe_is_enabled(&tk->tp)) { 1963 WARN_ON(1); 1964 return; 1965 } 1966 1967 __unregister_trace_kprobe(tk); 1968 1969 free_trace_kprobe(tk); 1970 } 1971 #endif /* CONFIG_PERF_EVENTS */ 1972 1973 static __init void enable_boot_kprobe_events(void) 1974 { 1975 struct trace_array *tr = top_trace_array(); 1976 struct trace_event_file *file; 1977 struct trace_kprobe *tk; 1978 struct dyn_event *pos; 1979 1980 guard(mutex)(&event_mutex); 1981 for_each_trace_kprobe(tk, pos) { 1982 list_for_each_entry(file, &tr->events, list) 1983 if (file->event_call == trace_probe_event_call(&tk->tp)) 1984 trace_event_enable_disable(file, 1, 0); 1985 } 1986 } 1987 1988 static __init void setup_boot_kprobe_events(void) 1989 { 1990 char *p, *cmd = kprobe_boot_events_buf; 1991 int ret; 1992 1993 strreplace(kprobe_boot_events_buf, ',', ' '); 1994 1995 while (cmd && *cmd != '\0') { 1996 p = strchr(cmd, ';'); 1997 if (p) 1998 *p++ = '\0'; 1999 2000 ret = create_or_delete_trace_kprobe(cmd); 2001 if (ret) 2002 pr_warn("Failed to add event(%d): %s\n", ret, cmd); 2003 2004 cmd = p; 2005 } 2006 2007 enable_boot_kprobe_events(); 2008 } 2009 2010 /* 2011 * Register dynevent at core_initcall. This allows kernel to setup kprobe 2012 * events in postcore_initcall without tracefs. 2013 */ 2014 static __init int init_kprobe_trace_early(void) 2015 { 2016 int ret; 2017 2018 ret = dyn_event_register(&trace_kprobe_ops); 2019 if (ret) 2020 return ret; 2021 2022 if (trace_kprobe_register_module_notifier()) 2023 return -EINVAL; 2024 2025 return 0; 2026 } 2027 core_initcall(init_kprobe_trace_early); 2028 2029 /* Make a tracefs interface for controlling probe points */ 2030 static __init int init_kprobe_trace(void) 2031 { 2032 int ret; 2033 2034 ret = tracing_init_dentry(); 2035 if (ret) 2036 return 0; 2037 2038 /* Event list interface */ 2039 trace_create_file("kprobe_events", TRACE_MODE_WRITE, 2040 NULL, NULL, &kprobe_events_ops); 2041 2042 /* Profile interface */ 2043 trace_create_file("kprobe_profile", TRACE_MODE_READ, 2044 NULL, NULL, &kprobe_profile_ops); 2045 2046 setup_boot_kprobe_events(); 2047 2048 return 0; 2049 } 2050 fs_initcall(init_kprobe_trace); 2051 2052 2053 #ifdef CONFIG_FTRACE_STARTUP_TEST 2054 static __init struct trace_event_file * 2055 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 2056 { 2057 struct trace_event_file *file; 2058 2059 list_for_each_entry(file, &tr->events, list) 2060 if (file->event_call == trace_probe_event_call(&tk->tp)) 2061 return file; 2062 2063 return NULL; 2064 } 2065 2066 /* 2067 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 2068 * stage, we can do this lockless. 2069 */ 2070 static __init int kprobe_trace_self_tests_init(void) 2071 { 2072 int ret, warn = 0; 2073 int (*target)(int, int, int, int, int, int); 2074 struct trace_kprobe *tk; 2075 struct trace_event_file *file; 2076 2077 if (tracing_is_disabled()) 2078 return -ENODEV; 2079 2080 if (tracing_selftest_disabled) 2081 return 0; 2082 2083 target = kprobe_trace_selftest_target; 2084 2085 pr_info("Testing kprobe tracing: "); 2086 2087 ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)"); 2088 if (WARN_ONCE(ret, "error on probing function entry.")) { 2089 warn++; 2090 } else { 2091 /* Enable trace point */ 2092 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 2093 if (WARN_ONCE(tk == NULL, "error on probing function entry.")) { 2094 warn++; 2095 } else { 2096 file = find_trace_probe_file(tk, top_trace_array()); 2097 if (WARN_ONCE(file == NULL, "error on getting probe file.")) { 2098 warn++; 2099 } else 2100 enable_trace_kprobe( 2101 trace_probe_event_call(&tk->tp), file); 2102 } 2103 } 2104 2105 ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval"); 2106 if (WARN_ONCE(ret, "error on probing function return.")) { 2107 warn++; 2108 } else { 2109 /* Enable trace point */ 2110 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 2111 if (WARN_ONCE(tk == NULL, "error on getting 2nd new probe.")) { 2112 warn++; 2113 } else { 2114 file = find_trace_probe_file(tk, top_trace_array()); 2115 if (WARN_ONCE(file == NULL, "error on getting probe file.")) { 2116 warn++; 2117 } else 2118 enable_trace_kprobe( 2119 trace_probe_event_call(&tk->tp), file); 2120 } 2121 } 2122 2123 if (warn) 2124 goto end; 2125 2126 ret = target(1, 2, 3, 4, 5, 6); 2127 2128 /* 2129 * Not expecting an error here, the check is only to prevent the 2130 * optimizer from removing the call to target() as otherwise there 2131 * are no side-effects and the call is never performed. 2132 */ 2133 if (ret != 21) 2134 warn++; 2135 2136 /* Disable trace points before removing it */ 2137 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 2138 if (WARN_ONCE(tk == NULL, "error on getting test probe.")) { 2139 warn++; 2140 } else { 2141 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1, 2142 "incorrect number of testprobe hits.")) 2143 warn++; 2144 2145 file = find_trace_probe_file(tk, top_trace_array()); 2146 if (WARN_ONCE(file == NULL, "error on getting probe file.")) { 2147 warn++; 2148 } else 2149 disable_trace_kprobe( 2150 trace_probe_event_call(&tk->tp), file); 2151 } 2152 2153 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 2154 if (WARN_ONCE(tk == NULL, "error on getting 2nd test probe.")) { 2155 warn++; 2156 } else { 2157 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1, 2158 "incorrect number of testprobe2 hits.")) 2159 warn++; 2160 2161 file = find_trace_probe_file(tk, top_trace_array()); 2162 if (WARN_ONCE(file == NULL, "error on getting probe file.")) { 2163 warn++; 2164 } else 2165 disable_trace_kprobe( 2166 trace_probe_event_call(&tk->tp), file); 2167 } 2168 2169 ret = create_or_delete_trace_kprobe("-:testprobe"); 2170 if (WARN_ONCE(ret, "error on deleting a probe.")) 2171 warn++; 2172 2173 ret = create_or_delete_trace_kprobe("-:testprobe2"); 2174 if (WARN_ONCE(ret, "error on deleting a probe.")) 2175 warn++; 2176 2177 2178 end: 2179 /* 2180 * Wait for the optimizer work to finish. Otherwise it might fiddle 2181 * with probes in already freed __init text. 2182 */ 2183 wait_for_kprobe_optimizer(); 2184 if (warn) 2185 pr_cont("NG: Some tests are failed. Please check them.\n"); 2186 else 2187 pr_cont("OK\n"); 2188 return 0; 2189 } 2190 2191 late_initcall(kprobe_trace_self_tests_init); 2192 2193 #endif 2194