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 #define trace_kprobe_list_empty() list_empty(&dyn_event_list) 86 87 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk) 88 { 89 return tk->rp.handler != NULL; 90 } 91 92 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk) 93 { 94 return tk->symbol ? tk->symbol : "unknown"; 95 } 96 97 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk) 98 { 99 return tk->rp.kp.offset; 100 } 101 102 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk) 103 { 104 return kprobe_gone(&tk->rp.kp); 105 } 106 107 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, 108 struct module *mod) 109 { 110 int len = strlen(module_name(mod)); 111 const char *name = trace_kprobe_symbol(tk); 112 113 return strncmp(module_name(mod), name, len) == 0 && name[len] == ':'; 114 } 115 116 #ifdef CONFIG_MODULES 117 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) 118 { 119 char *p; 120 bool ret; 121 122 if (!tk->symbol) 123 return false; 124 p = strchr(tk->symbol, ':'); 125 if (!p) 126 return true; 127 *p = '\0'; 128 scoped_guard(rcu) 129 ret = !!find_module(tk->symbol); 130 *p = ':'; 131 132 return ret; 133 } 134 #else 135 static inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) 136 { 137 return false; 138 } 139 #endif 140 141 static bool trace_kprobe_is_busy(struct dyn_event *ev) 142 { 143 struct trace_kprobe *tk = to_trace_kprobe(ev); 144 145 return trace_probe_is_enabled(&tk->tp); 146 } 147 148 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk, 149 int argc, const char **argv) 150 { 151 char buf[MAX_ARGSTR_LEN + 1]; 152 153 if (!argc) 154 return true; 155 156 if (!tk->symbol) 157 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr); 158 else if (tk->rp.kp.offset) 159 snprintf(buf, sizeof(buf), "%s+%u", 160 trace_kprobe_symbol(tk), tk->rp.kp.offset); 161 else 162 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk)); 163 if (strcmp(buf, argv[0])) 164 return false; 165 argc--; argv++; 166 167 return trace_probe_match_command_args(&tk->tp, argc, argv); 168 } 169 170 static bool trace_kprobe_match(const char *system, const char *event, 171 int argc, const char **argv, struct dyn_event *ev) 172 { 173 struct trace_kprobe *tk = to_trace_kprobe(ev); 174 175 return (event[0] == '\0' || 176 strcmp(trace_probe_name(&tk->tp), event) == 0) && 177 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) && 178 trace_kprobe_match_command_head(tk, argc, argv); 179 } 180 181 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) 182 { 183 unsigned long nhit = 0; 184 int cpu; 185 186 for_each_possible_cpu(cpu) 187 nhit += *per_cpu_ptr(tk->nhit, cpu); 188 189 return nhit; 190 } 191 192 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk) 193 { 194 return !(list_empty(&tk->rp.kp.list) && 195 hlist_unhashed(&tk->rp.kp.hlist)); 196 } 197 198 /* Return 0 if it fails to find the symbol address */ 199 static nokprobe_inline 200 unsigned long trace_kprobe_address(struct trace_kprobe *tk) 201 { 202 unsigned long addr; 203 204 if (tk->symbol) { 205 addr = (unsigned long) 206 kallsyms_lookup_name(trace_kprobe_symbol(tk)); 207 if (addr) 208 addr += tk->rp.kp.offset; 209 } else { 210 addr = (unsigned long)tk->rp.kp.addr; 211 } 212 return addr; 213 } 214 215 static nokprobe_inline struct trace_kprobe * 216 trace_kprobe_primary_from_call(struct trace_event_call *call) 217 { 218 struct trace_probe *tp; 219 220 tp = trace_probe_primary_from_call(call); 221 if (WARN_ON_ONCE(!tp)) 222 return NULL; 223 224 return container_of(tp, struct trace_kprobe, tp); 225 } 226 227 bool trace_kprobe_on_func_entry(struct trace_event_call *call) 228 { 229 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 230 231 return tk ? (kprobe_on_func_entry(tk->rp.kp.addr, 232 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name, 233 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) == 0) : false; 234 } 235 236 bool trace_kprobe_error_injectable(struct trace_event_call *call) 237 { 238 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 239 240 return tk ? within_error_injection_list(trace_kprobe_address(tk)) : 241 false; 242 } 243 244 static int register_kprobe_event(struct trace_kprobe *tk); 245 static int unregister_kprobe_event(struct trace_kprobe *tk); 246 247 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); 248 static int kretprobe_dispatcher(struct kretprobe_instance *ri, 249 struct pt_regs *regs); 250 251 static void free_trace_kprobe(struct trace_kprobe *tk) 252 { 253 if (tk) { 254 trace_probe_cleanup(&tk->tp); 255 kfree(tk->symbol); 256 free_percpu(tk->nhit); 257 kfree(tk); 258 } 259 } 260 261 DEFINE_FREE(free_trace_kprobe, struct trace_kprobe *, 262 if (!IS_ERR_OR_NULL(_T)) free_trace_kprobe(_T)) 263 264 /* 265 * Allocate new trace_probe and initialize it (including kprobes). 266 */ 267 static struct trace_kprobe *alloc_trace_kprobe(const char *group, 268 const char *event, 269 void *addr, 270 const char *symbol, 271 unsigned long offs, 272 int maxactive, 273 int nargs, bool is_return) 274 { 275 struct trace_kprobe *tk __free(free_trace_kprobe) = NULL; 276 int ret = -ENOMEM; 277 278 tk = kzalloc(struct_size(tk, tp.args, nargs), GFP_KERNEL); 279 if (!tk) 280 return ERR_PTR(ret); 281 282 tk->nhit = alloc_percpu(unsigned long); 283 if (!tk->nhit) 284 return ERR_PTR(ret); 285 286 if (symbol) { 287 tk->symbol = kstrdup(symbol, GFP_KERNEL); 288 if (!tk->symbol) 289 return ERR_PTR(ret); 290 tk->rp.kp.symbol_name = tk->symbol; 291 tk->rp.kp.offset = offs; 292 } else 293 tk->rp.kp.addr = addr; 294 295 if (is_return) 296 tk->rp.handler = kretprobe_dispatcher; 297 else 298 tk->rp.kp.pre_handler = kprobe_dispatcher; 299 300 tk->rp.maxactive = maxactive; 301 INIT_HLIST_NODE(&tk->rp.kp.hlist); 302 INIT_LIST_HEAD(&tk->rp.kp.list); 303 304 ret = trace_probe_init(&tk->tp, event, group, false, nargs); 305 if (ret < 0) 306 return ERR_PTR(ret); 307 308 dyn_event_init(&tk->devent, &trace_kprobe_ops); 309 return_ptr(tk); 310 } 311 312 static struct trace_kprobe *find_trace_kprobe(const char *event, 313 const char *group) 314 { 315 struct dyn_event *pos; 316 struct trace_kprobe *tk; 317 318 for_each_trace_kprobe(tk, pos) 319 if (strcmp(trace_probe_name(&tk->tp), event) == 0 && 320 strcmp(trace_probe_group_name(&tk->tp), group) == 0) 321 return tk; 322 return NULL; 323 } 324 325 static inline int __enable_trace_kprobe(struct trace_kprobe *tk) 326 { 327 int ret = 0; 328 329 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) { 330 if (trace_kprobe_is_return(tk)) 331 ret = enable_kretprobe(&tk->rp); 332 else 333 ret = enable_kprobe(&tk->rp.kp); 334 } 335 336 return ret; 337 } 338 339 static void __disable_trace_kprobe(struct trace_probe *tp) 340 { 341 struct trace_kprobe *tk; 342 343 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) { 344 if (!trace_kprobe_is_registered(tk)) 345 continue; 346 if (trace_kprobe_is_return(tk)) 347 disable_kretprobe(&tk->rp); 348 else 349 disable_kprobe(&tk->rp.kp); 350 } 351 } 352 353 /* 354 * Enable trace_probe 355 * if the file is NULL, enable "perf" handler, or enable "trace" handler. 356 */ 357 static int enable_trace_kprobe(struct trace_event_call *call, 358 struct trace_event_file *file) 359 { 360 struct trace_probe *tp; 361 struct trace_kprobe *tk; 362 bool enabled; 363 int ret = 0; 364 365 tp = trace_probe_primary_from_call(call); 366 if (WARN_ON_ONCE(!tp)) 367 return -ENODEV; 368 enabled = trace_probe_is_enabled(tp); 369 370 /* This also changes "enabled" state */ 371 if (file) { 372 ret = trace_probe_add_file(tp, file); 373 if (ret) 374 return ret; 375 } else 376 trace_probe_set_flag(tp, TP_FLAG_PROFILE); 377 378 if (enabled) 379 return 0; 380 381 list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) { 382 if (trace_kprobe_has_gone(tk)) 383 continue; 384 ret = __enable_trace_kprobe(tk); 385 if (ret) 386 break; 387 enabled = true; 388 } 389 390 if (ret) { 391 /* Failed to enable one of them. Roll back all */ 392 if (enabled) 393 __disable_trace_kprobe(tp); 394 if (file) 395 trace_probe_remove_file(tp, file); 396 else 397 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 398 } 399 400 return ret; 401 } 402 403 /* 404 * Disable trace_probe 405 * if the file is NULL, disable "perf" handler, or disable "trace" handler. 406 */ 407 static int disable_trace_kprobe(struct trace_event_call *call, 408 struct trace_event_file *file) 409 { 410 struct trace_probe *tp; 411 412 tp = trace_probe_primary_from_call(call); 413 if (WARN_ON_ONCE(!tp)) 414 return -ENODEV; 415 416 if (file) { 417 if (!trace_probe_get_file_link(tp, file)) 418 return -ENOENT; 419 if (!trace_probe_has_single_file(tp)) 420 goto out; 421 trace_probe_clear_flag(tp, TP_FLAG_TRACE); 422 } else 423 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 424 425 if (!trace_probe_is_enabled(tp)) 426 __disable_trace_kprobe(tp); 427 428 out: 429 if (file) 430 /* 431 * Synchronization is done in below function. For perf event, 432 * file == NULL and perf_trace_event_unreg() calls 433 * tracepoint_synchronize_unregister() to ensure synchronize 434 * event. We don't need to care about it. 435 */ 436 trace_probe_remove_file(tp, file); 437 438 return 0; 439 } 440 441 #if defined(CONFIG_DYNAMIC_FTRACE) && \ 442 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) 443 static bool __within_notrace_func(unsigned long addr) 444 { 445 unsigned long offset, size; 446 447 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) 448 return false; 449 450 /* Get the entry address of the target function */ 451 addr -= offset; 452 453 /* 454 * Since ftrace_location_range() does inclusive range check, we need 455 * to subtract 1 byte from the end address. 456 */ 457 return !ftrace_location_range(addr, addr + size - 1); 458 } 459 460 static bool within_notrace_func(struct trace_kprobe *tk) 461 { 462 unsigned long addr = trace_kprobe_address(tk); 463 char symname[KSYM_NAME_LEN], *p; 464 465 if (!__within_notrace_func(addr)) 466 return false; 467 468 /* Check if the address is on a suffixed-symbol */ 469 if (!lookup_symbol_name(addr, symname)) { 470 p = strchr(symname, '.'); 471 if (!p) 472 return true; 473 *p = '\0'; 474 addr = (unsigned long)kprobe_lookup_name(symname, 0); 475 if (addr) 476 return __within_notrace_func(addr); 477 } 478 479 return true; 480 } 481 #else 482 #define within_notrace_func(tk) (false) 483 #endif 484 485 /* Internal register function - just handle k*probes and flags */ 486 static int __register_trace_kprobe(struct trace_kprobe *tk) 487 { 488 int i, ret; 489 490 ret = security_locked_down(LOCKDOWN_KPROBES); 491 if (ret) 492 return ret; 493 494 if (trace_kprobe_is_registered(tk)) 495 return -EINVAL; 496 497 if (within_notrace_func(tk)) { 498 pr_warn("Could not probe notrace function %ps\n", 499 (void *)trace_kprobe_address(tk)); 500 return -EINVAL; 501 } 502 503 for (i = 0; i < tk->tp.nr_args; i++) { 504 ret = traceprobe_update_arg(&tk->tp.args[i]); 505 if (ret) 506 return ret; 507 } 508 509 /* Set/clear disabled flag according to tp->flag */ 510 if (trace_probe_is_enabled(&tk->tp)) 511 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; 512 else 513 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; 514 515 if (trace_kprobe_is_return(tk)) 516 ret = register_kretprobe(&tk->rp); 517 else 518 ret = register_kprobe(&tk->rp.kp); 519 520 return ret; 521 } 522 523 /* Internal unregister function - just handle k*probes and flags */ 524 static void __unregister_trace_kprobe(struct trace_kprobe *tk) 525 { 526 if (trace_kprobe_is_registered(tk)) { 527 if (trace_kprobe_is_return(tk)) 528 unregister_kretprobe(&tk->rp); 529 else 530 unregister_kprobe(&tk->rp.kp); 531 /* Cleanup kprobe for reuse and mark it unregistered */ 532 INIT_HLIST_NODE(&tk->rp.kp.hlist); 533 INIT_LIST_HEAD(&tk->rp.kp.list); 534 if (tk->rp.kp.symbol_name) 535 tk->rp.kp.addr = NULL; 536 } 537 } 538 539 /* Unregister a trace_probe and probe_event */ 540 static int unregister_trace_kprobe(struct trace_kprobe *tk) 541 { 542 /* If other probes are on the event, just unregister kprobe */ 543 if (trace_probe_has_sibling(&tk->tp)) 544 goto unreg; 545 546 /* Enabled event can not be unregistered */ 547 if (trace_probe_is_enabled(&tk->tp)) 548 return -EBUSY; 549 550 /* If there's a reference to the dynamic event */ 551 if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp))) 552 return -EBUSY; 553 554 /* Will fail if probe is being used by ftrace or perf */ 555 if (unregister_kprobe_event(tk)) 556 return -EBUSY; 557 558 unreg: 559 __unregister_trace_kprobe(tk); 560 dyn_event_remove(&tk->devent); 561 trace_probe_unlink(&tk->tp); 562 563 return 0; 564 } 565 566 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig, 567 struct trace_kprobe *comp) 568 { 569 struct trace_probe_event *tpe = orig->tp.event; 570 int i; 571 572 list_for_each_entry(orig, &tpe->probes, tp.list) { 573 if (strcmp(trace_kprobe_symbol(orig), 574 trace_kprobe_symbol(comp)) || 575 trace_kprobe_offset(orig) != trace_kprobe_offset(comp)) 576 continue; 577 578 /* 579 * trace_probe_compare_arg_type() ensured that nr_args and 580 * each argument name and type are same. Let's compare comm. 581 */ 582 for (i = 0; i < orig->tp.nr_args; i++) { 583 if (strcmp(orig->tp.args[i].comm, 584 comp->tp.args[i].comm)) 585 break; 586 } 587 588 if (i == orig->tp.nr_args) 589 return true; 590 } 591 592 return false; 593 } 594 595 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to) 596 { 597 int ret; 598 599 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp); 600 if (ret) { 601 /* Note that argument starts index = 2 */ 602 trace_probe_log_set_index(ret + 1); 603 trace_probe_log_err(0, DIFF_ARG_TYPE); 604 return -EEXIST; 605 } 606 if (trace_kprobe_has_same_kprobe(to, tk)) { 607 trace_probe_log_set_index(0); 608 trace_probe_log_err(0, SAME_PROBE); 609 return -EEXIST; 610 } 611 612 /* Append to existing event */ 613 ret = trace_probe_append(&tk->tp, &to->tp); 614 if (ret) 615 return ret; 616 617 /* Register k*probe */ 618 ret = __register_trace_kprobe(tk); 619 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 620 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 621 ret = 0; 622 } 623 624 if (ret) 625 trace_probe_unlink(&tk->tp); 626 else 627 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp)); 628 629 return ret; 630 } 631 632 /* Register a trace_probe and probe_event */ 633 static int register_trace_kprobe(struct trace_kprobe *tk) 634 { 635 struct trace_kprobe *old_tk; 636 int ret; 637 638 guard(mutex)(&event_mutex); 639 640 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp), 641 trace_probe_group_name(&tk->tp)); 642 if (old_tk) { 643 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) { 644 trace_probe_log_set_index(0); 645 trace_probe_log_err(0, DIFF_PROBE_TYPE); 646 return -EEXIST; 647 } 648 return append_trace_kprobe(tk, old_tk); 649 } 650 651 /* Register new event */ 652 ret = register_kprobe_event(tk); 653 if (ret) { 654 if (ret == -EEXIST) { 655 trace_probe_log_set_index(0); 656 trace_probe_log_err(0, EVENT_EXIST); 657 } else 658 pr_warn("Failed to register probe event(%d)\n", ret); 659 return ret; 660 } 661 662 /* Register k*probe */ 663 ret = __register_trace_kprobe(tk); 664 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 665 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 666 ret = 0; 667 } 668 669 if (ret < 0) 670 unregister_kprobe_event(tk); 671 else 672 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp)); 673 674 return ret; 675 } 676 677 #ifdef CONFIG_MODULES 678 static int validate_module_probe_symbol(const char *modname, const char *symbol); 679 680 static int register_module_trace_kprobe(struct module *mod, struct trace_kprobe *tk) 681 { 682 const char *p; 683 int ret = 0; 684 685 p = strchr(trace_kprobe_symbol(tk), ':'); 686 if (p) 687 ret = validate_module_probe_symbol(module_name(mod), p + 1); 688 if (!ret) 689 ret = __register_trace_kprobe(tk); 690 return ret; 691 } 692 693 /* Module notifier call back, checking event on the module */ 694 static int trace_kprobe_module_callback(struct notifier_block *nb, 695 unsigned long val, void *data) 696 { 697 struct module *mod = data; 698 struct dyn_event *pos; 699 struct trace_kprobe *tk; 700 int ret; 701 702 if (val != MODULE_STATE_COMING) 703 return NOTIFY_DONE; 704 705 /* Update probes on coming module */ 706 guard(mutex)(&event_mutex); 707 for_each_trace_kprobe(tk, pos) { 708 if (trace_kprobe_within_module(tk, mod)) { 709 /* Don't need to check busy - this should have gone. */ 710 __unregister_trace_kprobe(tk); 711 ret = register_module_trace_kprobe(mod, tk); 712 if (ret) 713 pr_warn("Failed to re-register probe %s on %s: %d\n", 714 trace_probe_name(&tk->tp), 715 module_name(mod), ret); 716 } 717 } 718 719 return NOTIFY_DONE; 720 } 721 722 static struct notifier_block trace_kprobe_module_nb = { 723 .notifier_call = trace_kprobe_module_callback, 724 .priority = 2 /* Invoked after kprobe and jump_label module callback */ 725 }; 726 static int trace_kprobe_register_module_notifier(void) 727 { 728 return register_module_notifier(&trace_kprobe_module_nb); 729 } 730 #else 731 static int trace_kprobe_register_module_notifier(void) 732 { 733 return 0; 734 } 735 #endif /* CONFIG_MODULES */ 736 737 static int count_symbols(void *data, unsigned long unused) 738 { 739 unsigned int *count = data; 740 741 (*count)++; 742 743 return 0; 744 } 745 746 struct sym_count_ctx { 747 unsigned int count; 748 const char *name; 749 }; 750 751 static int count_mod_symbols(void *data, const char *name, unsigned long unused) 752 { 753 struct sym_count_ctx *ctx = data; 754 755 if (strcmp(name, ctx->name) == 0) 756 ctx->count++; 757 758 return 0; 759 } 760 761 static unsigned int number_of_same_symbols(const char *mod, const char *func_name) 762 { 763 struct sym_count_ctx ctx = { .count = 0, .name = func_name }; 764 765 if (!mod) 766 kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count); 767 768 module_kallsyms_on_each_symbol(mod, count_mod_symbols, &ctx); 769 770 return ctx.count; 771 } 772 773 static int validate_module_probe_symbol(const char *modname, const char *symbol) 774 { 775 unsigned int count = number_of_same_symbols(modname, symbol); 776 777 if (count > 1) { 778 /* 779 * Users should use ADDR to remove the ambiguity of 780 * using KSYM only. 781 */ 782 return -EADDRNOTAVAIL; 783 } else if (count == 0) { 784 /* 785 * We can return ENOENT earlier than when register the 786 * kprobe. 787 */ 788 return -ENOENT; 789 } 790 return 0; 791 } 792 793 #ifdef CONFIG_MODULES 794 /* Return NULL if the module is not loaded or under unloading. */ 795 static struct module *try_module_get_by_name(const char *name) 796 { 797 struct module *mod; 798 799 guard(rcu)(); 800 mod = find_module(name); 801 if (mod && !try_module_get(mod)) 802 mod = NULL; 803 return mod; 804 } 805 #else 806 #define try_module_get_by_name(name) (NULL) 807 #endif 808 809 static int validate_probe_symbol(char *symbol) 810 { 811 struct module *mod = NULL; 812 char *modname = NULL, *p; 813 int ret = 0; 814 815 p = strchr(symbol, ':'); 816 if (p) { 817 modname = symbol; 818 symbol = p + 1; 819 *p = '\0'; 820 mod = try_module_get_by_name(modname); 821 if (!mod) 822 goto out; 823 } 824 825 ret = validate_module_probe_symbol(modname, symbol); 826 out: 827 if (p) 828 *p = ':'; 829 if (mod) 830 module_put(mod); 831 return ret; 832 } 833 834 static int trace_kprobe_entry_handler(struct kretprobe_instance *ri, 835 struct pt_regs *regs); 836 837 static int trace_kprobe_create_internal(int argc, const char *argv[], 838 struct traceprobe_parse_context *ctx) 839 { 840 /* 841 * Argument syntax: 842 * - Add kprobe: 843 * p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] 844 * - Add kretprobe: 845 * r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS] 846 * Or 847 * p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS] 848 * 849 * Fetch args: 850 * $retval : fetch return value 851 * $stack : fetch stack address 852 * $stackN : fetch Nth of stack (N:0-) 853 * $comm : fetch current task comm 854 * @ADDR : fetch memory at ADDR (ADDR should be in kernel) 855 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) 856 * %REG : fetch register REG 857 * Dereferencing memory fetch: 858 * +|-offs(ARG) : fetch memory at ARG +|- offs address. 859 * Alias name of args: 860 * NAME=FETCHARG : set NAME as alias of FETCHARG. 861 * Type of args: 862 * FETCHARG:TYPE : use TYPE instead of unsigned long. 863 */ 864 struct trace_kprobe *tk __free(free_trace_kprobe) = NULL; 865 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM; 866 const char **new_argv __free(kfree) = NULL; 867 int i, len, new_argc = 0, ret = 0; 868 char *symbol __free(kfree) = NULL; 869 char *ebuf __free(kfree) = NULL; 870 char *gbuf __free(kfree) = NULL; 871 char *abuf __free(kfree) = NULL; 872 char *dbuf __free(kfree) = NULL; 873 enum probe_print_type ptype; 874 bool is_return = false; 875 int maxactive = 0; 876 void *addr = NULL; 877 char *tmp = NULL; 878 long offset = 0; 879 880 switch (argv[0][0]) { 881 case 'r': 882 is_return = true; 883 break; 884 case 'p': 885 break; 886 default: 887 return -ECANCELED; 888 } 889 if (argc < 2) 890 return -ECANCELED; 891 892 event = strchr(&argv[0][1], ':'); 893 if (event) 894 event++; 895 896 if (isdigit(argv[0][1])) { 897 char *buf __free(kfree) = NULL; 898 899 if (!is_return) { 900 trace_probe_log_err(1, BAD_MAXACT_TYPE); 901 return -EINVAL; 902 } 903 if (event) 904 len = event - &argv[0][1] - 1; 905 else 906 len = strlen(&argv[0][1]); 907 if (len > MAX_EVENT_NAME_LEN - 1) { 908 trace_probe_log_err(1, BAD_MAXACT); 909 return -EINVAL; 910 } 911 buf = kmemdup(&argv[0][1], len + 1, GFP_KERNEL); 912 if (!buf) 913 return -ENOMEM; 914 buf[len] = '\0'; 915 ret = kstrtouint(buf, 0, &maxactive); 916 if (ret || !maxactive) { 917 trace_probe_log_err(1, BAD_MAXACT); 918 return -EINVAL; 919 } 920 /* kretprobes instances are iterated over via a list. The 921 * maximum should stay reasonable. 922 */ 923 if (maxactive > KRETPROBE_MAXACTIVE_MAX) { 924 trace_probe_log_err(1, MAXACT_TOO_BIG); 925 return -EINVAL; 926 } 927 } 928 929 /* try to parse an address. if that fails, try to read the 930 * input as a symbol. */ 931 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { 932 trace_probe_log_set_index(1); 933 /* Check whether uprobe event specified */ 934 if (strchr(argv[1], '/') && strchr(argv[1], ':')) 935 return -ECANCELED; 936 937 /* a symbol specified */ 938 symbol = kstrdup(argv[1], GFP_KERNEL); 939 if (!symbol) 940 return -ENOMEM; 941 942 tmp = strchr(symbol, '%'); 943 if (tmp) { 944 if (!strcmp(tmp, "%return")) { 945 *tmp = '\0'; 946 is_return = true; 947 } else { 948 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX); 949 return -EINVAL; 950 } 951 } 952 953 /* TODO: support .init module functions */ 954 ret = traceprobe_split_symbol_offset(symbol, &offset); 955 if (ret || offset < 0 || offset > UINT_MAX) { 956 trace_probe_log_err(0, BAD_PROBE_ADDR); 957 return -EINVAL; 958 } 959 ret = validate_probe_symbol(symbol); 960 if (ret) { 961 if (ret == -EADDRNOTAVAIL) 962 trace_probe_log_err(0, NON_UNIQ_SYMBOL); 963 else 964 trace_probe_log_err(0, BAD_PROBE_ADDR); 965 return -EINVAL; 966 } 967 if (is_return) 968 ctx->flags |= TPARG_FL_RETURN; 969 ret = kprobe_on_func_entry(NULL, symbol, offset); 970 if (ret == 0 && !is_return) 971 ctx->flags |= TPARG_FL_FENTRY; 972 /* Defer the ENOENT case until register kprobe */ 973 if (ret == -EINVAL && is_return) { 974 trace_probe_log_err(0, BAD_RETPROBE); 975 return -EINVAL; 976 } 977 } 978 979 trace_probe_log_set_index(0); 980 if (event) { 981 gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL); 982 if (!gbuf) 983 return -ENOMEM; 984 ret = traceprobe_parse_event_name(&event, &group, gbuf, 985 event - argv[0]); 986 if (ret) 987 return ret; 988 } 989 990 if (!event) { 991 /* Make a new event name */ 992 ebuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL); 993 if (!ebuf) 994 return -ENOMEM; 995 if (symbol) 996 snprintf(ebuf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", 997 is_return ? 'r' : 'p', symbol, offset); 998 else 999 snprintf(ebuf, MAX_EVENT_NAME_LEN, "%c_0x%p", 1000 is_return ? 'r' : 'p', addr); 1001 sanitize_event_name(ebuf); 1002 event = ebuf; 1003 } 1004 1005 abuf = kmalloc(MAX_BTF_ARGS_LEN, GFP_KERNEL); 1006 if (!abuf) 1007 return -ENOMEM; 1008 argc -= 2; argv += 2; 1009 ctx->funcname = symbol; 1010 new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc, 1011 abuf, MAX_BTF_ARGS_LEN, ctx); 1012 if (IS_ERR(new_argv)) { 1013 ret = PTR_ERR(new_argv); 1014 new_argv = NULL; 1015 return ret; 1016 } 1017 if (new_argv) { 1018 argc = new_argc; 1019 argv = new_argv; 1020 } 1021 if (argc > MAX_TRACE_ARGS) { 1022 trace_probe_log_set_index(2); 1023 trace_probe_log_err(0, TOO_MANY_ARGS); 1024 return -E2BIG; 1025 } 1026 1027 ret = traceprobe_expand_dentry_args(argc, argv, &dbuf); 1028 if (ret) 1029 return ret; 1030 1031 /* setup a probe */ 1032 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, 1033 argc, is_return); 1034 if (IS_ERR(tk)) { 1035 ret = PTR_ERR(tk); 1036 /* This must return -ENOMEM, else there is a bug */ 1037 WARN_ON_ONCE(ret != -ENOMEM); 1038 return ret; /* We know tk is not allocated */ 1039 } 1040 1041 /* parse arguments */ 1042 for (i = 0; i < argc; i++) { 1043 trace_probe_log_set_index(i + 2); 1044 ctx->offset = 0; 1045 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], ctx); 1046 if (ret) 1047 return ret; /* This can be -ENOMEM */ 1048 } 1049 /* entry handler for kretprobe */ 1050 if (is_return && tk->tp.entry_arg) { 1051 tk->rp.entry_handler = trace_kprobe_entry_handler; 1052 tk->rp.data_size = traceprobe_get_entry_data_size(&tk->tp); 1053 } 1054 1055 ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; 1056 ret = traceprobe_set_print_fmt(&tk->tp, ptype); 1057 if (ret < 0) 1058 return ret; 1059 1060 ret = register_trace_kprobe(tk); 1061 if (ret) { 1062 trace_probe_log_set_index(1); 1063 if (ret == -EILSEQ) 1064 trace_probe_log_err(0, BAD_INSN_BNDRY); 1065 else if (ret == -ENOENT) 1066 trace_probe_log_err(0, BAD_PROBE_ADDR); 1067 else if (ret != -ENOMEM && ret != -EEXIST) 1068 trace_probe_log_err(0, FAIL_REG_PROBE); 1069 return ret; 1070 } 1071 /* 1072 * Here, 'tk' has been registered to the list successfully, 1073 * so we don't need to free it. 1074 */ 1075 tk = NULL; 1076 1077 return 0; 1078 } 1079 1080 static int trace_kprobe_create_cb(int argc, const char *argv[]) 1081 { 1082 struct traceprobe_parse_context *ctx __free(traceprobe_parse_context) = NULL; 1083 int ret; 1084 1085 ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); 1086 if (!ctx) 1087 return -ENOMEM; 1088 ctx->flags = TPARG_FL_KERNEL; 1089 1090 trace_probe_log_init("trace_kprobe", argc, argv); 1091 1092 ret = trace_kprobe_create_internal(argc, argv, ctx); 1093 1094 trace_probe_log_clear(); 1095 return ret; 1096 } 1097 1098 static int trace_kprobe_create(const char *raw_command) 1099 { 1100 return trace_probe_create(raw_command, trace_kprobe_create_cb); 1101 } 1102 1103 static int create_or_delete_trace_kprobe(const char *raw_command) 1104 { 1105 int ret; 1106 1107 if (raw_command[0] == '-') 1108 return dyn_event_release(raw_command, &trace_kprobe_ops); 1109 1110 ret = dyn_event_create(raw_command, &trace_kprobe_ops); 1111 return ret == -ECANCELED ? -EINVAL : ret; 1112 } 1113 1114 static int trace_kprobe_run_command(struct dynevent_cmd *cmd) 1115 { 1116 return create_or_delete_trace_kprobe(cmd->seq.buffer); 1117 } 1118 1119 /** 1120 * kprobe_event_cmd_init - Initialize a kprobe event command object 1121 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1122 * @buf: A pointer to the buffer used to build the command 1123 * @maxlen: The length of the buffer passed in @buf 1124 * 1125 * Initialize a synthetic event command object. Use this before 1126 * calling any of the other kprobe_event functions. 1127 */ 1128 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) 1129 { 1130 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE, 1131 trace_kprobe_run_command); 1132 } 1133 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init); 1134 1135 /** 1136 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list 1137 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1138 * @kretprobe: Is this a return probe? 1139 * @name: The name of the kprobe event 1140 * @loc: The location of the kprobe event 1141 * @...: Variable number of arg (pairs), one pair for each field 1142 * 1143 * NOTE: Users normally won't want to call this function directly, but 1144 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically 1145 * adds a NULL to the end of the arg list. If this function is used 1146 * directly, make sure the last arg in the variable arg list is NULL. 1147 * 1148 * Generate a kprobe event command to be executed by 1149 * kprobe_event_gen_cmd_end(). This function can be used to generate the 1150 * complete command or only the first part of it; in the latter case, 1151 * kprobe_event_add_fields() can be used to add more fields following this. 1152 * 1153 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This 1154 * returns -EINVAL if @loc == NULL. 1155 * 1156 * Return: 0 if successful, error otherwise. 1157 */ 1158 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, 1159 const char *name, const char *loc, ...) 1160 { 1161 char buf[MAX_EVENT_NAME_LEN]; 1162 struct dynevent_arg arg; 1163 va_list args; 1164 int ret; 1165 1166 if (cmd->type != DYNEVENT_TYPE_KPROBE) 1167 return -EINVAL; 1168 1169 if (!loc) 1170 return -EINVAL; 1171 1172 if (kretprobe) 1173 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name); 1174 else 1175 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name); 1176 1177 ret = dynevent_str_add(cmd, buf); 1178 if (ret) 1179 return ret; 1180 1181 dynevent_arg_init(&arg, 0); 1182 arg.str = loc; 1183 ret = dynevent_arg_add(cmd, &arg, NULL); 1184 if (ret) 1185 return ret; 1186 1187 va_start(args, loc); 1188 for (;;) { 1189 const char *field; 1190 1191 field = va_arg(args, const char *); 1192 if (!field) 1193 break; 1194 1195 if (++cmd->n_fields > MAX_TRACE_ARGS) { 1196 ret = -EINVAL; 1197 break; 1198 } 1199 1200 arg.str = field; 1201 ret = dynevent_arg_add(cmd, &arg, NULL); 1202 if (ret) 1203 break; 1204 } 1205 va_end(args); 1206 1207 return ret; 1208 } 1209 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start); 1210 1211 /** 1212 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list 1213 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1214 * @...: Variable number of arg (pairs), one pair for each field 1215 * 1216 * NOTE: Users normally won't want to call this function directly, but 1217 * rather use the kprobe_event_add_fields() wrapper, which 1218 * automatically adds a NULL to the end of the arg list. If this 1219 * function is used directly, make sure the last arg in the variable 1220 * arg list is NULL. 1221 * 1222 * Add probe fields to an existing kprobe command using a variable 1223 * list of args. Fields are added in the same order they're listed. 1224 * 1225 * Return: 0 if successful, error otherwise. 1226 */ 1227 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...) 1228 { 1229 struct dynevent_arg arg; 1230 va_list args; 1231 int ret = 0; 1232 1233 if (cmd->type != DYNEVENT_TYPE_KPROBE) 1234 return -EINVAL; 1235 1236 dynevent_arg_init(&arg, 0); 1237 1238 va_start(args, cmd); 1239 for (;;) { 1240 const char *field; 1241 1242 field = va_arg(args, const char *); 1243 if (!field) 1244 break; 1245 1246 if (++cmd->n_fields > MAX_TRACE_ARGS) { 1247 ret = -EINVAL; 1248 break; 1249 } 1250 1251 arg.str = field; 1252 ret = dynevent_arg_add(cmd, &arg, NULL); 1253 if (ret) 1254 break; 1255 } 1256 va_end(args); 1257 1258 return ret; 1259 } 1260 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields); 1261 1262 /** 1263 * kprobe_event_delete - Delete a kprobe event 1264 * @name: The name of the kprobe event to delete 1265 * 1266 * Delete a kprobe event with the give @name from kernel code rather 1267 * than directly from the command line. 1268 * 1269 * Return: 0 if successful, error otherwise. 1270 */ 1271 int kprobe_event_delete(const char *name) 1272 { 1273 char buf[MAX_EVENT_NAME_LEN]; 1274 1275 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name); 1276 1277 return create_or_delete_trace_kprobe(buf); 1278 } 1279 EXPORT_SYMBOL_GPL(kprobe_event_delete); 1280 1281 static int trace_kprobe_release(struct dyn_event *ev) 1282 { 1283 struct trace_kprobe *tk = to_trace_kprobe(ev); 1284 int ret = unregister_trace_kprobe(tk); 1285 1286 if (!ret) 1287 free_trace_kprobe(tk); 1288 return ret; 1289 } 1290 1291 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) 1292 { 1293 struct trace_kprobe *tk = to_trace_kprobe(ev); 1294 int i; 1295 1296 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 1297 if (trace_kprobe_is_return(tk) && tk->rp.maxactive) 1298 seq_printf(m, "%d", tk->rp.maxactive); 1299 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), 1300 trace_probe_name(&tk->tp)); 1301 1302 if (!tk->symbol) 1303 seq_printf(m, " 0x%p", tk->rp.kp.addr); 1304 else if (tk->rp.kp.offset) 1305 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 1306 tk->rp.kp.offset); 1307 else 1308 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 1309 1310 for (i = 0; i < tk->tp.nr_args; i++) 1311 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 1312 seq_putc(m, '\n'); 1313 1314 return 0; 1315 } 1316 1317 static int probes_seq_show(struct seq_file *m, void *v) 1318 { 1319 struct dyn_event *ev = v; 1320 1321 if (!is_trace_kprobe(ev)) 1322 return 0; 1323 1324 return trace_kprobe_show(m, ev); 1325 } 1326 1327 static const struct seq_operations probes_seq_op = { 1328 .start = dyn_event_seq_start, 1329 .next = dyn_event_seq_next, 1330 .stop = dyn_event_seq_stop, 1331 .show = probes_seq_show 1332 }; 1333 1334 static int probes_open(struct inode *inode, struct file *file) 1335 { 1336 int ret; 1337 1338 ret = security_locked_down(LOCKDOWN_TRACEFS); 1339 if (ret) 1340 return ret; 1341 1342 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 1343 ret = dyn_events_release_all(&trace_kprobe_ops); 1344 if (ret < 0) 1345 return ret; 1346 } 1347 1348 return seq_open(file, &probes_seq_op); 1349 } 1350 1351 static ssize_t probes_write(struct file *file, const char __user *buffer, 1352 size_t count, loff_t *ppos) 1353 { 1354 return trace_parse_run_command(file, buffer, count, ppos, 1355 create_or_delete_trace_kprobe); 1356 } 1357 1358 static const struct file_operations kprobe_events_ops = { 1359 .owner = THIS_MODULE, 1360 .open = probes_open, 1361 .read = seq_read, 1362 .llseek = seq_lseek, 1363 .release = seq_release, 1364 .write = probes_write, 1365 }; 1366 1367 static unsigned long trace_kprobe_missed(struct trace_kprobe *tk) 1368 { 1369 return trace_kprobe_is_return(tk) ? 1370 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed; 1371 } 1372 1373 /* Probes profiling interfaces */ 1374 static int probes_profile_seq_show(struct seq_file *m, void *v) 1375 { 1376 struct dyn_event *ev = v; 1377 struct trace_kprobe *tk; 1378 unsigned long nmissed; 1379 1380 if (!is_trace_kprobe(ev)) 1381 return 0; 1382 1383 tk = to_trace_kprobe(ev); 1384 nmissed = trace_kprobe_missed(tk); 1385 seq_printf(m, " %-44s %15lu %15lu\n", 1386 trace_probe_name(&tk->tp), 1387 trace_kprobe_nhit(tk), 1388 nmissed); 1389 1390 return 0; 1391 } 1392 1393 static const struct seq_operations profile_seq_op = { 1394 .start = dyn_event_seq_start, 1395 .next = dyn_event_seq_next, 1396 .stop = dyn_event_seq_stop, 1397 .show = probes_profile_seq_show 1398 }; 1399 1400 static int profile_open(struct inode *inode, struct file *file) 1401 { 1402 int ret; 1403 1404 ret = security_locked_down(LOCKDOWN_TRACEFS); 1405 if (ret) 1406 return ret; 1407 1408 return seq_open(file, &profile_seq_op); 1409 } 1410 1411 static const struct file_operations kprobe_profile_ops = { 1412 .owner = THIS_MODULE, 1413 .open = profile_open, 1414 .read = seq_read, 1415 .llseek = seq_lseek, 1416 .release = seq_release, 1417 }; 1418 1419 /* Note that we don't verify it, since the code does not come from user space */ 1420 static int 1421 process_fetch_insn(struct fetch_insn *code, void *rec, void *edata, 1422 void *dest, void *base) 1423 { 1424 struct pt_regs *regs = rec; 1425 unsigned long val; 1426 int ret; 1427 1428 retry: 1429 /* 1st stage: get value from context */ 1430 switch (code->op) { 1431 case FETCH_OP_REG: 1432 val = regs_get_register(regs, code->param); 1433 break; 1434 case FETCH_OP_STACK: 1435 val = regs_get_kernel_stack_nth(regs, code->param); 1436 break; 1437 case FETCH_OP_STACKP: 1438 val = kernel_stack_pointer(regs); 1439 break; 1440 case FETCH_OP_RETVAL: 1441 val = regs_return_value(regs); 1442 break; 1443 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 1444 case FETCH_OP_ARG: 1445 val = regs_get_kernel_argument(regs, code->param); 1446 break; 1447 case FETCH_OP_EDATA: 1448 val = *(unsigned long *)((unsigned long)edata + code->offset); 1449 break; 1450 #endif 1451 case FETCH_NOP_SYMBOL: /* Ignore a place holder */ 1452 code++; 1453 goto retry; 1454 default: 1455 ret = process_common_fetch_insn(code, &val); 1456 if (ret < 0) 1457 return ret; 1458 } 1459 code++; 1460 1461 return process_fetch_insn_bottom(code, val, dest, base); 1462 } 1463 NOKPROBE_SYMBOL(process_fetch_insn) 1464 1465 /* Kprobe handler */ 1466 static nokprobe_inline void 1467 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 1468 struct trace_event_file *trace_file) 1469 { 1470 struct kprobe_trace_entry_head *entry; 1471 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1472 struct trace_event_buffer fbuffer; 1473 int dsize; 1474 1475 WARN_ON(call != trace_file->event_call); 1476 1477 if (trace_trigger_soft_disabled(trace_file)) 1478 return; 1479 1480 dsize = __get_data_size(&tk->tp, regs, NULL); 1481 1482 entry = trace_event_buffer_reserve(&fbuffer, trace_file, 1483 sizeof(*entry) + tk->tp.size + dsize); 1484 if (!entry) 1485 return; 1486 1487 fbuffer.regs = regs; 1488 entry->ip = (unsigned long)tk->rp.kp.addr; 1489 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize); 1490 1491 trace_event_buffer_commit(&fbuffer); 1492 } 1493 1494 static void 1495 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 1496 { 1497 struct event_file_link *link; 1498 1499 trace_probe_for_each_link_rcu(link, &tk->tp) 1500 __kprobe_trace_func(tk, regs, link->file); 1501 } 1502 NOKPROBE_SYMBOL(kprobe_trace_func); 1503 1504 /* Kretprobe handler */ 1505 1506 static int trace_kprobe_entry_handler(struct kretprobe_instance *ri, 1507 struct pt_regs *regs) 1508 { 1509 struct kretprobe *rp = get_kretprobe(ri); 1510 struct trace_kprobe *tk; 1511 1512 /* 1513 * There is a small chance that get_kretprobe(ri) returns NULL when 1514 * the kretprobe is unregister on another CPU between kretprobe's 1515 * trampoline_handler and this function. 1516 */ 1517 if (unlikely(!rp)) 1518 return -ENOENT; 1519 1520 tk = container_of(rp, struct trace_kprobe, rp); 1521 1522 /* store argument values into ri->data as entry data */ 1523 if (tk->tp.entry_arg) 1524 store_trace_entry_data(ri->data, &tk->tp, regs); 1525 1526 return 0; 1527 } 1528 1529 1530 static nokprobe_inline void 1531 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1532 struct pt_regs *regs, 1533 struct trace_event_file *trace_file) 1534 { 1535 struct kretprobe_trace_entry_head *entry; 1536 struct trace_event_buffer fbuffer; 1537 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1538 int dsize; 1539 1540 WARN_ON(call != trace_file->event_call); 1541 1542 if (trace_trigger_soft_disabled(trace_file)) 1543 return; 1544 1545 dsize = __get_data_size(&tk->tp, regs, ri->data); 1546 1547 entry = trace_event_buffer_reserve(&fbuffer, trace_file, 1548 sizeof(*entry) + tk->tp.size + dsize); 1549 if (!entry) 1550 return; 1551 1552 fbuffer.regs = regs; 1553 entry->func = (unsigned long)tk->rp.kp.addr; 1554 entry->ret_ip = get_kretprobe_retaddr(ri); 1555 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize); 1556 1557 trace_event_buffer_commit(&fbuffer); 1558 } 1559 1560 static void 1561 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1562 struct pt_regs *regs) 1563 { 1564 struct event_file_link *link; 1565 1566 trace_probe_for_each_link_rcu(link, &tk->tp) 1567 __kretprobe_trace_func(tk, ri, regs, link->file); 1568 } 1569 NOKPROBE_SYMBOL(kretprobe_trace_func); 1570 1571 /* Event entry printers */ 1572 static enum print_line_t 1573 print_kprobe_event(struct trace_iterator *iter, int flags, 1574 struct trace_event *event) 1575 { 1576 struct kprobe_trace_entry_head *field; 1577 struct trace_seq *s = &iter->seq; 1578 struct trace_probe *tp; 1579 1580 field = (struct kprobe_trace_entry_head *)iter->ent; 1581 tp = trace_probe_primary_from_call( 1582 container_of(event, struct trace_event_call, event)); 1583 if (WARN_ON_ONCE(!tp)) 1584 goto out; 1585 1586 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1587 1588 if (!seq_print_ip_sym_offset(s, field->ip, flags)) 1589 goto out; 1590 1591 trace_seq_putc(s, ')'); 1592 1593 if (trace_probe_print_args(s, tp->args, tp->nr_args, 1594 (u8 *)&field[1], field) < 0) 1595 goto out; 1596 1597 trace_seq_putc(s, '\n'); 1598 out: 1599 return trace_handle_return(s); 1600 } 1601 1602 static enum print_line_t 1603 print_kretprobe_event(struct trace_iterator *iter, int flags, 1604 struct trace_event *event) 1605 { 1606 struct kretprobe_trace_entry_head *field; 1607 struct trace_seq *s = &iter->seq; 1608 struct trace_probe *tp; 1609 1610 field = (struct kretprobe_trace_entry_head *)iter->ent; 1611 tp = trace_probe_primary_from_call( 1612 container_of(event, struct trace_event_call, event)); 1613 if (WARN_ON_ONCE(!tp)) 1614 goto out; 1615 1616 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1617 1618 if (!seq_print_ip_sym_offset(s, field->ret_ip, flags)) 1619 goto out; 1620 1621 trace_seq_puts(s, " <- "); 1622 1623 if (!seq_print_ip_sym_no_offset(s, field->func, flags)) 1624 goto out; 1625 1626 trace_seq_putc(s, ')'); 1627 1628 if (trace_probe_print_args(s, tp->args, tp->nr_args, 1629 (u8 *)&field[1], field) < 0) 1630 goto out; 1631 1632 trace_seq_putc(s, '\n'); 1633 1634 out: 1635 return trace_handle_return(s); 1636 } 1637 1638 1639 static int kprobe_event_define_fields(struct trace_event_call *event_call) 1640 { 1641 int ret; 1642 struct kprobe_trace_entry_head field; 1643 struct trace_probe *tp; 1644 1645 tp = trace_probe_primary_from_call(event_call); 1646 if (WARN_ON_ONCE(!tp)) 1647 return -ENOENT; 1648 1649 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1650 1651 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1652 } 1653 1654 static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1655 { 1656 int ret; 1657 struct kretprobe_trace_entry_head field; 1658 struct trace_probe *tp; 1659 1660 tp = trace_probe_primary_from_call(event_call); 1661 if (WARN_ON_ONCE(!tp)) 1662 return -ENOENT; 1663 1664 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1665 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1666 1667 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1668 } 1669 1670 #ifdef CONFIG_PERF_EVENTS 1671 1672 /* Kprobe profile handler */ 1673 static int 1674 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1675 { 1676 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1677 struct kprobe_trace_entry_head *entry; 1678 struct hlist_head *head; 1679 int size, __size, dsize; 1680 int rctx; 1681 1682 if (bpf_prog_array_valid(call)) { 1683 unsigned long orig_ip = instruction_pointer(regs); 1684 int ret; 1685 1686 ret = trace_call_bpf(call, regs); 1687 1688 /* 1689 * We need to check and see if we modified the pc of the 1690 * pt_regs, and if so return 1 so that we don't do the 1691 * single stepping. 1692 */ 1693 if (orig_ip != instruction_pointer(regs)) 1694 return 1; 1695 if (!ret) 1696 return 0; 1697 } 1698 1699 head = this_cpu_ptr(call->perf_events); 1700 if (hlist_empty(head)) 1701 return 0; 1702 1703 dsize = __get_data_size(&tk->tp, regs, NULL); 1704 __size = sizeof(*entry) + tk->tp.size + dsize; 1705 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1706 size -= sizeof(u32); 1707 1708 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1709 if (!entry) 1710 return 0; 1711 1712 entry->ip = (unsigned long)tk->rp.kp.addr; 1713 memset(&entry[1], 0, dsize); 1714 store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize); 1715 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1716 head, NULL); 1717 return 0; 1718 } 1719 NOKPROBE_SYMBOL(kprobe_perf_func); 1720 1721 /* Kretprobe profile handler */ 1722 static void 1723 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1724 struct pt_regs *regs) 1725 { 1726 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1727 struct kretprobe_trace_entry_head *entry; 1728 struct hlist_head *head; 1729 int size, __size, dsize; 1730 int rctx; 1731 1732 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1733 return; 1734 1735 head = this_cpu_ptr(call->perf_events); 1736 if (hlist_empty(head)) 1737 return; 1738 1739 dsize = __get_data_size(&tk->tp, regs, ri->data); 1740 __size = sizeof(*entry) + tk->tp.size + dsize; 1741 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1742 size -= sizeof(u32); 1743 1744 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1745 if (!entry) 1746 return; 1747 1748 entry->func = (unsigned long)tk->rp.kp.addr; 1749 entry->ret_ip = get_kretprobe_retaddr(ri); 1750 store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize); 1751 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1752 head, NULL); 1753 } 1754 NOKPROBE_SYMBOL(kretprobe_perf_func); 1755 1756 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, 1757 const char **symbol, u64 *probe_offset, 1758 u64 *probe_addr, unsigned long *missed, 1759 bool perf_type_tracepoint) 1760 { 1761 const char *pevent = trace_event_name(event->tp_event); 1762 const char *group = event->tp_event->class->system; 1763 struct trace_kprobe *tk; 1764 1765 if (perf_type_tracepoint) 1766 tk = find_trace_kprobe(pevent, group); 1767 else 1768 tk = trace_kprobe_primary_from_call(event->tp_event); 1769 if (!tk) 1770 return -EINVAL; 1771 1772 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE 1773 : BPF_FD_TYPE_KPROBE; 1774 *probe_offset = tk->rp.kp.offset; 1775 *probe_addr = kallsyms_show_value(current_cred()) ? 1776 (unsigned long)tk->rp.kp.addr : 0; 1777 *symbol = tk->symbol; 1778 if (missed) 1779 *missed = trace_kprobe_missed(tk); 1780 return 0; 1781 } 1782 #endif /* CONFIG_PERF_EVENTS */ 1783 1784 /* 1785 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1786 * 1787 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1788 * lockless, but we can't race with this __init function. 1789 */ 1790 static int kprobe_register(struct trace_event_call *event, 1791 enum trace_reg type, void *data) 1792 { 1793 struct trace_event_file *file = data; 1794 1795 switch (type) { 1796 case TRACE_REG_REGISTER: 1797 return enable_trace_kprobe(event, file); 1798 case TRACE_REG_UNREGISTER: 1799 return disable_trace_kprobe(event, file); 1800 1801 #ifdef CONFIG_PERF_EVENTS 1802 case TRACE_REG_PERF_REGISTER: 1803 return enable_trace_kprobe(event, NULL); 1804 case TRACE_REG_PERF_UNREGISTER: 1805 return disable_trace_kprobe(event, NULL); 1806 case TRACE_REG_PERF_OPEN: 1807 case TRACE_REG_PERF_CLOSE: 1808 case TRACE_REG_PERF_ADD: 1809 case TRACE_REG_PERF_DEL: 1810 return 0; 1811 #endif 1812 } 1813 return 0; 1814 } 1815 1816 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1817 { 1818 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1819 unsigned int flags = trace_probe_load_flag(&tk->tp); 1820 int ret = 0; 1821 1822 raw_cpu_inc(*tk->nhit); 1823 1824 if (flags & TP_FLAG_TRACE) 1825 kprobe_trace_func(tk, regs); 1826 #ifdef CONFIG_PERF_EVENTS 1827 if (flags & TP_FLAG_PROFILE) 1828 ret = kprobe_perf_func(tk, regs); 1829 #endif 1830 return ret; 1831 } 1832 NOKPROBE_SYMBOL(kprobe_dispatcher); 1833 1834 static int 1835 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1836 { 1837 struct kretprobe *rp = get_kretprobe(ri); 1838 struct trace_kprobe *tk; 1839 unsigned int flags; 1840 1841 /* 1842 * There is a small chance that get_kretprobe(ri) returns NULL when 1843 * the kretprobe is unregister on another CPU between kretprobe's 1844 * trampoline_handler and this function. 1845 */ 1846 if (unlikely(!rp)) 1847 return 0; 1848 1849 tk = container_of(rp, struct trace_kprobe, rp); 1850 raw_cpu_inc(*tk->nhit); 1851 1852 flags = trace_probe_load_flag(&tk->tp); 1853 if (flags & TP_FLAG_TRACE) 1854 kretprobe_trace_func(tk, ri, regs); 1855 #ifdef CONFIG_PERF_EVENTS 1856 if (flags & TP_FLAG_PROFILE) 1857 kretprobe_perf_func(tk, ri, regs); 1858 #endif 1859 return 0; /* We don't tweak kernel, so just return 0 */ 1860 } 1861 NOKPROBE_SYMBOL(kretprobe_dispatcher); 1862 1863 static struct trace_event_functions kretprobe_funcs = { 1864 .trace = print_kretprobe_event 1865 }; 1866 1867 static struct trace_event_functions kprobe_funcs = { 1868 .trace = print_kprobe_event 1869 }; 1870 1871 static struct trace_event_fields kretprobe_fields_array[] = { 1872 { .type = TRACE_FUNCTION_TYPE, 1873 .define_fields = kretprobe_event_define_fields }, 1874 {} 1875 }; 1876 1877 static struct trace_event_fields kprobe_fields_array[] = { 1878 { .type = TRACE_FUNCTION_TYPE, 1879 .define_fields = kprobe_event_define_fields }, 1880 {} 1881 }; 1882 1883 static inline void init_trace_event_call(struct trace_kprobe *tk) 1884 { 1885 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1886 1887 if (trace_kprobe_is_return(tk)) { 1888 call->event.funcs = &kretprobe_funcs; 1889 call->class->fields_array = kretprobe_fields_array; 1890 } else { 1891 call->event.funcs = &kprobe_funcs; 1892 call->class->fields_array = kprobe_fields_array; 1893 } 1894 1895 call->flags = TRACE_EVENT_FL_KPROBE; 1896 call->class->reg = kprobe_register; 1897 } 1898 1899 static int register_kprobe_event(struct trace_kprobe *tk) 1900 { 1901 init_trace_event_call(tk); 1902 1903 return trace_probe_register_event_call(&tk->tp); 1904 } 1905 1906 static int unregister_kprobe_event(struct trace_kprobe *tk) 1907 { 1908 return trace_probe_unregister_event_call(&tk->tp); 1909 } 1910 1911 #ifdef CONFIG_PERF_EVENTS 1912 1913 /* create a trace_kprobe, but don't add it to global lists */ 1914 struct trace_event_call * 1915 create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 1916 bool is_return) 1917 { 1918 enum probe_print_type ptype; 1919 struct trace_kprobe *tk __free(free_trace_kprobe) = NULL; 1920 int ret; 1921 char *event; 1922 1923 if (func) { 1924 ret = validate_probe_symbol(func); 1925 if (ret) 1926 return ERR_PTR(ret); 1927 } 1928 1929 /* 1930 * local trace_kprobes are not added to dyn_event, so they are never 1931 * searched in find_trace_kprobe(). Therefore, there is no concern of 1932 * duplicated name here. 1933 */ 1934 event = func ? func : "DUMMY_EVENT"; 1935 1936 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, 1937 offs, 0 /* maxactive */, 0 /* nargs */, 1938 is_return); 1939 1940 if (IS_ERR(tk)) { 1941 pr_info("Failed to allocate trace_probe.(%d)\n", 1942 (int)PTR_ERR(tk)); 1943 return ERR_CAST(tk); 1944 } 1945 1946 init_trace_event_call(tk); 1947 1948 ptype = trace_kprobe_is_return(tk) ? 1949 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL; 1950 if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) 1951 return ERR_PTR(-ENOMEM); 1952 1953 ret = __register_trace_kprobe(tk); 1954 if (ret < 0) 1955 return ERR_PTR(ret); 1956 1957 return trace_probe_event_call(&(no_free_ptr(tk)->tp)); 1958 } 1959 1960 void destroy_local_trace_kprobe(struct trace_event_call *event_call) 1961 { 1962 struct trace_kprobe *tk; 1963 1964 tk = trace_kprobe_primary_from_call(event_call); 1965 if (unlikely(!tk)) 1966 return; 1967 1968 if (trace_probe_is_enabled(&tk->tp)) { 1969 WARN_ON(1); 1970 return; 1971 } 1972 1973 __unregister_trace_kprobe(tk); 1974 1975 free_trace_kprobe(tk); 1976 } 1977 #endif /* CONFIG_PERF_EVENTS */ 1978 1979 static __init void enable_boot_kprobe_events(void) 1980 { 1981 struct trace_array *tr = top_trace_array(); 1982 struct trace_event_file *file; 1983 struct trace_kprobe *tk; 1984 struct dyn_event *pos; 1985 1986 if (trace_kprobe_list_empty()) 1987 return; 1988 1989 guard(mutex)(&event_mutex); 1990 for_each_trace_kprobe(tk, pos) { 1991 list_for_each_entry(file, &tr->events, list) 1992 if (file->event_call == trace_probe_event_call(&tk->tp)) 1993 trace_event_enable_disable(file, 1, 0); 1994 } 1995 } 1996 1997 static __init void setup_boot_kprobe_events(void) 1998 { 1999 char *p, *cmd = kprobe_boot_events_buf; 2000 int ret; 2001 2002 strreplace(kprobe_boot_events_buf, ',', ' '); 2003 2004 while (cmd && *cmd != '\0') { 2005 p = strchr(cmd, ';'); 2006 if (p) 2007 *p++ = '\0'; 2008 2009 ret = create_or_delete_trace_kprobe(cmd); 2010 if (ret) 2011 pr_warn("Failed to add event(%d): %s\n", ret, cmd); 2012 2013 cmd = p; 2014 } 2015 2016 enable_boot_kprobe_events(); 2017 } 2018 2019 /* 2020 * Register dynevent at core_initcall. This allows kernel to setup kprobe 2021 * events in postcore_initcall without tracefs. 2022 */ 2023 static __init int init_kprobe_trace_early(void) 2024 { 2025 int ret; 2026 2027 ret = dyn_event_register(&trace_kprobe_ops); 2028 if (ret) 2029 return ret; 2030 2031 if (trace_kprobe_register_module_notifier()) 2032 return -EINVAL; 2033 2034 return 0; 2035 } 2036 core_initcall(init_kprobe_trace_early); 2037 2038 /* Make a tracefs interface for controlling probe points */ 2039 static __init int init_kprobe_trace(void) 2040 { 2041 int ret; 2042 2043 ret = tracing_init_dentry(); 2044 if (ret) 2045 return 0; 2046 2047 /* Event list interface */ 2048 trace_create_file("kprobe_events", TRACE_MODE_WRITE, 2049 NULL, NULL, &kprobe_events_ops); 2050 2051 /* Profile interface */ 2052 trace_create_file("kprobe_profile", TRACE_MODE_READ, 2053 NULL, NULL, &kprobe_profile_ops); 2054 2055 /* If no 'kprobe_event=' cmd is provided, return directly. */ 2056 if (kprobe_boot_events_buf[0] == '\0') 2057 return 0; 2058 2059 setup_boot_kprobe_events(); 2060 2061 return 0; 2062 } 2063 fs_initcall(init_kprobe_trace); 2064 2065 2066 #ifdef CONFIG_FTRACE_STARTUP_TEST 2067 static __init struct trace_event_file * 2068 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 2069 { 2070 struct trace_event_file *file; 2071 2072 list_for_each_entry(file, &tr->events, list) 2073 if (file->event_call == trace_probe_event_call(&tk->tp)) 2074 return file; 2075 2076 return NULL; 2077 } 2078 2079 /* 2080 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 2081 * stage, we can do this lockless. 2082 */ 2083 static __init int kprobe_trace_self_tests_init(void) 2084 { 2085 int ret, warn = 0; 2086 int (*target)(int, int, int, int, int, int); 2087 struct trace_kprobe *tk; 2088 struct trace_event_file *file; 2089 2090 if (unlikely(tracing_disabled)) 2091 return -ENODEV; 2092 2093 if (tracing_selftest_disabled) 2094 return 0; 2095 2096 target = kprobe_trace_selftest_target; 2097 2098 pr_info("Testing kprobe tracing: "); 2099 2100 ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)"); 2101 if (WARN_ONCE(ret, "error on probing function entry.")) { 2102 warn++; 2103 } else { 2104 /* Enable trace point */ 2105 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 2106 if (WARN_ONCE(tk == NULL, "error on probing function entry.")) { 2107 warn++; 2108 } else { 2109 file = find_trace_probe_file(tk, top_trace_array()); 2110 if (WARN_ONCE(file == NULL, "error on getting probe file.")) { 2111 warn++; 2112 } else 2113 enable_trace_kprobe( 2114 trace_probe_event_call(&tk->tp), file); 2115 } 2116 } 2117 2118 ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval"); 2119 if (WARN_ONCE(ret, "error on probing function return.")) { 2120 warn++; 2121 } else { 2122 /* Enable trace point */ 2123 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 2124 if (WARN_ONCE(tk == NULL, "error on getting 2nd new probe.")) { 2125 warn++; 2126 } else { 2127 file = find_trace_probe_file(tk, top_trace_array()); 2128 if (WARN_ONCE(file == NULL, "error on getting probe file.")) { 2129 warn++; 2130 } else 2131 enable_trace_kprobe( 2132 trace_probe_event_call(&tk->tp), file); 2133 } 2134 } 2135 2136 if (warn) 2137 goto end; 2138 2139 ret = target(1, 2, 3, 4, 5, 6); 2140 2141 /* 2142 * Not expecting an error here, the check is only to prevent the 2143 * optimizer from removing the call to target() as otherwise there 2144 * are no side-effects and the call is never performed. 2145 */ 2146 if (ret != 21) 2147 warn++; 2148 2149 /* Disable trace points before removing it */ 2150 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 2151 if (WARN_ONCE(tk == NULL, "error on getting test probe.")) { 2152 warn++; 2153 } else { 2154 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1, 2155 "incorrect number of testprobe hits.")) 2156 warn++; 2157 2158 file = find_trace_probe_file(tk, top_trace_array()); 2159 if (WARN_ONCE(file == NULL, "error on getting probe file.")) { 2160 warn++; 2161 } else 2162 disable_trace_kprobe( 2163 trace_probe_event_call(&tk->tp), file); 2164 } 2165 2166 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 2167 if (WARN_ONCE(tk == NULL, "error on getting 2nd test probe.")) { 2168 warn++; 2169 } else { 2170 if (WARN_ONCE(trace_kprobe_nhit(tk) != 1, 2171 "incorrect number of testprobe2 hits.")) 2172 warn++; 2173 2174 file = find_trace_probe_file(tk, top_trace_array()); 2175 if (WARN_ONCE(file == NULL, "error on getting probe file.")) { 2176 warn++; 2177 } else 2178 disable_trace_kprobe( 2179 trace_probe_event_call(&tk->tp), file); 2180 } 2181 2182 ret = create_or_delete_trace_kprobe("-:testprobe"); 2183 if (WARN_ONCE(ret, "error on deleting a probe.")) 2184 warn++; 2185 2186 ret = create_or_delete_trace_kprobe("-:testprobe2"); 2187 if (WARN_ONCE(ret, "error on deleting a probe.")) 2188 warn++; 2189 2190 2191 end: 2192 /* 2193 * Wait for the optimizer work to finish. Otherwise it might fiddle 2194 * with probes in already freed __init text. 2195 */ 2196 wait_for_kprobe_optimizer(); 2197 if (warn) 2198 pr_cont("NG: Some tests are failed. Please check them.\n"); 2199 else 2200 pr_cont("OK\n"); 2201 return 0; 2202 } 2203 2204 late_initcall(kprobe_trace_self_tests_init); 2205 2206 #endif 2207