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/security.h> 11 #include <linux/module.h> 12 #include <linux/uaccess.h> 13 #include <linux/rculist.h> 14 #include <linux/error-injection.h> 15 16 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */ 17 18 #include "trace_dynevent.h" 19 #include "trace_kprobe_selftest.h" 20 #include "trace_probe.h" 21 #include "trace_probe_tmpl.h" 22 23 #define KPROBE_EVENT_SYSTEM "kprobes" 24 #define KRETPROBE_MAXACTIVE_MAX 4096 25 26 /* Kprobe early definition from command line */ 27 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata; 28 static bool kprobe_boot_events_enabled __initdata; 29 30 static int __init set_kprobe_boot_events(char *str) 31 { 32 strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE); 33 return 0; 34 } 35 __setup("kprobe_event=", set_kprobe_boot_events); 36 37 static int trace_kprobe_create(int argc, const char **argv); 38 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev); 39 static int trace_kprobe_release(struct dyn_event *ev); 40 static bool trace_kprobe_is_busy(struct dyn_event *ev); 41 static bool trace_kprobe_match(const char *system, const char *event, 42 int argc, const char **argv, struct dyn_event *ev); 43 44 static struct dyn_event_operations trace_kprobe_ops = { 45 .create = trace_kprobe_create, 46 .show = trace_kprobe_show, 47 .is_busy = trace_kprobe_is_busy, 48 .free = trace_kprobe_release, 49 .match = trace_kprobe_match, 50 }; 51 52 /* 53 * Kprobe event core functions 54 */ 55 struct trace_kprobe { 56 struct dyn_event devent; 57 struct kretprobe rp; /* Use rp.kp for kprobe use */ 58 unsigned long __percpu *nhit; 59 const char *symbol; /* symbol name */ 60 struct trace_probe tp; 61 }; 62 63 static bool is_trace_kprobe(struct dyn_event *ev) 64 { 65 return ev->ops == &trace_kprobe_ops; 66 } 67 68 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev) 69 { 70 return container_of(ev, struct trace_kprobe, devent); 71 } 72 73 /** 74 * for_each_trace_kprobe - iterate over the trace_kprobe list 75 * @pos: the struct trace_kprobe * for each entry 76 * @dpos: the struct dyn_event * to use as a loop cursor 77 */ 78 #define for_each_trace_kprobe(pos, dpos) \ 79 for_each_dyn_event(dpos) \ 80 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos))) 81 82 #define SIZEOF_TRACE_KPROBE(n) \ 83 (offsetof(struct trace_kprobe, tp.args) + \ 84 (sizeof(struct probe_arg) * (n))) 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(mod->name); 110 const char *name = trace_kprobe_symbol(tk); 111 return strncmp(mod->name, name, len) == 0 && name[len] == ':'; 112 } 113 114 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) 115 { 116 char *p; 117 bool ret; 118 119 if (!tk->symbol) 120 return false; 121 p = strchr(tk->symbol, ':'); 122 if (!p) 123 return true; 124 *p = '\0'; 125 mutex_lock(&module_mutex); 126 ret = !!find_module(tk->symbol); 127 mutex_unlock(&module_mutex); 128 *p = ':'; 129 130 return ret; 131 } 132 133 static bool trace_kprobe_is_busy(struct dyn_event *ev) 134 { 135 struct trace_kprobe *tk = to_trace_kprobe(ev); 136 137 return trace_probe_is_enabled(&tk->tp); 138 } 139 140 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk, 141 int argc, const char **argv) 142 { 143 char buf[MAX_ARGSTR_LEN + 1]; 144 145 if (!argc) 146 return true; 147 148 if (!tk->symbol) 149 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr); 150 else if (tk->rp.kp.offset) 151 snprintf(buf, sizeof(buf), "%s+%u", 152 trace_kprobe_symbol(tk), tk->rp.kp.offset); 153 else 154 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk)); 155 if (strcmp(buf, argv[0])) 156 return false; 157 argc--; argv++; 158 159 return trace_probe_match_command_args(&tk->tp, argc, argv); 160 } 161 162 static bool trace_kprobe_match(const char *system, const char *event, 163 int argc, const char **argv, struct dyn_event *ev) 164 { 165 struct trace_kprobe *tk = to_trace_kprobe(ev); 166 167 return strcmp(trace_probe_name(&tk->tp), event) == 0 && 168 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) && 169 trace_kprobe_match_command_head(tk, argc, argv); 170 } 171 172 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) 173 { 174 unsigned long nhit = 0; 175 int cpu; 176 177 for_each_possible_cpu(cpu) 178 nhit += *per_cpu_ptr(tk->nhit, cpu); 179 180 return nhit; 181 } 182 183 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk) 184 { 185 return !(list_empty(&tk->rp.kp.list) && 186 hlist_unhashed(&tk->rp.kp.hlist)); 187 } 188 189 /* Return 0 if it fails to find the symbol address */ 190 static nokprobe_inline 191 unsigned long trace_kprobe_address(struct trace_kprobe *tk) 192 { 193 unsigned long addr; 194 195 if (tk->symbol) { 196 addr = (unsigned long) 197 kallsyms_lookup_name(trace_kprobe_symbol(tk)); 198 if (addr) 199 addr += tk->rp.kp.offset; 200 } else { 201 addr = (unsigned long)tk->rp.kp.addr; 202 } 203 return addr; 204 } 205 206 static nokprobe_inline struct trace_kprobe * 207 trace_kprobe_primary_from_call(struct trace_event_call *call) 208 { 209 struct trace_probe *tp; 210 211 tp = trace_probe_primary_from_call(call); 212 if (WARN_ON_ONCE(!tp)) 213 return NULL; 214 215 return container_of(tp, struct trace_kprobe, tp); 216 } 217 218 bool trace_kprobe_on_func_entry(struct trace_event_call *call) 219 { 220 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 221 222 return tk ? kprobe_on_func_entry(tk->rp.kp.addr, 223 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name, 224 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false; 225 } 226 227 bool trace_kprobe_error_injectable(struct trace_event_call *call) 228 { 229 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 230 231 return tk ? within_error_injection_list(trace_kprobe_address(tk)) : 232 false; 233 } 234 235 static int register_kprobe_event(struct trace_kprobe *tk); 236 static int unregister_kprobe_event(struct trace_kprobe *tk); 237 238 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); 239 static int kretprobe_dispatcher(struct kretprobe_instance *ri, 240 struct pt_regs *regs); 241 242 static void free_trace_kprobe(struct trace_kprobe *tk) 243 { 244 if (tk) { 245 trace_probe_cleanup(&tk->tp); 246 kfree(tk->symbol); 247 free_percpu(tk->nhit); 248 kfree(tk); 249 } 250 } 251 252 /* 253 * Allocate new trace_probe and initialize it (including kprobes). 254 */ 255 static struct trace_kprobe *alloc_trace_kprobe(const char *group, 256 const char *event, 257 void *addr, 258 const char *symbol, 259 unsigned long offs, 260 int maxactive, 261 int nargs, bool is_return) 262 { 263 struct trace_kprobe *tk; 264 int ret = -ENOMEM; 265 266 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL); 267 if (!tk) 268 return ERR_PTR(ret); 269 270 tk->nhit = alloc_percpu(unsigned long); 271 if (!tk->nhit) 272 goto error; 273 274 if (symbol) { 275 tk->symbol = kstrdup(symbol, GFP_KERNEL); 276 if (!tk->symbol) 277 goto error; 278 tk->rp.kp.symbol_name = tk->symbol; 279 tk->rp.kp.offset = offs; 280 } else 281 tk->rp.kp.addr = addr; 282 283 if (is_return) 284 tk->rp.handler = kretprobe_dispatcher; 285 else 286 tk->rp.kp.pre_handler = kprobe_dispatcher; 287 288 tk->rp.maxactive = maxactive; 289 INIT_HLIST_NODE(&tk->rp.kp.hlist); 290 INIT_LIST_HEAD(&tk->rp.kp.list); 291 292 ret = trace_probe_init(&tk->tp, event, group, false); 293 if (ret < 0) 294 goto error; 295 296 dyn_event_init(&tk->devent, &trace_kprobe_ops); 297 return tk; 298 error: 299 free_trace_kprobe(tk); 300 return ERR_PTR(ret); 301 } 302 303 static struct trace_kprobe *find_trace_kprobe(const char *event, 304 const char *group) 305 { 306 struct dyn_event *pos; 307 struct trace_kprobe *tk; 308 309 for_each_trace_kprobe(tk, pos) 310 if (strcmp(trace_probe_name(&tk->tp), event) == 0 && 311 strcmp(trace_probe_group_name(&tk->tp), group) == 0) 312 return tk; 313 return NULL; 314 } 315 316 static inline int __enable_trace_kprobe(struct trace_kprobe *tk) 317 { 318 int ret = 0; 319 320 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) { 321 if (trace_kprobe_is_return(tk)) 322 ret = enable_kretprobe(&tk->rp); 323 else 324 ret = enable_kprobe(&tk->rp.kp); 325 } 326 327 return ret; 328 } 329 330 static void __disable_trace_kprobe(struct trace_probe *tp) 331 { 332 struct trace_probe *pos; 333 struct trace_kprobe *tk; 334 335 list_for_each_entry(pos, trace_probe_probe_list(tp), list) { 336 tk = container_of(pos, struct trace_kprobe, tp); 337 if (!trace_kprobe_is_registered(tk)) 338 continue; 339 if (trace_kprobe_is_return(tk)) 340 disable_kretprobe(&tk->rp); 341 else 342 disable_kprobe(&tk->rp.kp); 343 } 344 } 345 346 /* 347 * Enable trace_probe 348 * if the file is NULL, enable "perf" handler, or enable "trace" handler. 349 */ 350 static int enable_trace_kprobe(struct trace_event_call *call, 351 struct trace_event_file *file) 352 { 353 struct trace_probe *pos, *tp; 354 struct trace_kprobe *tk; 355 bool enabled; 356 int ret = 0; 357 358 tp = trace_probe_primary_from_call(call); 359 if (WARN_ON_ONCE(!tp)) 360 return -ENODEV; 361 enabled = trace_probe_is_enabled(tp); 362 363 /* This also changes "enabled" state */ 364 if (file) { 365 ret = trace_probe_add_file(tp, file); 366 if (ret) 367 return ret; 368 } else 369 trace_probe_set_flag(tp, TP_FLAG_PROFILE); 370 371 if (enabled) 372 return 0; 373 374 list_for_each_entry(pos, trace_probe_probe_list(tp), list) { 375 tk = container_of(pos, struct trace_kprobe, tp); 376 if (trace_kprobe_has_gone(tk)) 377 continue; 378 ret = __enable_trace_kprobe(tk); 379 if (ret) 380 break; 381 enabled = true; 382 } 383 384 if (ret) { 385 /* Failed to enable one of them. Roll back all */ 386 if (enabled) 387 __disable_trace_kprobe(tp); 388 if (file) 389 trace_probe_remove_file(tp, file); 390 else 391 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 392 } 393 394 return ret; 395 } 396 397 /* 398 * Disable trace_probe 399 * if the file is NULL, disable "perf" handler, or disable "trace" handler. 400 */ 401 static int disable_trace_kprobe(struct trace_event_call *call, 402 struct trace_event_file *file) 403 { 404 struct trace_probe *tp; 405 406 tp = trace_probe_primary_from_call(call); 407 if (WARN_ON_ONCE(!tp)) 408 return -ENODEV; 409 410 if (file) { 411 if (!trace_probe_get_file_link(tp, file)) 412 return -ENOENT; 413 if (!trace_probe_has_single_file(tp)) 414 goto out; 415 trace_probe_clear_flag(tp, TP_FLAG_TRACE); 416 } else 417 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 418 419 if (!trace_probe_is_enabled(tp)) 420 __disable_trace_kprobe(tp); 421 422 out: 423 if (file) 424 /* 425 * Synchronization is done in below function. For perf event, 426 * file == NULL and perf_trace_event_unreg() calls 427 * tracepoint_synchronize_unregister() to ensure synchronize 428 * event. We don't need to care about it. 429 */ 430 trace_probe_remove_file(tp, file); 431 432 return 0; 433 } 434 435 #if defined(CONFIG_KPROBES_ON_FTRACE) && \ 436 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) 437 static bool __within_notrace_func(unsigned long addr) 438 { 439 unsigned long offset, size; 440 441 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) 442 return false; 443 444 /* Get the entry address of the target function */ 445 addr -= offset; 446 447 /* 448 * Since ftrace_location_range() does inclusive range check, we need 449 * to subtract 1 byte from the end address. 450 */ 451 return !ftrace_location_range(addr, addr + size - 1); 452 } 453 454 static bool within_notrace_func(struct trace_kprobe *tk) 455 { 456 unsigned long addr = trace_kprobe_address(tk); 457 char symname[KSYM_NAME_LEN], *p; 458 459 if (!__within_notrace_func(addr)) 460 return false; 461 462 /* Check if the address is on a suffixed-symbol */ 463 if (!lookup_symbol_name(addr, symname)) { 464 p = strchr(symname, '.'); 465 if (!p) 466 return true; 467 *p = '\0'; 468 addr = (unsigned long)kprobe_lookup_name(symname, 0); 469 if (addr) 470 return __within_notrace_func(addr); 471 } 472 473 return true; 474 } 475 #else 476 #define within_notrace_func(tk) (false) 477 #endif 478 479 /* Internal register function - just handle k*probes and flags */ 480 static int __register_trace_kprobe(struct trace_kprobe *tk) 481 { 482 int i, ret; 483 484 ret = security_locked_down(LOCKDOWN_KPROBES); 485 if (ret) 486 return ret; 487 488 if (trace_kprobe_is_registered(tk)) 489 return -EINVAL; 490 491 if (within_notrace_func(tk)) { 492 pr_warn("Could not probe notrace function %s\n", 493 trace_kprobe_symbol(tk)); 494 return -EINVAL; 495 } 496 497 for (i = 0; i < tk->tp.nr_args; i++) { 498 ret = traceprobe_update_arg(&tk->tp.args[i]); 499 if (ret) 500 return ret; 501 } 502 503 /* Set/clear disabled flag according to tp->flag */ 504 if (trace_probe_is_enabled(&tk->tp)) 505 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; 506 else 507 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; 508 509 if (trace_kprobe_is_return(tk)) 510 ret = register_kretprobe(&tk->rp); 511 else 512 ret = register_kprobe(&tk->rp.kp); 513 514 return ret; 515 } 516 517 /* Internal unregister function - just handle k*probes and flags */ 518 static void __unregister_trace_kprobe(struct trace_kprobe *tk) 519 { 520 if (trace_kprobe_is_registered(tk)) { 521 if (trace_kprobe_is_return(tk)) 522 unregister_kretprobe(&tk->rp); 523 else 524 unregister_kprobe(&tk->rp.kp); 525 /* Cleanup kprobe for reuse and mark it unregistered */ 526 INIT_HLIST_NODE(&tk->rp.kp.hlist); 527 INIT_LIST_HEAD(&tk->rp.kp.list); 528 if (tk->rp.kp.symbol_name) 529 tk->rp.kp.addr = NULL; 530 } 531 } 532 533 /* Unregister a trace_probe and probe_event */ 534 static int unregister_trace_kprobe(struct trace_kprobe *tk) 535 { 536 /* If other probes are on the event, just unregister kprobe */ 537 if (trace_probe_has_sibling(&tk->tp)) 538 goto unreg; 539 540 /* Enabled event can not be unregistered */ 541 if (trace_probe_is_enabled(&tk->tp)) 542 return -EBUSY; 543 544 /* Will fail if probe is being used by ftrace or perf */ 545 if (unregister_kprobe_event(tk)) 546 return -EBUSY; 547 548 unreg: 549 __unregister_trace_kprobe(tk); 550 dyn_event_remove(&tk->devent); 551 trace_probe_unlink(&tk->tp); 552 553 return 0; 554 } 555 556 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig, 557 struct trace_kprobe *comp) 558 { 559 struct trace_probe_event *tpe = orig->tp.event; 560 struct trace_probe *pos; 561 int i; 562 563 list_for_each_entry(pos, &tpe->probes, list) { 564 orig = container_of(pos, struct trace_kprobe, tp); 565 if (strcmp(trace_kprobe_symbol(orig), 566 trace_kprobe_symbol(comp)) || 567 trace_kprobe_offset(orig) != trace_kprobe_offset(comp)) 568 continue; 569 570 /* 571 * trace_probe_compare_arg_type() ensured that nr_args and 572 * each argument name and type are same. Let's compare comm. 573 */ 574 for (i = 0; i < orig->tp.nr_args; i++) { 575 if (strcmp(orig->tp.args[i].comm, 576 comp->tp.args[i].comm)) 577 break; 578 } 579 580 if (i == orig->tp.nr_args) 581 return true; 582 } 583 584 return false; 585 } 586 587 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to) 588 { 589 int ret; 590 591 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp); 592 if (ret) { 593 /* Note that argument starts index = 2 */ 594 trace_probe_log_set_index(ret + 1); 595 trace_probe_log_err(0, DIFF_ARG_TYPE); 596 return -EEXIST; 597 } 598 if (trace_kprobe_has_same_kprobe(to, tk)) { 599 trace_probe_log_set_index(0); 600 trace_probe_log_err(0, SAME_PROBE); 601 return -EEXIST; 602 } 603 604 /* Append to existing event */ 605 ret = trace_probe_append(&tk->tp, &to->tp); 606 if (ret) 607 return ret; 608 609 /* Register k*probe */ 610 ret = __register_trace_kprobe(tk); 611 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 612 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 613 ret = 0; 614 } 615 616 if (ret) 617 trace_probe_unlink(&tk->tp); 618 else 619 dyn_event_add(&tk->devent); 620 621 return ret; 622 } 623 624 /* Register a trace_probe and probe_event */ 625 static int register_trace_kprobe(struct trace_kprobe *tk) 626 { 627 struct trace_kprobe *old_tk; 628 int ret; 629 630 mutex_lock(&event_mutex); 631 632 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp), 633 trace_probe_group_name(&tk->tp)); 634 if (old_tk) { 635 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) { 636 trace_probe_log_set_index(0); 637 trace_probe_log_err(0, DIFF_PROBE_TYPE); 638 ret = -EEXIST; 639 } else { 640 ret = append_trace_kprobe(tk, old_tk); 641 } 642 goto end; 643 } 644 645 /* Register new event */ 646 ret = register_kprobe_event(tk); 647 if (ret) { 648 pr_warn("Failed to register probe event(%d)\n", ret); 649 goto end; 650 } 651 652 /* Register k*probe */ 653 ret = __register_trace_kprobe(tk); 654 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 655 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 656 ret = 0; 657 } 658 659 if (ret < 0) 660 unregister_kprobe_event(tk); 661 else 662 dyn_event_add(&tk->devent); 663 664 end: 665 mutex_unlock(&event_mutex); 666 return ret; 667 } 668 669 /* Module notifier call back, checking event on the module */ 670 static int trace_kprobe_module_callback(struct notifier_block *nb, 671 unsigned long val, void *data) 672 { 673 struct module *mod = data; 674 struct dyn_event *pos; 675 struct trace_kprobe *tk; 676 int ret; 677 678 if (val != MODULE_STATE_COMING) 679 return NOTIFY_DONE; 680 681 /* Update probes on coming module */ 682 mutex_lock(&event_mutex); 683 for_each_trace_kprobe(tk, pos) { 684 if (trace_kprobe_within_module(tk, mod)) { 685 /* Don't need to check busy - this should have gone. */ 686 __unregister_trace_kprobe(tk); 687 ret = __register_trace_kprobe(tk); 688 if (ret) 689 pr_warn("Failed to re-register probe %s on %s: %d\n", 690 trace_probe_name(&tk->tp), 691 mod->name, ret); 692 } 693 } 694 mutex_unlock(&event_mutex); 695 696 return NOTIFY_DONE; 697 } 698 699 static struct notifier_block trace_kprobe_module_nb = { 700 .notifier_call = trace_kprobe_module_callback, 701 .priority = 1 /* Invoked after kprobe module callback */ 702 }; 703 704 /* Convert certain expected symbols into '_' when generating event names */ 705 static inline void sanitize_event_name(char *name) 706 { 707 while (*name++ != '\0') 708 if (*name == ':' || *name == '.') 709 *name = '_'; 710 } 711 712 static int trace_kprobe_create(int argc, const char *argv[]) 713 { 714 /* 715 * Argument syntax: 716 * - Add kprobe: 717 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] 718 * - Add kretprobe: 719 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] 720 * Fetch args: 721 * $retval : fetch return value 722 * $stack : fetch stack address 723 * $stackN : fetch Nth of stack (N:0-) 724 * $comm : fetch current task comm 725 * @ADDR : fetch memory at ADDR (ADDR should be in kernel) 726 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) 727 * %REG : fetch register REG 728 * Dereferencing memory fetch: 729 * +|-offs(ARG) : fetch memory at ARG +|- offs address. 730 * Alias name of args: 731 * NAME=FETCHARG : set NAME as alias of FETCHARG. 732 * Type of args: 733 * FETCHARG:TYPE : use TYPE instead of unsigned long. 734 */ 735 struct trace_kprobe *tk = NULL; 736 int i, len, ret = 0; 737 bool is_return = false; 738 char *symbol = NULL, *tmp = NULL; 739 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM; 740 int maxactive = 0; 741 long offset = 0; 742 void *addr = NULL; 743 char buf[MAX_EVENT_NAME_LEN]; 744 unsigned int flags = TPARG_FL_KERNEL; 745 746 switch (argv[0][0]) { 747 case 'r': 748 is_return = true; 749 flags |= TPARG_FL_RETURN; 750 break; 751 case 'p': 752 break; 753 default: 754 return -ECANCELED; 755 } 756 if (argc < 2) 757 return -ECANCELED; 758 759 trace_probe_log_init("trace_kprobe", argc, argv); 760 761 event = strchr(&argv[0][1], ':'); 762 if (event) 763 event++; 764 765 if (isdigit(argv[0][1])) { 766 if (!is_return) { 767 trace_probe_log_err(1, MAXACT_NO_KPROBE); 768 goto parse_error; 769 } 770 if (event) 771 len = event - &argv[0][1] - 1; 772 else 773 len = strlen(&argv[0][1]); 774 if (len > MAX_EVENT_NAME_LEN - 1) { 775 trace_probe_log_err(1, BAD_MAXACT); 776 goto parse_error; 777 } 778 memcpy(buf, &argv[0][1], len); 779 buf[len] = '\0'; 780 ret = kstrtouint(buf, 0, &maxactive); 781 if (ret || !maxactive) { 782 trace_probe_log_err(1, BAD_MAXACT); 783 goto parse_error; 784 } 785 /* kretprobes instances are iterated over via a list. The 786 * maximum should stay reasonable. 787 */ 788 if (maxactive > KRETPROBE_MAXACTIVE_MAX) { 789 trace_probe_log_err(1, MAXACT_TOO_BIG); 790 goto parse_error; 791 } 792 } 793 794 /* try to parse an address. if that fails, try to read the 795 * input as a symbol. */ 796 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { 797 trace_probe_log_set_index(1); 798 /* Check whether uprobe event specified */ 799 if (strchr(argv[1], '/') && strchr(argv[1], ':')) { 800 ret = -ECANCELED; 801 goto error; 802 } 803 /* a symbol specified */ 804 symbol = kstrdup(argv[1], GFP_KERNEL); 805 if (!symbol) 806 return -ENOMEM; 807 /* TODO: support .init module functions */ 808 ret = traceprobe_split_symbol_offset(symbol, &offset); 809 if (ret || offset < 0 || offset > UINT_MAX) { 810 trace_probe_log_err(0, BAD_PROBE_ADDR); 811 goto parse_error; 812 } 813 if (kprobe_on_func_entry(NULL, symbol, offset)) 814 flags |= TPARG_FL_FENTRY; 815 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { 816 trace_probe_log_err(0, BAD_RETPROBE); 817 goto parse_error; 818 } 819 } 820 821 trace_probe_log_set_index(0); 822 if (event) { 823 ret = traceprobe_parse_event_name(&event, &group, buf, 824 event - argv[0]); 825 if (ret) 826 goto parse_error; 827 } else { 828 /* Make a new event name */ 829 if (symbol) 830 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", 831 is_return ? 'r' : 'p', symbol, offset); 832 else 833 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", 834 is_return ? 'r' : 'p', addr); 835 sanitize_event_name(buf); 836 event = buf; 837 } 838 839 /* setup a probe */ 840 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, 841 argc - 2, is_return); 842 if (IS_ERR(tk)) { 843 ret = PTR_ERR(tk); 844 /* This must return -ENOMEM, else there is a bug */ 845 WARN_ON_ONCE(ret != -ENOMEM); 846 goto out; /* We know tk is not allocated */ 847 } 848 argc -= 2; argv += 2; 849 850 /* parse arguments */ 851 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 852 tmp = kstrdup(argv[i], GFP_KERNEL); 853 if (!tmp) { 854 ret = -ENOMEM; 855 goto error; 856 } 857 858 trace_probe_log_set_index(i + 2); 859 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags); 860 kfree(tmp); 861 if (ret) 862 goto error; /* This can be -ENOMEM */ 863 } 864 865 ret = traceprobe_set_print_fmt(&tk->tp, is_return); 866 if (ret < 0) 867 goto error; 868 869 ret = register_trace_kprobe(tk); 870 if (ret) { 871 trace_probe_log_set_index(1); 872 if (ret == -EILSEQ) 873 trace_probe_log_err(0, BAD_INSN_BNDRY); 874 else if (ret == -ENOENT) 875 trace_probe_log_err(0, BAD_PROBE_ADDR); 876 else if (ret != -ENOMEM && ret != -EEXIST) 877 trace_probe_log_err(0, FAIL_REG_PROBE); 878 goto error; 879 } 880 881 out: 882 trace_probe_log_clear(); 883 kfree(symbol); 884 return ret; 885 886 parse_error: 887 ret = -EINVAL; 888 error: 889 free_trace_kprobe(tk); 890 goto out; 891 } 892 893 static int create_or_delete_trace_kprobe(int argc, char **argv) 894 { 895 int ret; 896 897 if (argv[0][0] == '-') 898 return dyn_event_release(argc, argv, &trace_kprobe_ops); 899 900 ret = trace_kprobe_create(argc, (const char **)argv); 901 return ret == -ECANCELED ? -EINVAL : ret; 902 } 903 904 static int trace_kprobe_run_command(struct dynevent_cmd *cmd) 905 { 906 return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe); 907 } 908 909 /** 910 * kprobe_event_cmd_init - Initialize a kprobe event command object 911 * @cmd: A pointer to the dynevent_cmd struct representing the new event 912 * @buf: A pointer to the buffer used to build the command 913 * @maxlen: The length of the buffer passed in @buf 914 * 915 * Initialize a synthetic event command object. Use this before 916 * calling any of the other kprobe_event functions. 917 */ 918 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) 919 { 920 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE, 921 trace_kprobe_run_command); 922 } 923 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init); 924 925 /** 926 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list 927 * @cmd: A pointer to the dynevent_cmd struct representing the new event 928 * @name: The name of the kprobe event 929 * @loc: The location of the kprobe event 930 * @kretprobe: Is this a return probe? 931 * @args: Variable number of arg (pairs), one pair for each field 932 * 933 * NOTE: Users normally won't want to call this function directly, but 934 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically 935 * adds a NULL to the end of the arg list. If this function is used 936 * directly, make sure the last arg in the variable arg list is NULL. 937 * 938 * Generate a kprobe event command to be executed by 939 * kprobe_event_gen_cmd_end(). This function can be used to generate the 940 * complete command or only the first part of it; in the latter case, 941 * kprobe_event_add_fields() can be used to add more fields following this. 942 * 943 * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This 944 * returns -EINVAL if @loc == NULL. 945 * 946 * Return: 0 if successful, error otherwise. 947 */ 948 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, 949 const char *name, const char *loc, ...) 950 { 951 char buf[MAX_EVENT_NAME_LEN]; 952 struct dynevent_arg arg; 953 va_list args; 954 int ret; 955 956 if (cmd->type != DYNEVENT_TYPE_KPROBE) 957 return -EINVAL; 958 959 if (!loc) 960 return -EINVAL; 961 962 if (kretprobe) 963 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name); 964 else 965 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name); 966 967 ret = dynevent_str_add(cmd, buf); 968 if (ret) 969 return ret; 970 971 dynevent_arg_init(&arg, 0); 972 arg.str = loc; 973 ret = dynevent_arg_add(cmd, &arg, NULL); 974 if (ret) 975 return ret; 976 977 va_start(args, loc); 978 for (;;) { 979 const char *field; 980 981 field = va_arg(args, const char *); 982 if (!field) 983 break; 984 985 if (++cmd->n_fields > MAX_TRACE_ARGS) { 986 ret = -EINVAL; 987 break; 988 } 989 990 arg.str = field; 991 ret = dynevent_arg_add(cmd, &arg, NULL); 992 if (ret) 993 break; 994 } 995 va_end(args); 996 997 return ret; 998 } 999 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start); 1000 1001 /** 1002 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list 1003 * @cmd: A pointer to the dynevent_cmd struct representing the new event 1004 * @args: Variable number of arg (pairs), one pair for each field 1005 * 1006 * NOTE: Users normally won't want to call this function directly, but 1007 * rather use the kprobe_event_add_fields() wrapper, which 1008 * automatically adds a NULL to the end of the arg list. If this 1009 * function is used directly, make sure the last arg in the variable 1010 * arg list is NULL. 1011 * 1012 * Add probe fields to an existing kprobe command using a variable 1013 * list of args. Fields are added in the same order they're listed. 1014 * 1015 * Return: 0 if successful, error otherwise. 1016 */ 1017 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...) 1018 { 1019 struct dynevent_arg arg; 1020 va_list args; 1021 int ret = 0; 1022 1023 if (cmd->type != DYNEVENT_TYPE_KPROBE) 1024 return -EINVAL; 1025 1026 dynevent_arg_init(&arg, 0); 1027 1028 va_start(args, cmd); 1029 for (;;) { 1030 const char *field; 1031 1032 field = va_arg(args, const char *); 1033 if (!field) 1034 break; 1035 1036 if (++cmd->n_fields > MAX_TRACE_ARGS) { 1037 ret = -EINVAL; 1038 break; 1039 } 1040 1041 arg.str = field; 1042 ret = dynevent_arg_add(cmd, &arg, NULL); 1043 if (ret) 1044 break; 1045 } 1046 va_end(args); 1047 1048 return ret; 1049 } 1050 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields); 1051 1052 /** 1053 * kprobe_event_delete - Delete a kprobe event 1054 * @name: The name of the kprobe event to delete 1055 * 1056 * Delete a kprobe event with the give @name from kernel code rather 1057 * than directly from the command line. 1058 * 1059 * Return: 0 if successful, error otherwise. 1060 */ 1061 int kprobe_event_delete(const char *name) 1062 { 1063 char buf[MAX_EVENT_NAME_LEN]; 1064 1065 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name); 1066 1067 return trace_run_command(buf, create_or_delete_trace_kprobe); 1068 } 1069 EXPORT_SYMBOL_GPL(kprobe_event_delete); 1070 1071 static int trace_kprobe_release(struct dyn_event *ev) 1072 { 1073 struct trace_kprobe *tk = to_trace_kprobe(ev); 1074 int ret = unregister_trace_kprobe(tk); 1075 1076 if (!ret) 1077 free_trace_kprobe(tk); 1078 return ret; 1079 } 1080 1081 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) 1082 { 1083 struct trace_kprobe *tk = to_trace_kprobe(ev); 1084 int i; 1085 1086 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 1087 if (trace_kprobe_is_return(tk) && tk->rp.maxactive) 1088 seq_printf(m, "%d", tk->rp.maxactive); 1089 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), 1090 trace_probe_name(&tk->tp)); 1091 1092 if (!tk->symbol) 1093 seq_printf(m, " 0x%p", tk->rp.kp.addr); 1094 else if (tk->rp.kp.offset) 1095 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 1096 tk->rp.kp.offset); 1097 else 1098 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 1099 1100 for (i = 0; i < tk->tp.nr_args; i++) 1101 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 1102 seq_putc(m, '\n'); 1103 1104 return 0; 1105 } 1106 1107 static int probes_seq_show(struct seq_file *m, void *v) 1108 { 1109 struct dyn_event *ev = v; 1110 1111 if (!is_trace_kprobe(ev)) 1112 return 0; 1113 1114 return trace_kprobe_show(m, ev); 1115 } 1116 1117 static const struct seq_operations probes_seq_op = { 1118 .start = dyn_event_seq_start, 1119 .next = dyn_event_seq_next, 1120 .stop = dyn_event_seq_stop, 1121 .show = probes_seq_show 1122 }; 1123 1124 static int probes_open(struct inode *inode, struct file *file) 1125 { 1126 int ret; 1127 1128 ret = security_locked_down(LOCKDOWN_TRACEFS); 1129 if (ret) 1130 return ret; 1131 1132 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 1133 ret = dyn_events_release_all(&trace_kprobe_ops); 1134 if (ret < 0) 1135 return ret; 1136 } 1137 1138 return seq_open(file, &probes_seq_op); 1139 } 1140 1141 static ssize_t probes_write(struct file *file, const char __user *buffer, 1142 size_t count, loff_t *ppos) 1143 { 1144 return trace_parse_run_command(file, buffer, count, ppos, 1145 create_or_delete_trace_kprobe); 1146 } 1147 1148 static const struct file_operations kprobe_events_ops = { 1149 .owner = THIS_MODULE, 1150 .open = probes_open, 1151 .read = seq_read, 1152 .llseek = seq_lseek, 1153 .release = seq_release, 1154 .write = probes_write, 1155 }; 1156 1157 /* Probes profiling interfaces */ 1158 static int probes_profile_seq_show(struct seq_file *m, void *v) 1159 { 1160 struct dyn_event *ev = v; 1161 struct trace_kprobe *tk; 1162 1163 if (!is_trace_kprobe(ev)) 1164 return 0; 1165 1166 tk = to_trace_kprobe(ev); 1167 seq_printf(m, " %-44s %15lu %15lu\n", 1168 trace_probe_name(&tk->tp), 1169 trace_kprobe_nhit(tk), 1170 tk->rp.kp.nmissed); 1171 1172 return 0; 1173 } 1174 1175 static const struct seq_operations profile_seq_op = { 1176 .start = dyn_event_seq_start, 1177 .next = dyn_event_seq_next, 1178 .stop = dyn_event_seq_stop, 1179 .show = probes_profile_seq_show 1180 }; 1181 1182 static int profile_open(struct inode *inode, struct file *file) 1183 { 1184 int ret; 1185 1186 ret = security_locked_down(LOCKDOWN_TRACEFS); 1187 if (ret) 1188 return ret; 1189 1190 return seq_open(file, &profile_seq_op); 1191 } 1192 1193 static const struct file_operations kprobe_profile_ops = { 1194 .owner = THIS_MODULE, 1195 .open = profile_open, 1196 .read = seq_read, 1197 .llseek = seq_lseek, 1198 .release = seq_release, 1199 }; 1200 1201 /* Kprobe specific fetch functions */ 1202 1203 /* Return the length of string -- including null terminal byte */ 1204 static nokprobe_inline int 1205 fetch_store_strlen_user(unsigned long addr) 1206 { 1207 const void __user *uaddr = (__force const void __user *)addr; 1208 1209 return strnlen_user_nofault(uaddr, MAX_STRING_SIZE); 1210 } 1211 1212 /* Return the length of string -- including null terminal byte */ 1213 static nokprobe_inline int 1214 fetch_store_strlen(unsigned long addr) 1215 { 1216 int ret, len = 0; 1217 u8 c; 1218 1219 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 1220 if (addr < TASK_SIZE) 1221 return fetch_store_strlen_user(addr); 1222 #endif 1223 1224 do { 1225 ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1); 1226 len++; 1227 } while (c && ret == 0 && len < MAX_STRING_SIZE); 1228 1229 return (ret < 0) ? ret : len; 1230 } 1231 1232 /* 1233 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf 1234 * with max length and relative data location. 1235 */ 1236 static nokprobe_inline int 1237 fetch_store_string_user(unsigned long addr, void *dest, void *base) 1238 { 1239 const void __user *uaddr = (__force const void __user *)addr; 1240 int maxlen = get_loc_len(*(u32 *)dest); 1241 void *__dest; 1242 long ret; 1243 1244 if (unlikely(!maxlen)) 1245 return -ENOMEM; 1246 1247 __dest = get_loc_data(dest, base); 1248 1249 ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); 1250 if (ret >= 0) 1251 *(u32 *)dest = make_data_loc(ret, __dest - base); 1252 1253 return ret; 1254 } 1255 1256 /* 1257 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max 1258 * length and relative data location. 1259 */ 1260 static nokprobe_inline int 1261 fetch_store_string(unsigned long addr, void *dest, void *base) 1262 { 1263 int maxlen = get_loc_len(*(u32 *)dest); 1264 void *__dest; 1265 long ret; 1266 1267 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 1268 if ((unsigned long)addr < TASK_SIZE) 1269 return fetch_store_string_user(addr, dest, base); 1270 #endif 1271 1272 if (unlikely(!maxlen)) 1273 return -ENOMEM; 1274 1275 __dest = get_loc_data(dest, base); 1276 1277 /* 1278 * Try to get string again, since the string can be changed while 1279 * probing. 1280 */ 1281 ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); 1282 if (ret >= 0) 1283 *(u32 *)dest = make_data_loc(ret, __dest - base); 1284 1285 return ret; 1286 } 1287 1288 static nokprobe_inline int 1289 probe_mem_read_user(void *dest, void *src, size_t size) 1290 { 1291 const void __user *uaddr = (__force const void __user *)src; 1292 1293 return copy_from_user_nofault(dest, uaddr, size); 1294 } 1295 1296 static nokprobe_inline int 1297 probe_mem_read(void *dest, void *src, size_t size) 1298 { 1299 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE 1300 if ((unsigned long)src < TASK_SIZE) 1301 return probe_mem_read_user(dest, src, size); 1302 #endif 1303 return copy_from_kernel_nofault(dest, src, size); 1304 } 1305 1306 /* Note that we don't verify it, since the code does not come from user space */ 1307 static int 1308 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 1309 void *base) 1310 { 1311 unsigned long val; 1312 1313 retry: 1314 /* 1st stage: get value from context */ 1315 switch (code->op) { 1316 case FETCH_OP_REG: 1317 val = regs_get_register(regs, code->param); 1318 break; 1319 case FETCH_OP_STACK: 1320 val = regs_get_kernel_stack_nth(regs, code->param); 1321 break; 1322 case FETCH_OP_STACKP: 1323 val = kernel_stack_pointer(regs); 1324 break; 1325 case FETCH_OP_RETVAL: 1326 val = regs_return_value(regs); 1327 break; 1328 case FETCH_OP_IMM: 1329 val = code->immediate; 1330 break; 1331 case FETCH_OP_COMM: 1332 val = (unsigned long)current->comm; 1333 break; 1334 case FETCH_OP_DATA: 1335 val = (unsigned long)code->data; 1336 break; 1337 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 1338 case FETCH_OP_ARG: 1339 val = regs_get_kernel_argument(regs, code->param); 1340 break; 1341 #endif 1342 case FETCH_NOP_SYMBOL: /* Ignore a place holder */ 1343 code++; 1344 goto retry; 1345 default: 1346 return -EILSEQ; 1347 } 1348 code++; 1349 1350 return process_fetch_insn_bottom(code, val, dest, base); 1351 } 1352 NOKPROBE_SYMBOL(process_fetch_insn) 1353 1354 /* Kprobe handler */ 1355 static nokprobe_inline void 1356 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 1357 struct trace_event_file *trace_file) 1358 { 1359 struct kprobe_trace_entry_head *entry; 1360 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1361 struct trace_event_buffer fbuffer; 1362 int dsize; 1363 1364 WARN_ON(call != trace_file->event_call); 1365 1366 if (trace_trigger_soft_disabled(trace_file)) 1367 return; 1368 1369 local_save_flags(fbuffer.flags); 1370 fbuffer.pc = preempt_count(); 1371 fbuffer.trace_file = trace_file; 1372 1373 dsize = __get_data_size(&tk->tp, regs); 1374 1375 fbuffer.event = 1376 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file, 1377 call->event.type, 1378 sizeof(*entry) + tk->tp.size + dsize, 1379 fbuffer.flags, fbuffer.pc); 1380 if (!fbuffer.event) 1381 return; 1382 1383 fbuffer.regs = regs; 1384 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); 1385 entry->ip = (unsigned long)tk->rp.kp.addr; 1386 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1387 1388 trace_event_buffer_commit(&fbuffer); 1389 } 1390 1391 static void 1392 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 1393 { 1394 struct event_file_link *link; 1395 1396 trace_probe_for_each_link_rcu(link, &tk->tp) 1397 __kprobe_trace_func(tk, regs, link->file); 1398 } 1399 NOKPROBE_SYMBOL(kprobe_trace_func); 1400 1401 /* Kretprobe handler */ 1402 static nokprobe_inline void 1403 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1404 struct pt_regs *regs, 1405 struct trace_event_file *trace_file) 1406 { 1407 struct kretprobe_trace_entry_head *entry; 1408 struct trace_event_buffer fbuffer; 1409 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1410 int dsize; 1411 1412 WARN_ON(call != trace_file->event_call); 1413 1414 if (trace_trigger_soft_disabled(trace_file)) 1415 return; 1416 1417 local_save_flags(fbuffer.flags); 1418 fbuffer.pc = preempt_count(); 1419 fbuffer.trace_file = trace_file; 1420 1421 dsize = __get_data_size(&tk->tp, regs); 1422 fbuffer.event = 1423 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file, 1424 call->event.type, 1425 sizeof(*entry) + tk->tp.size + dsize, 1426 fbuffer.flags, fbuffer.pc); 1427 if (!fbuffer.event) 1428 return; 1429 1430 fbuffer.regs = regs; 1431 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); 1432 entry->func = (unsigned long)tk->rp.kp.addr; 1433 entry->ret_ip = (unsigned long)ri->ret_addr; 1434 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1435 1436 trace_event_buffer_commit(&fbuffer); 1437 } 1438 1439 static void 1440 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1441 struct pt_regs *regs) 1442 { 1443 struct event_file_link *link; 1444 1445 trace_probe_for_each_link_rcu(link, &tk->tp) 1446 __kretprobe_trace_func(tk, ri, regs, link->file); 1447 } 1448 NOKPROBE_SYMBOL(kretprobe_trace_func); 1449 1450 /* Event entry printers */ 1451 static enum print_line_t 1452 print_kprobe_event(struct trace_iterator *iter, int flags, 1453 struct trace_event *event) 1454 { 1455 struct kprobe_trace_entry_head *field; 1456 struct trace_seq *s = &iter->seq; 1457 struct trace_probe *tp; 1458 1459 field = (struct kprobe_trace_entry_head *)iter->ent; 1460 tp = trace_probe_primary_from_call( 1461 container_of(event, struct trace_event_call, event)); 1462 if (WARN_ON_ONCE(!tp)) 1463 goto out; 1464 1465 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1466 1467 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) 1468 goto out; 1469 1470 trace_seq_putc(s, ')'); 1471 1472 if (print_probe_args(s, tp->args, tp->nr_args, 1473 (u8 *)&field[1], field) < 0) 1474 goto out; 1475 1476 trace_seq_putc(s, '\n'); 1477 out: 1478 return trace_handle_return(s); 1479 } 1480 1481 static enum print_line_t 1482 print_kretprobe_event(struct trace_iterator *iter, int flags, 1483 struct trace_event *event) 1484 { 1485 struct kretprobe_trace_entry_head *field; 1486 struct trace_seq *s = &iter->seq; 1487 struct trace_probe *tp; 1488 1489 field = (struct kretprobe_trace_entry_head *)iter->ent; 1490 tp = trace_probe_primary_from_call( 1491 container_of(event, struct trace_event_call, event)); 1492 if (WARN_ON_ONCE(!tp)) 1493 goto out; 1494 1495 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1496 1497 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) 1498 goto out; 1499 1500 trace_seq_puts(s, " <- "); 1501 1502 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) 1503 goto out; 1504 1505 trace_seq_putc(s, ')'); 1506 1507 if (print_probe_args(s, tp->args, tp->nr_args, 1508 (u8 *)&field[1], field) < 0) 1509 goto out; 1510 1511 trace_seq_putc(s, '\n'); 1512 1513 out: 1514 return trace_handle_return(s); 1515 } 1516 1517 1518 static int kprobe_event_define_fields(struct trace_event_call *event_call) 1519 { 1520 int ret; 1521 struct kprobe_trace_entry_head field; 1522 struct trace_probe *tp; 1523 1524 tp = trace_probe_primary_from_call(event_call); 1525 if (WARN_ON_ONCE(!tp)) 1526 return -ENOENT; 1527 1528 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1529 1530 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1531 } 1532 1533 static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1534 { 1535 int ret; 1536 struct kretprobe_trace_entry_head field; 1537 struct trace_probe *tp; 1538 1539 tp = trace_probe_primary_from_call(event_call); 1540 if (WARN_ON_ONCE(!tp)) 1541 return -ENOENT; 1542 1543 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1544 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1545 1546 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1547 } 1548 1549 #ifdef CONFIG_PERF_EVENTS 1550 1551 /* Kprobe profile handler */ 1552 static int 1553 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1554 { 1555 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1556 struct kprobe_trace_entry_head *entry; 1557 struct hlist_head *head; 1558 int size, __size, dsize; 1559 int rctx; 1560 1561 if (bpf_prog_array_valid(call)) { 1562 unsigned long orig_ip = instruction_pointer(regs); 1563 int ret; 1564 1565 ret = trace_call_bpf(call, regs); 1566 1567 /* 1568 * We need to check and see if we modified the pc of the 1569 * pt_regs, and if so return 1 so that we don't do the 1570 * single stepping. 1571 */ 1572 if (orig_ip != instruction_pointer(regs)) 1573 return 1; 1574 if (!ret) 1575 return 0; 1576 } 1577 1578 head = this_cpu_ptr(call->perf_events); 1579 if (hlist_empty(head)) 1580 return 0; 1581 1582 dsize = __get_data_size(&tk->tp, regs); 1583 __size = sizeof(*entry) + tk->tp.size + dsize; 1584 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1585 size -= sizeof(u32); 1586 1587 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1588 if (!entry) 1589 return 0; 1590 1591 entry->ip = (unsigned long)tk->rp.kp.addr; 1592 memset(&entry[1], 0, dsize); 1593 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1594 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1595 head, NULL); 1596 return 0; 1597 } 1598 NOKPROBE_SYMBOL(kprobe_perf_func); 1599 1600 /* Kretprobe profile handler */ 1601 static void 1602 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1603 struct pt_regs *regs) 1604 { 1605 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1606 struct kretprobe_trace_entry_head *entry; 1607 struct hlist_head *head; 1608 int size, __size, dsize; 1609 int rctx; 1610 1611 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1612 return; 1613 1614 head = this_cpu_ptr(call->perf_events); 1615 if (hlist_empty(head)) 1616 return; 1617 1618 dsize = __get_data_size(&tk->tp, regs); 1619 __size = sizeof(*entry) + tk->tp.size + dsize; 1620 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1621 size -= sizeof(u32); 1622 1623 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1624 if (!entry) 1625 return; 1626 1627 entry->func = (unsigned long)tk->rp.kp.addr; 1628 entry->ret_ip = (unsigned long)ri->ret_addr; 1629 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1630 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1631 head, NULL); 1632 } 1633 NOKPROBE_SYMBOL(kretprobe_perf_func); 1634 1635 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, 1636 const char **symbol, u64 *probe_offset, 1637 u64 *probe_addr, bool perf_type_tracepoint) 1638 { 1639 const char *pevent = trace_event_name(event->tp_event); 1640 const char *group = event->tp_event->class->system; 1641 struct trace_kprobe *tk; 1642 1643 if (perf_type_tracepoint) 1644 tk = find_trace_kprobe(pevent, group); 1645 else 1646 tk = trace_kprobe_primary_from_call(event->tp_event); 1647 if (!tk) 1648 return -EINVAL; 1649 1650 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE 1651 : BPF_FD_TYPE_KPROBE; 1652 if (tk->symbol) { 1653 *symbol = tk->symbol; 1654 *probe_offset = tk->rp.kp.offset; 1655 *probe_addr = 0; 1656 } else { 1657 *symbol = NULL; 1658 *probe_offset = 0; 1659 *probe_addr = (unsigned long)tk->rp.kp.addr; 1660 } 1661 return 0; 1662 } 1663 #endif /* CONFIG_PERF_EVENTS */ 1664 1665 /* 1666 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1667 * 1668 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1669 * lockless, but we can't race with this __init function. 1670 */ 1671 static int kprobe_register(struct trace_event_call *event, 1672 enum trace_reg type, void *data) 1673 { 1674 struct trace_event_file *file = data; 1675 1676 switch (type) { 1677 case TRACE_REG_REGISTER: 1678 return enable_trace_kprobe(event, file); 1679 case TRACE_REG_UNREGISTER: 1680 return disable_trace_kprobe(event, file); 1681 1682 #ifdef CONFIG_PERF_EVENTS 1683 case TRACE_REG_PERF_REGISTER: 1684 return enable_trace_kprobe(event, NULL); 1685 case TRACE_REG_PERF_UNREGISTER: 1686 return disable_trace_kprobe(event, NULL); 1687 case TRACE_REG_PERF_OPEN: 1688 case TRACE_REG_PERF_CLOSE: 1689 case TRACE_REG_PERF_ADD: 1690 case TRACE_REG_PERF_DEL: 1691 return 0; 1692 #endif 1693 } 1694 return 0; 1695 } 1696 1697 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1698 { 1699 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1700 int ret = 0; 1701 1702 raw_cpu_inc(*tk->nhit); 1703 1704 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1705 kprobe_trace_func(tk, regs); 1706 #ifdef CONFIG_PERF_EVENTS 1707 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1708 ret = kprobe_perf_func(tk, regs); 1709 #endif 1710 return ret; 1711 } 1712 NOKPROBE_SYMBOL(kprobe_dispatcher); 1713 1714 static int 1715 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1716 { 1717 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp); 1718 1719 raw_cpu_inc(*tk->nhit); 1720 1721 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1722 kretprobe_trace_func(tk, ri, regs); 1723 #ifdef CONFIG_PERF_EVENTS 1724 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1725 kretprobe_perf_func(tk, ri, regs); 1726 #endif 1727 return 0; /* We don't tweek kernel, so just return 0 */ 1728 } 1729 NOKPROBE_SYMBOL(kretprobe_dispatcher); 1730 1731 static struct trace_event_functions kretprobe_funcs = { 1732 .trace = print_kretprobe_event 1733 }; 1734 1735 static struct trace_event_functions kprobe_funcs = { 1736 .trace = print_kprobe_event 1737 }; 1738 1739 static struct trace_event_fields kretprobe_fields_array[] = { 1740 { .type = TRACE_FUNCTION_TYPE, 1741 .define_fields = kretprobe_event_define_fields }, 1742 {} 1743 }; 1744 1745 static struct trace_event_fields kprobe_fields_array[] = { 1746 { .type = TRACE_FUNCTION_TYPE, 1747 .define_fields = kprobe_event_define_fields }, 1748 {} 1749 }; 1750 1751 static inline void init_trace_event_call(struct trace_kprobe *tk) 1752 { 1753 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1754 1755 if (trace_kprobe_is_return(tk)) { 1756 call->event.funcs = &kretprobe_funcs; 1757 call->class->fields_array = kretprobe_fields_array; 1758 } else { 1759 call->event.funcs = &kprobe_funcs; 1760 call->class->fields_array = kprobe_fields_array; 1761 } 1762 1763 call->flags = TRACE_EVENT_FL_KPROBE; 1764 call->class->reg = kprobe_register; 1765 } 1766 1767 static int register_kprobe_event(struct trace_kprobe *tk) 1768 { 1769 init_trace_event_call(tk); 1770 1771 return trace_probe_register_event_call(&tk->tp); 1772 } 1773 1774 static int unregister_kprobe_event(struct trace_kprobe *tk) 1775 { 1776 return trace_probe_unregister_event_call(&tk->tp); 1777 } 1778 1779 #ifdef CONFIG_PERF_EVENTS 1780 /* create a trace_kprobe, but don't add it to global lists */ 1781 struct trace_event_call * 1782 create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 1783 bool is_return) 1784 { 1785 struct trace_kprobe *tk; 1786 int ret; 1787 char *event; 1788 1789 /* 1790 * local trace_kprobes are not added to dyn_event, so they are never 1791 * searched in find_trace_kprobe(). Therefore, there is no concern of 1792 * duplicated name here. 1793 */ 1794 event = func ? func : "DUMMY_EVENT"; 1795 1796 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, 1797 offs, 0 /* maxactive */, 0 /* nargs */, 1798 is_return); 1799 1800 if (IS_ERR(tk)) { 1801 pr_info("Failed to allocate trace_probe.(%d)\n", 1802 (int)PTR_ERR(tk)); 1803 return ERR_CAST(tk); 1804 } 1805 1806 init_trace_event_call(tk); 1807 1808 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) { 1809 ret = -ENOMEM; 1810 goto error; 1811 } 1812 1813 ret = __register_trace_kprobe(tk); 1814 if (ret < 0) 1815 goto error; 1816 1817 return trace_probe_event_call(&tk->tp); 1818 error: 1819 free_trace_kprobe(tk); 1820 return ERR_PTR(ret); 1821 } 1822 1823 void destroy_local_trace_kprobe(struct trace_event_call *event_call) 1824 { 1825 struct trace_kprobe *tk; 1826 1827 tk = trace_kprobe_primary_from_call(event_call); 1828 if (unlikely(!tk)) 1829 return; 1830 1831 if (trace_probe_is_enabled(&tk->tp)) { 1832 WARN_ON(1); 1833 return; 1834 } 1835 1836 __unregister_trace_kprobe(tk); 1837 1838 free_trace_kprobe(tk); 1839 } 1840 #endif /* CONFIG_PERF_EVENTS */ 1841 1842 static __init void enable_boot_kprobe_events(void) 1843 { 1844 struct trace_array *tr = top_trace_array(); 1845 struct trace_event_file *file; 1846 struct trace_kprobe *tk; 1847 struct dyn_event *pos; 1848 1849 mutex_lock(&event_mutex); 1850 for_each_trace_kprobe(tk, pos) { 1851 list_for_each_entry(file, &tr->events, list) 1852 if (file->event_call == trace_probe_event_call(&tk->tp)) 1853 trace_event_enable_disable(file, 1, 0); 1854 } 1855 mutex_unlock(&event_mutex); 1856 } 1857 1858 static __init void setup_boot_kprobe_events(void) 1859 { 1860 char *p, *cmd = kprobe_boot_events_buf; 1861 int ret; 1862 1863 strreplace(kprobe_boot_events_buf, ',', ' '); 1864 1865 while (cmd && *cmd != '\0') { 1866 p = strchr(cmd, ';'); 1867 if (p) 1868 *p++ = '\0'; 1869 1870 ret = trace_run_command(cmd, create_or_delete_trace_kprobe); 1871 if (ret) 1872 pr_warn("Failed to add event(%d): %s\n", ret, cmd); 1873 else 1874 kprobe_boot_events_enabled = true; 1875 1876 cmd = p; 1877 } 1878 1879 enable_boot_kprobe_events(); 1880 } 1881 1882 /* 1883 * Register dynevent at subsys_initcall. This allows kernel to setup kprobe 1884 * events in fs_initcall without tracefs. 1885 */ 1886 static __init int init_kprobe_trace_early(void) 1887 { 1888 int ret; 1889 1890 ret = dyn_event_register(&trace_kprobe_ops); 1891 if (ret) 1892 return ret; 1893 1894 if (register_module_notifier(&trace_kprobe_module_nb)) 1895 return -EINVAL; 1896 1897 return 0; 1898 } 1899 subsys_initcall(init_kprobe_trace_early); 1900 1901 /* Make a tracefs interface for controlling probe points */ 1902 static __init int init_kprobe_trace(void) 1903 { 1904 struct dentry *d_tracer; 1905 struct dentry *entry; 1906 1907 d_tracer = tracing_init_dentry(); 1908 if (IS_ERR(d_tracer)) 1909 return 0; 1910 1911 entry = tracefs_create_file("kprobe_events", 0644, d_tracer, 1912 NULL, &kprobe_events_ops); 1913 1914 /* Event list interface */ 1915 if (!entry) 1916 pr_warn("Could not create tracefs 'kprobe_events' entry\n"); 1917 1918 /* Profile interface */ 1919 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer, 1920 NULL, &kprobe_profile_ops); 1921 1922 if (!entry) 1923 pr_warn("Could not create tracefs 'kprobe_profile' entry\n"); 1924 1925 setup_boot_kprobe_events(); 1926 1927 return 0; 1928 } 1929 fs_initcall(init_kprobe_trace); 1930 1931 1932 #ifdef CONFIG_FTRACE_STARTUP_TEST 1933 static __init struct trace_event_file * 1934 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 1935 { 1936 struct trace_event_file *file; 1937 1938 list_for_each_entry(file, &tr->events, list) 1939 if (file->event_call == trace_probe_event_call(&tk->tp)) 1940 return file; 1941 1942 return NULL; 1943 } 1944 1945 /* 1946 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 1947 * stage, we can do this lockless. 1948 */ 1949 static __init int kprobe_trace_self_tests_init(void) 1950 { 1951 int ret, warn = 0; 1952 int (*target)(int, int, int, int, int, int); 1953 struct trace_kprobe *tk; 1954 struct trace_event_file *file; 1955 1956 if (tracing_is_disabled()) 1957 return -ENODEV; 1958 1959 if (kprobe_boot_events_enabled) { 1960 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n"); 1961 return 0; 1962 } 1963 1964 target = kprobe_trace_selftest_target; 1965 1966 pr_info("Testing kprobe tracing: "); 1967 1968 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)", 1969 create_or_delete_trace_kprobe); 1970 if (WARN_ON_ONCE(ret)) { 1971 pr_warn("error on probing function entry.\n"); 1972 warn++; 1973 } else { 1974 /* Enable trace point */ 1975 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1976 if (WARN_ON_ONCE(tk == NULL)) { 1977 pr_warn("error on getting new probe.\n"); 1978 warn++; 1979 } else { 1980 file = find_trace_probe_file(tk, top_trace_array()); 1981 if (WARN_ON_ONCE(file == NULL)) { 1982 pr_warn("error on getting probe file.\n"); 1983 warn++; 1984 } else 1985 enable_trace_kprobe( 1986 trace_probe_event_call(&tk->tp), file); 1987 } 1988 } 1989 1990 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval", 1991 create_or_delete_trace_kprobe); 1992 if (WARN_ON_ONCE(ret)) { 1993 pr_warn("error on probing function return.\n"); 1994 warn++; 1995 } else { 1996 /* Enable trace point */ 1997 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1998 if (WARN_ON_ONCE(tk == NULL)) { 1999 pr_warn("error on getting 2nd new probe.\n"); 2000 warn++; 2001 } else { 2002 file = find_trace_probe_file(tk, top_trace_array()); 2003 if (WARN_ON_ONCE(file == NULL)) { 2004 pr_warn("error on getting probe file.\n"); 2005 warn++; 2006 } else 2007 enable_trace_kprobe( 2008 trace_probe_event_call(&tk->tp), file); 2009 } 2010 } 2011 2012 if (warn) 2013 goto end; 2014 2015 ret = target(1, 2, 3, 4, 5, 6); 2016 2017 /* 2018 * Not expecting an error here, the check is only to prevent the 2019 * optimizer from removing the call to target() as otherwise there 2020 * are no side-effects and the call is never performed. 2021 */ 2022 if (ret != 21) 2023 warn++; 2024 2025 /* Disable trace points before removing it */ 2026 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 2027 if (WARN_ON_ONCE(tk == NULL)) { 2028 pr_warn("error on getting test probe.\n"); 2029 warn++; 2030 } else { 2031 if (trace_kprobe_nhit(tk) != 1) { 2032 pr_warn("incorrect number of testprobe hits\n"); 2033 warn++; 2034 } 2035 2036 file = find_trace_probe_file(tk, top_trace_array()); 2037 if (WARN_ON_ONCE(file == NULL)) { 2038 pr_warn("error on getting probe file.\n"); 2039 warn++; 2040 } else 2041 disable_trace_kprobe( 2042 trace_probe_event_call(&tk->tp), file); 2043 } 2044 2045 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 2046 if (WARN_ON_ONCE(tk == NULL)) { 2047 pr_warn("error on getting 2nd test probe.\n"); 2048 warn++; 2049 } else { 2050 if (trace_kprobe_nhit(tk) != 1) { 2051 pr_warn("incorrect number of testprobe2 hits\n"); 2052 warn++; 2053 } 2054 2055 file = find_trace_probe_file(tk, top_trace_array()); 2056 if (WARN_ON_ONCE(file == NULL)) { 2057 pr_warn("error on getting probe file.\n"); 2058 warn++; 2059 } else 2060 disable_trace_kprobe( 2061 trace_probe_event_call(&tk->tp), file); 2062 } 2063 2064 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe); 2065 if (WARN_ON_ONCE(ret)) { 2066 pr_warn("error on deleting a probe.\n"); 2067 warn++; 2068 } 2069 2070 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe); 2071 if (WARN_ON_ONCE(ret)) { 2072 pr_warn("error on deleting a probe.\n"); 2073 warn++; 2074 } 2075 2076 end: 2077 ret = dyn_events_release_all(&trace_kprobe_ops); 2078 if (WARN_ON_ONCE(ret)) { 2079 pr_warn("error on cleaning up probes.\n"); 2080 warn++; 2081 } 2082 /* 2083 * Wait for the optimizer work to finish. Otherwise it might fiddle 2084 * with probes in already freed __init text. 2085 */ 2086 wait_for_kprobe_optimizer(); 2087 if (warn) 2088 pr_cont("NG: Some tests are failed. Please check them.\n"); 2089 else 2090 pr_cont("OK\n"); 2091 return 0; 2092 } 2093 2094 late_initcall(kprobe_trace_self_tests_init); 2095 2096 #endif 2097