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/module.h> 11 #include <linux/uaccess.h> 12 #include <linux/rculist.h> 13 #include <linux/error-injection.h> 14 15 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */ 16 17 #include "trace_dynevent.h" 18 #include "trace_kprobe_selftest.h" 19 #include "trace_probe.h" 20 #include "trace_probe_tmpl.h" 21 22 #define KPROBE_EVENT_SYSTEM "kprobes" 23 #define KRETPROBE_MAXACTIVE_MAX 4096 24 #define MAX_KPROBE_CMDLINE_SIZE 1024 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); 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(struct trace_kprobe *tk) 438 { 439 unsigned long offset, size, addr; 440 441 addr = trace_kprobe_address(tk); 442 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) 443 return false; 444 445 /* Get the entry address of the target function */ 446 addr -= offset; 447 448 /* 449 * Since ftrace_location_range() does inclusive range check, we need 450 * to subtract 1 byte from the end address. 451 */ 452 return !ftrace_location_range(addr, addr + size - 1); 453 } 454 #else 455 #define within_notrace_func(tk) (false) 456 #endif 457 458 /* Internal register function - just handle k*probes and flags */ 459 static int __register_trace_kprobe(struct trace_kprobe *tk) 460 { 461 int i, ret; 462 463 if (trace_kprobe_is_registered(tk)) 464 return -EINVAL; 465 466 if (within_notrace_func(tk)) { 467 pr_warn("Could not probe notrace function %s\n", 468 trace_kprobe_symbol(tk)); 469 return -EINVAL; 470 } 471 472 for (i = 0; i < tk->tp.nr_args; i++) { 473 ret = traceprobe_update_arg(&tk->tp.args[i]); 474 if (ret) 475 return ret; 476 } 477 478 /* Set/clear disabled flag according to tp->flag */ 479 if (trace_probe_is_enabled(&tk->tp)) 480 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; 481 else 482 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; 483 484 if (trace_kprobe_is_return(tk)) 485 ret = register_kretprobe(&tk->rp); 486 else 487 ret = register_kprobe(&tk->rp.kp); 488 489 return ret; 490 } 491 492 /* Internal unregister function - just handle k*probes and flags */ 493 static void __unregister_trace_kprobe(struct trace_kprobe *tk) 494 { 495 if (trace_kprobe_is_registered(tk)) { 496 if (trace_kprobe_is_return(tk)) 497 unregister_kretprobe(&tk->rp); 498 else 499 unregister_kprobe(&tk->rp.kp); 500 /* Cleanup kprobe for reuse and mark it unregistered */ 501 INIT_HLIST_NODE(&tk->rp.kp.hlist); 502 INIT_LIST_HEAD(&tk->rp.kp.list); 503 if (tk->rp.kp.symbol_name) 504 tk->rp.kp.addr = NULL; 505 } 506 } 507 508 /* Unregister a trace_probe and probe_event */ 509 static int unregister_trace_kprobe(struct trace_kprobe *tk) 510 { 511 /* If other probes are on the event, just unregister kprobe */ 512 if (trace_probe_has_sibling(&tk->tp)) 513 goto unreg; 514 515 /* Enabled event can not be unregistered */ 516 if (trace_probe_is_enabled(&tk->tp)) 517 return -EBUSY; 518 519 /* Will fail if probe is being used by ftrace or perf */ 520 if (unregister_kprobe_event(tk)) 521 return -EBUSY; 522 523 unreg: 524 __unregister_trace_kprobe(tk); 525 dyn_event_remove(&tk->devent); 526 trace_probe_unlink(&tk->tp); 527 528 return 0; 529 } 530 531 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig, 532 struct trace_kprobe *comp) 533 { 534 struct trace_probe_event *tpe = orig->tp.event; 535 struct trace_probe *pos; 536 int i; 537 538 list_for_each_entry(pos, &tpe->probes, list) { 539 orig = container_of(pos, struct trace_kprobe, tp); 540 if (strcmp(trace_kprobe_symbol(orig), 541 trace_kprobe_symbol(comp)) || 542 trace_kprobe_offset(orig) != trace_kprobe_offset(comp)) 543 continue; 544 545 /* 546 * trace_probe_compare_arg_type() ensured that nr_args and 547 * each argument name and type are same. Let's compare comm. 548 */ 549 for (i = 0; i < orig->tp.nr_args; i++) { 550 if (strcmp(orig->tp.args[i].comm, 551 comp->tp.args[i].comm)) 552 continue; 553 } 554 555 return true; 556 } 557 558 return false; 559 } 560 561 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to) 562 { 563 int ret; 564 565 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp); 566 if (ret) { 567 /* Note that argument starts index = 2 */ 568 trace_probe_log_set_index(ret + 1); 569 trace_probe_log_err(0, DIFF_ARG_TYPE); 570 return -EEXIST; 571 } 572 if (trace_kprobe_has_same_kprobe(to, tk)) { 573 trace_probe_log_set_index(0); 574 trace_probe_log_err(0, SAME_PROBE); 575 return -EEXIST; 576 } 577 578 /* Append to existing event */ 579 ret = trace_probe_append(&tk->tp, &to->tp); 580 if (ret) 581 return ret; 582 583 /* Register k*probe */ 584 ret = __register_trace_kprobe(tk); 585 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 586 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 587 ret = 0; 588 } 589 590 if (ret) 591 trace_probe_unlink(&tk->tp); 592 else 593 dyn_event_add(&tk->devent); 594 595 return ret; 596 } 597 598 /* Register a trace_probe and probe_event */ 599 static int register_trace_kprobe(struct trace_kprobe *tk) 600 { 601 struct trace_kprobe *old_tk; 602 int ret; 603 604 mutex_lock(&event_mutex); 605 606 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp), 607 trace_probe_group_name(&tk->tp)); 608 if (old_tk) { 609 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) { 610 trace_probe_log_set_index(0); 611 trace_probe_log_err(0, DIFF_PROBE_TYPE); 612 ret = -EEXIST; 613 } else { 614 ret = append_trace_kprobe(tk, old_tk); 615 } 616 goto end; 617 } 618 619 /* Register new event */ 620 ret = register_kprobe_event(tk); 621 if (ret) { 622 pr_warn("Failed to register probe event(%d)\n", ret); 623 goto end; 624 } 625 626 /* Register k*probe */ 627 ret = __register_trace_kprobe(tk); 628 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 629 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 630 ret = 0; 631 } 632 633 if (ret < 0) 634 unregister_kprobe_event(tk); 635 else 636 dyn_event_add(&tk->devent); 637 638 end: 639 mutex_unlock(&event_mutex); 640 return ret; 641 } 642 643 /* Module notifier call back, checking event on the module */ 644 static int trace_kprobe_module_callback(struct notifier_block *nb, 645 unsigned long val, void *data) 646 { 647 struct module *mod = data; 648 struct dyn_event *pos; 649 struct trace_kprobe *tk; 650 int ret; 651 652 if (val != MODULE_STATE_COMING) 653 return NOTIFY_DONE; 654 655 /* Update probes on coming module */ 656 mutex_lock(&event_mutex); 657 for_each_trace_kprobe(tk, pos) { 658 if (trace_kprobe_within_module(tk, mod)) { 659 /* Don't need to check busy - this should have gone. */ 660 __unregister_trace_kprobe(tk); 661 ret = __register_trace_kprobe(tk); 662 if (ret) 663 pr_warn("Failed to re-register probe %s on %s: %d\n", 664 trace_probe_name(&tk->tp), 665 mod->name, ret); 666 } 667 } 668 mutex_unlock(&event_mutex); 669 670 return NOTIFY_DONE; 671 } 672 673 static struct notifier_block trace_kprobe_module_nb = { 674 .notifier_call = trace_kprobe_module_callback, 675 .priority = 1 /* Invoked after kprobe module callback */ 676 }; 677 678 /* Convert certain expected symbols into '_' when generating event names */ 679 static inline void sanitize_event_name(char *name) 680 { 681 while (*name++ != '\0') 682 if (*name == ':' || *name == '.') 683 *name = '_'; 684 } 685 686 static int trace_kprobe_create(int argc, const char *argv[]) 687 { 688 /* 689 * Argument syntax: 690 * - Add kprobe: 691 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] 692 * - Add kretprobe: 693 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] 694 * Fetch args: 695 * $retval : fetch return value 696 * $stack : fetch stack address 697 * $stackN : fetch Nth of stack (N:0-) 698 * $comm : fetch current task comm 699 * @ADDR : fetch memory at ADDR (ADDR should be in kernel) 700 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) 701 * %REG : fetch register REG 702 * Dereferencing memory fetch: 703 * +|-offs(ARG) : fetch memory at ARG +|- offs address. 704 * Alias name of args: 705 * NAME=FETCHARG : set NAME as alias of FETCHARG. 706 * Type of args: 707 * FETCHARG:TYPE : use TYPE instead of unsigned long. 708 */ 709 struct trace_kprobe *tk = NULL; 710 int i, len, ret = 0; 711 bool is_return = false; 712 char *symbol = NULL, *tmp = NULL; 713 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM; 714 int maxactive = 0; 715 long offset = 0; 716 void *addr = NULL; 717 char buf[MAX_EVENT_NAME_LEN]; 718 unsigned int flags = TPARG_FL_KERNEL; 719 720 switch (argv[0][0]) { 721 case 'r': 722 is_return = true; 723 flags |= TPARG_FL_RETURN; 724 break; 725 case 'p': 726 break; 727 default: 728 return -ECANCELED; 729 } 730 if (argc < 2) 731 return -ECANCELED; 732 733 trace_probe_log_init("trace_kprobe", argc, argv); 734 735 event = strchr(&argv[0][1], ':'); 736 if (event) 737 event++; 738 739 if (isdigit(argv[0][1])) { 740 if (!is_return) { 741 trace_probe_log_err(1, MAXACT_NO_KPROBE); 742 goto parse_error; 743 } 744 if (event) 745 len = event - &argv[0][1] - 1; 746 else 747 len = strlen(&argv[0][1]); 748 if (len > MAX_EVENT_NAME_LEN - 1) { 749 trace_probe_log_err(1, BAD_MAXACT); 750 goto parse_error; 751 } 752 memcpy(buf, &argv[0][1], len); 753 buf[len] = '\0'; 754 ret = kstrtouint(buf, 0, &maxactive); 755 if (ret || !maxactive) { 756 trace_probe_log_err(1, BAD_MAXACT); 757 goto parse_error; 758 } 759 /* kretprobes instances are iterated over via a list. The 760 * maximum should stay reasonable. 761 */ 762 if (maxactive > KRETPROBE_MAXACTIVE_MAX) { 763 trace_probe_log_err(1, MAXACT_TOO_BIG); 764 goto parse_error; 765 } 766 } 767 768 /* try to parse an address. if that fails, try to read the 769 * input as a symbol. */ 770 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { 771 trace_probe_log_set_index(1); 772 /* Check whether uprobe event specified */ 773 if (strchr(argv[1], '/') && strchr(argv[1], ':')) { 774 ret = -ECANCELED; 775 goto error; 776 } 777 /* a symbol specified */ 778 symbol = kstrdup(argv[1], GFP_KERNEL); 779 if (!symbol) 780 return -ENOMEM; 781 /* TODO: support .init module functions */ 782 ret = traceprobe_split_symbol_offset(symbol, &offset); 783 if (ret || offset < 0 || offset > UINT_MAX) { 784 trace_probe_log_err(0, BAD_PROBE_ADDR); 785 goto parse_error; 786 } 787 if (kprobe_on_func_entry(NULL, symbol, offset)) 788 flags |= TPARG_FL_FENTRY; 789 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { 790 trace_probe_log_err(0, BAD_RETPROBE); 791 goto parse_error; 792 } 793 } 794 795 trace_probe_log_set_index(0); 796 if (event) { 797 ret = traceprobe_parse_event_name(&event, &group, buf, 798 event - argv[0]); 799 if (ret) 800 goto parse_error; 801 } else { 802 /* Make a new event name */ 803 if (symbol) 804 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", 805 is_return ? 'r' : 'p', symbol, offset); 806 else 807 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", 808 is_return ? 'r' : 'p', addr); 809 sanitize_event_name(buf); 810 event = buf; 811 } 812 813 /* setup a probe */ 814 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, 815 argc - 2, is_return); 816 if (IS_ERR(tk)) { 817 ret = PTR_ERR(tk); 818 /* This must return -ENOMEM, else there is a bug */ 819 WARN_ON_ONCE(ret != -ENOMEM); 820 goto out; /* We know tk is not allocated */ 821 } 822 argc -= 2; argv += 2; 823 824 /* parse arguments */ 825 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 826 tmp = kstrdup(argv[i], GFP_KERNEL); 827 if (!tmp) { 828 ret = -ENOMEM; 829 goto error; 830 } 831 832 trace_probe_log_set_index(i + 2); 833 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags); 834 kfree(tmp); 835 if (ret) 836 goto error; /* This can be -ENOMEM */ 837 } 838 839 ret = traceprobe_set_print_fmt(&tk->tp, is_return); 840 if (ret < 0) 841 goto error; 842 843 ret = register_trace_kprobe(tk); 844 if (ret) { 845 trace_probe_log_set_index(1); 846 if (ret == -EILSEQ) 847 trace_probe_log_err(0, BAD_INSN_BNDRY); 848 else if (ret == -ENOENT) 849 trace_probe_log_err(0, BAD_PROBE_ADDR); 850 else if (ret != -ENOMEM && ret != -EEXIST) 851 trace_probe_log_err(0, FAIL_REG_PROBE); 852 goto error; 853 } 854 855 out: 856 trace_probe_log_clear(); 857 kfree(symbol); 858 return ret; 859 860 parse_error: 861 ret = -EINVAL; 862 error: 863 free_trace_kprobe(tk); 864 goto out; 865 } 866 867 static int create_or_delete_trace_kprobe(int argc, char **argv) 868 { 869 int ret; 870 871 if (argv[0][0] == '-') 872 return dyn_event_release(argc, argv, &trace_kprobe_ops); 873 874 ret = trace_kprobe_create(argc, (const char **)argv); 875 return ret == -ECANCELED ? -EINVAL : ret; 876 } 877 878 static int trace_kprobe_release(struct dyn_event *ev) 879 { 880 struct trace_kprobe *tk = to_trace_kprobe(ev); 881 int ret = unregister_trace_kprobe(tk); 882 883 if (!ret) 884 free_trace_kprobe(tk); 885 return ret; 886 } 887 888 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) 889 { 890 struct trace_kprobe *tk = to_trace_kprobe(ev); 891 int i; 892 893 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 894 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), 895 trace_probe_name(&tk->tp)); 896 897 if (!tk->symbol) 898 seq_printf(m, " 0x%p", tk->rp.kp.addr); 899 else if (tk->rp.kp.offset) 900 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 901 tk->rp.kp.offset); 902 else 903 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 904 905 for (i = 0; i < tk->tp.nr_args; i++) 906 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 907 seq_putc(m, '\n'); 908 909 return 0; 910 } 911 912 static int probes_seq_show(struct seq_file *m, void *v) 913 { 914 struct dyn_event *ev = v; 915 916 if (!is_trace_kprobe(ev)) 917 return 0; 918 919 return trace_kprobe_show(m, ev); 920 } 921 922 static const struct seq_operations probes_seq_op = { 923 .start = dyn_event_seq_start, 924 .next = dyn_event_seq_next, 925 .stop = dyn_event_seq_stop, 926 .show = probes_seq_show 927 }; 928 929 static int probes_open(struct inode *inode, struct file *file) 930 { 931 int ret; 932 933 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 934 ret = dyn_events_release_all(&trace_kprobe_ops); 935 if (ret < 0) 936 return ret; 937 } 938 939 return seq_open(file, &probes_seq_op); 940 } 941 942 static ssize_t probes_write(struct file *file, const char __user *buffer, 943 size_t count, loff_t *ppos) 944 { 945 return trace_parse_run_command(file, buffer, count, ppos, 946 create_or_delete_trace_kprobe); 947 } 948 949 static const struct file_operations kprobe_events_ops = { 950 .owner = THIS_MODULE, 951 .open = probes_open, 952 .read = seq_read, 953 .llseek = seq_lseek, 954 .release = seq_release, 955 .write = probes_write, 956 }; 957 958 /* Probes profiling interfaces */ 959 static int probes_profile_seq_show(struct seq_file *m, void *v) 960 { 961 struct dyn_event *ev = v; 962 struct trace_kprobe *tk; 963 964 if (!is_trace_kprobe(ev)) 965 return 0; 966 967 tk = to_trace_kprobe(ev); 968 seq_printf(m, " %-44s %15lu %15lu\n", 969 trace_probe_name(&tk->tp), 970 trace_kprobe_nhit(tk), 971 tk->rp.kp.nmissed); 972 973 return 0; 974 } 975 976 static const struct seq_operations profile_seq_op = { 977 .start = dyn_event_seq_start, 978 .next = dyn_event_seq_next, 979 .stop = dyn_event_seq_stop, 980 .show = probes_profile_seq_show 981 }; 982 983 static int profile_open(struct inode *inode, struct file *file) 984 { 985 return seq_open(file, &profile_seq_op); 986 } 987 988 static const struct file_operations kprobe_profile_ops = { 989 .owner = THIS_MODULE, 990 .open = profile_open, 991 .read = seq_read, 992 .llseek = seq_lseek, 993 .release = seq_release, 994 }; 995 996 /* Kprobe specific fetch functions */ 997 998 /* Return the length of string -- including null terminal byte */ 999 static nokprobe_inline int 1000 fetch_store_strlen(unsigned long addr) 1001 { 1002 int ret, len = 0; 1003 u8 c; 1004 1005 do { 1006 ret = probe_kernel_read(&c, (u8 *)addr + len, 1); 1007 len++; 1008 } while (c && ret == 0 && len < MAX_STRING_SIZE); 1009 1010 return (ret < 0) ? ret : len; 1011 } 1012 1013 /* Return the length of string -- including null terminal byte */ 1014 static nokprobe_inline int 1015 fetch_store_strlen_user(unsigned long addr) 1016 { 1017 const void __user *uaddr = (__force const void __user *)addr; 1018 1019 return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE); 1020 } 1021 1022 /* 1023 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max 1024 * length and relative data location. 1025 */ 1026 static nokprobe_inline int 1027 fetch_store_string(unsigned long addr, void *dest, void *base) 1028 { 1029 int maxlen = get_loc_len(*(u32 *)dest); 1030 void *__dest; 1031 long ret; 1032 1033 if (unlikely(!maxlen)) 1034 return -ENOMEM; 1035 1036 __dest = get_loc_data(dest, base); 1037 1038 /* 1039 * Try to get string again, since the string can be changed while 1040 * probing. 1041 */ 1042 ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen); 1043 if (ret >= 0) 1044 *(u32 *)dest = make_data_loc(ret, __dest - base); 1045 1046 return ret; 1047 } 1048 1049 /* 1050 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf 1051 * with max length and relative data location. 1052 */ 1053 static nokprobe_inline int 1054 fetch_store_string_user(unsigned long addr, void *dest, void *base) 1055 { 1056 const void __user *uaddr = (__force const void __user *)addr; 1057 int maxlen = get_loc_len(*(u32 *)dest); 1058 void *__dest; 1059 long ret; 1060 1061 if (unlikely(!maxlen)) 1062 return -ENOMEM; 1063 1064 __dest = get_loc_data(dest, base); 1065 1066 ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen); 1067 if (ret >= 0) 1068 *(u32 *)dest = make_data_loc(ret, __dest - base); 1069 1070 return ret; 1071 } 1072 1073 static nokprobe_inline int 1074 probe_mem_read(void *dest, void *src, size_t size) 1075 { 1076 return probe_kernel_read(dest, src, size); 1077 } 1078 1079 static nokprobe_inline int 1080 probe_mem_read_user(void *dest, void *src, size_t size) 1081 { 1082 const void __user *uaddr = (__force const void __user *)src; 1083 1084 return probe_user_read(dest, uaddr, size); 1085 } 1086 1087 /* Note that we don't verify it, since the code does not come from user space */ 1088 static int 1089 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 1090 void *base) 1091 { 1092 unsigned long val; 1093 1094 retry: 1095 /* 1st stage: get value from context */ 1096 switch (code->op) { 1097 case FETCH_OP_REG: 1098 val = regs_get_register(regs, code->param); 1099 break; 1100 case FETCH_OP_STACK: 1101 val = regs_get_kernel_stack_nth(regs, code->param); 1102 break; 1103 case FETCH_OP_STACKP: 1104 val = kernel_stack_pointer(regs); 1105 break; 1106 case FETCH_OP_RETVAL: 1107 val = regs_return_value(regs); 1108 break; 1109 case FETCH_OP_IMM: 1110 val = code->immediate; 1111 break; 1112 case FETCH_OP_COMM: 1113 val = (unsigned long)current->comm; 1114 break; 1115 case FETCH_OP_DATA: 1116 val = (unsigned long)code->data; 1117 break; 1118 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 1119 case FETCH_OP_ARG: 1120 val = regs_get_kernel_argument(regs, code->param); 1121 break; 1122 #endif 1123 case FETCH_NOP_SYMBOL: /* Ignore a place holder */ 1124 code++; 1125 goto retry; 1126 default: 1127 return -EILSEQ; 1128 } 1129 code++; 1130 1131 return process_fetch_insn_bottom(code, val, dest, base); 1132 } 1133 NOKPROBE_SYMBOL(process_fetch_insn) 1134 1135 /* Kprobe handler */ 1136 static nokprobe_inline void 1137 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 1138 struct trace_event_file *trace_file) 1139 { 1140 struct kprobe_trace_entry_head *entry; 1141 struct ring_buffer_event *event; 1142 struct ring_buffer *buffer; 1143 int size, dsize, pc; 1144 unsigned long irq_flags; 1145 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1146 1147 WARN_ON(call != trace_file->event_call); 1148 1149 if (trace_trigger_soft_disabled(trace_file)) 1150 return; 1151 1152 local_save_flags(irq_flags); 1153 pc = preempt_count(); 1154 1155 dsize = __get_data_size(&tk->tp, regs); 1156 size = sizeof(*entry) + tk->tp.size + dsize; 1157 1158 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 1159 call->event.type, 1160 size, irq_flags, pc); 1161 if (!event) 1162 return; 1163 1164 entry = ring_buffer_event_data(event); 1165 entry->ip = (unsigned long)tk->rp.kp.addr; 1166 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1167 1168 event_trigger_unlock_commit_regs(trace_file, buffer, event, 1169 entry, irq_flags, pc, regs); 1170 } 1171 1172 static void 1173 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 1174 { 1175 struct event_file_link *link; 1176 1177 trace_probe_for_each_link_rcu(link, &tk->tp) 1178 __kprobe_trace_func(tk, regs, link->file); 1179 } 1180 NOKPROBE_SYMBOL(kprobe_trace_func); 1181 1182 /* Kretprobe handler */ 1183 static nokprobe_inline void 1184 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1185 struct pt_regs *regs, 1186 struct trace_event_file *trace_file) 1187 { 1188 struct kretprobe_trace_entry_head *entry; 1189 struct ring_buffer_event *event; 1190 struct ring_buffer *buffer; 1191 int size, pc, dsize; 1192 unsigned long irq_flags; 1193 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1194 1195 WARN_ON(call != trace_file->event_call); 1196 1197 if (trace_trigger_soft_disabled(trace_file)) 1198 return; 1199 1200 local_save_flags(irq_flags); 1201 pc = preempt_count(); 1202 1203 dsize = __get_data_size(&tk->tp, regs); 1204 size = sizeof(*entry) + tk->tp.size + dsize; 1205 1206 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 1207 call->event.type, 1208 size, irq_flags, pc); 1209 if (!event) 1210 return; 1211 1212 entry = ring_buffer_event_data(event); 1213 entry->func = (unsigned long)tk->rp.kp.addr; 1214 entry->ret_ip = (unsigned long)ri->ret_addr; 1215 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1216 1217 event_trigger_unlock_commit_regs(trace_file, buffer, event, 1218 entry, irq_flags, pc, regs); 1219 } 1220 1221 static void 1222 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1223 struct pt_regs *regs) 1224 { 1225 struct event_file_link *link; 1226 1227 trace_probe_for_each_link_rcu(link, &tk->tp) 1228 __kretprobe_trace_func(tk, ri, regs, link->file); 1229 } 1230 NOKPROBE_SYMBOL(kretprobe_trace_func); 1231 1232 /* Event entry printers */ 1233 static enum print_line_t 1234 print_kprobe_event(struct trace_iterator *iter, int flags, 1235 struct trace_event *event) 1236 { 1237 struct kprobe_trace_entry_head *field; 1238 struct trace_seq *s = &iter->seq; 1239 struct trace_probe *tp; 1240 1241 field = (struct kprobe_trace_entry_head *)iter->ent; 1242 tp = trace_probe_primary_from_call( 1243 container_of(event, struct trace_event_call, event)); 1244 if (WARN_ON_ONCE(!tp)) 1245 goto out; 1246 1247 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1248 1249 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) 1250 goto out; 1251 1252 trace_seq_putc(s, ')'); 1253 1254 if (print_probe_args(s, tp->args, tp->nr_args, 1255 (u8 *)&field[1], field) < 0) 1256 goto out; 1257 1258 trace_seq_putc(s, '\n'); 1259 out: 1260 return trace_handle_return(s); 1261 } 1262 1263 static enum print_line_t 1264 print_kretprobe_event(struct trace_iterator *iter, int flags, 1265 struct trace_event *event) 1266 { 1267 struct kretprobe_trace_entry_head *field; 1268 struct trace_seq *s = &iter->seq; 1269 struct trace_probe *tp; 1270 1271 field = (struct kretprobe_trace_entry_head *)iter->ent; 1272 tp = trace_probe_primary_from_call( 1273 container_of(event, struct trace_event_call, event)); 1274 if (WARN_ON_ONCE(!tp)) 1275 goto out; 1276 1277 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1278 1279 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) 1280 goto out; 1281 1282 trace_seq_puts(s, " <- "); 1283 1284 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) 1285 goto out; 1286 1287 trace_seq_putc(s, ')'); 1288 1289 if (print_probe_args(s, tp->args, tp->nr_args, 1290 (u8 *)&field[1], field) < 0) 1291 goto out; 1292 1293 trace_seq_putc(s, '\n'); 1294 1295 out: 1296 return trace_handle_return(s); 1297 } 1298 1299 1300 static int kprobe_event_define_fields(struct trace_event_call *event_call) 1301 { 1302 int ret; 1303 struct kprobe_trace_entry_head field; 1304 struct trace_probe *tp; 1305 1306 tp = trace_probe_primary_from_call(event_call); 1307 if (WARN_ON_ONCE(!tp)) 1308 return -ENOENT; 1309 1310 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1311 1312 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1313 } 1314 1315 static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1316 { 1317 int ret; 1318 struct kretprobe_trace_entry_head field; 1319 struct trace_probe *tp; 1320 1321 tp = trace_probe_primary_from_call(event_call); 1322 if (WARN_ON_ONCE(!tp)) 1323 return -ENOENT; 1324 1325 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1326 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1327 1328 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1329 } 1330 1331 #ifdef CONFIG_PERF_EVENTS 1332 1333 /* Kprobe profile handler */ 1334 static int 1335 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1336 { 1337 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1338 struct kprobe_trace_entry_head *entry; 1339 struct hlist_head *head; 1340 int size, __size, dsize; 1341 int rctx; 1342 1343 if (bpf_prog_array_valid(call)) { 1344 unsigned long orig_ip = instruction_pointer(regs); 1345 int ret; 1346 1347 ret = trace_call_bpf(call, regs); 1348 1349 /* 1350 * We need to check and see if we modified the pc of the 1351 * pt_regs, and if so return 1 so that we don't do the 1352 * single stepping. 1353 */ 1354 if (orig_ip != instruction_pointer(regs)) 1355 return 1; 1356 if (!ret) 1357 return 0; 1358 } 1359 1360 head = this_cpu_ptr(call->perf_events); 1361 if (hlist_empty(head)) 1362 return 0; 1363 1364 dsize = __get_data_size(&tk->tp, regs); 1365 __size = sizeof(*entry) + tk->tp.size + dsize; 1366 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1367 size -= sizeof(u32); 1368 1369 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1370 if (!entry) 1371 return 0; 1372 1373 entry->ip = (unsigned long)tk->rp.kp.addr; 1374 memset(&entry[1], 0, dsize); 1375 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1376 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1377 head, NULL); 1378 return 0; 1379 } 1380 NOKPROBE_SYMBOL(kprobe_perf_func); 1381 1382 /* Kretprobe profile handler */ 1383 static void 1384 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1385 struct pt_regs *regs) 1386 { 1387 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1388 struct kretprobe_trace_entry_head *entry; 1389 struct hlist_head *head; 1390 int size, __size, dsize; 1391 int rctx; 1392 1393 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1394 return; 1395 1396 head = this_cpu_ptr(call->perf_events); 1397 if (hlist_empty(head)) 1398 return; 1399 1400 dsize = __get_data_size(&tk->tp, regs); 1401 __size = sizeof(*entry) + tk->tp.size + dsize; 1402 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1403 size -= sizeof(u32); 1404 1405 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1406 if (!entry) 1407 return; 1408 1409 entry->func = (unsigned long)tk->rp.kp.addr; 1410 entry->ret_ip = (unsigned long)ri->ret_addr; 1411 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1412 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1413 head, NULL); 1414 } 1415 NOKPROBE_SYMBOL(kretprobe_perf_func); 1416 1417 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, 1418 const char **symbol, u64 *probe_offset, 1419 u64 *probe_addr, bool perf_type_tracepoint) 1420 { 1421 const char *pevent = trace_event_name(event->tp_event); 1422 const char *group = event->tp_event->class->system; 1423 struct trace_kprobe *tk; 1424 1425 if (perf_type_tracepoint) 1426 tk = find_trace_kprobe(pevent, group); 1427 else 1428 tk = event->tp_event->data; 1429 if (!tk) 1430 return -EINVAL; 1431 1432 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE 1433 : BPF_FD_TYPE_KPROBE; 1434 if (tk->symbol) { 1435 *symbol = tk->symbol; 1436 *probe_offset = tk->rp.kp.offset; 1437 *probe_addr = 0; 1438 } else { 1439 *symbol = NULL; 1440 *probe_offset = 0; 1441 *probe_addr = (unsigned long)tk->rp.kp.addr; 1442 } 1443 return 0; 1444 } 1445 #endif /* CONFIG_PERF_EVENTS */ 1446 1447 /* 1448 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1449 * 1450 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1451 * lockless, but we can't race with this __init function. 1452 */ 1453 static int kprobe_register(struct trace_event_call *event, 1454 enum trace_reg type, void *data) 1455 { 1456 struct trace_event_file *file = data; 1457 1458 switch (type) { 1459 case TRACE_REG_REGISTER: 1460 return enable_trace_kprobe(event, file); 1461 case TRACE_REG_UNREGISTER: 1462 return disable_trace_kprobe(event, file); 1463 1464 #ifdef CONFIG_PERF_EVENTS 1465 case TRACE_REG_PERF_REGISTER: 1466 return enable_trace_kprobe(event, NULL); 1467 case TRACE_REG_PERF_UNREGISTER: 1468 return disable_trace_kprobe(event, NULL); 1469 case TRACE_REG_PERF_OPEN: 1470 case TRACE_REG_PERF_CLOSE: 1471 case TRACE_REG_PERF_ADD: 1472 case TRACE_REG_PERF_DEL: 1473 return 0; 1474 #endif 1475 } 1476 return 0; 1477 } 1478 1479 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1480 { 1481 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1482 int ret = 0; 1483 1484 raw_cpu_inc(*tk->nhit); 1485 1486 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1487 kprobe_trace_func(tk, regs); 1488 #ifdef CONFIG_PERF_EVENTS 1489 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1490 ret = kprobe_perf_func(tk, regs); 1491 #endif 1492 return ret; 1493 } 1494 NOKPROBE_SYMBOL(kprobe_dispatcher); 1495 1496 static int 1497 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1498 { 1499 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp); 1500 1501 raw_cpu_inc(*tk->nhit); 1502 1503 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1504 kretprobe_trace_func(tk, ri, regs); 1505 #ifdef CONFIG_PERF_EVENTS 1506 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1507 kretprobe_perf_func(tk, ri, regs); 1508 #endif 1509 return 0; /* We don't tweek kernel, so just return 0 */ 1510 } 1511 NOKPROBE_SYMBOL(kretprobe_dispatcher); 1512 1513 static struct trace_event_functions kretprobe_funcs = { 1514 .trace = print_kretprobe_event 1515 }; 1516 1517 static struct trace_event_functions kprobe_funcs = { 1518 .trace = print_kprobe_event 1519 }; 1520 1521 static inline void init_trace_event_call(struct trace_kprobe *tk) 1522 { 1523 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1524 1525 if (trace_kprobe_is_return(tk)) { 1526 call->event.funcs = &kretprobe_funcs; 1527 call->class->define_fields = kretprobe_event_define_fields; 1528 } else { 1529 call->event.funcs = &kprobe_funcs; 1530 call->class->define_fields = kprobe_event_define_fields; 1531 } 1532 1533 call->flags = TRACE_EVENT_FL_KPROBE; 1534 call->class->reg = kprobe_register; 1535 } 1536 1537 static int register_kprobe_event(struct trace_kprobe *tk) 1538 { 1539 init_trace_event_call(tk); 1540 1541 return trace_probe_register_event_call(&tk->tp); 1542 } 1543 1544 static int unregister_kprobe_event(struct trace_kprobe *tk) 1545 { 1546 return trace_probe_unregister_event_call(&tk->tp); 1547 } 1548 1549 #ifdef CONFIG_PERF_EVENTS 1550 /* create a trace_kprobe, but don't add it to global lists */ 1551 struct trace_event_call * 1552 create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 1553 bool is_return) 1554 { 1555 struct trace_kprobe *tk; 1556 int ret; 1557 char *event; 1558 1559 /* 1560 * local trace_kprobes are not added to dyn_event, so they are never 1561 * searched in find_trace_kprobe(). Therefore, there is no concern of 1562 * duplicated name here. 1563 */ 1564 event = func ? func : "DUMMY_EVENT"; 1565 1566 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, 1567 offs, 0 /* maxactive */, 0 /* nargs */, 1568 is_return); 1569 1570 if (IS_ERR(tk)) { 1571 pr_info("Failed to allocate trace_probe.(%d)\n", 1572 (int)PTR_ERR(tk)); 1573 return ERR_CAST(tk); 1574 } 1575 1576 init_trace_event_call(tk); 1577 1578 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) { 1579 ret = -ENOMEM; 1580 goto error; 1581 } 1582 1583 ret = __register_trace_kprobe(tk); 1584 if (ret < 0) 1585 goto error; 1586 1587 return trace_probe_event_call(&tk->tp); 1588 error: 1589 free_trace_kprobe(tk); 1590 return ERR_PTR(ret); 1591 } 1592 1593 void destroy_local_trace_kprobe(struct trace_event_call *event_call) 1594 { 1595 struct trace_kprobe *tk; 1596 1597 tk = trace_kprobe_primary_from_call(event_call); 1598 if (unlikely(!tk)) 1599 return; 1600 1601 if (trace_probe_is_enabled(&tk->tp)) { 1602 WARN_ON(1); 1603 return; 1604 } 1605 1606 __unregister_trace_kprobe(tk); 1607 1608 free_trace_kprobe(tk); 1609 } 1610 #endif /* CONFIG_PERF_EVENTS */ 1611 1612 static __init void enable_boot_kprobe_events(void) 1613 { 1614 struct trace_array *tr = top_trace_array(); 1615 struct trace_event_file *file; 1616 struct trace_kprobe *tk; 1617 struct dyn_event *pos; 1618 1619 mutex_lock(&event_mutex); 1620 for_each_trace_kprobe(tk, pos) { 1621 list_for_each_entry(file, &tr->events, list) 1622 if (file->event_call == trace_probe_event_call(&tk->tp)) 1623 trace_event_enable_disable(file, 1, 0); 1624 } 1625 mutex_unlock(&event_mutex); 1626 } 1627 1628 static __init void setup_boot_kprobe_events(void) 1629 { 1630 char *p, *cmd = kprobe_boot_events_buf; 1631 int ret; 1632 1633 strreplace(kprobe_boot_events_buf, ',', ' '); 1634 1635 while (cmd && *cmd != '\0') { 1636 p = strchr(cmd, ';'); 1637 if (p) 1638 *p++ = '\0'; 1639 1640 ret = trace_run_command(cmd, create_or_delete_trace_kprobe); 1641 if (ret) 1642 pr_warn("Failed to add event(%d): %s\n", ret, cmd); 1643 else 1644 kprobe_boot_events_enabled = true; 1645 1646 cmd = p; 1647 } 1648 1649 enable_boot_kprobe_events(); 1650 } 1651 1652 /* Make a tracefs interface for controlling probe points */ 1653 static __init int init_kprobe_trace(void) 1654 { 1655 struct dentry *d_tracer; 1656 struct dentry *entry; 1657 int ret; 1658 1659 ret = dyn_event_register(&trace_kprobe_ops); 1660 if (ret) 1661 return ret; 1662 1663 if (register_module_notifier(&trace_kprobe_module_nb)) 1664 return -EINVAL; 1665 1666 d_tracer = tracing_init_dentry(); 1667 if (IS_ERR(d_tracer)) 1668 return 0; 1669 1670 entry = tracefs_create_file("kprobe_events", 0644, d_tracer, 1671 NULL, &kprobe_events_ops); 1672 1673 /* Event list interface */ 1674 if (!entry) 1675 pr_warn("Could not create tracefs 'kprobe_events' entry\n"); 1676 1677 /* Profile interface */ 1678 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer, 1679 NULL, &kprobe_profile_ops); 1680 1681 if (!entry) 1682 pr_warn("Could not create tracefs 'kprobe_profile' entry\n"); 1683 1684 setup_boot_kprobe_events(); 1685 1686 return 0; 1687 } 1688 fs_initcall(init_kprobe_trace); 1689 1690 1691 #ifdef CONFIG_FTRACE_STARTUP_TEST 1692 static __init struct trace_event_file * 1693 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 1694 { 1695 struct trace_event_file *file; 1696 1697 list_for_each_entry(file, &tr->events, list) 1698 if (file->event_call == trace_probe_event_call(&tk->tp)) 1699 return file; 1700 1701 return NULL; 1702 } 1703 1704 /* 1705 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 1706 * stage, we can do this lockless. 1707 */ 1708 static __init int kprobe_trace_self_tests_init(void) 1709 { 1710 int ret, warn = 0; 1711 int (*target)(int, int, int, int, int, int); 1712 struct trace_kprobe *tk; 1713 struct trace_event_file *file; 1714 1715 if (tracing_is_disabled()) 1716 return -ENODEV; 1717 1718 if (kprobe_boot_events_enabled) { 1719 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n"); 1720 return 0; 1721 } 1722 1723 target = kprobe_trace_selftest_target; 1724 1725 pr_info("Testing kprobe tracing: "); 1726 1727 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)", 1728 create_or_delete_trace_kprobe); 1729 if (WARN_ON_ONCE(ret)) { 1730 pr_warn("error on probing function entry.\n"); 1731 warn++; 1732 } else { 1733 /* Enable trace point */ 1734 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1735 if (WARN_ON_ONCE(tk == NULL)) { 1736 pr_warn("error on getting new probe.\n"); 1737 warn++; 1738 } else { 1739 file = find_trace_probe_file(tk, top_trace_array()); 1740 if (WARN_ON_ONCE(file == NULL)) { 1741 pr_warn("error on getting probe file.\n"); 1742 warn++; 1743 } else 1744 enable_trace_kprobe( 1745 trace_probe_event_call(&tk->tp), file); 1746 } 1747 } 1748 1749 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval", 1750 create_or_delete_trace_kprobe); 1751 if (WARN_ON_ONCE(ret)) { 1752 pr_warn("error on probing function return.\n"); 1753 warn++; 1754 } else { 1755 /* Enable trace point */ 1756 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1757 if (WARN_ON_ONCE(tk == NULL)) { 1758 pr_warn("error on getting 2nd new probe.\n"); 1759 warn++; 1760 } else { 1761 file = find_trace_probe_file(tk, top_trace_array()); 1762 if (WARN_ON_ONCE(file == NULL)) { 1763 pr_warn("error on getting probe file.\n"); 1764 warn++; 1765 } else 1766 enable_trace_kprobe( 1767 trace_probe_event_call(&tk->tp), file); 1768 } 1769 } 1770 1771 if (warn) 1772 goto end; 1773 1774 ret = target(1, 2, 3, 4, 5, 6); 1775 1776 /* 1777 * Not expecting an error here, the check is only to prevent the 1778 * optimizer from removing the call to target() as otherwise there 1779 * are no side-effects and the call is never performed. 1780 */ 1781 if (ret != 21) 1782 warn++; 1783 1784 /* Disable trace points before removing it */ 1785 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1786 if (WARN_ON_ONCE(tk == NULL)) { 1787 pr_warn("error on getting test probe.\n"); 1788 warn++; 1789 } else { 1790 if (trace_kprobe_nhit(tk) != 1) { 1791 pr_warn("incorrect number of testprobe hits\n"); 1792 warn++; 1793 } 1794 1795 file = find_trace_probe_file(tk, top_trace_array()); 1796 if (WARN_ON_ONCE(file == NULL)) { 1797 pr_warn("error on getting probe file.\n"); 1798 warn++; 1799 } else 1800 disable_trace_kprobe( 1801 trace_probe_event_call(&tk->tp), file); 1802 } 1803 1804 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1805 if (WARN_ON_ONCE(tk == NULL)) { 1806 pr_warn("error on getting 2nd test probe.\n"); 1807 warn++; 1808 } else { 1809 if (trace_kprobe_nhit(tk) != 1) { 1810 pr_warn("incorrect number of testprobe2 hits\n"); 1811 warn++; 1812 } 1813 1814 file = find_trace_probe_file(tk, top_trace_array()); 1815 if (WARN_ON_ONCE(file == NULL)) { 1816 pr_warn("error on getting probe file.\n"); 1817 warn++; 1818 } else 1819 disable_trace_kprobe( 1820 trace_probe_event_call(&tk->tp), file); 1821 } 1822 1823 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe); 1824 if (WARN_ON_ONCE(ret)) { 1825 pr_warn("error on deleting a probe.\n"); 1826 warn++; 1827 } 1828 1829 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe); 1830 if (WARN_ON_ONCE(ret)) { 1831 pr_warn("error on deleting a probe.\n"); 1832 warn++; 1833 } 1834 1835 end: 1836 ret = dyn_events_release_all(&trace_kprobe_ops); 1837 if (WARN_ON_ONCE(ret)) { 1838 pr_warn("error on cleaning up probes.\n"); 1839 warn++; 1840 } 1841 /* 1842 * Wait for the optimizer work to finish. Otherwise it might fiddle 1843 * with probes in already freed __init text. 1844 */ 1845 wait_for_kprobe_optimizer(); 1846 if (warn) 1847 pr_cont("NG: Some tests are failed. Please check them.\n"); 1848 else 1849 pr_cont("OK\n"); 1850 return 0; 1851 } 1852 1853 late_initcall(kprobe_trace_self_tests_init); 1854 1855 #endif 1856