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 "trace_dynevent.h" 16 #include "trace_kprobe_selftest.h" 17 #include "trace_probe.h" 18 #include "trace_probe_tmpl.h" 19 20 #define KPROBE_EVENT_SYSTEM "kprobes" 21 #define KRETPROBE_MAXACTIVE_MAX 4096 22 23 static int trace_kprobe_create(int argc, const char **argv); 24 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev); 25 static int trace_kprobe_release(struct dyn_event *ev); 26 static bool trace_kprobe_is_busy(struct dyn_event *ev); 27 static bool trace_kprobe_match(const char *system, const char *event, 28 struct dyn_event *ev); 29 30 static struct dyn_event_operations trace_kprobe_ops = { 31 .create = trace_kprobe_create, 32 .show = trace_kprobe_show, 33 .is_busy = trace_kprobe_is_busy, 34 .free = trace_kprobe_release, 35 .match = trace_kprobe_match, 36 }; 37 38 /** 39 * Kprobe event core functions 40 */ 41 struct trace_kprobe { 42 struct dyn_event devent; 43 struct kretprobe rp; /* Use rp.kp for kprobe use */ 44 unsigned long __percpu *nhit; 45 const char *symbol; /* symbol name */ 46 struct trace_probe tp; 47 }; 48 49 static bool is_trace_kprobe(struct dyn_event *ev) 50 { 51 return ev->ops == &trace_kprobe_ops; 52 } 53 54 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev) 55 { 56 return container_of(ev, struct trace_kprobe, devent); 57 } 58 59 /** 60 * for_each_trace_kprobe - iterate over the trace_kprobe list 61 * @pos: the struct trace_kprobe * for each entry 62 * @dpos: the struct dyn_event * to use as a loop cursor 63 */ 64 #define for_each_trace_kprobe(pos, dpos) \ 65 for_each_dyn_event(dpos) \ 66 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos))) 67 68 #define SIZEOF_TRACE_KPROBE(n) \ 69 (offsetof(struct trace_kprobe, tp.args) + \ 70 (sizeof(struct probe_arg) * (n))) 71 72 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk) 73 { 74 return tk->rp.handler != NULL; 75 } 76 77 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk) 78 { 79 return tk->symbol ? tk->symbol : "unknown"; 80 } 81 82 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk) 83 { 84 return tk->rp.kp.offset; 85 } 86 87 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk) 88 { 89 return !!(kprobe_gone(&tk->rp.kp)); 90 } 91 92 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, 93 struct module *mod) 94 { 95 int len = strlen(mod->name); 96 const char *name = trace_kprobe_symbol(tk); 97 return strncmp(mod->name, name, len) == 0 && name[len] == ':'; 98 } 99 100 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) 101 { 102 char *p; 103 bool ret; 104 105 if (!tk->symbol) 106 return false; 107 p = strchr(tk->symbol, ':'); 108 if (!p) 109 return true; 110 *p = '\0'; 111 mutex_lock(&module_mutex); 112 ret = !!find_module(tk->symbol); 113 mutex_unlock(&module_mutex); 114 *p = ':'; 115 116 return ret; 117 } 118 119 static bool trace_kprobe_is_busy(struct dyn_event *ev) 120 { 121 struct trace_kprobe *tk = to_trace_kprobe(ev); 122 123 return trace_probe_is_enabled(&tk->tp); 124 } 125 126 static bool trace_kprobe_match(const char *system, const char *event, 127 struct dyn_event *ev) 128 { 129 struct trace_kprobe *tk = to_trace_kprobe(ev); 130 131 return strcmp(trace_event_name(&tk->tp.call), event) == 0 && 132 (!system || strcmp(tk->tp.call.class->system, system) == 0); 133 } 134 135 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) 136 { 137 unsigned long nhit = 0; 138 int cpu; 139 140 for_each_possible_cpu(cpu) 141 nhit += *per_cpu_ptr(tk->nhit, cpu); 142 143 return nhit; 144 } 145 146 /* Return 0 if it fails to find the symbol address */ 147 static nokprobe_inline 148 unsigned long trace_kprobe_address(struct trace_kprobe *tk) 149 { 150 unsigned long addr; 151 152 if (tk->symbol) { 153 addr = (unsigned long) 154 kallsyms_lookup_name(trace_kprobe_symbol(tk)); 155 if (addr) 156 addr += tk->rp.kp.offset; 157 } else { 158 addr = (unsigned long)tk->rp.kp.addr; 159 } 160 return addr; 161 } 162 163 bool trace_kprobe_on_func_entry(struct trace_event_call *call) 164 { 165 struct trace_kprobe *tk = (struct trace_kprobe *)call->data; 166 167 return kprobe_on_func_entry(tk->rp.kp.addr, 168 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name, 169 tk->rp.kp.addr ? 0 : tk->rp.kp.offset); 170 } 171 172 bool trace_kprobe_error_injectable(struct trace_event_call *call) 173 { 174 struct trace_kprobe *tk = (struct trace_kprobe *)call->data; 175 176 return within_error_injection_list(trace_kprobe_address(tk)); 177 } 178 179 static int register_kprobe_event(struct trace_kprobe *tk); 180 static int unregister_kprobe_event(struct trace_kprobe *tk); 181 182 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); 183 static int kretprobe_dispatcher(struct kretprobe_instance *ri, 184 struct pt_regs *regs); 185 186 /* 187 * Allocate new trace_probe and initialize it (including kprobes). 188 */ 189 static struct trace_kprobe *alloc_trace_kprobe(const char *group, 190 const char *event, 191 void *addr, 192 const char *symbol, 193 unsigned long offs, 194 int maxactive, 195 int nargs, bool is_return) 196 { 197 struct trace_kprobe *tk; 198 int ret = -ENOMEM; 199 200 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL); 201 if (!tk) 202 return ERR_PTR(ret); 203 204 tk->nhit = alloc_percpu(unsigned long); 205 if (!tk->nhit) 206 goto error; 207 208 if (symbol) { 209 tk->symbol = kstrdup(symbol, GFP_KERNEL); 210 if (!tk->symbol) 211 goto error; 212 tk->rp.kp.symbol_name = tk->symbol; 213 tk->rp.kp.offset = offs; 214 } else 215 tk->rp.kp.addr = addr; 216 217 if (is_return) 218 tk->rp.handler = kretprobe_dispatcher; 219 else 220 tk->rp.kp.pre_handler = kprobe_dispatcher; 221 222 tk->rp.maxactive = maxactive; 223 224 if (!event || !is_good_name(event)) { 225 ret = -EINVAL; 226 goto error; 227 } 228 229 tk->tp.call.class = &tk->tp.class; 230 tk->tp.call.name = kstrdup(event, GFP_KERNEL); 231 if (!tk->tp.call.name) 232 goto error; 233 234 if (!group || !is_good_name(group)) { 235 ret = -EINVAL; 236 goto error; 237 } 238 239 tk->tp.class.system = kstrdup(group, GFP_KERNEL); 240 if (!tk->tp.class.system) 241 goto error; 242 243 dyn_event_init(&tk->devent, &trace_kprobe_ops); 244 INIT_LIST_HEAD(&tk->tp.files); 245 return tk; 246 error: 247 kfree(tk->tp.call.name); 248 kfree(tk->symbol); 249 free_percpu(tk->nhit); 250 kfree(tk); 251 return ERR_PTR(ret); 252 } 253 254 static void free_trace_kprobe(struct trace_kprobe *tk) 255 { 256 int i; 257 258 if (!tk) 259 return; 260 261 for (i = 0; i < tk->tp.nr_args; i++) 262 traceprobe_free_probe_arg(&tk->tp.args[i]); 263 264 kfree(tk->tp.call.class->system); 265 kfree(tk->tp.call.name); 266 kfree(tk->symbol); 267 free_percpu(tk->nhit); 268 kfree(tk); 269 } 270 271 static struct trace_kprobe *find_trace_kprobe(const char *event, 272 const char *group) 273 { 274 struct dyn_event *pos; 275 struct trace_kprobe *tk; 276 277 for_each_trace_kprobe(tk, pos) 278 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 && 279 strcmp(tk->tp.call.class->system, group) == 0) 280 return tk; 281 return NULL; 282 } 283 284 static inline int __enable_trace_kprobe(struct trace_kprobe *tk) 285 { 286 int ret = 0; 287 288 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) { 289 if (trace_kprobe_is_return(tk)) 290 ret = enable_kretprobe(&tk->rp); 291 else 292 ret = enable_kprobe(&tk->rp.kp); 293 } 294 295 return ret; 296 } 297 298 /* 299 * Enable trace_probe 300 * if the file is NULL, enable "perf" handler, or enable "trace" handler. 301 */ 302 static int 303 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) 304 { 305 struct event_file_link *link; 306 int ret = 0; 307 308 if (file) { 309 link = kmalloc(sizeof(*link), GFP_KERNEL); 310 if (!link) { 311 ret = -ENOMEM; 312 goto out; 313 } 314 315 link->file = file; 316 list_add_tail_rcu(&link->list, &tk->tp.files); 317 318 tk->tp.flags |= TP_FLAG_TRACE; 319 ret = __enable_trace_kprobe(tk); 320 if (ret) { 321 list_del_rcu(&link->list); 322 kfree(link); 323 tk->tp.flags &= ~TP_FLAG_TRACE; 324 } 325 326 } else { 327 tk->tp.flags |= TP_FLAG_PROFILE; 328 ret = __enable_trace_kprobe(tk); 329 if (ret) 330 tk->tp.flags &= ~TP_FLAG_PROFILE; 331 } 332 out: 333 return ret; 334 } 335 336 /* 337 * Disable trace_probe 338 * if the file is NULL, disable "perf" handler, or disable "trace" handler. 339 */ 340 static int 341 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) 342 { 343 struct event_file_link *link = NULL; 344 int wait = 0; 345 int ret = 0; 346 347 if (file) { 348 link = find_event_file_link(&tk->tp, file); 349 if (!link) { 350 ret = -EINVAL; 351 goto out; 352 } 353 354 list_del_rcu(&link->list); 355 wait = 1; 356 if (!list_empty(&tk->tp.files)) 357 goto out; 358 359 tk->tp.flags &= ~TP_FLAG_TRACE; 360 } else 361 tk->tp.flags &= ~TP_FLAG_PROFILE; 362 363 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) { 364 if (trace_kprobe_is_return(tk)) 365 disable_kretprobe(&tk->rp); 366 else 367 disable_kprobe(&tk->rp.kp); 368 wait = 1; 369 } 370 371 /* 372 * if tk is not added to any list, it must be a local trace_kprobe 373 * created with perf_event_open. We don't need to wait for these 374 * trace_kprobes 375 */ 376 if (list_empty(&tk->devent.list)) 377 wait = 0; 378 out: 379 if (wait) { 380 /* 381 * Synchronize with kprobe_trace_func/kretprobe_trace_func 382 * to ensure disabled (all running handlers are finished). 383 * This is not only for kfree(), but also the caller, 384 * trace_remove_event_call() supposes it for releasing 385 * event_call related objects, which will be accessed in 386 * the kprobe_trace_func/kretprobe_trace_func. 387 */ 388 synchronize_rcu(); 389 kfree(link); /* Ignored if link == NULL */ 390 } 391 392 return ret; 393 } 394 395 #if defined(CONFIG_KPROBES_ON_FTRACE) && \ 396 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) 397 static bool within_notrace_func(struct trace_kprobe *tk) 398 { 399 unsigned long offset, size, addr; 400 401 addr = trace_kprobe_address(tk); 402 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) 403 return false; 404 405 /* Get the entry address of the target function */ 406 addr -= offset; 407 408 /* 409 * Since ftrace_location_range() does inclusive range check, we need 410 * to subtract 1 byte from the end address. 411 */ 412 return !ftrace_location_range(addr, addr + size - 1); 413 } 414 #else 415 #define within_notrace_func(tk) (false) 416 #endif 417 418 /* Internal register function - just handle k*probes and flags */ 419 static int __register_trace_kprobe(struct trace_kprobe *tk) 420 { 421 int i, ret; 422 423 if (trace_probe_is_registered(&tk->tp)) 424 return -EINVAL; 425 426 if (within_notrace_func(tk)) { 427 pr_warn("Could not probe notrace function %s\n", 428 trace_kprobe_symbol(tk)); 429 return -EINVAL; 430 } 431 432 for (i = 0; i < tk->tp.nr_args; i++) { 433 ret = traceprobe_update_arg(&tk->tp.args[i]); 434 if (ret) 435 return ret; 436 } 437 438 /* Set/clear disabled flag according to tp->flag */ 439 if (trace_probe_is_enabled(&tk->tp)) 440 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; 441 else 442 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; 443 444 if (trace_kprobe_is_return(tk)) 445 ret = register_kretprobe(&tk->rp); 446 else 447 ret = register_kprobe(&tk->rp.kp); 448 449 if (ret == 0) { 450 tk->tp.flags |= TP_FLAG_REGISTERED; 451 } else if (ret == -EILSEQ) { 452 pr_warn("Probing address(0x%p) is not an instruction boundary.\n", 453 tk->rp.kp.addr); 454 ret = -EINVAL; 455 } 456 return ret; 457 } 458 459 /* Internal unregister function - just handle k*probes and flags */ 460 static void __unregister_trace_kprobe(struct trace_kprobe *tk) 461 { 462 if (trace_probe_is_registered(&tk->tp)) { 463 if (trace_kprobe_is_return(tk)) 464 unregister_kretprobe(&tk->rp); 465 else 466 unregister_kprobe(&tk->rp.kp); 467 tk->tp.flags &= ~TP_FLAG_REGISTERED; 468 /* Cleanup kprobe for reuse */ 469 if (tk->rp.kp.symbol_name) 470 tk->rp.kp.addr = NULL; 471 } 472 } 473 474 /* Unregister a trace_probe and probe_event */ 475 static int unregister_trace_kprobe(struct trace_kprobe *tk) 476 { 477 /* Enabled event can not be unregistered */ 478 if (trace_probe_is_enabled(&tk->tp)) 479 return -EBUSY; 480 481 /* Will fail if probe is being used by ftrace or perf */ 482 if (unregister_kprobe_event(tk)) 483 return -EBUSY; 484 485 __unregister_trace_kprobe(tk); 486 dyn_event_remove(&tk->devent); 487 488 return 0; 489 } 490 491 /* Register a trace_probe and probe_event */ 492 static int register_trace_kprobe(struct trace_kprobe *tk) 493 { 494 struct trace_kprobe *old_tk; 495 int ret; 496 497 mutex_lock(&event_mutex); 498 499 /* Delete old (same name) event if exist */ 500 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call), 501 tk->tp.call.class->system); 502 if (old_tk) { 503 ret = unregister_trace_kprobe(old_tk); 504 if (ret < 0) 505 goto end; 506 free_trace_kprobe(old_tk); 507 } 508 509 /* Register new event */ 510 ret = register_kprobe_event(tk); 511 if (ret) { 512 pr_warn("Failed to register probe event(%d)\n", ret); 513 goto end; 514 } 515 516 /* Register k*probe */ 517 ret = __register_trace_kprobe(tk); 518 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 519 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 520 ret = 0; 521 } 522 523 if (ret < 0) 524 unregister_kprobe_event(tk); 525 else 526 dyn_event_add(&tk->devent); 527 528 end: 529 mutex_unlock(&event_mutex); 530 return ret; 531 } 532 533 /* Module notifier call back, checking event on the module */ 534 static int trace_kprobe_module_callback(struct notifier_block *nb, 535 unsigned long val, void *data) 536 { 537 struct module *mod = data; 538 struct dyn_event *pos; 539 struct trace_kprobe *tk; 540 int ret; 541 542 if (val != MODULE_STATE_COMING) 543 return NOTIFY_DONE; 544 545 /* Update probes on coming module */ 546 mutex_lock(&event_mutex); 547 for_each_trace_kprobe(tk, pos) { 548 if (trace_kprobe_within_module(tk, mod)) { 549 /* Don't need to check busy - this should have gone. */ 550 __unregister_trace_kprobe(tk); 551 ret = __register_trace_kprobe(tk); 552 if (ret) 553 pr_warn("Failed to re-register probe %s on %s: %d\n", 554 trace_event_name(&tk->tp.call), 555 mod->name, ret); 556 } 557 } 558 mutex_unlock(&event_mutex); 559 560 return NOTIFY_DONE; 561 } 562 563 static struct notifier_block trace_kprobe_module_nb = { 564 .notifier_call = trace_kprobe_module_callback, 565 .priority = 1 /* Invoked after kprobe module callback */ 566 }; 567 568 /* Convert certain expected symbols into '_' when generating event names */ 569 static inline void sanitize_event_name(char *name) 570 { 571 while (*name++ != '\0') 572 if (*name == ':' || *name == '.') 573 *name = '_'; 574 } 575 576 static int trace_kprobe_create(int argc, const char *argv[]) 577 { 578 /* 579 * Argument syntax: 580 * - Add kprobe: 581 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] 582 * - Add kretprobe: 583 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] 584 * Fetch args: 585 * $retval : fetch return value 586 * $stack : fetch stack address 587 * $stackN : fetch Nth of stack (N:0-) 588 * $comm : fetch current task comm 589 * @ADDR : fetch memory at ADDR (ADDR should be in kernel) 590 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) 591 * %REG : fetch register REG 592 * Dereferencing memory fetch: 593 * +|-offs(ARG) : fetch memory at ARG +|- offs address. 594 * Alias name of args: 595 * NAME=FETCHARG : set NAME as alias of FETCHARG. 596 * Type of args: 597 * FETCHARG:TYPE : use TYPE instead of unsigned long. 598 */ 599 struct trace_kprobe *tk; 600 int i, len, ret = 0; 601 bool is_return = false; 602 char *symbol = NULL, *tmp = NULL; 603 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM; 604 int maxactive = 0; 605 long offset = 0; 606 void *addr = NULL; 607 char buf[MAX_EVENT_NAME_LEN]; 608 unsigned int flags = TPARG_FL_KERNEL; 609 610 switch (argv[0][0]) { 611 case 'r': 612 is_return = true; 613 flags |= TPARG_FL_RETURN; 614 break; 615 case 'p': 616 break; 617 default: 618 return -ECANCELED; 619 } 620 if (argc < 2) 621 return -ECANCELED; 622 623 event = strchr(&argv[0][1], ':'); 624 if (event) 625 event++; 626 627 if (is_return && isdigit(argv[0][1])) { 628 if (event) 629 len = event - &argv[0][1] - 1; 630 else 631 len = strlen(&argv[0][1]); 632 if (len > MAX_EVENT_NAME_LEN - 1) 633 return -E2BIG; 634 memcpy(buf, &argv[0][1], len); 635 buf[len] = '\0'; 636 ret = kstrtouint(buf, 0, &maxactive); 637 if (ret) { 638 pr_info("Failed to parse maxactive.\n"); 639 return ret; 640 } 641 /* kretprobes instances are iterated over via a list. The 642 * maximum should stay reasonable. 643 */ 644 if (maxactive > KRETPROBE_MAXACTIVE_MAX) { 645 pr_info("Maxactive is too big (%d > %d).\n", 646 maxactive, KRETPROBE_MAXACTIVE_MAX); 647 return -E2BIG; 648 } 649 } 650 651 /* try to parse an address. if that fails, try to read the 652 * input as a symbol. */ 653 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { 654 /* Check whether uprobe event specified */ 655 if (strchr(argv[1], '/') && strchr(argv[1], ':')) 656 return -ECANCELED; 657 /* a symbol specified */ 658 symbol = kstrdup(argv[1], GFP_KERNEL); 659 if (!symbol) 660 return -ENOMEM; 661 /* TODO: support .init module functions */ 662 ret = traceprobe_split_symbol_offset(symbol, &offset); 663 if (ret || offset < 0 || offset > UINT_MAX) { 664 pr_info("Failed to parse either an address or a symbol.\n"); 665 goto out; 666 } 667 if (kprobe_on_func_entry(NULL, symbol, offset)) 668 flags |= TPARG_FL_FENTRY; 669 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { 670 pr_info("Given offset is not valid for return probe.\n"); 671 ret = -EINVAL; 672 goto out; 673 } 674 } 675 argc -= 2; argv += 2; 676 677 if (event) { 678 ret = traceprobe_parse_event_name(&event, &group, buf); 679 if (ret) 680 goto out; 681 } else { 682 /* Make a new event name */ 683 if (symbol) 684 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", 685 is_return ? 'r' : 'p', symbol, offset); 686 else 687 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", 688 is_return ? 'r' : 'p', addr); 689 sanitize_event_name(buf); 690 event = buf; 691 } 692 693 /* setup a probe */ 694 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, 695 argc, is_return); 696 if (IS_ERR(tk)) { 697 pr_info("Failed to allocate trace_probe.(%d)\n", 698 (int)PTR_ERR(tk)); 699 ret = PTR_ERR(tk); 700 goto out; 701 } 702 703 /* parse arguments */ 704 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 705 tmp = kstrdup(argv[i], GFP_KERNEL); 706 if (!tmp) { 707 ret = -ENOMEM; 708 goto error; 709 } 710 711 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags); 712 kfree(tmp); 713 if (ret) 714 goto error; 715 } 716 717 ret = register_trace_kprobe(tk); 718 if (ret) 719 goto error; 720 out: 721 kfree(symbol); 722 return ret; 723 724 error: 725 free_trace_kprobe(tk); 726 goto out; 727 } 728 729 static int create_or_delete_trace_kprobe(int argc, char **argv) 730 { 731 int ret; 732 733 if (argv[0][0] == '-') 734 return dyn_event_release(argc, argv, &trace_kprobe_ops); 735 736 ret = trace_kprobe_create(argc, (const char **)argv); 737 return ret == -ECANCELED ? -EINVAL : ret; 738 } 739 740 static int trace_kprobe_release(struct dyn_event *ev) 741 { 742 struct trace_kprobe *tk = to_trace_kprobe(ev); 743 int ret = unregister_trace_kprobe(tk); 744 745 if (!ret) 746 free_trace_kprobe(tk); 747 return ret; 748 } 749 750 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) 751 { 752 struct trace_kprobe *tk = to_trace_kprobe(ev); 753 int i; 754 755 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 756 seq_printf(m, ":%s/%s", tk->tp.call.class->system, 757 trace_event_name(&tk->tp.call)); 758 759 if (!tk->symbol) 760 seq_printf(m, " 0x%p", tk->rp.kp.addr); 761 else if (tk->rp.kp.offset) 762 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 763 tk->rp.kp.offset); 764 else 765 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 766 767 for (i = 0; i < tk->tp.nr_args; i++) 768 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 769 seq_putc(m, '\n'); 770 771 return 0; 772 } 773 774 static int probes_seq_show(struct seq_file *m, void *v) 775 { 776 struct dyn_event *ev = v; 777 778 if (!is_trace_kprobe(ev)) 779 return 0; 780 781 return trace_kprobe_show(m, ev); 782 } 783 784 static const struct seq_operations probes_seq_op = { 785 .start = dyn_event_seq_start, 786 .next = dyn_event_seq_next, 787 .stop = dyn_event_seq_stop, 788 .show = probes_seq_show 789 }; 790 791 static int probes_open(struct inode *inode, struct file *file) 792 { 793 int ret; 794 795 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 796 ret = dyn_events_release_all(&trace_kprobe_ops); 797 if (ret < 0) 798 return ret; 799 } 800 801 return seq_open(file, &probes_seq_op); 802 } 803 804 static ssize_t probes_write(struct file *file, const char __user *buffer, 805 size_t count, loff_t *ppos) 806 { 807 return trace_parse_run_command(file, buffer, count, ppos, 808 create_or_delete_trace_kprobe); 809 } 810 811 static const struct file_operations kprobe_events_ops = { 812 .owner = THIS_MODULE, 813 .open = probes_open, 814 .read = seq_read, 815 .llseek = seq_lseek, 816 .release = seq_release, 817 .write = probes_write, 818 }; 819 820 /* Probes profiling interfaces */ 821 static int probes_profile_seq_show(struct seq_file *m, void *v) 822 { 823 struct dyn_event *ev = v; 824 struct trace_kprobe *tk; 825 826 if (!is_trace_kprobe(ev)) 827 return 0; 828 829 tk = to_trace_kprobe(ev); 830 seq_printf(m, " %-44s %15lu %15lu\n", 831 trace_event_name(&tk->tp.call), 832 trace_kprobe_nhit(tk), 833 tk->rp.kp.nmissed); 834 835 return 0; 836 } 837 838 static const struct seq_operations profile_seq_op = { 839 .start = dyn_event_seq_start, 840 .next = dyn_event_seq_next, 841 .stop = dyn_event_seq_stop, 842 .show = probes_profile_seq_show 843 }; 844 845 static int profile_open(struct inode *inode, struct file *file) 846 { 847 return seq_open(file, &profile_seq_op); 848 } 849 850 static const struct file_operations kprobe_profile_ops = { 851 .owner = THIS_MODULE, 852 .open = profile_open, 853 .read = seq_read, 854 .llseek = seq_lseek, 855 .release = seq_release, 856 }; 857 858 /* Kprobe specific fetch functions */ 859 860 /* Return the length of string -- including null terminal byte */ 861 static nokprobe_inline int 862 fetch_store_strlen(unsigned long addr) 863 { 864 mm_segment_t old_fs; 865 int ret, len = 0; 866 u8 c; 867 868 old_fs = get_fs(); 869 set_fs(KERNEL_DS); 870 pagefault_disable(); 871 872 do { 873 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1); 874 len++; 875 } while (c && ret == 0 && len < MAX_STRING_SIZE); 876 877 pagefault_enable(); 878 set_fs(old_fs); 879 880 return (ret < 0) ? ret : len; 881 } 882 883 /* 884 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max 885 * length and relative data location. 886 */ 887 static nokprobe_inline int 888 fetch_store_string(unsigned long addr, void *dest, void *base) 889 { 890 int maxlen = get_loc_len(*(u32 *)dest); 891 u8 *dst = get_loc_data(dest, base); 892 long ret; 893 894 if (unlikely(!maxlen)) 895 return -ENOMEM; 896 /* 897 * Try to get string again, since the string can be changed while 898 * probing. 899 */ 900 ret = strncpy_from_unsafe(dst, (void *)addr, maxlen); 901 902 if (ret >= 0) 903 *(u32 *)dest = make_data_loc(ret, (void *)dst - base); 904 return ret; 905 } 906 907 static nokprobe_inline int 908 probe_mem_read(void *dest, void *src, size_t size) 909 { 910 return probe_kernel_read(dest, src, size); 911 } 912 913 /* Note that we don't verify it, since the code does not come from user space */ 914 static int 915 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 916 void *base) 917 { 918 unsigned long val; 919 920 retry: 921 /* 1st stage: get value from context */ 922 switch (code->op) { 923 case FETCH_OP_REG: 924 val = regs_get_register(regs, code->param); 925 break; 926 case FETCH_OP_STACK: 927 val = regs_get_kernel_stack_nth(regs, code->param); 928 break; 929 case FETCH_OP_STACKP: 930 val = kernel_stack_pointer(regs); 931 break; 932 case FETCH_OP_RETVAL: 933 val = regs_return_value(regs); 934 break; 935 case FETCH_OP_IMM: 936 val = code->immediate; 937 break; 938 case FETCH_OP_COMM: 939 val = (unsigned long)current->comm; 940 break; 941 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 942 case FETCH_OP_ARG: 943 val = regs_get_kernel_argument(regs, code->param); 944 break; 945 #endif 946 case FETCH_NOP_SYMBOL: /* Ignore a place holder */ 947 code++; 948 goto retry; 949 default: 950 return -EILSEQ; 951 } 952 code++; 953 954 return process_fetch_insn_bottom(code, val, dest, base); 955 } 956 NOKPROBE_SYMBOL(process_fetch_insn) 957 958 /* Kprobe handler */ 959 static nokprobe_inline void 960 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 961 struct trace_event_file *trace_file) 962 { 963 struct kprobe_trace_entry_head *entry; 964 struct ring_buffer_event *event; 965 struct ring_buffer *buffer; 966 int size, dsize, pc; 967 unsigned long irq_flags; 968 struct trace_event_call *call = &tk->tp.call; 969 970 WARN_ON(call != trace_file->event_call); 971 972 if (trace_trigger_soft_disabled(trace_file)) 973 return; 974 975 local_save_flags(irq_flags); 976 pc = preempt_count(); 977 978 dsize = __get_data_size(&tk->tp, regs); 979 size = sizeof(*entry) + tk->tp.size + dsize; 980 981 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 982 call->event.type, 983 size, irq_flags, pc); 984 if (!event) 985 return; 986 987 entry = ring_buffer_event_data(event); 988 entry->ip = (unsigned long)tk->rp.kp.addr; 989 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 990 991 event_trigger_unlock_commit_regs(trace_file, buffer, event, 992 entry, irq_flags, pc, regs); 993 } 994 995 static void 996 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 997 { 998 struct event_file_link *link; 999 1000 list_for_each_entry_rcu(link, &tk->tp.files, list) 1001 __kprobe_trace_func(tk, regs, link->file); 1002 } 1003 NOKPROBE_SYMBOL(kprobe_trace_func); 1004 1005 /* Kretprobe handler */ 1006 static nokprobe_inline void 1007 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1008 struct pt_regs *regs, 1009 struct trace_event_file *trace_file) 1010 { 1011 struct kretprobe_trace_entry_head *entry; 1012 struct ring_buffer_event *event; 1013 struct ring_buffer *buffer; 1014 int size, pc, dsize; 1015 unsigned long irq_flags; 1016 struct trace_event_call *call = &tk->tp.call; 1017 1018 WARN_ON(call != trace_file->event_call); 1019 1020 if (trace_trigger_soft_disabled(trace_file)) 1021 return; 1022 1023 local_save_flags(irq_flags); 1024 pc = preempt_count(); 1025 1026 dsize = __get_data_size(&tk->tp, regs); 1027 size = sizeof(*entry) + tk->tp.size + dsize; 1028 1029 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 1030 call->event.type, 1031 size, irq_flags, pc); 1032 if (!event) 1033 return; 1034 1035 entry = ring_buffer_event_data(event); 1036 entry->func = (unsigned long)tk->rp.kp.addr; 1037 entry->ret_ip = (unsigned long)ri->ret_addr; 1038 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1039 1040 event_trigger_unlock_commit_regs(trace_file, buffer, event, 1041 entry, irq_flags, pc, regs); 1042 } 1043 1044 static void 1045 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1046 struct pt_regs *regs) 1047 { 1048 struct event_file_link *link; 1049 1050 list_for_each_entry_rcu(link, &tk->tp.files, list) 1051 __kretprobe_trace_func(tk, ri, regs, link->file); 1052 } 1053 NOKPROBE_SYMBOL(kretprobe_trace_func); 1054 1055 /* Event entry printers */ 1056 static enum print_line_t 1057 print_kprobe_event(struct trace_iterator *iter, int flags, 1058 struct trace_event *event) 1059 { 1060 struct kprobe_trace_entry_head *field; 1061 struct trace_seq *s = &iter->seq; 1062 struct trace_probe *tp; 1063 1064 field = (struct kprobe_trace_entry_head *)iter->ent; 1065 tp = container_of(event, struct trace_probe, call.event); 1066 1067 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call)); 1068 1069 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) 1070 goto out; 1071 1072 trace_seq_putc(s, ')'); 1073 1074 if (print_probe_args(s, tp->args, tp->nr_args, 1075 (u8 *)&field[1], field) < 0) 1076 goto out; 1077 1078 trace_seq_putc(s, '\n'); 1079 out: 1080 return trace_handle_return(s); 1081 } 1082 1083 static enum print_line_t 1084 print_kretprobe_event(struct trace_iterator *iter, int flags, 1085 struct trace_event *event) 1086 { 1087 struct kretprobe_trace_entry_head *field; 1088 struct trace_seq *s = &iter->seq; 1089 struct trace_probe *tp; 1090 1091 field = (struct kretprobe_trace_entry_head *)iter->ent; 1092 tp = container_of(event, struct trace_probe, call.event); 1093 1094 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call)); 1095 1096 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) 1097 goto out; 1098 1099 trace_seq_puts(s, " <- "); 1100 1101 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) 1102 goto out; 1103 1104 trace_seq_putc(s, ')'); 1105 1106 if (print_probe_args(s, tp->args, tp->nr_args, 1107 (u8 *)&field[1], field) < 0) 1108 goto out; 1109 1110 trace_seq_putc(s, '\n'); 1111 1112 out: 1113 return trace_handle_return(s); 1114 } 1115 1116 1117 static int kprobe_event_define_fields(struct trace_event_call *event_call) 1118 { 1119 int ret; 1120 struct kprobe_trace_entry_head field; 1121 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data; 1122 1123 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1124 1125 return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp); 1126 } 1127 1128 static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1129 { 1130 int ret; 1131 struct kretprobe_trace_entry_head field; 1132 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data; 1133 1134 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1135 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1136 1137 return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp); 1138 } 1139 1140 #ifdef CONFIG_PERF_EVENTS 1141 1142 /* Kprobe profile handler */ 1143 static int 1144 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1145 { 1146 struct trace_event_call *call = &tk->tp.call; 1147 struct kprobe_trace_entry_head *entry; 1148 struct hlist_head *head; 1149 int size, __size, dsize; 1150 int rctx; 1151 1152 if (bpf_prog_array_valid(call)) { 1153 unsigned long orig_ip = instruction_pointer(regs); 1154 int ret; 1155 1156 ret = trace_call_bpf(call, regs); 1157 1158 /* 1159 * We need to check and see if we modified the pc of the 1160 * pt_regs, and if so return 1 so that we don't do the 1161 * single stepping. 1162 */ 1163 if (orig_ip != instruction_pointer(regs)) 1164 return 1; 1165 if (!ret) 1166 return 0; 1167 } 1168 1169 head = this_cpu_ptr(call->perf_events); 1170 if (hlist_empty(head)) 1171 return 0; 1172 1173 dsize = __get_data_size(&tk->tp, regs); 1174 __size = sizeof(*entry) + tk->tp.size + dsize; 1175 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1176 size -= sizeof(u32); 1177 1178 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1179 if (!entry) 1180 return 0; 1181 1182 entry->ip = (unsigned long)tk->rp.kp.addr; 1183 memset(&entry[1], 0, dsize); 1184 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1185 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1186 head, NULL); 1187 return 0; 1188 } 1189 NOKPROBE_SYMBOL(kprobe_perf_func); 1190 1191 /* Kretprobe profile handler */ 1192 static void 1193 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1194 struct pt_regs *regs) 1195 { 1196 struct trace_event_call *call = &tk->tp.call; 1197 struct kretprobe_trace_entry_head *entry; 1198 struct hlist_head *head; 1199 int size, __size, dsize; 1200 int rctx; 1201 1202 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1203 return; 1204 1205 head = this_cpu_ptr(call->perf_events); 1206 if (hlist_empty(head)) 1207 return; 1208 1209 dsize = __get_data_size(&tk->tp, regs); 1210 __size = sizeof(*entry) + tk->tp.size + dsize; 1211 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1212 size -= sizeof(u32); 1213 1214 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1215 if (!entry) 1216 return; 1217 1218 entry->func = (unsigned long)tk->rp.kp.addr; 1219 entry->ret_ip = (unsigned long)ri->ret_addr; 1220 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1221 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1222 head, NULL); 1223 } 1224 NOKPROBE_SYMBOL(kretprobe_perf_func); 1225 1226 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, 1227 const char **symbol, u64 *probe_offset, 1228 u64 *probe_addr, bool perf_type_tracepoint) 1229 { 1230 const char *pevent = trace_event_name(event->tp_event); 1231 const char *group = event->tp_event->class->system; 1232 struct trace_kprobe *tk; 1233 1234 if (perf_type_tracepoint) 1235 tk = find_trace_kprobe(pevent, group); 1236 else 1237 tk = event->tp_event->data; 1238 if (!tk) 1239 return -EINVAL; 1240 1241 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE 1242 : BPF_FD_TYPE_KPROBE; 1243 if (tk->symbol) { 1244 *symbol = tk->symbol; 1245 *probe_offset = tk->rp.kp.offset; 1246 *probe_addr = 0; 1247 } else { 1248 *symbol = NULL; 1249 *probe_offset = 0; 1250 *probe_addr = (unsigned long)tk->rp.kp.addr; 1251 } 1252 return 0; 1253 } 1254 #endif /* CONFIG_PERF_EVENTS */ 1255 1256 /* 1257 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1258 * 1259 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1260 * lockless, but we can't race with this __init function. 1261 */ 1262 static int kprobe_register(struct trace_event_call *event, 1263 enum trace_reg type, void *data) 1264 { 1265 struct trace_kprobe *tk = (struct trace_kprobe *)event->data; 1266 struct trace_event_file *file = data; 1267 1268 switch (type) { 1269 case TRACE_REG_REGISTER: 1270 return enable_trace_kprobe(tk, file); 1271 case TRACE_REG_UNREGISTER: 1272 return disable_trace_kprobe(tk, file); 1273 1274 #ifdef CONFIG_PERF_EVENTS 1275 case TRACE_REG_PERF_REGISTER: 1276 return enable_trace_kprobe(tk, NULL); 1277 case TRACE_REG_PERF_UNREGISTER: 1278 return disable_trace_kprobe(tk, NULL); 1279 case TRACE_REG_PERF_OPEN: 1280 case TRACE_REG_PERF_CLOSE: 1281 case TRACE_REG_PERF_ADD: 1282 case TRACE_REG_PERF_DEL: 1283 return 0; 1284 #endif 1285 } 1286 return 0; 1287 } 1288 1289 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1290 { 1291 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1292 int ret = 0; 1293 1294 raw_cpu_inc(*tk->nhit); 1295 1296 if (tk->tp.flags & TP_FLAG_TRACE) 1297 kprobe_trace_func(tk, regs); 1298 #ifdef CONFIG_PERF_EVENTS 1299 if (tk->tp.flags & TP_FLAG_PROFILE) 1300 ret = kprobe_perf_func(tk, regs); 1301 #endif 1302 return ret; 1303 } 1304 NOKPROBE_SYMBOL(kprobe_dispatcher); 1305 1306 static int 1307 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1308 { 1309 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp); 1310 1311 raw_cpu_inc(*tk->nhit); 1312 1313 if (tk->tp.flags & TP_FLAG_TRACE) 1314 kretprobe_trace_func(tk, ri, regs); 1315 #ifdef CONFIG_PERF_EVENTS 1316 if (tk->tp.flags & TP_FLAG_PROFILE) 1317 kretprobe_perf_func(tk, ri, regs); 1318 #endif 1319 return 0; /* We don't tweek kernel, so just return 0 */ 1320 } 1321 NOKPROBE_SYMBOL(kretprobe_dispatcher); 1322 1323 static struct trace_event_functions kretprobe_funcs = { 1324 .trace = print_kretprobe_event 1325 }; 1326 1327 static struct trace_event_functions kprobe_funcs = { 1328 .trace = print_kprobe_event 1329 }; 1330 1331 static inline void init_trace_event_call(struct trace_kprobe *tk, 1332 struct trace_event_call *call) 1333 { 1334 INIT_LIST_HEAD(&call->class->fields); 1335 if (trace_kprobe_is_return(tk)) { 1336 call->event.funcs = &kretprobe_funcs; 1337 call->class->define_fields = kretprobe_event_define_fields; 1338 } else { 1339 call->event.funcs = &kprobe_funcs; 1340 call->class->define_fields = kprobe_event_define_fields; 1341 } 1342 1343 call->flags = TRACE_EVENT_FL_KPROBE; 1344 call->class->reg = kprobe_register; 1345 call->data = tk; 1346 } 1347 1348 static int register_kprobe_event(struct trace_kprobe *tk) 1349 { 1350 struct trace_event_call *call = &tk->tp.call; 1351 int ret = 0; 1352 1353 init_trace_event_call(tk, call); 1354 1355 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) 1356 return -ENOMEM; 1357 ret = register_trace_event(&call->event); 1358 if (!ret) { 1359 kfree(call->print_fmt); 1360 return -ENODEV; 1361 } 1362 ret = trace_add_event_call(call); 1363 if (ret) { 1364 pr_info("Failed to register kprobe event: %s\n", 1365 trace_event_name(call)); 1366 kfree(call->print_fmt); 1367 unregister_trace_event(&call->event); 1368 } 1369 return ret; 1370 } 1371 1372 static int unregister_kprobe_event(struct trace_kprobe *tk) 1373 { 1374 int ret; 1375 1376 /* tp->event is unregistered in trace_remove_event_call() */ 1377 ret = trace_remove_event_call(&tk->tp.call); 1378 if (!ret) 1379 kfree(tk->tp.call.print_fmt); 1380 return ret; 1381 } 1382 1383 #ifdef CONFIG_PERF_EVENTS 1384 /* create a trace_kprobe, but don't add it to global lists */ 1385 struct trace_event_call * 1386 create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 1387 bool is_return) 1388 { 1389 struct trace_kprobe *tk; 1390 int ret; 1391 char *event; 1392 1393 /* 1394 * local trace_kprobes are not added to dyn_event, so they are never 1395 * searched in find_trace_kprobe(). Therefore, there is no concern of 1396 * duplicated name here. 1397 */ 1398 event = func ? func : "DUMMY_EVENT"; 1399 1400 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, 1401 offs, 0 /* maxactive */, 0 /* nargs */, 1402 is_return); 1403 1404 if (IS_ERR(tk)) { 1405 pr_info("Failed to allocate trace_probe.(%d)\n", 1406 (int)PTR_ERR(tk)); 1407 return ERR_CAST(tk); 1408 } 1409 1410 init_trace_event_call(tk, &tk->tp.call); 1411 1412 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) { 1413 ret = -ENOMEM; 1414 goto error; 1415 } 1416 1417 ret = __register_trace_kprobe(tk); 1418 if (ret < 0) { 1419 kfree(tk->tp.call.print_fmt); 1420 goto error; 1421 } 1422 1423 return &tk->tp.call; 1424 error: 1425 free_trace_kprobe(tk); 1426 return ERR_PTR(ret); 1427 } 1428 1429 void destroy_local_trace_kprobe(struct trace_event_call *event_call) 1430 { 1431 struct trace_kprobe *tk; 1432 1433 tk = container_of(event_call, struct trace_kprobe, tp.call); 1434 1435 if (trace_probe_is_enabled(&tk->tp)) { 1436 WARN_ON(1); 1437 return; 1438 } 1439 1440 __unregister_trace_kprobe(tk); 1441 1442 kfree(tk->tp.call.print_fmt); 1443 free_trace_kprobe(tk); 1444 } 1445 #endif /* CONFIG_PERF_EVENTS */ 1446 1447 /* Make a tracefs interface for controlling probe points */ 1448 static __init int init_kprobe_trace(void) 1449 { 1450 struct dentry *d_tracer; 1451 struct dentry *entry; 1452 int ret; 1453 1454 ret = dyn_event_register(&trace_kprobe_ops); 1455 if (ret) 1456 return ret; 1457 1458 if (register_module_notifier(&trace_kprobe_module_nb)) 1459 return -EINVAL; 1460 1461 d_tracer = tracing_init_dentry(); 1462 if (IS_ERR(d_tracer)) 1463 return 0; 1464 1465 entry = tracefs_create_file("kprobe_events", 0644, d_tracer, 1466 NULL, &kprobe_events_ops); 1467 1468 /* Event list interface */ 1469 if (!entry) 1470 pr_warn("Could not create tracefs 'kprobe_events' entry\n"); 1471 1472 /* Profile interface */ 1473 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer, 1474 NULL, &kprobe_profile_ops); 1475 1476 if (!entry) 1477 pr_warn("Could not create tracefs 'kprobe_profile' entry\n"); 1478 return 0; 1479 } 1480 fs_initcall(init_kprobe_trace); 1481 1482 1483 #ifdef CONFIG_FTRACE_STARTUP_TEST 1484 static __init struct trace_event_file * 1485 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 1486 { 1487 struct trace_event_file *file; 1488 1489 list_for_each_entry(file, &tr->events, list) 1490 if (file->event_call == &tk->tp.call) 1491 return file; 1492 1493 return NULL; 1494 } 1495 1496 /* 1497 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 1498 * stage, we can do this lockless. 1499 */ 1500 static __init int kprobe_trace_self_tests_init(void) 1501 { 1502 int ret, warn = 0; 1503 int (*target)(int, int, int, int, int, int); 1504 struct trace_kprobe *tk; 1505 struct trace_event_file *file; 1506 1507 if (tracing_is_disabled()) 1508 return -ENODEV; 1509 1510 target = kprobe_trace_selftest_target; 1511 1512 pr_info("Testing kprobe tracing: "); 1513 1514 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)", 1515 create_or_delete_trace_kprobe); 1516 if (WARN_ON_ONCE(ret)) { 1517 pr_warn("error on probing function entry.\n"); 1518 warn++; 1519 } else { 1520 /* Enable trace point */ 1521 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1522 if (WARN_ON_ONCE(tk == NULL)) { 1523 pr_warn("error on getting new probe.\n"); 1524 warn++; 1525 } else { 1526 file = find_trace_probe_file(tk, top_trace_array()); 1527 if (WARN_ON_ONCE(file == NULL)) { 1528 pr_warn("error on getting probe file.\n"); 1529 warn++; 1530 } else 1531 enable_trace_kprobe(tk, file); 1532 } 1533 } 1534 1535 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval", 1536 create_or_delete_trace_kprobe); 1537 if (WARN_ON_ONCE(ret)) { 1538 pr_warn("error on probing function return.\n"); 1539 warn++; 1540 } else { 1541 /* Enable trace point */ 1542 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1543 if (WARN_ON_ONCE(tk == NULL)) { 1544 pr_warn("error on getting 2nd new probe.\n"); 1545 warn++; 1546 } else { 1547 file = find_trace_probe_file(tk, top_trace_array()); 1548 if (WARN_ON_ONCE(file == NULL)) { 1549 pr_warn("error on getting probe file.\n"); 1550 warn++; 1551 } else 1552 enable_trace_kprobe(tk, file); 1553 } 1554 } 1555 1556 if (warn) 1557 goto end; 1558 1559 ret = target(1, 2, 3, 4, 5, 6); 1560 1561 /* 1562 * Not expecting an error here, the check is only to prevent the 1563 * optimizer from removing the call to target() as otherwise there 1564 * are no side-effects and the call is never performed. 1565 */ 1566 if (ret != 21) 1567 warn++; 1568 1569 /* Disable trace points before removing it */ 1570 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1571 if (WARN_ON_ONCE(tk == NULL)) { 1572 pr_warn("error on getting test probe.\n"); 1573 warn++; 1574 } else { 1575 if (trace_kprobe_nhit(tk) != 1) { 1576 pr_warn("incorrect number of testprobe hits\n"); 1577 warn++; 1578 } 1579 1580 file = find_trace_probe_file(tk, top_trace_array()); 1581 if (WARN_ON_ONCE(file == NULL)) { 1582 pr_warn("error on getting probe file.\n"); 1583 warn++; 1584 } else 1585 disable_trace_kprobe(tk, file); 1586 } 1587 1588 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1589 if (WARN_ON_ONCE(tk == NULL)) { 1590 pr_warn("error on getting 2nd test probe.\n"); 1591 warn++; 1592 } else { 1593 if (trace_kprobe_nhit(tk) != 1) { 1594 pr_warn("incorrect number of testprobe2 hits\n"); 1595 warn++; 1596 } 1597 1598 file = find_trace_probe_file(tk, top_trace_array()); 1599 if (WARN_ON_ONCE(file == NULL)) { 1600 pr_warn("error on getting probe file.\n"); 1601 warn++; 1602 } else 1603 disable_trace_kprobe(tk, file); 1604 } 1605 1606 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe); 1607 if (WARN_ON_ONCE(ret)) { 1608 pr_warn("error on deleting a probe.\n"); 1609 warn++; 1610 } 1611 1612 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe); 1613 if (WARN_ON_ONCE(ret)) { 1614 pr_warn("error on deleting a probe.\n"); 1615 warn++; 1616 } 1617 1618 end: 1619 ret = dyn_events_release_all(&trace_kprobe_ops); 1620 if (WARN_ON_ONCE(ret)) { 1621 pr_warn("error on cleaning up probes.\n"); 1622 warn++; 1623 } 1624 /* 1625 * Wait for the optimizer work to finish. Otherwise it might fiddle 1626 * with probes in already freed __init text. 1627 */ 1628 wait_for_kprobe_optimizer(); 1629 if (warn) 1630 pr_cont("NG: Some tests are failed. Please check them.\n"); 1631 else 1632 pr_cont("OK\n"); 1633 return 0; 1634 } 1635 1636 late_initcall(kprobe_trace_self_tests_init); 1637 1638 #endif 1639