1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * uprobes-based tracing events 4 * 5 * Copyright (C) IBM Corporation, 2010-2012 6 * Author: Srikar Dronamraju <srikar@linux.vnet.ibm.com> 7 */ 8 #define pr_fmt(fmt) "trace_uprobe: " fmt 9 10 #include <linux/ctype.h> 11 #include <linux/module.h> 12 #include <linux/uaccess.h> 13 #include <linux/uprobes.h> 14 #include <linux/namei.h> 15 #include <linux/string.h> 16 #include <linux/rculist.h> 17 18 #include "trace_dynevent.h" 19 #include "trace_probe.h" 20 #include "trace_probe_tmpl.h" 21 22 #define UPROBE_EVENT_SYSTEM "uprobes" 23 24 struct uprobe_trace_entry_head { 25 struct trace_entry ent; 26 unsigned long vaddr[]; 27 }; 28 29 #define SIZEOF_TRACE_ENTRY(is_return) \ 30 (sizeof(struct uprobe_trace_entry_head) + \ 31 sizeof(unsigned long) * (is_return ? 2 : 1)) 32 33 #define DATAOF_TRACE_ENTRY(entry, is_return) \ 34 ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return)) 35 36 struct trace_uprobe_filter { 37 rwlock_t rwlock; 38 int nr_systemwide; 39 struct list_head perf_events; 40 }; 41 42 static int trace_uprobe_create(int argc, const char **argv); 43 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev); 44 static int trace_uprobe_release(struct dyn_event *ev); 45 static bool trace_uprobe_is_busy(struct dyn_event *ev); 46 static bool trace_uprobe_match(const char *system, const char *event, 47 struct dyn_event *ev); 48 49 static struct dyn_event_operations trace_uprobe_ops = { 50 .create = trace_uprobe_create, 51 .show = trace_uprobe_show, 52 .is_busy = trace_uprobe_is_busy, 53 .free = trace_uprobe_release, 54 .match = trace_uprobe_match, 55 }; 56 57 /* 58 * uprobe event core functions 59 */ 60 struct trace_uprobe { 61 struct dyn_event devent; 62 struct trace_uprobe_filter filter; 63 struct uprobe_consumer consumer; 64 struct path path; 65 struct inode *inode; 66 char *filename; 67 unsigned long offset; 68 unsigned long ref_ctr_offset; 69 unsigned long nhit; 70 struct trace_probe tp; 71 }; 72 73 static bool is_trace_uprobe(struct dyn_event *ev) 74 { 75 return ev->ops == &trace_uprobe_ops; 76 } 77 78 static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev) 79 { 80 return container_of(ev, struct trace_uprobe, devent); 81 } 82 83 /** 84 * for_each_trace_uprobe - iterate over the trace_uprobe list 85 * @pos: the struct trace_uprobe * for each entry 86 * @dpos: the struct dyn_event * to use as a loop cursor 87 */ 88 #define for_each_trace_uprobe(pos, dpos) \ 89 for_each_dyn_event(dpos) \ 90 if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos))) 91 92 #define SIZEOF_TRACE_UPROBE(n) \ 93 (offsetof(struct trace_uprobe, tp.args) + \ 94 (sizeof(struct probe_arg) * (n))) 95 96 static int register_uprobe_event(struct trace_uprobe *tu); 97 static int unregister_uprobe_event(struct trace_uprobe *tu); 98 99 struct uprobe_dispatch_data { 100 struct trace_uprobe *tu; 101 unsigned long bp_addr; 102 }; 103 104 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs); 105 static int uretprobe_dispatcher(struct uprobe_consumer *con, 106 unsigned long func, struct pt_regs *regs); 107 108 #ifdef CONFIG_STACK_GROWSUP 109 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 110 { 111 return addr - (n * sizeof(long)); 112 } 113 #else 114 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n) 115 { 116 return addr + (n * sizeof(long)); 117 } 118 #endif 119 120 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) 121 { 122 unsigned long ret; 123 unsigned long addr = user_stack_pointer(regs); 124 125 addr = adjust_stack_addr(addr, n); 126 127 if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret))) 128 return 0; 129 130 return ret; 131 } 132 133 /* 134 * Uprobes-specific fetch functions 135 */ 136 static nokprobe_inline int 137 probe_mem_read(void *dest, void *src, size_t size) 138 { 139 void __user *vaddr = (void __force __user *)src; 140 141 return copy_from_user(dest, vaddr, size) ? -EFAULT : 0; 142 } 143 /* 144 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max 145 * length and relative data location. 146 */ 147 static nokprobe_inline int 148 fetch_store_string(unsigned long addr, void *dest, void *base) 149 { 150 long ret; 151 u32 loc = *(u32 *)dest; 152 int maxlen = get_loc_len(loc); 153 u8 *dst = get_loc_data(dest, base); 154 void __user *src = (void __force __user *) addr; 155 156 if (unlikely(!maxlen)) 157 return -ENOMEM; 158 159 if (addr == FETCH_TOKEN_COMM) 160 ret = strlcpy(dst, current->comm, maxlen); 161 else 162 ret = strncpy_from_user(dst, src, maxlen); 163 if (ret >= 0) { 164 if (ret == maxlen) 165 dst[ret - 1] = '\0'; 166 else 167 /* 168 * Include the terminating null byte. In this case it 169 * was copied by strncpy_from_user but not accounted 170 * for in ret. 171 */ 172 ret++; 173 *(u32 *)dest = make_data_loc(ret, (void *)dst - base); 174 } 175 176 return ret; 177 } 178 179 /* Return the length of string -- including null terminal byte */ 180 static nokprobe_inline int 181 fetch_store_strlen(unsigned long addr) 182 { 183 int len; 184 void __user *vaddr = (void __force __user *) addr; 185 186 if (addr == FETCH_TOKEN_COMM) 187 len = strlen(current->comm) + 1; 188 else 189 len = strnlen_user(vaddr, MAX_STRING_SIZE); 190 191 return (len > MAX_STRING_SIZE) ? 0 : len; 192 } 193 194 static unsigned long translate_user_vaddr(unsigned long file_offset) 195 { 196 unsigned long base_addr; 197 struct uprobe_dispatch_data *udd; 198 199 udd = (void *) current->utask->vaddr; 200 201 base_addr = udd->bp_addr - udd->tu->offset; 202 return base_addr + file_offset; 203 } 204 205 /* Note that we don't verify it, since the code does not come from user space */ 206 static int 207 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 208 void *base) 209 { 210 unsigned long val; 211 212 /* 1st stage: get value from context */ 213 switch (code->op) { 214 case FETCH_OP_REG: 215 val = regs_get_register(regs, code->param); 216 break; 217 case FETCH_OP_STACK: 218 val = get_user_stack_nth(regs, code->param); 219 break; 220 case FETCH_OP_STACKP: 221 val = user_stack_pointer(regs); 222 break; 223 case FETCH_OP_RETVAL: 224 val = regs_return_value(regs); 225 break; 226 case FETCH_OP_IMM: 227 val = code->immediate; 228 break; 229 case FETCH_OP_COMM: 230 val = FETCH_TOKEN_COMM; 231 break; 232 case FETCH_OP_FOFFS: 233 val = translate_user_vaddr(code->immediate); 234 break; 235 default: 236 return -EILSEQ; 237 } 238 code++; 239 240 return process_fetch_insn_bottom(code, val, dest, base); 241 } 242 NOKPROBE_SYMBOL(process_fetch_insn) 243 244 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) 245 { 246 rwlock_init(&filter->rwlock); 247 filter->nr_systemwide = 0; 248 INIT_LIST_HEAD(&filter->perf_events); 249 } 250 251 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter) 252 { 253 return !filter->nr_systemwide && list_empty(&filter->perf_events); 254 } 255 256 static inline bool is_ret_probe(struct trace_uprobe *tu) 257 { 258 return tu->consumer.ret_handler != NULL; 259 } 260 261 static bool trace_uprobe_is_busy(struct dyn_event *ev) 262 { 263 struct trace_uprobe *tu = to_trace_uprobe(ev); 264 265 return trace_probe_is_enabled(&tu->tp); 266 } 267 268 static bool trace_uprobe_match(const char *system, const char *event, 269 struct dyn_event *ev) 270 { 271 struct trace_uprobe *tu = to_trace_uprobe(ev); 272 273 return strcmp(trace_event_name(&tu->tp.call), event) == 0 && 274 (!system || strcmp(tu->tp.call.class->system, system) == 0); 275 } 276 277 /* 278 * Allocate new trace_uprobe and initialize it (including uprobes). 279 */ 280 static struct trace_uprobe * 281 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) 282 { 283 struct trace_uprobe *tu; 284 285 if (!event || !group) 286 return ERR_PTR(-EINVAL); 287 288 tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL); 289 if (!tu) 290 return ERR_PTR(-ENOMEM); 291 292 tu->tp.call.class = &tu->tp.class; 293 tu->tp.call.name = kstrdup(event, GFP_KERNEL); 294 if (!tu->tp.call.name) 295 goto error; 296 297 tu->tp.class.system = kstrdup(group, GFP_KERNEL); 298 if (!tu->tp.class.system) 299 goto error; 300 301 dyn_event_init(&tu->devent, &trace_uprobe_ops); 302 INIT_LIST_HEAD(&tu->tp.files); 303 tu->consumer.handler = uprobe_dispatcher; 304 if (is_ret) 305 tu->consumer.ret_handler = uretprobe_dispatcher; 306 init_trace_uprobe_filter(&tu->filter); 307 return tu; 308 309 error: 310 kfree(tu->tp.call.name); 311 kfree(tu); 312 313 return ERR_PTR(-ENOMEM); 314 } 315 316 static void free_trace_uprobe(struct trace_uprobe *tu) 317 { 318 int i; 319 320 if (!tu) 321 return; 322 323 for (i = 0; i < tu->tp.nr_args; i++) 324 traceprobe_free_probe_arg(&tu->tp.args[i]); 325 326 path_put(&tu->path); 327 kfree(tu->tp.call.class->system); 328 kfree(tu->tp.call.name); 329 kfree(tu->filename); 330 kfree(tu); 331 } 332 333 static struct trace_uprobe *find_probe_event(const char *event, const char *group) 334 { 335 struct dyn_event *pos; 336 struct trace_uprobe *tu; 337 338 for_each_trace_uprobe(tu, pos) 339 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 && 340 strcmp(tu->tp.call.class->system, group) == 0) 341 return tu; 342 343 return NULL; 344 } 345 346 /* Unregister a trace_uprobe and probe_event */ 347 static int unregister_trace_uprobe(struct trace_uprobe *tu) 348 { 349 int ret; 350 351 ret = unregister_uprobe_event(tu); 352 if (ret) 353 return ret; 354 355 dyn_event_remove(&tu->devent); 356 free_trace_uprobe(tu); 357 return 0; 358 } 359 360 /* 361 * Uprobe with multiple reference counter is not allowed. i.e. 362 * If inode and offset matches, reference counter offset *must* 363 * match as well. Though, there is one exception: If user is 364 * replacing old trace_uprobe with new one(same group/event), 365 * then we allow same uprobe with new reference counter as far 366 * as the new one does not conflict with any other existing 367 * ones. 368 */ 369 static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new) 370 { 371 struct dyn_event *pos; 372 struct trace_uprobe *tmp, *old = NULL; 373 struct inode *new_inode = d_real_inode(new->path.dentry); 374 375 old = find_probe_event(trace_event_name(&new->tp.call), 376 new->tp.call.class->system); 377 378 for_each_trace_uprobe(tmp, pos) { 379 if ((old ? old != tmp : true) && 380 new_inode == d_real_inode(tmp->path.dentry) && 381 new->offset == tmp->offset && 382 new->ref_ctr_offset != tmp->ref_ctr_offset) { 383 pr_warn("Reference counter offset mismatch."); 384 return ERR_PTR(-EINVAL); 385 } 386 } 387 return old; 388 } 389 390 /* Register a trace_uprobe and probe_event */ 391 static int register_trace_uprobe(struct trace_uprobe *tu) 392 { 393 struct trace_uprobe *old_tu; 394 int ret; 395 396 mutex_lock(&event_mutex); 397 398 /* register as an event */ 399 old_tu = find_old_trace_uprobe(tu); 400 if (IS_ERR(old_tu)) { 401 ret = PTR_ERR(old_tu); 402 goto end; 403 } 404 405 if (old_tu) { 406 /* delete old event */ 407 ret = unregister_trace_uprobe(old_tu); 408 if (ret) 409 goto end; 410 } 411 412 ret = register_uprobe_event(tu); 413 if (ret) { 414 pr_warn("Failed to register probe event(%d)\n", ret); 415 goto end; 416 } 417 418 dyn_event_add(&tu->devent); 419 420 end: 421 mutex_unlock(&event_mutex); 422 423 return ret; 424 } 425 426 /* 427 * Argument syntax: 428 * - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS] 429 * 430 * - Remove uprobe: -:[GRP/]EVENT 431 */ 432 static int trace_uprobe_create(int argc, const char **argv) 433 { 434 struct trace_uprobe *tu; 435 const char *event = NULL, *group = UPROBE_EVENT_SYSTEM; 436 char *arg, *filename, *rctr, *rctr_end, *tmp; 437 char buf[MAX_EVENT_NAME_LEN]; 438 struct path path; 439 unsigned long offset, ref_ctr_offset; 440 bool is_return = false; 441 int i, ret; 442 443 ret = 0; 444 ref_ctr_offset = 0; 445 446 /* argc must be >= 1 */ 447 if (argv[0][0] == 'r') 448 is_return = true; 449 else if (argv[0][0] != 'p' || argc < 2) 450 return -ECANCELED; 451 452 if (argv[0][1] == ':') 453 event = &argv[0][2]; 454 455 if (!strchr(argv[1], '/')) 456 return -ECANCELED; 457 458 filename = kstrdup(argv[1], GFP_KERNEL); 459 if (!filename) 460 return -ENOMEM; 461 462 /* Find the last occurrence, in case the path contains ':' too. */ 463 arg = strrchr(filename, ':'); 464 if (!arg || !isdigit(arg[1])) { 465 kfree(filename); 466 return -ECANCELED; 467 } 468 469 trace_probe_log_init("trace_uprobe", argc, argv); 470 trace_probe_log_set_index(1); /* filename is the 2nd argument */ 471 472 *arg++ = '\0'; 473 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 474 if (ret) { 475 trace_probe_log_err(0, FILE_NOT_FOUND); 476 kfree(filename); 477 trace_probe_log_clear(); 478 return ret; 479 } 480 if (!d_is_reg(path.dentry)) { 481 trace_probe_log_err(0, NO_REGULAR_FILE); 482 ret = -EINVAL; 483 goto fail_address_parse; 484 } 485 486 /* Parse reference counter offset if specified. */ 487 rctr = strchr(arg, '('); 488 if (rctr) { 489 rctr_end = strchr(rctr, ')'); 490 if (!rctr_end) { 491 ret = -EINVAL; 492 rctr_end = rctr + strlen(rctr); 493 trace_probe_log_err(rctr_end - filename, 494 REFCNT_OPEN_BRACE); 495 goto fail_address_parse; 496 } else if (rctr_end[1] != '\0') { 497 ret = -EINVAL; 498 trace_probe_log_err(rctr_end + 1 - filename, 499 BAD_REFCNT_SUFFIX); 500 goto fail_address_parse; 501 } 502 503 *rctr++ = '\0'; 504 *rctr_end = '\0'; 505 ret = kstrtoul(rctr, 0, &ref_ctr_offset); 506 if (ret) { 507 trace_probe_log_err(rctr - filename, BAD_REFCNT); 508 goto fail_address_parse; 509 } 510 } 511 512 /* Parse uprobe offset. */ 513 ret = kstrtoul(arg, 0, &offset); 514 if (ret) { 515 trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS); 516 goto fail_address_parse; 517 } 518 519 /* setup a probe */ 520 trace_probe_log_set_index(0); 521 if (event) { 522 ret = traceprobe_parse_event_name(&event, &group, buf, 523 event - argv[0]); 524 if (ret) 525 goto fail_address_parse; 526 } else { 527 char *tail; 528 char *ptr; 529 530 tail = kstrdup(kbasename(filename), GFP_KERNEL); 531 if (!tail) { 532 ret = -ENOMEM; 533 goto fail_address_parse; 534 } 535 536 ptr = strpbrk(tail, ".-_"); 537 if (ptr) 538 *ptr = '\0'; 539 540 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 541 event = buf; 542 kfree(tail); 543 } 544 545 argc -= 2; 546 argv += 2; 547 548 tu = alloc_trace_uprobe(group, event, argc, is_return); 549 if (IS_ERR(tu)) { 550 ret = PTR_ERR(tu); 551 /* This must return -ENOMEM otherwise there is a bug */ 552 WARN_ON_ONCE(ret != -ENOMEM); 553 goto fail_address_parse; 554 } 555 tu->offset = offset; 556 tu->ref_ctr_offset = ref_ctr_offset; 557 tu->path = path; 558 tu->filename = filename; 559 560 /* parse arguments */ 561 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 562 tmp = kstrdup(argv[i], GFP_KERNEL); 563 if (!tmp) { 564 ret = -ENOMEM; 565 goto error; 566 } 567 568 trace_probe_log_set_index(i + 2); 569 ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp, 570 is_return ? TPARG_FL_RETURN : 0); 571 kfree(tmp); 572 if (ret) 573 goto error; 574 } 575 576 ret = register_trace_uprobe(tu); 577 if (!ret) 578 goto out; 579 580 error: 581 free_trace_uprobe(tu); 582 out: 583 trace_probe_log_clear(); 584 return ret; 585 586 fail_address_parse: 587 trace_probe_log_clear(); 588 path_put(&path); 589 kfree(filename); 590 591 return ret; 592 } 593 594 static int create_or_delete_trace_uprobe(int argc, char **argv) 595 { 596 int ret; 597 598 if (argv[0][0] == '-') 599 return dyn_event_release(argc, argv, &trace_uprobe_ops); 600 601 ret = trace_uprobe_create(argc, (const char **)argv); 602 return ret == -ECANCELED ? -EINVAL : ret; 603 } 604 605 static int trace_uprobe_release(struct dyn_event *ev) 606 { 607 struct trace_uprobe *tu = to_trace_uprobe(ev); 608 609 return unregister_trace_uprobe(tu); 610 } 611 612 /* Probes listing interfaces */ 613 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev) 614 { 615 struct trace_uprobe *tu = to_trace_uprobe(ev); 616 char c = is_ret_probe(tu) ? 'r' : 'p'; 617 int i; 618 619 seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system, 620 trace_event_name(&tu->tp.call), tu->filename, 621 (int)(sizeof(void *) * 2), tu->offset); 622 623 if (tu->ref_ctr_offset) 624 seq_printf(m, "(0x%lx)", tu->ref_ctr_offset); 625 626 for (i = 0; i < tu->tp.nr_args; i++) 627 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 628 629 seq_putc(m, '\n'); 630 return 0; 631 } 632 633 static int probes_seq_show(struct seq_file *m, void *v) 634 { 635 struct dyn_event *ev = v; 636 637 if (!is_trace_uprobe(ev)) 638 return 0; 639 640 return trace_uprobe_show(m, ev); 641 } 642 643 static const struct seq_operations probes_seq_op = { 644 .start = dyn_event_seq_start, 645 .next = dyn_event_seq_next, 646 .stop = dyn_event_seq_stop, 647 .show = probes_seq_show 648 }; 649 650 static int probes_open(struct inode *inode, struct file *file) 651 { 652 int ret; 653 654 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 655 ret = dyn_events_release_all(&trace_uprobe_ops); 656 if (ret) 657 return ret; 658 } 659 660 return seq_open(file, &probes_seq_op); 661 } 662 663 static ssize_t probes_write(struct file *file, const char __user *buffer, 664 size_t count, loff_t *ppos) 665 { 666 return trace_parse_run_command(file, buffer, count, ppos, 667 create_or_delete_trace_uprobe); 668 } 669 670 static const struct file_operations uprobe_events_ops = { 671 .owner = THIS_MODULE, 672 .open = probes_open, 673 .read = seq_read, 674 .llseek = seq_lseek, 675 .release = seq_release, 676 .write = probes_write, 677 }; 678 679 /* Probes profiling interfaces */ 680 static int probes_profile_seq_show(struct seq_file *m, void *v) 681 { 682 struct dyn_event *ev = v; 683 struct trace_uprobe *tu; 684 685 if (!is_trace_uprobe(ev)) 686 return 0; 687 688 tu = to_trace_uprobe(ev); 689 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 690 trace_event_name(&tu->tp.call), tu->nhit); 691 return 0; 692 } 693 694 static const struct seq_operations profile_seq_op = { 695 .start = dyn_event_seq_start, 696 .next = dyn_event_seq_next, 697 .stop = dyn_event_seq_stop, 698 .show = probes_profile_seq_show 699 }; 700 701 static int profile_open(struct inode *inode, struct file *file) 702 { 703 return seq_open(file, &profile_seq_op); 704 } 705 706 static const struct file_operations uprobe_profile_ops = { 707 .owner = THIS_MODULE, 708 .open = profile_open, 709 .read = seq_read, 710 .llseek = seq_lseek, 711 .release = seq_release, 712 }; 713 714 struct uprobe_cpu_buffer { 715 struct mutex mutex; 716 void *buf; 717 }; 718 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 719 static int uprobe_buffer_refcnt; 720 721 static int uprobe_buffer_init(void) 722 { 723 int cpu, err_cpu; 724 725 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 726 if (uprobe_cpu_buffer == NULL) 727 return -ENOMEM; 728 729 for_each_possible_cpu(cpu) { 730 struct page *p = alloc_pages_node(cpu_to_node(cpu), 731 GFP_KERNEL, 0); 732 if (p == NULL) { 733 err_cpu = cpu; 734 goto err; 735 } 736 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 737 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 738 } 739 740 return 0; 741 742 err: 743 for_each_possible_cpu(cpu) { 744 if (cpu == err_cpu) 745 break; 746 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 747 } 748 749 free_percpu(uprobe_cpu_buffer); 750 return -ENOMEM; 751 } 752 753 static int uprobe_buffer_enable(void) 754 { 755 int ret = 0; 756 757 BUG_ON(!mutex_is_locked(&event_mutex)); 758 759 if (uprobe_buffer_refcnt++ == 0) { 760 ret = uprobe_buffer_init(); 761 if (ret < 0) 762 uprobe_buffer_refcnt--; 763 } 764 765 return ret; 766 } 767 768 static void uprobe_buffer_disable(void) 769 { 770 int cpu; 771 772 BUG_ON(!mutex_is_locked(&event_mutex)); 773 774 if (--uprobe_buffer_refcnt == 0) { 775 for_each_possible_cpu(cpu) 776 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 777 cpu)->buf); 778 779 free_percpu(uprobe_cpu_buffer); 780 uprobe_cpu_buffer = NULL; 781 } 782 } 783 784 static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 785 { 786 struct uprobe_cpu_buffer *ucb; 787 int cpu; 788 789 cpu = raw_smp_processor_id(); 790 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 791 792 /* 793 * Use per-cpu buffers for fastest access, but we might migrate 794 * so the mutex makes sure we have sole access to it. 795 */ 796 mutex_lock(&ucb->mutex); 797 798 return ucb; 799 } 800 801 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 802 { 803 mutex_unlock(&ucb->mutex); 804 } 805 806 static void __uprobe_trace_func(struct trace_uprobe *tu, 807 unsigned long func, struct pt_regs *regs, 808 struct uprobe_cpu_buffer *ucb, int dsize, 809 struct trace_event_file *trace_file) 810 { 811 struct uprobe_trace_entry_head *entry; 812 struct ring_buffer_event *event; 813 struct ring_buffer *buffer; 814 void *data; 815 int size, esize; 816 struct trace_event_call *call = &tu->tp.call; 817 818 WARN_ON(call != trace_file->event_call); 819 820 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 821 return; 822 823 if (trace_trigger_soft_disabled(trace_file)) 824 return; 825 826 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 827 size = esize + tu->tp.size + dsize; 828 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 829 call->event.type, size, 0, 0); 830 if (!event) 831 return; 832 833 entry = ring_buffer_event_data(event); 834 if (is_ret_probe(tu)) { 835 entry->vaddr[0] = func; 836 entry->vaddr[1] = instruction_pointer(regs); 837 data = DATAOF_TRACE_ENTRY(entry, true); 838 } else { 839 entry->vaddr[0] = instruction_pointer(regs); 840 data = DATAOF_TRACE_ENTRY(entry, false); 841 } 842 843 memcpy(data, ucb->buf, tu->tp.size + dsize); 844 845 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); 846 } 847 848 /* uprobe handler */ 849 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 850 struct uprobe_cpu_buffer *ucb, int dsize) 851 { 852 struct event_file_link *link; 853 854 if (is_ret_probe(tu)) 855 return 0; 856 857 rcu_read_lock(); 858 list_for_each_entry_rcu(link, &tu->tp.files, list) 859 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 860 rcu_read_unlock(); 861 862 return 0; 863 } 864 865 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 866 struct pt_regs *regs, 867 struct uprobe_cpu_buffer *ucb, int dsize) 868 { 869 struct event_file_link *link; 870 871 rcu_read_lock(); 872 list_for_each_entry_rcu(link, &tu->tp.files, list) 873 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 874 rcu_read_unlock(); 875 } 876 877 /* Event entry printers */ 878 static enum print_line_t 879 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 880 { 881 struct uprobe_trace_entry_head *entry; 882 struct trace_seq *s = &iter->seq; 883 struct trace_uprobe *tu; 884 u8 *data; 885 886 entry = (struct uprobe_trace_entry_head *)iter->ent; 887 tu = container_of(event, struct trace_uprobe, tp.call.event); 888 889 if (is_ret_probe(tu)) { 890 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 891 trace_event_name(&tu->tp.call), 892 entry->vaddr[1], entry->vaddr[0]); 893 data = DATAOF_TRACE_ENTRY(entry, true); 894 } else { 895 trace_seq_printf(s, "%s: (0x%lx)", 896 trace_event_name(&tu->tp.call), 897 entry->vaddr[0]); 898 data = DATAOF_TRACE_ENTRY(entry, false); 899 } 900 901 if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0) 902 goto out; 903 904 trace_seq_putc(s, '\n'); 905 906 out: 907 return trace_handle_return(s); 908 } 909 910 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 911 enum uprobe_filter_ctx ctx, 912 struct mm_struct *mm); 913 914 static int 915 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, 916 filter_func_t filter) 917 { 918 bool enabled = trace_probe_is_enabled(&tu->tp); 919 struct event_file_link *link = NULL; 920 int ret; 921 922 if (file) { 923 if (tu->tp.flags & TP_FLAG_PROFILE) 924 return -EINTR; 925 926 link = kmalloc(sizeof(*link), GFP_KERNEL); 927 if (!link) 928 return -ENOMEM; 929 930 link->file = file; 931 list_add_tail_rcu(&link->list, &tu->tp.files); 932 933 tu->tp.flags |= TP_FLAG_TRACE; 934 } else { 935 if (tu->tp.flags & TP_FLAG_TRACE) 936 return -EINTR; 937 938 tu->tp.flags |= TP_FLAG_PROFILE; 939 } 940 941 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 942 943 if (enabled) 944 return 0; 945 946 ret = uprobe_buffer_enable(); 947 if (ret) 948 goto err_flags; 949 950 tu->consumer.filter = filter; 951 tu->inode = d_real_inode(tu->path.dentry); 952 if (tu->ref_ctr_offset) { 953 ret = uprobe_register_refctr(tu->inode, tu->offset, 954 tu->ref_ctr_offset, &tu->consumer); 955 } else { 956 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 957 } 958 959 if (ret) 960 goto err_buffer; 961 962 return 0; 963 964 err_buffer: 965 uprobe_buffer_disable(); 966 967 err_flags: 968 if (file) { 969 list_del(&link->list); 970 kfree(link); 971 tu->tp.flags &= ~TP_FLAG_TRACE; 972 } else { 973 tu->tp.flags &= ~TP_FLAG_PROFILE; 974 } 975 return ret; 976 } 977 978 static void 979 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) 980 { 981 if (!trace_probe_is_enabled(&tu->tp)) 982 return; 983 984 if (file) { 985 struct event_file_link *link; 986 987 link = find_event_file_link(&tu->tp, file); 988 if (!link) 989 return; 990 991 list_del_rcu(&link->list); 992 /* synchronize with u{,ret}probe_trace_func */ 993 synchronize_rcu(); 994 kfree(link); 995 996 if (!list_empty(&tu->tp.files)) 997 return; 998 } 999 1000 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 1001 1002 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 1003 tu->inode = NULL; 1004 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; 1005 1006 uprobe_buffer_disable(); 1007 } 1008 1009 static int uprobe_event_define_fields(struct trace_event_call *event_call) 1010 { 1011 int ret, size; 1012 struct uprobe_trace_entry_head field; 1013 struct trace_uprobe *tu = event_call->data; 1014 1015 if (is_ret_probe(tu)) { 1016 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 1017 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 1018 size = SIZEOF_TRACE_ENTRY(true); 1019 } else { 1020 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 1021 size = SIZEOF_TRACE_ENTRY(false); 1022 } 1023 1024 return traceprobe_define_arg_fields(event_call, size, &tu->tp); 1025 } 1026 1027 #ifdef CONFIG_PERF_EVENTS 1028 static bool 1029 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1030 { 1031 struct perf_event *event; 1032 1033 if (filter->nr_systemwide) 1034 return true; 1035 1036 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1037 if (event->hw.target->mm == mm) 1038 return true; 1039 } 1040 1041 return false; 1042 } 1043 1044 static inline bool 1045 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1046 { 1047 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); 1048 } 1049 1050 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1051 { 1052 bool done; 1053 1054 write_lock(&tu->filter.rwlock); 1055 if (event->hw.target) { 1056 list_del(&event->hw.tp_list); 1057 done = tu->filter.nr_systemwide || 1058 (event->hw.target->flags & PF_EXITING) || 1059 uprobe_filter_event(tu, event); 1060 } else { 1061 tu->filter.nr_systemwide--; 1062 done = tu->filter.nr_systemwide; 1063 } 1064 write_unlock(&tu->filter.rwlock); 1065 1066 if (!done) 1067 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1068 1069 return 0; 1070 } 1071 1072 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1073 { 1074 bool done; 1075 int err; 1076 1077 write_lock(&tu->filter.rwlock); 1078 if (event->hw.target) { 1079 /* 1080 * event->parent != NULL means copy_process(), we can avoid 1081 * uprobe_apply(). current->mm must be probed and we can rely 1082 * on dup_mmap() which preserves the already installed bp's. 1083 * 1084 * attr.enable_on_exec means that exec/mmap will install the 1085 * breakpoints we need. 1086 */ 1087 done = tu->filter.nr_systemwide || 1088 event->parent || event->attr.enable_on_exec || 1089 uprobe_filter_event(tu, event); 1090 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1091 } else { 1092 done = tu->filter.nr_systemwide; 1093 tu->filter.nr_systemwide++; 1094 } 1095 write_unlock(&tu->filter.rwlock); 1096 1097 err = 0; 1098 if (!done) { 1099 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1100 if (err) 1101 uprobe_perf_close(tu, event); 1102 } 1103 return err; 1104 } 1105 1106 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1107 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1108 { 1109 struct trace_uprobe *tu; 1110 int ret; 1111 1112 tu = container_of(uc, struct trace_uprobe, consumer); 1113 read_lock(&tu->filter.rwlock); 1114 ret = __uprobe_perf_filter(&tu->filter, mm); 1115 read_unlock(&tu->filter.rwlock); 1116 1117 return ret; 1118 } 1119 1120 static void __uprobe_perf_func(struct trace_uprobe *tu, 1121 unsigned long func, struct pt_regs *regs, 1122 struct uprobe_cpu_buffer *ucb, int dsize) 1123 { 1124 struct trace_event_call *call = &tu->tp.call; 1125 struct uprobe_trace_entry_head *entry; 1126 struct hlist_head *head; 1127 void *data; 1128 int size, esize; 1129 int rctx; 1130 1131 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1132 return; 1133 1134 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1135 1136 size = esize + tu->tp.size + dsize; 1137 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1138 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1139 return; 1140 1141 preempt_disable(); 1142 head = this_cpu_ptr(call->perf_events); 1143 if (hlist_empty(head)) 1144 goto out; 1145 1146 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1147 if (!entry) 1148 goto out; 1149 1150 if (is_ret_probe(tu)) { 1151 entry->vaddr[0] = func; 1152 entry->vaddr[1] = instruction_pointer(regs); 1153 data = DATAOF_TRACE_ENTRY(entry, true); 1154 } else { 1155 entry->vaddr[0] = instruction_pointer(regs); 1156 data = DATAOF_TRACE_ENTRY(entry, false); 1157 } 1158 1159 memcpy(data, ucb->buf, tu->tp.size + dsize); 1160 1161 if (size - esize > tu->tp.size + dsize) { 1162 int len = tu->tp.size + dsize; 1163 1164 memset(data + len, 0, size - esize - len); 1165 } 1166 1167 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1168 head, NULL); 1169 out: 1170 preempt_enable(); 1171 } 1172 1173 /* uprobe profile handler */ 1174 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1175 struct uprobe_cpu_buffer *ucb, int dsize) 1176 { 1177 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1178 return UPROBE_HANDLER_REMOVE; 1179 1180 if (!is_ret_probe(tu)) 1181 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1182 return 0; 1183 } 1184 1185 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1186 struct pt_regs *regs, 1187 struct uprobe_cpu_buffer *ucb, int dsize) 1188 { 1189 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1190 } 1191 1192 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type, 1193 const char **filename, u64 *probe_offset, 1194 bool perf_type_tracepoint) 1195 { 1196 const char *pevent = trace_event_name(event->tp_event); 1197 const char *group = event->tp_event->class->system; 1198 struct trace_uprobe *tu; 1199 1200 if (perf_type_tracepoint) 1201 tu = find_probe_event(pevent, group); 1202 else 1203 tu = event->tp_event->data; 1204 if (!tu) 1205 return -EINVAL; 1206 1207 *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE 1208 : BPF_FD_TYPE_UPROBE; 1209 *filename = tu->filename; 1210 *probe_offset = tu->offset; 1211 return 0; 1212 } 1213 #endif /* CONFIG_PERF_EVENTS */ 1214 1215 static int 1216 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, 1217 void *data) 1218 { 1219 struct trace_uprobe *tu = event->data; 1220 struct trace_event_file *file = data; 1221 1222 switch (type) { 1223 case TRACE_REG_REGISTER: 1224 return probe_event_enable(tu, file, NULL); 1225 1226 case TRACE_REG_UNREGISTER: 1227 probe_event_disable(tu, file); 1228 return 0; 1229 1230 #ifdef CONFIG_PERF_EVENTS 1231 case TRACE_REG_PERF_REGISTER: 1232 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1233 1234 case TRACE_REG_PERF_UNREGISTER: 1235 probe_event_disable(tu, NULL); 1236 return 0; 1237 1238 case TRACE_REG_PERF_OPEN: 1239 return uprobe_perf_open(tu, data); 1240 1241 case TRACE_REG_PERF_CLOSE: 1242 return uprobe_perf_close(tu, data); 1243 1244 #endif 1245 default: 1246 return 0; 1247 } 1248 return 0; 1249 } 1250 1251 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1252 { 1253 struct trace_uprobe *tu; 1254 struct uprobe_dispatch_data udd; 1255 struct uprobe_cpu_buffer *ucb; 1256 int dsize, esize; 1257 int ret = 0; 1258 1259 1260 tu = container_of(con, struct trace_uprobe, consumer); 1261 tu->nhit++; 1262 1263 udd.tu = tu; 1264 udd.bp_addr = instruction_pointer(regs); 1265 1266 current->utask->vaddr = (unsigned long) &udd; 1267 1268 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1269 return 0; 1270 1271 dsize = __get_data_size(&tu->tp, regs); 1272 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1273 1274 ucb = uprobe_buffer_get(); 1275 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1276 1277 if (tu->tp.flags & TP_FLAG_TRACE) 1278 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1279 1280 #ifdef CONFIG_PERF_EVENTS 1281 if (tu->tp.flags & TP_FLAG_PROFILE) 1282 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1283 #endif 1284 uprobe_buffer_put(ucb); 1285 return ret; 1286 } 1287 1288 static int uretprobe_dispatcher(struct uprobe_consumer *con, 1289 unsigned long func, struct pt_regs *regs) 1290 { 1291 struct trace_uprobe *tu; 1292 struct uprobe_dispatch_data udd; 1293 struct uprobe_cpu_buffer *ucb; 1294 int dsize, esize; 1295 1296 tu = container_of(con, struct trace_uprobe, consumer); 1297 1298 udd.tu = tu; 1299 udd.bp_addr = func; 1300 1301 current->utask->vaddr = (unsigned long) &udd; 1302 1303 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1304 return 0; 1305 1306 dsize = __get_data_size(&tu->tp, regs); 1307 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1308 1309 ucb = uprobe_buffer_get(); 1310 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1311 1312 if (tu->tp.flags & TP_FLAG_TRACE) 1313 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1314 1315 #ifdef CONFIG_PERF_EVENTS 1316 if (tu->tp.flags & TP_FLAG_PROFILE) 1317 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1318 #endif 1319 uprobe_buffer_put(ucb); 1320 return 0; 1321 } 1322 1323 static struct trace_event_functions uprobe_funcs = { 1324 .trace = print_uprobe_event 1325 }; 1326 1327 static inline void init_trace_event_call(struct trace_uprobe *tu, 1328 struct trace_event_call *call) 1329 { 1330 INIT_LIST_HEAD(&call->class->fields); 1331 call->event.funcs = &uprobe_funcs; 1332 call->class->define_fields = uprobe_event_define_fields; 1333 1334 call->flags = TRACE_EVENT_FL_UPROBE; 1335 call->class->reg = trace_uprobe_register; 1336 call->data = tu; 1337 } 1338 1339 static int register_uprobe_event(struct trace_uprobe *tu) 1340 { 1341 struct trace_event_call *call = &tu->tp.call; 1342 int ret = 0; 1343 1344 init_trace_event_call(tu, call); 1345 1346 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) 1347 return -ENOMEM; 1348 1349 ret = register_trace_event(&call->event); 1350 if (!ret) { 1351 kfree(call->print_fmt); 1352 return -ENODEV; 1353 } 1354 1355 ret = trace_add_event_call(call); 1356 1357 if (ret) { 1358 pr_info("Failed to register uprobe event: %s\n", 1359 trace_event_name(call)); 1360 kfree(call->print_fmt); 1361 unregister_trace_event(&call->event); 1362 } 1363 1364 return ret; 1365 } 1366 1367 static int unregister_uprobe_event(struct trace_uprobe *tu) 1368 { 1369 int ret; 1370 1371 /* tu->event is unregistered in trace_remove_event_call() */ 1372 ret = trace_remove_event_call(&tu->tp.call); 1373 if (ret) 1374 return ret; 1375 kfree(tu->tp.call.print_fmt); 1376 tu->tp.call.print_fmt = NULL; 1377 return 0; 1378 } 1379 1380 #ifdef CONFIG_PERF_EVENTS 1381 struct trace_event_call * 1382 create_local_trace_uprobe(char *name, unsigned long offs, 1383 unsigned long ref_ctr_offset, bool is_return) 1384 { 1385 struct trace_uprobe *tu; 1386 struct path path; 1387 int ret; 1388 1389 ret = kern_path(name, LOOKUP_FOLLOW, &path); 1390 if (ret) 1391 return ERR_PTR(ret); 1392 1393 if (!d_is_reg(path.dentry)) { 1394 path_put(&path); 1395 return ERR_PTR(-EINVAL); 1396 } 1397 1398 /* 1399 * local trace_kprobes are not added to dyn_event, so they are never 1400 * searched in find_trace_kprobe(). Therefore, there is no concern of 1401 * duplicated name "DUMMY_EVENT" here. 1402 */ 1403 tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0, 1404 is_return); 1405 1406 if (IS_ERR(tu)) { 1407 pr_info("Failed to allocate trace_uprobe.(%d)\n", 1408 (int)PTR_ERR(tu)); 1409 path_put(&path); 1410 return ERR_CAST(tu); 1411 } 1412 1413 tu->offset = offs; 1414 tu->path = path; 1415 tu->ref_ctr_offset = ref_ctr_offset; 1416 tu->filename = kstrdup(name, GFP_KERNEL); 1417 init_trace_event_call(tu, &tu->tp.call); 1418 1419 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) { 1420 ret = -ENOMEM; 1421 goto error; 1422 } 1423 1424 return &tu->tp.call; 1425 error: 1426 free_trace_uprobe(tu); 1427 return ERR_PTR(ret); 1428 } 1429 1430 void destroy_local_trace_uprobe(struct trace_event_call *event_call) 1431 { 1432 struct trace_uprobe *tu; 1433 1434 tu = container_of(event_call, struct trace_uprobe, tp.call); 1435 1436 kfree(tu->tp.call.print_fmt); 1437 tu->tp.call.print_fmt = NULL; 1438 1439 free_trace_uprobe(tu); 1440 } 1441 #endif /* CONFIG_PERF_EVENTS */ 1442 1443 /* Make a trace interface for controling probe points */ 1444 static __init int init_uprobe_trace(void) 1445 { 1446 struct dentry *d_tracer; 1447 int ret; 1448 1449 ret = dyn_event_register(&trace_uprobe_ops); 1450 if (ret) 1451 return ret; 1452 1453 d_tracer = tracing_init_dentry(); 1454 if (IS_ERR(d_tracer)) 1455 return 0; 1456 1457 trace_create_file("uprobe_events", 0644, d_tracer, 1458 NULL, &uprobe_events_ops); 1459 /* Profile interface */ 1460 trace_create_file("uprobe_profile", 0444, d_tracer, 1461 NULL, &uprobe_profile_ops); 1462 return 0; 1463 } 1464 1465 fs_initcall(init_uprobe_trace); 1466