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 static int trace_uprobe_create(int argc, const char **argv) 431 { 432 struct trace_uprobe *tu; 433 const char *event = NULL, *group = UPROBE_EVENT_SYSTEM; 434 char *arg, *filename, *rctr, *rctr_end, *tmp; 435 char buf[MAX_EVENT_NAME_LEN]; 436 struct path path; 437 unsigned long offset, ref_ctr_offset; 438 bool is_return = false; 439 int i, ret; 440 441 ret = 0; 442 ref_ctr_offset = 0; 443 444 switch (argv[0][0]) { 445 case 'r': 446 is_return = true; 447 break; 448 case 'p': 449 break; 450 default: 451 return -ECANCELED; 452 } 453 454 if (argc < 2) 455 return -ECANCELED; 456 457 if (argv[0][1] == ':') 458 event = &argv[0][2]; 459 460 if (!strchr(argv[1], '/')) 461 return -ECANCELED; 462 463 filename = kstrdup(argv[1], GFP_KERNEL); 464 if (!filename) 465 return -ENOMEM; 466 467 /* Find the last occurrence, in case the path contains ':' too. */ 468 arg = strrchr(filename, ':'); 469 if (!arg || !isdigit(arg[1])) { 470 kfree(filename); 471 return -ECANCELED; 472 } 473 474 trace_probe_log_init("trace_uprobe", argc, argv); 475 trace_probe_log_set_index(1); /* filename is the 2nd argument */ 476 477 *arg++ = '\0'; 478 ret = kern_path(filename, LOOKUP_FOLLOW, &path); 479 if (ret) { 480 trace_probe_log_err(0, FILE_NOT_FOUND); 481 kfree(filename); 482 trace_probe_log_clear(); 483 return ret; 484 } 485 if (!d_is_reg(path.dentry)) { 486 trace_probe_log_err(0, NO_REGULAR_FILE); 487 ret = -EINVAL; 488 goto fail_address_parse; 489 } 490 491 /* Parse reference counter offset if specified. */ 492 rctr = strchr(arg, '('); 493 if (rctr) { 494 rctr_end = strchr(rctr, ')'); 495 if (!rctr_end) { 496 ret = -EINVAL; 497 rctr_end = rctr + strlen(rctr); 498 trace_probe_log_err(rctr_end - filename, 499 REFCNT_OPEN_BRACE); 500 goto fail_address_parse; 501 } else if (rctr_end[1] != '\0') { 502 ret = -EINVAL; 503 trace_probe_log_err(rctr_end + 1 - filename, 504 BAD_REFCNT_SUFFIX); 505 goto fail_address_parse; 506 } 507 508 *rctr++ = '\0'; 509 *rctr_end = '\0'; 510 ret = kstrtoul(rctr, 0, &ref_ctr_offset); 511 if (ret) { 512 trace_probe_log_err(rctr - filename, BAD_REFCNT); 513 goto fail_address_parse; 514 } 515 } 516 517 /* Parse uprobe offset. */ 518 ret = kstrtoul(arg, 0, &offset); 519 if (ret) { 520 trace_probe_log_err(arg - filename, BAD_UPROBE_OFFS); 521 goto fail_address_parse; 522 } 523 524 /* setup a probe */ 525 trace_probe_log_set_index(0); 526 if (event) { 527 ret = traceprobe_parse_event_name(&event, &group, buf, 528 event - argv[0]); 529 if (ret) 530 goto fail_address_parse; 531 } else { 532 char *tail; 533 char *ptr; 534 535 tail = kstrdup(kbasename(filename), GFP_KERNEL); 536 if (!tail) { 537 ret = -ENOMEM; 538 goto fail_address_parse; 539 } 540 541 ptr = strpbrk(tail, ".-_"); 542 if (ptr) 543 *ptr = '\0'; 544 545 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset); 546 event = buf; 547 kfree(tail); 548 } 549 550 argc -= 2; 551 argv += 2; 552 553 tu = alloc_trace_uprobe(group, event, argc, is_return); 554 if (IS_ERR(tu)) { 555 ret = PTR_ERR(tu); 556 /* This must return -ENOMEM otherwise there is a bug */ 557 WARN_ON_ONCE(ret != -ENOMEM); 558 goto fail_address_parse; 559 } 560 tu->offset = offset; 561 tu->ref_ctr_offset = ref_ctr_offset; 562 tu->path = path; 563 tu->filename = filename; 564 565 /* parse arguments */ 566 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 567 tmp = kstrdup(argv[i], GFP_KERNEL); 568 if (!tmp) { 569 ret = -ENOMEM; 570 goto error; 571 } 572 573 trace_probe_log_set_index(i + 2); 574 ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp, 575 is_return ? TPARG_FL_RETURN : 0); 576 kfree(tmp); 577 if (ret) 578 goto error; 579 } 580 581 ret = register_trace_uprobe(tu); 582 if (!ret) 583 goto out; 584 585 error: 586 free_trace_uprobe(tu); 587 out: 588 trace_probe_log_clear(); 589 return ret; 590 591 fail_address_parse: 592 trace_probe_log_clear(); 593 path_put(&path); 594 kfree(filename); 595 596 return ret; 597 } 598 599 static int create_or_delete_trace_uprobe(int argc, char **argv) 600 { 601 int ret; 602 603 if (argv[0][0] == '-') 604 return dyn_event_release(argc, argv, &trace_uprobe_ops); 605 606 ret = trace_uprobe_create(argc, (const char **)argv); 607 return ret == -ECANCELED ? -EINVAL : ret; 608 } 609 610 static int trace_uprobe_release(struct dyn_event *ev) 611 { 612 struct trace_uprobe *tu = to_trace_uprobe(ev); 613 614 return unregister_trace_uprobe(tu); 615 } 616 617 /* Probes listing interfaces */ 618 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev) 619 { 620 struct trace_uprobe *tu = to_trace_uprobe(ev); 621 char c = is_ret_probe(tu) ? 'r' : 'p'; 622 int i; 623 624 seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system, 625 trace_event_name(&tu->tp.call), tu->filename, 626 (int)(sizeof(void *) * 2), tu->offset); 627 628 if (tu->ref_ctr_offset) 629 seq_printf(m, "(0x%lx)", tu->ref_ctr_offset); 630 631 for (i = 0; i < tu->tp.nr_args; i++) 632 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm); 633 634 seq_putc(m, '\n'); 635 return 0; 636 } 637 638 static int probes_seq_show(struct seq_file *m, void *v) 639 { 640 struct dyn_event *ev = v; 641 642 if (!is_trace_uprobe(ev)) 643 return 0; 644 645 return trace_uprobe_show(m, ev); 646 } 647 648 static const struct seq_operations probes_seq_op = { 649 .start = dyn_event_seq_start, 650 .next = dyn_event_seq_next, 651 .stop = dyn_event_seq_stop, 652 .show = probes_seq_show 653 }; 654 655 static int probes_open(struct inode *inode, struct file *file) 656 { 657 int ret; 658 659 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 660 ret = dyn_events_release_all(&trace_uprobe_ops); 661 if (ret) 662 return ret; 663 } 664 665 return seq_open(file, &probes_seq_op); 666 } 667 668 static ssize_t probes_write(struct file *file, const char __user *buffer, 669 size_t count, loff_t *ppos) 670 { 671 return trace_parse_run_command(file, buffer, count, ppos, 672 create_or_delete_trace_uprobe); 673 } 674 675 static const struct file_operations uprobe_events_ops = { 676 .owner = THIS_MODULE, 677 .open = probes_open, 678 .read = seq_read, 679 .llseek = seq_lseek, 680 .release = seq_release, 681 .write = probes_write, 682 }; 683 684 /* Probes profiling interfaces */ 685 static int probes_profile_seq_show(struct seq_file *m, void *v) 686 { 687 struct dyn_event *ev = v; 688 struct trace_uprobe *tu; 689 690 if (!is_trace_uprobe(ev)) 691 return 0; 692 693 tu = to_trace_uprobe(ev); 694 seq_printf(m, " %s %-44s %15lu\n", tu->filename, 695 trace_event_name(&tu->tp.call), tu->nhit); 696 return 0; 697 } 698 699 static const struct seq_operations profile_seq_op = { 700 .start = dyn_event_seq_start, 701 .next = dyn_event_seq_next, 702 .stop = dyn_event_seq_stop, 703 .show = probes_profile_seq_show 704 }; 705 706 static int profile_open(struct inode *inode, struct file *file) 707 { 708 return seq_open(file, &profile_seq_op); 709 } 710 711 static const struct file_operations uprobe_profile_ops = { 712 .owner = THIS_MODULE, 713 .open = profile_open, 714 .read = seq_read, 715 .llseek = seq_lseek, 716 .release = seq_release, 717 }; 718 719 struct uprobe_cpu_buffer { 720 struct mutex mutex; 721 void *buf; 722 }; 723 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer; 724 static int uprobe_buffer_refcnt; 725 726 static int uprobe_buffer_init(void) 727 { 728 int cpu, err_cpu; 729 730 uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer); 731 if (uprobe_cpu_buffer == NULL) 732 return -ENOMEM; 733 734 for_each_possible_cpu(cpu) { 735 struct page *p = alloc_pages_node(cpu_to_node(cpu), 736 GFP_KERNEL, 0); 737 if (p == NULL) { 738 err_cpu = cpu; 739 goto err; 740 } 741 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p); 742 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex); 743 } 744 745 return 0; 746 747 err: 748 for_each_possible_cpu(cpu) { 749 if (cpu == err_cpu) 750 break; 751 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf); 752 } 753 754 free_percpu(uprobe_cpu_buffer); 755 return -ENOMEM; 756 } 757 758 static int uprobe_buffer_enable(void) 759 { 760 int ret = 0; 761 762 BUG_ON(!mutex_is_locked(&event_mutex)); 763 764 if (uprobe_buffer_refcnt++ == 0) { 765 ret = uprobe_buffer_init(); 766 if (ret < 0) 767 uprobe_buffer_refcnt--; 768 } 769 770 return ret; 771 } 772 773 static void uprobe_buffer_disable(void) 774 { 775 int cpu; 776 777 BUG_ON(!mutex_is_locked(&event_mutex)); 778 779 if (--uprobe_buffer_refcnt == 0) { 780 for_each_possible_cpu(cpu) 781 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, 782 cpu)->buf); 783 784 free_percpu(uprobe_cpu_buffer); 785 uprobe_cpu_buffer = NULL; 786 } 787 } 788 789 static struct uprobe_cpu_buffer *uprobe_buffer_get(void) 790 { 791 struct uprobe_cpu_buffer *ucb; 792 int cpu; 793 794 cpu = raw_smp_processor_id(); 795 ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu); 796 797 /* 798 * Use per-cpu buffers for fastest access, but we might migrate 799 * so the mutex makes sure we have sole access to it. 800 */ 801 mutex_lock(&ucb->mutex); 802 803 return ucb; 804 } 805 806 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) 807 { 808 mutex_unlock(&ucb->mutex); 809 } 810 811 static void __uprobe_trace_func(struct trace_uprobe *tu, 812 unsigned long func, struct pt_regs *regs, 813 struct uprobe_cpu_buffer *ucb, int dsize, 814 struct trace_event_file *trace_file) 815 { 816 struct uprobe_trace_entry_head *entry; 817 struct ring_buffer_event *event; 818 struct ring_buffer *buffer; 819 void *data; 820 int size, esize; 821 struct trace_event_call *call = &tu->tp.call; 822 823 WARN_ON(call != trace_file->event_call); 824 825 if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) 826 return; 827 828 if (trace_trigger_soft_disabled(trace_file)) 829 return; 830 831 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 832 size = esize + tu->tp.size + dsize; 833 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 834 call->event.type, size, 0, 0); 835 if (!event) 836 return; 837 838 entry = ring_buffer_event_data(event); 839 if (is_ret_probe(tu)) { 840 entry->vaddr[0] = func; 841 entry->vaddr[1] = instruction_pointer(regs); 842 data = DATAOF_TRACE_ENTRY(entry, true); 843 } else { 844 entry->vaddr[0] = instruction_pointer(regs); 845 data = DATAOF_TRACE_ENTRY(entry, false); 846 } 847 848 memcpy(data, ucb->buf, tu->tp.size + dsize); 849 850 event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0); 851 } 852 853 /* uprobe handler */ 854 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, 855 struct uprobe_cpu_buffer *ucb, int dsize) 856 { 857 struct event_file_link *link; 858 859 if (is_ret_probe(tu)) 860 return 0; 861 862 rcu_read_lock(); 863 list_for_each_entry_rcu(link, &tu->tp.files, list) 864 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); 865 rcu_read_unlock(); 866 867 return 0; 868 } 869 870 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, 871 struct pt_regs *regs, 872 struct uprobe_cpu_buffer *ucb, int dsize) 873 { 874 struct event_file_link *link; 875 876 rcu_read_lock(); 877 list_for_each_entry_rcu(link, &tu->tp.files, list) 878 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); 879 rcu_read_unlock(); 880 } 881 882 /* Event entry printers */ 883 static enum print_line_t 884 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event) 885 { 886 struct uprobe_trace_entry_head *entry; 887 struct trace_seq *s = &iter->seq; 888 struct trace_uprobe *tu; 889 u8 *data; 890 891 entry = (struct uprobe_trace_entry_head *)iter->ent; 892 tu = container_of(event, struct trace_uprobe, tp.call.event); 893 894 if (is_ret_probe(tu)) { 895 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)", 896 trace_event_name(&tu->tp.call), 897 entry->vaddr[1], entry->vaddr[0]); 898 data = DATAOF_TRACE_ENTRY(entry, true); 899 } else { 900 trace_seq_printf(s, "%s: (0x%lx)", 901 trace_event_name(&tu->tp.call), 902 entry->vaddr[0]); 903 data = DATAOF_TRACE_ENTRY(entry, false); 904 } 905 906 if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0) 907 goto out; 908 909 trace_seq_putc(s, '\n'); 910 911 out: 912 return trace_handle_return(s); 913 } 914 915 typedef bool (*filter_func_t)(struct uprobe_consumer *self, 916 enum uprobe_filter_ctx ctx, 917 struct mm_struct *mm); 918 919 static int 920 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file, 921 filter_func_t filter) 922 { 923 bool enabled = trace_probe_is_enabled(&tu->tp); 924 struct event_file_link *link = NULL; 925 int ret; 926 927 if (file) { 928 if (tu->tp.flags & TP_FLAG_PROFILE) 929 return -EINTR; 930 931 link = kmalloc(sizeof(*link), GFP_KERNEL); 932 if (!link) 933 return -ENOMEM; 934 935 link->file = file; 936 list_add_tail_rcu(&link->list, &tu->tp.files); 937 938 tu->tp.flags |= TP_FLAG_TRACE; 939 } else { 940 if (tu->tp.flags & TP_FLAG_TRACE) 941 return -EINTR; 942 943 tu->tp.flags |= TP_FLAG_PROFILE; 944 } 945 946 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 947 948 if (enabled) 949 return 0; 950 951 ret = uprobe_buffer_enable(); 952 if (ret) 953 goto err_flags; 954 955 tu->consumer.filter = filter; 956 tu->inode = d_real_inode(tu->path.dentry); 957 if (tu->ref_ctr_offset) { 958 ret = uprobe_register_refctr(tu->inode, tu->offset, 959 tu->ref_ctr_offset, &tu->consumer); 960 } else { 961 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); 962 } 963 964 if (ret) 965 goto err_buffer; 966 967 return 0; 968 969 err_buffer: 970 uprobe_buffer_disable(); 971 972 err_flags: 973 if (file) { 974 list_del(&link->list); 975 kfree(link); 976 tu->tp.flags &= ~TP_FLAG_TRACE; 977 } else { 978 tu->tp.flags &= ~TP_FLAG_PROFILE; 979 } 980 return ret; 981 } 982 983 static void 984 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file) 985 { 986 if (!trace_probe_is_enabled(&tu->tp)) 987 return; 988 989 if (file) { 990 struct event_file_link *link; 991 992 link = find_event_file_link(&tu->tp, file); 993 if (!link) 994 return; 995 996 list_del_rcu(&link->list); 997 /* synchronize with u{,ret}probe_trace_func */ 998 synchronize_rcu(); 999 kfree(link); 1000 1001 if (!list_empty(&tu->tp.files)) 1002 return; 1003 } 1004 1005 WARN_ON(!uprobe_filter_is_empty(&tu->filter)); 1006 1007 uprobe_unregister(tu->inode, tu->offset, &tu->consumer); 1008 tu->inode = NULL; 1009 tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; 1010 1011 uprobe_buffer_disable(); 1012 } 1013 1014 static int uprobe_event_define_fields(struct trace_event_call *event_call) 1015 { 1016 int ret, size; 1017 struct uprobe_trace_entry_head field; 1018 struct trace_uprobe *tu = event_call->data; 1019 1020 if (is_ret_probe(tu)) { 1021 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0); 1022 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0); 1023 size = SIZEOF_TRACE_ENTRY(true); 1024 } else { 1025 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); 1026 size = SIZEOF_TRACE_ENTRY(false); 1027 } 1028 1029 return traceprobe_define_arg_fields(event_call, size, &tu->tp); 1030 } 1031 1032 #ifdef CONFIG_PERF_EVENTS 1033 static bool 1034 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm) 1035 { 1036 struct perf_event *event; 1037 1038 if (filter->nr_systemwide) 1039 return true; 1040 1041 list_for_each_entry(event, &filter->perf_events, hw.tp_list) { 1042 if (event->hw.target->mm == mm) 1043 return true; 1044 } 1045 1046 return false; 1047 } 1048 1049 static inline bool 1050 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event) 1051 { 1052 return __uprobe_perf_filter(&tu->filter, event->hw.target->mm); 1053 } 1054 1055 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event) 1056 { 1057 bool done; 1058 1059 write_lock(&tu->filter.rwlock); 1060 if (event->hw.target) { 1061 list_del(&event->hw.tp_list); 1062 done = tu->filter.nr_systemwide || 1063 (event->hw.target->flags & PF_EXITING) || 1064 uprobe_filter_event(tu, event); 1065 } else { 1066 tu->filter.nr_systemwide--; 1067 done = tu->filter.nr_systemwide; 1068 } 1069 write_unlock(&tu->filter.rwlock); 1070 1071 if (!done) 1072 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false); 1073 1074 return 0; 1075 } 1076 1077 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event) 1078 { 1079 bool done; 1080 int err; 1081 1082 write_lock(&tu->filter.rwlock); 1083 if (event->hw.target) { 1084 /* 1085 * event->parent != NULL means copy_process(), we can avoid 1086 * uprobe_apply(). current->mm must be probed and we can rely 1087 * on dup_mmap() which preserves the already installed bp's. 1088 * 1089 * attr.enable_on_exec means that exec/mmap will install the 1090 * breakpoints we need. 1091 */ 1092 done = tu->filter.nr_systemwide || 1093 event->parent || event->attr.enable_on_exec || 1094 uprobe_filter_event(tu, event); 1095 list_add(&event->hw.tp_list, &tu->filter.perf_events); 1096 } else { 1097 done = tu->filter.nr_systemwide; 1098 tu->filter.nr_systemwide++; 1099 } 1100 write_unlock(&tu->filter.rwlock); 1101 1102 err = 0; 1103 if (!done) { 1104 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true); 1105 if (err) 1106 uprobe_perf_close(tu, event); 1107 } 1108 return err; 1109 } 1110 1111 static bool uprobe_perf_filter(struct uprobe_consumer *uc, 1112 enum uprobe_filter_ctx ctx, struct mm_struct *mm) 1113 { 1114 struct trace_uprobe *tu; 1115 int ret; 1116 1117 tu = container_of(uc, struct trace_uprobe, consumer); 1118 read_lock(&tu->filter.rwlock); 1119 ret = __uprobe_perf_filter(&tu->filter, mm); 1120 read_unlock(&tu->filter.rwlock); 1121 1122 return ret; 1123 } 1124 1125 static void __uprobe_perf_func(struct trace_uprobe *tu, 1126 unsigned long func, struct pt_regs *regs, 1127 struct uprobe_cpu_buffer *ucb, int dsize) 1128 { 1129 struct trace_event_call *call = &tu->tp.call; 1130 struct uprobe_trace_entry_head *entry; 1131 struct hlist_head *head; 1132 void *data; 1133 int size, esize; 1134 int rctx; 1135 1136 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1137 return; 1138 1139 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1140 1141 size = esize + tu->tp.size + dsize; 1142 size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32); 1143 if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough")) 1144 return; 1145 1146 preempt_disable(); 1147 head = this_cpu_ptr(call->perf_events); 1148 if (hlist_empty(head)) 1149 goto out; 1150 1151 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1152 if (!entry) 1153 goto out; 1154 1155 if (is_ret_probe(tu)) { 1156 entry->vaddr[0] = func; 1157 entry->vaddr[1] = instruction_pointer(regs); 1158 data = DATAOF_TRACE_ENTRY(entry, true); 1159 } else { 1160 entry->vaddr[0] = instruction_pointer(regs); 1161 data = DATAOF_TRACE_ENTRY(entry, false); 1162 } 1163 1164 memcpy(data, ucb->buf, tu->tp.size + dsize); 1165 1166 if (size - esize > tu->tp.size + dsize) { 1167 int len = tu->tp.size + dsize; 1168 1169 memset(data + len, 0, size - esize - len); 1170 } 1171 1172 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1173 head, NULL); 1174 out: 1175 preempt_enable(); 1176 } 1177 1178 /* uprobe profile handler */ 1179 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs, 1180 struct uprobe_cpu_buffer *ucb, int dsize) 1181 { 1182 if (!uprobe_perf_filter(&tu->consumer, 0, current->mm)) 1183 return UPROBE_HANDLER_REMOVE; 1184 1185 if (!is_ret_probe(tu)) 1186 __uprobe_perf_func(tu, 0, regs, ucb, dsize); 1187 return 0; 1188 } 1189 1190 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, 1191 struct pt_regs *regs, 1192 struct uprobe_cpu_buffer *ucb, int dsize) 1193 { 1194 __uprobe_perf_func(tu, func, regs, ucb, dsize); 1195 } 1196 1197 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type, 1198 const char **filename, u64 *probe_offset, 1199 bool perf_type_tracepoint) 1200 { 1201 const char *pevent = trace_event_name(event->tp_event); 1202 const char *group = event->tp_event->class->system; 1203 struct trace_uprobe *tu; 1204 1205 if (perf_type_tracepoint) 1206 tu = find_probe_event(pevent, group); 1207 else 1208 tu = event->tp_event->data; 1209 if (!tu) 1210 return -EINVAL; 1211 1212 *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE 1213 : BPF_FD_TYPE_UPROBE; 1214 *filename = tu->filename; 1215 *probe_offset = tu->offset; 1216 return 0; 1217 } 1218 #endif /* CONFIG_PERF_EVENTS */ 1219 1220 static int 1221 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type, 1222 void *data) 1223 { 1224 struct trace_uprobe *tu = event->data; 1225 struct trace_event_file *file = data; 1226 1227 switch (type) { 1228 case TRACE_REG_REGISTER: 1229 return probe_event_enable(tu, file, NULL); 1230 1231 case TRACE_REG_UNREGISTER: 1232 probe_event_disable(tu, file); 1233 return 0; 1234 1235 #ifdef CONFIG_PERF_EVENTS 1236 case TRACE_REG_PERF_REGISTER: 1237 return probe_event_enable(tu, NULL, uprobe_perf_filter); 1238 1239 case TRACE_REG_PERF_UNREGISTER: 1240 probe_event_disable(tu, NULL); 1241 return 0; 1242 1243 case TRACE_REG_PERF_OPEN: 1244 return uprobe_perf_open(tu, data); 1245 1246 case TRACE_REG_PERF_CLOSE: 1247 return uprobe_perf_close(tu, data); 1248 1249 #endif 1250 default: 1251 return 0; 1252 } 1253 return 0; 1254 } 1255 1256 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) 1257 { 1258 struct trace_uprobe *tu; 1259 struct uprobe_dispatch_data udd; 1260 struct uprobe_cpu_buffer *ucb; 1261 int dsize, esize; 1262 int ret = 0; 1263 1264 1265 tu = container_of(con, struct trace_uprobe, consumer); 1266 tu->nhit++; 1267 1268 udd.tu = tu; 1269 udd.bp_addr = instruction_pointer(regs); 1270 1271 current->utask->vaddr = (unsigned long) &udd; 1272 1273 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1274 return 0; 1275 1276 dsize = __get_data_size(&tu->tp, regs); 1277 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1278 1279 ucb = uprobe_buffer_get(); 1280 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1281 1282 if (tu->tp.flags & TP_FLAG_TRACE) 1283 ret |= uprobe_trace_func(tu, regs, ucb, dsize); 1284 1285 #ifdef CONFIG_PERF_EVENTS 1286 if (tu->tp.flags & TP_FLAG_PROFILE) 1287 ret |= uprobe_perf_func(tu, regs, ucb, dsize); 1288 #endif 1289 uprobe_buffer_put(ucb); 1290 return ret; 1291 } 1292 1293 static int uretprobe_dispatcher(struct uprobe_consumer *con, 1294 unsigned long func, struct pt_regs *regs) 1295 { 1296 struct trace_uprobe *tu; 1297 struct uprobe_dispatch_data udd; 1298 struct uprobe_cpu_buffer *ucb; 1299 int dsize, esize; 1300 1301 tu = container_of(con, struct trace_uprobe, consumer); 1302 1303 udd.tu = tu; 1304 udd.bp_addr = func; 1305 1306 current->utask->vaddr = (unsigned long) &udd; 1307 1308 if (WARN_ON_ONCE(!uprobe_cpu_buffer)) 1309 return 0; 1310 1311 dsize = __get_data_size(&tu->tp, regs); 1312 esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); 1313 1314 ucb = uprobe_buffer_get(); 1315 store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize); 1316 1317 if (tu->tp.flags & TP_FLAG_TRACE) 1318 uretprobe_trace_func(tu, func, regs, ucb, dsize); 1319 1320 #ifdef CONFIG_PERF_EVENTS 1321 if (tu->tp.flags & TP_FLAG_PROFILE) 1322 uretprobe_perf_func(tu, func, regs, ucb, dsize); 1323 #endif 1324 uprobe_buffer_put(ucb); 1325 return 0; 1326 } 1327 1328 static struct trace_event_functions uprobe_funcs = { 1329 .trace = print_uprobe_event 1330 }; 1331 1332 static inline void init_trace_event_call(struct trace_uprobe *tu, 1333 struct trace_event_call *call) 1334 { 1335 INIT_LIST_HEAD(&call->class->fields); 1336 call->event.funcs = &uprobe_funcs; 1337 call->class->define_fields = uprobe_event_define_fields; 1338 1339 call->flags = TRACE_EVENT_FL_UPROBE; 1340 call->class->reg = trace_uprobe_register; 1341 call->data = tu; 1342 } 1343 1344 static int register_uprobe_event(struct trace_uprobe *tu) 1345 { 1346 struct trace_event_call *call = &tu->tp.call; 1347 int ret = 0; 1348 1349 init_trace_event_call(tu, call); 1350 1351 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) 1352 return -ENOMEM; 1353 1354 ret = register_trace_event(&call->event); 1355 if (!ret) { 1356 kfree(call->print_fmt); 1357 return -ENODEV; 1358 } 1359 1360 ret = trace_add_event_call(call); 1361 1362 if (ret) { 1363 pr_info("Failed to register uprobe event: %s\n", 1364 trace_event_name(call)); 1365 kfree(call->print_fmt); 1366 unregister_trace_event(&call->event); 1367 } 1368 1369 return ret; 1370 } 1371 1372 static int unregister_uprobe_event(struct trace_uprobe *tu) 1373 { 1374 int ret; 1375 1376 /* tu->event is unregistered in trace_remove_event_call() */ 1377 ret = trace_remove_event_call(&tu->tp.call); 1378 if (ret) 1379 return ret; 1380 kfree(tu->tp.call.print_fmt); 1381 tu->tp.call.print_fmt = NULL; 1382 return 0; 1383 } 1384 1385 #ifdef CONFIG_PERF_EVENTS 1386 struct trace_event_call * 1387 create_local_trace_uprobe(char *name, unsigned long offs, 1388 unsigned long ref_ctr_offset, bool is_return) 1389 { 1390 struct trace_uprobe *tu; 1391 struct path path; 1392 int ret; 1393 1394 ret = kern_path(name, LOOKUP_FOLLOW, &path); 1395 if (ret) 1396 return ERR_PTR(ret); 1397 1398 if (!d_is_reg(path.dentry)) { 1399 path_put(&path); 1400 return ERR_PTR(-EINVAL); 1401 } 1402 1403 /* 1404 * local trace_kprobes are not added to dyn_event, so they are never 1405 * searched in find_trace_kprobe(). Therefore, there is no concern of 1406 * duplicated name "DUMMY_EVENT" here. 1407 */ 1408 tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0, 1409 is_return); 1410 1411 if (IS_ERR(tu)) { 1412 pr_info("Failed to allocate trace_uprobe.(%d)\n", 1413 (int)PTR_ERR(tu)); 1414 path_put(&path); 1415 return ERR_CAST(tu); 1416 } 1417 1418 tu->offset = offs; 1419 tu->path = path; 1420 tu->ref_ctr_offset = ref_ctr_offset; 1421 tu->filename = kstrdup(name, GFP_KERNEL); 1422 init_trace_event_call(tu, &tu->tp.call); 1423 1424 if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) { 1425 ret = -ENOMEM; 1426 goto error; 1427 } 1428 1429 return &tu->tp.call; 1430 error: 1431 free_trace_uprobe(tu); 1432 return ERR_PTR(ret); 1433 } 1434 1435 void destroy_local_trace_uprobe(struct trace_event_call *event_call) 1436 { 1437 struct trace_uprobe *tu; 1438 1439 tu = container_of(event_call, struct trace_uprobe, tp.call); 1440 1441 kfree(tu->tp.call.print_fmt); 1442 tu->tp.call.print_fmt = NULL; 1443 1444 free_trace_uprobe(tu); 1445 } 1446 #endif /* CONFIG_PERF_EVENTS */ 1447 1448 /* Make a trace interface for controling probe points */ 1449 static __init int init_uprobe_trace(void) 1450 { 1451 struct dentry *d_tracer; 1452 int ret; 1453 1454 ret = dyn_event_register(&trace_uprobe_ops); 1455 if (ret) 1456 return ret; 1457 1458 d_tracer = tracing_init_dentry(); 1459 if (IS_ERR(d_tracer)) 1460 return 0; 1461 1462 trace_create_file("uprobe_events", 0644, d_tracer, 1463 NULL, &uprobe_events_ops); 1464 /* Profile interface */ 1465 trace_create_file("uprobe_profile", 0444, d_tracer, 1466 NULL, &uprobe_profile_ops); 1467 return 0; 1468 } 1469 1470 fs_initcall(init_uprobe_trace); 1471