1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Kprobes-based tracing events 4 * 5 * Created by Masami Hiramatsu <mhiramat@redhat.com> 6 * 7 */ 8 #define pr_fmt(fmt) "trace_kprobe: " fmt 9 10 #include <linux/security.h> 11 #include <linux/module.h> 12 #include <linux/uaccess.h> 13 #include <linux/rculist.h> 14 #include <linux/error-injection.h> 15 16 #include <asm/setup.h> /* for COMMAND_LINE_SIZE */ 17 18 #include "trace_dynevent.h" 19 #include "trace_kprobe_selftest.h" 20 #include "trace_probe.h" 21 #include "trace_probe_tmpl.h" 22 23 #define KPROBE_EVENT_SYSTEM "kprobes" 24 #define KRETPROBE_MAXACTIVE_MAX 4096 25 26 /* Kprobe early definition from command line */ 27 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata; 28 static bool kprobe_boot_events_enabled __initdata; 29 30 static int __init set_kprobe_boot_events(char *str) 31 { 32 strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE); 33 return 0; 34 } 35 __setup("kprobe_event=", set_kprobe_boot_events); 36 37 static int trace_kprobe_create(int argc, const char **argv); 38 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev); 39 static int trace_kprobe_release(struct dyn_event *ev); 40 static bool trace_kprobe_is_busy(struct dyn_event *ev); 41 static bool trace_kprobe_match(const char *system, const char *event, 42 int argc, const char **argv, struct dyn_event *ev); 43 44 static struct dyn_event_operations trace_kprobe_ops = { 45 .create = trace_kprobe_create, 46 .show = trace_kprobe_show, 47 .is_busy = trace_kprobe_is_busy, 48 .free = trace_kprobe_release, 49 .match = trace_kprobe_match, 50 }; 51 52 /* 53 * Kprobe event core functions 54 */ 55 struct trace_kprobe { 56 struct dyn_event devent; 57 struct kretprobe rp; /* Use rp.kp for kprobe use */ 58 unsigned long __percpu *nhit; 59 const char *symbol; /* symbol name */ 60 struct trace_probe tp; 61 }; 62 63 static bool is_trace_kprobe(struct dyn_event *ev) 64 { 65 return ev->ops == &trace_kprobe_ops; 66 } 67 68 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev) 69 { 70 return container_of(ev, struct trace_kprobe, devent); 71 } 72 73 /** 74 * for_each_trace_kprobe - iterate over the trace_kprobe list 75 * @pos: the struct trace_kprobe * for each entry 76 * @dpos: the struct dyn_event * to use as a loop cursor 77 */ 78 #define for_each_trace_kprobe(pos, dpos) \ 79 for_each_dyn_event(dpos) \ 80 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos))) 81 82 #define SIZEOF_TRACE_KPROBE(n) \ 83 (offsetof(struct trace_kprobe, tp.args) + \ 84 (sizeof(struct probe_arg) * (n))) 85 86 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk) 87 { 88 return tk->rp.handler != NULL; 89 } 90 91 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk) 92 { 93 return tk->symbol ? tk->symbol : "unknown"; 94 } 95 96 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk) 97 { 98 return tk->rp.kp.offset; 99 } 100 101 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk) 102 { 103 return !!(kprobe_gone(&tk->rp.kp)); 104 } 105 106 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, 107 struct module *mod) 108 { 109 int len = strlen(mod->name); 110 const char *name = trace_kprobe_symbol(tk); 111 return strncmp(mod->name, name, len) == 0 && name[len] == ':'; 112 } 113 114 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) 115 { 116 char *p; 117 bool ret; 118 119 if (!tk->symbol) 120 return false; 121 p = strchr(tk->symbol, ':'); 122 if (!p) 123 return true; 124 *p = '\0'; 125 mutex_lock(&module_mutex); 126 ret = !!find_module(tk->symbol); 127 mutex_unlock(&module_mutex); 128 *p = ':'; 129 130 return ret; 131 } 132 133 static bool trace_kprobe_is_busy(struct dyn_event *ev) 134 { 135 struct trace_kprobe *tk = to_trace_kprobe(ev); 136 137 return trace_probe_is_enabled(&tk->tp); 138 } 139 140 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk, 141 int argc, const char **argv) 142 { 143 char buf[MAX_ARGSTR_LEN + 1]; 144 145 if (!argc) 146 return true; 147 148 if (!tk->symbol) 149 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr); 150 else if (tk->rp.kp.offset) 151 snprintf(buf, sizeof(buf), "%s+%u", 152 trace_kprobe_symbol(tk), tk->rp.kp.offset); 153 else 154 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk)); 155 if (strcmp(buf, argv[0])) 156 return false; 157 argc--; argv++; 158 159 return trace_probe_match_command_args(&tk->tp, argc, argv); 160 } 161 162 static bool trace_kprobe_match(const char *system, const char *event, 163 int argc, const char **argv, struct dyn_event *ev) 164 { 165 struct trace_kprobe *tk = to_trace_kprobe(ev); 166 167 return strcmp(trace_probe_name(&tk->tp), event) == 0 && 168 (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) && 169 trace_kprobe_match_command_head(tk, argc, argv); 170 } 171 172 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) 173 { 174 unsigned long nhit = 0; 175 int cpu; 176 177 for_each_possible_cpu(cpu) 178 nhit += *per_cpu_ptr(tk->nhit, cpu); 179 180 return nhit; 181 } 182 183 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk) 184 { 185 return !(list_empty(&tk->rp.kp.list) && 186 hlist_unhashed(&tk->rp.kp.hlist)); 187 } 188 189 /* Return 0 if it fails to find the symbol address */ 190 static nokprobe_inline 191 unsigned long trace_kprobe_address(struct trace_kprobe *tk) 192 { 193 unsigned long addr; 194 195 if (tk->symbol) { 196 addr = (unsigned long) 197 kallsyms_lookup_name(trace_kprobe_symbol(tk)); 198 if (addr) 199 addr += tk->rp.kp.offset; 200 } else { 201 addr = (unsigned long)tk->rp.kp.addr; 202 } 203 return addr; 204 } 205 206 static nokprobe_inline struct trace_kprobe * 207 trace_kprobe_primary_from_call(struct trace_event_call *call) 208 { 209 struct trace_probe *tp; 210 211 tp = trace_probe_primary_from_call(call); 212 if (WARN_ON_ONCE(!tp)) 213 return NULL; 214 215 return container_of(tp, struct trace_kprobe, tp); 216 } 217 218 bool trace_kprobe_on_func_entry(struct trace_event_call *call) 219 { 220 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 221 222 return tk ? kprobe_on_func_entry(tk->rp.kp.addr, 223 tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name, 224 tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false; 225 } 226 227 bool trace_kprobe_error_injectable(struct trace_event_call *call) 228 { 229 struct trace_kprobe *tk = trace_kprobe_primary_from_call(call); 230 231 return tk ? within_error_injection_list(trace_kprobe_address(tk)) : 232 false; 233 } 234 235 static int register_kprobe_event(struct trace_kprobe *tk); 236 static int unregister_kprobe_event(struct trace_kprobe *tk); 237 238 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); 239 static int kretprobe_dispatcher(struct kretprobe_instance *ri, 240 struct pt_regs *regs); 241 242 static void free_trace_kprobe(struct trace_kprobe *tk) 243 { 244 if (tk) { 245 trace_probe_cleanup(&tk->tp); 246 kfree(tk->symbol); 247 free_percpu(tk->nhit); 248 kfree(tk); 249 } 250 } 251 252 /* 253 * Allocate new trace_probe and initialize it (including kprobes). 254 */ 255 static struct trace_kprobe *alloc_trace_kprobe(const char *group, 256 const char *event, 257 void *addr, 258 const char *symbol, 259 unsigned long offs, 260 int maxactive, 261 int nargs, bool is_return) 262 { 263 struct trace_kprobe *tk; 264 int ret = -ENOMEM; 265 266 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL); 267 if (!tk) 268 return ERR_PTR(ret); 269 270 tk->nhit = alloc_percpu(unsigned long); 271 if (!tk->nhit) 272 goto error; 273 274 if (symbol) { 275 tk->symbol = kstrdup(symbol, GFP_KERNEL); 276 if (!tk->symbol) 277 goto error; 278 tk->rp.kp.symbol_name = tk->symbol; 279 tk->rp.kp.offset = offs; 280 } else 281 tk->rp.kp.addr = addr; 282 283 if (is_return) 284 tk->rp.handler = kretprobe_dispatcher; 285 else 286 tk->rp.kp.pre_handler = kprobe_dispatcher; 287 288 tk->rp.maxactive = maxactive; 289 INIT_HLIST_NODE(&tk->rp.kp.hlist); 290 INIT_LIST_HEAD(&tk->rp.kp.list); 291 292 ret = trace_probe_init(&tk->tp, event, group, false); 293 if (ret < 0) 294 goto error; 295 296 dyn_event_init(&tk->devent, &trace_kprobe_ops); 297 return tk; 298 error: 299 free_trace_kprobe(tk); 300 return ERR_PTR(ret); 301 } 302 303 static struct trace_kprobe *find_trace_kprobe(const char *event, 304 const char *group) 305 { 306 struct dyn_event *pos; 307 struct trace_kprobe *tk; 308 309 for_each_trace_kprobe(tk, pos) 310 if (strcmp(trace_probe_name(&tk->tp), event) == 0 && 311 strcmp(trace_probe_group_name(&tk->tp), group) == 0) 312 return tk; 313 return NULL; 314 } 315 316 static inline int __enable_trace_kprobe(struct trace_kprobe *tk) 317 { 318 int ret = 0; 319 320 if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) { 321 if (trace_kprobe_is_return(tk)) 322 ret = enable_kretprobe(&tk->rp); 323 else 324 ret = enable_kprobe(&tk->rp.kp); 325 } 326 327 return ret; 328 } 329 330 static void __disable_trace_kprobe(struct trace_probe *tp) 331 { 332 struct trace_probe *pos; 333 struct trace_kprobe *tk; 334 335 list_for_each_entry(pos, trace_probe_probe_list(tp), list) { 336 tk = container_of(pos, struct trace_kprobe, tp); 337 if (!trace_kprobe_is_registered(tk)) 338 continue; 339 if (trace_kprobe_is_return(tk)) 340 disable_kretprobe(&tk->rp); 341 else 342 disable_kprobe(&tk->rp.kp); 343 } 344 } 345 346 /* 347 * Enable trace_probe 348 * if the file is NULL, enable "perf" handler, or enable "trace" handler. 349 */ 350 static int enable_trace_kprobe(struct trace_event_call *call, 351 struct trace_event_file *file) 352 { 353 struct trace_probe *pos, *tp; 354 struct trace_kprobe *tk; 355 bool enabled; 356 int ret = 0; 357 358 tp = trace_probe_primary_from_call(call); 359 if (WARN_ON_ONCE(!tp)) 360 return -ENODEV; 361 enabled = trace_probe_is_enabled(tp); 362 363 /* This also changes "enabled" state */ 364 if (file) { 365 ret = trace_probe_add_file(tp, file); 366 if (ret) 367 return ret; 368 } else 369 trace_probe_set_flag(tp, TP_FLAG_PROFILE); 370 371 if (enabled) 372 return 0; 373 374 list_for_each_entry(pos, trace_probe_probe_list(tp), list) { 375 tk = container_of(pos, struct trace_kprobe, tp); 376 if (trace_kprobe_has_gone(tk)) 377 continue; 378 ret = __enable_trace_kprobe(tk); 379 if (ret) 380 break; 381 enabled = true; 382 } 383 384 if (ret) { 385 /* Failed to enable one of them. Roll back all */ 386 if (enabled) 387 __disable_trace_kprobe(tp); 388 if (file) 389 trace_probe_remove_file(tp, file); 390 else 391 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 392 } 393 394 return ret; 395 } 396 397 /* 398 * Disable trace_probe 399 * if the file is NULL, disable "perf" handler, or disable "trace" handler. 400 */ 401 static int disable_trace_kprobe(struct trace_event_call *call, 402 struct trace_event_file *file) 403 { 404 struct trace_probe *tp; 405 406 tp = trace_probe_primary_from_call(call); 407 if (WARN_ON_ONCE(!tp)) 408 return -ENODEV; 409 410 if (file) { 411 if (!trace_probe_get_file_link(tp, file)) 412 return -ENOENT; 413 if (!trace_probe_has_single_file(tp)) 414 goto out; 415 trace_probe_clear_flag(tp, TP_FLAG_TRACE); 416 } else 417 trace_probe_clear_flag(tp, TP_FLAG_PROFILE); 418 419 if (!trace_probe_is_enabled(tp)) 420 __disable_trace_kprobe(tp); 421 422 out: 423 if (file) 424 /* 425 * Synchronization is done in below function. For perf event, 426 * file == NULL and perf_trace_event_unreg() calls 427 * tracepoint_synchronize_unregister() to ensure synchronize 428 * event. We don't need to care about it. 429 */ 430 trace_probe_remove_file(tp, file); 431 432 return 0; 433 } 434 435 #if defined(CONFIG_KPROBES_ON_FTRACE) && \ 436 !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE) 437 static bool __within_notrace_func(unsigned long addr) 438 { 439 unsigned long offset, size; 440 441 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) 442 return false; 443 444 /* Get the entry address of the target function */ 445 addr -= offset; 446 447 /* 448 * Since ftrace_location_range() does inclusive range check, we need 449 * to subtract 1 byte from the end address. 450 */ 451 return !ftrace_location_range(addr, addr + size - 1); 452 } 453 454 static bool within_notrace_func(struct trace_kprobe *tk) 455 { 456 unsigned long addr = addr = trace_kprobe_address(tk); 457 char symname[KSYM_NAME_LEN], *p; 458 459 if (!__within_notrace_func(addr)) 460 return false; 461 462 /* Check if the address is on a suffixed-symbol */ 463 if (!lookup_symbol_name(addr, symname)) { 464 p = strchr(symname, '.'); 465 if (!p) 466 return true; 467 *p = '\0'; 468 addr = (unsigned long)kprobe_lookup_name(symname, 0); 469 if (addr) 470 return __within_notrace_func(addr); 471 } 472 473 return true; 474 } 475 #else 476 #define within_notrace_func(tk) (false) 477 #endif 478 479 /* Internal register function - just handle k*probes and flags */ 480 static int __register_trace_kprobe(struct trace_kprobe *tk) 481 { 482 int i, ret; 483 484 ret = security_locked_down(LOCKDOWN_KPROBES); 485 if (ret) 486 return ret; 487 488 if (trace_kprobe_is_registered(tk)) 489 return -EINVAL; 490 491 if (within_notrace_func(tk)) { 492 pr_warn("Could not probe notrace function %s\n", 493 trace_kprobe_symbol(tk)); 494 return -EINVAL; 495 } 496 497 for (i = 0; i < tk->tp.nr_args; i++) { 498 ret = traceprobe_update_arg(&tk->tp.args[i]); 499 if (ret) 500 return ret; 501 } 502 503 /* Set/clear disabled flag according to tp->flag */ 504 if (trace_probe_is_enabled(&tk->tp)) 505 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; 506 else 507 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; 508 509 if (trace_kprobe_is_return(tk)) 510 ret = register_kretprobe(&tk->rp); 511 else 512 ret = register_kprobe(&tk->rp.kp); 513 514 return ret; 515 } 516 517 /* Internal unregister function - just handle k*probes and flags */ 518 static void __unregister_trace_kprobe(struct trace_kprobe *tk) 519 { 520 if (trace_kprobe_is_registered(tk)) { 521 if (trace_kprobe_is_return(tk)) 522 unregister_kretprobe(&tk->rp); 523 else 524 unregister_kprobe(&tk->rp.kp); 525 /* Cleanup kprobe for reuse and mark it unregistered */ 526 INIT_HLIST_NODE(&tk->rp.kp.hlist); 527 INIT_LIST_HEAD(&tk->rp.kp.list); 528 if (tk->rp.kp.symbol_name) 529 tk->rp.kp.addr = NULL; 530 } 531 } 532 533 /* Unregister a trace_probe and probe_event */ 534 static int unregister_trace_kprobe(struct trace_kprobe *tk) 535 { 536 /* If other probes are on the event, just unregister kprobe */ 537 if (trace_probe_has_sibling(&tk->tp)) 538 goto unreg; 539 540 /* Enabled event can not be unregistered */ 541 if (trace_probe_is_enabled(&tk->tp)) 542 return -EBUSY; 543 544 /* Will fail if probe is being used by ftrace or perf */ 545 if (unregister_kprobe_event(tk)) 546 return -EBUSY; 547 548 unreg: 549 __unregister_trace_kprobe(tk); 550 dyn_event_remove(&tk->devent); 551 trace_probe_unlink(&tk->tp); 552 553 return 0; 554 } 555 556 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig, 557 struct trace_kprobe *comp) 558 { 559 struct trace_probe_event *tpe = orig->tp.event; 560 struct trace_probe *pos; 561 int i; 562 563 list_for_each_entry(pos, &tpe->probes, list) { 564 orig = container_of(pos, struct trace_kprobe, tp); 565 if (strcmp(trace_kprobe_symbol(orig), 566 trace_kprobe_symbol(comp)) || 567 trace_kprobe_offset(orig) != trace_kprobe_offset(comp)) 568 continue; 569 570 /* 571 * trace_probe_compare_arg_type() ensured that nr_args and 572 * each argument name and type are same. Let's compare comm. 573 */ 574 for (i = 0; i < orig->tp.nr_args; i++) { 575 if (strcmp(orig->tp.args[i].comm, 576 comp->tp.args[i].comm)) 577 break; 578 } 579 580 if (i == orig->tp.nr_args) 581 return true; 582 } 583 584 return false; 585 } 586 587 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to) 588 { 589 int ret; 590 591 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp); 592 if (ret) { 593 /* Note that argument starts index = 2 */ 594 trace_probe_log_set_index(ret + 1); 595 trace_probe_log_err(0, DIFF_ARG_TYPE); 596 return -EEXIST; 597 } 598 if (trace_kprobe_has_same_kprobe(to, tk)) { 599 trace_probe_log_set_index(0); 600 trace_probe_log_err(0, SAME_PROBE); 601 return -EEXIST; 602 } 603 604 /* Append to existing event */ 605 ret = trace_probe_append(&tk->tp, &to->tp); 606 if (ret) 607 return ret; 608 609 /* Register k*probe */ 610 ret = __register_trace_kprobe(tk); 611 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 612 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 613 ret = 0; 614 } 615 616 if (ret) 617 trace_probe_unlink(&tk->tp); 618 else 619 dyn_event_add(&tk->devent); 620 621 return ret; 622 } 623 624 /* Register a trace_probe and probe_event */ 625 static int register_trace_kprobe(struct trace_kprobe *tk) 626 { 627 struct trace_kprobe *old_tk; 628 int ret; 629 630 mutex_lock(&event_mutex); 631 632 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp), 633 trace_probe_group_name(&tk->tp)); 634 if (old_tk) { 635 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) { 636 trace_probe_log_set_index(0); 637 trace_probe_log_err(0, DIFF_PROBE_TYPE); 638 ret = -EEXIST; 639 } else { 640 ret = append_trace_kprobe(tk, old_tk); 641 } 642 goto end; 643 } 644 645 /* Register new event */ 646 ret = register_kprobe_event(tk); 647 if (ret) { 648 pr_warn("Failed to register probe event(%d)\n", ret); 649 goto end; 650 } 651 652 /* Register k*probe */ 653 ret = __register_trace_kprobe(tk); 654 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 655 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 656 ret = 0; 657 } 658 659 if (ret < 0) 660 unregister_kprobe_event(tk); 661 else 662 dyn_event_add(&tk->devent); 663 664 end: 665 mutex_unlock(&event_mutex); 666 return ret; 667 } 668 669 /* Module notifier call back, checking event on the module */ 670 static int trace_kprobe_module_callback(struct notifier_block *nb, 671 unsigned long val, void *data) 672 { 673 struct module *mod = data; 674 struct dyn_event *pos; 675 struct trace_kprobe *tk; 676 int ret; 677 678 if (val != MODULE_STATE_COMING) 679 return NOTIFY_DONE; 680 681 /* Update probes on coming module */ 682 mutex_lock(&event_mutex); 683 for_each_trace_kprobe(tk, pos) { 684 if (trace_kprobe_within_module(tk, mod)) { 685 /* Don't need to check busy - this should have gone. */ 686 __unregister_trace_kprobe(tk); 687 ret = __register_trace_kprobe(tk); 688 if (ret) 689 pr_warn("Failed to re-register probe %s on %s: %d\n", 690 trace_probe_name(&tk->tp), 691 mod->name, ret); 692 } 693 } 694 mutex_unlock(&event_mutex); 695 696 return NOTIFY_DONE; 697 } 698 699 static struct notifier_block trace_kprobe_module_nb = { 700 .notifier_call = trace_kprobe_module_callback, 701 .priority = 1 /* Invoked after kprobe module callback */ 702 }; 703 704 /* Convert certain expected symbols into '_' when generating event names */ 705 static inline void sanitize_event_name(char *name) 706 { 707 while (*name++ != '\0') 708 if (*name == ':' || *name == '.') 709 *name = '_'; 710 } 711 712 static int trace_kprobe_create(int argc, const char *argv[]) 713 { 714 /* 715 * Argument syntax: 716 * - Add kprobe: 717 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] 718 * - Add kretprobe: 719 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] 720 * Fetch args: 721 * $retval : fetch return value 722 * $stack : fetch stack address 723 * $stackN : fetch Nth of stack (N:0-) 724 * $comm : fetch current task comm 725 * @ADDR : fetch memory at ADDR (ADDR should be in kernel) 726 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) 727 * %REG : fetch register REG 728 * Dereferencing memory fetch: 729 * +|-offs(ARG) : fetch memory at ARG +|- offs address. 730 * Alias name of args: 731 * NAME=FETCHARG : set NAME as alias of FETCHARG. 732 * Type of args: 733 * FETCHARG:TYPE : use TYPE instead of unsigned long. 734 */ 735 struct trace_kprobe *tk = NULL; 736 int i, len, ret = 0; 737 bool is_return = false; 738 char *symbol = NULL, *tmp = NULL; 739 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM; 740 int maxactive = 0; 741 long offset = 0; 742 void *addr = NULL; 743 char buf[MAX_EVENT_NAME_LEN]; 744 unsigned int flags = TPARG_FL_KERNEL; 745 746 switch (argv[0][0]) { 747 case 'r': 748 is_return = true; 749 flags |= TPARG_FL_RETURN; 750 break; 751 case 'p': 752 break; 753 default: 754 return -ECANCELED; 755 } 756 if (argc < 2) 757 return -ECANCELED; 758 759 trace_probe_log_init("trace_kprobe", argc, argv); 760 761 event = strchr(&argv[0][1], ':'); 762 if (event) 763 event++; 764 765 if (isdigit(argv[0][1])) { 766 if (!is_return) { 767 trace_probe_log_err(1, MAXACT_NO_KPROBE); 768 goto parse_error; 769 } 770 if (event) 771 len = event - &argv[0][1] - 1; 772 else 773 len = strlen(&argv[0][1]); 774 if (len > MAX_EVENT_NAME_LEN - 1) { 775 trace_probe_log_err(1, BAD_MAXACT); 776 goto parse_error; 777 } 778 memcpy(buf, &argv[0][1], len); 779 buf[len] = '\0'; 780 ret = kstrtouint(buf, 0, &maxactive); 781 if (ret || !maxactive) { 782 trace_probe_log_err(1, BAD_MAXACT); 783 goto parse_error; 784 } 785 /* kretprobes instances are iterated over via a list. The 786 * maximum should stay reasonable. 787 */ 788 if (maxactive > KRETPROBE_MAXACTIVE_MAX) { 789 trace_probe_log_err(1, MAXACT_TOO_BIG); 790 goto parse_error; 791 } 792 } 793 794 /* try to parse an address. if that fails, try to read the 795 * input as a symbol. */ 796 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { 797 trace_probe_log_set_index(1); 798 /* Check whether uprobe event specified */ 799 if (strchr(argv[1], '/') && strchr(argv[1], ':')) { 800 ret = -ECANCELED; 801 goto error; 802 } 803 /* a symbol specified */ 804 symbol = kstrdup(argv[1], GFP_KERNEL); 805 if (!symbol) 806 return -ENOMEM; 807 /* TODO: support .init module functions */ 808 ret = traceprobe_split_symbol_offset(symbol, &offset); 809 if (ret || offset < 0 || offset > UINT_MAX) { 810 trace_probe_log_err(0, BAD_PROBE_ADDR); 811 goto parse_error; 812 } 813 if (kprobe_on_func_entry(NULL, symbol, offset)) 814 flags |= TPARG_FL_FENTRY; 815 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { 816 trace_probe_log_err(0, BAD_RETPROBE); 817 goto parse_error; 818 } 819 } 820 821 trace_probe_log_set_index(0); 822 if (event) { 823 ret = traceprobe_parse_event_name(&event, &group, buf, 824 event - argv[0]); 825 if (ret) 826 goto parse_error; 827 } else { 828 /* Make a new event name */ 829 if (symbol) 830 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", 831 is_return ? 'r' : 'p', symbol, offset); 832 else 833 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", 834 is_return ? 'r' : 'p', addr); 835 sanitize_event_name(buf); 836 event = buf; 837 } 838 839 /* setup a probe */ 840 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, 841 argc - 2, is_return); 842 if (IS_ERR(tk)) { 843 ret = PTR_ERR(tk); 844 /* This must return -ENOMEM, else there is a bug */ 845 WARN_ON_ONCE(ret != -ENOMEM); 846 goto out; /* We know tk is not allocated */ 847 } 848 argc -= 2; argv += 2; 849 850 /* parse arguments */ 851 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 852 tmp = kstrdup(argv[i], GFP_KERNEL); 853 if (!tmp) { 854 ret = -ENOMEM; 855 goto error; 856 } 857 858 trace_probe_log_set_index(i + 2); 859 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags); 860 kfree(tmp); 861 if (ret) 862 goto error; /* This can be -ENOMEM */ 863 } 864 865 ret = traceprobe_set_print_fmt(&tk->tp, is_return); 866 if (ret < 0) 867 goto error; 868 869 ret = register_trace_kprobe(tk); 870 if (ret) { 871 trace_probe_log_set_index(1); 872 if (ret == -EILSEQ) 873 trace_probe_log_err(0, BAD_INSN_BNDRY); 874 else if (ret == -ENOENT) 875 trace_probe_log_err(0, BAD_PROBE_ADDR); 876 else if (ret != -ENOMEM && ret != -EEXIST) 877 trace_probe_log_err(0, FAIL_REG_PROBE); 878 goto error; 879 } 880 881 out: 882 trace_probe_log_clear(); 883 kfree(symbol); 884 return ret; 885 886 parse_error: 887 ret = -EINVAL; 888 error: 889 free_trace_kprobe(tk); 890 goto out; 891 } 892 893 static int create_or_delete_trace_kprobe(int argc, char **argv) 894 { 895 int ret; 896 897 if (argv[0][0] == '-') 898 return dyn_event_release(argc, argv, &trace_kprobe_ops); 899 900 ret = trace_kprobe_create(argc, (const char **)argv); 901 return ret == -ECANCELED ? -EINVAL : ret; 902 } 903 904 static int trace_kprobe_run_command(struct dynevent_cmd *cmd) 905 { 906 return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe); 907 } 908 909 /** 910 * kprobe_event_cmd_init - Initialize a kprobe event command object 911 * @cmd: A pointer to the dynevent_cmd struct representing the new event 912 * @buf: A pointer to the buffer used to build the command 913 * @maxlen: The length of the buffer passed in @buf 914 * 915 * Initialize a synthetic event command object. Use this before 916 * calling any of the other kprobe_event functions. 917 */ 918 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen) 919 { 920 dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE, 921 trace_kprobe_run_command); 922 } 923 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init); 924 925 /** 926 * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list 927 * @cmd: A pointer to the dynevent_cmd struct representing the new event 928 * @name: The name of the kprobe event 929 * @loc: The location of the kprobe event 930 * @kretprobe: Is this a return probe? 931 * @args: Variable number of arg (pairs), one pair for each field 932 * 933 * NOTE: Users normally won't want to call this function directly, but 934 * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically 935 * adds a NULL to the end of the arg list. If this function is used 936 * directly, make sure the last arg in the variable arg list is NULL. 937 * 938 * Generate a kprobe event command to be executed by 939 * kprobe_event_gen_cmd_end(). This function can be used to generate the 940 * complete command or only the first part of it; in the latter case, 941 * kprobe_event_add_fields() can be used to add more fields following this. 942 * 943 * Return: 0 if successful, error otherwise. 944 */ 945 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe, 946 const char *name, const char *loc, ...) 947 { 948 char buf[MAX_EVENT_NAME_LEN]; 949 struct dynevent_arg arg; 950 va_list args; 951 int ret; 952 953 if (cmd->type != DYNEVENT_TYPE_KPROBE) 954 return -EINVAL; 955 956 if (kretprobe) 957 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name); 958 else 959 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name); 960 961 ret = dynevent_str_add(cmd, buf); 962 if (ret) 963 return ret; 964 965 dynevent_arg_init(&arg, 0); 966 arg.str = loc; 967 ret = dynevent_arg_add(cmd, &arg, NULL); 968 if (ret) 969 return ret; 970 971 va_start(args, loc); 972 for (;;) { 973 const char *field; 974 975 field = va_arg(args, const char *); 976 if (!field) 977 break; 978 979 if (++cmd->n_fields > MAX_TRACE_ARGS) { 980 ret = -EINVAL; 981 break; 982 } 983 984 arg.str = field; 985 ret = dynevent_arg_add(cmd, &arg, NULL); 986 if (ret) 987 break; 988 } 989 va_end(args); 990 991 return ret; 992 } 993 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start); 994 995 /** 996 * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list 997 * @cmd: A pointer to the dynevent_cmd struct representing the new event 998 * @args: Variable number of arg (pairs), one pair for each field 999 * 1000 * NOTE: Users normally won't want to call this function directly, but 1001 * rather use the kprobe_event_add_fields() wrapper, which 1002 * automatically adds a NULL to the end of the arg list. If this 1003 * function is used directly, make sure the last arg in the variable 1004 * arg list is NULL. 1005 * 1006 * Add probe fields to an existing kprobe command using a variable 1007 * list of args. Fields are added in the same order they're listed. 1008 * 1009 * Return: 0 if successful, error otherwise. 1010 */ 1011 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...) 1012 { 1013 struct dynevent_arg arg; 1014 va_list args; 1015 int ret = 0; 1016 1017 if (cmd->type != DYNEVENT_TYPE_KPROBE) 1018 return -EINVAL; 1019 1020 dynevent_arg_init(&arg, 0); 1021 1022 va_start(args, cmd); 1023 for (;;) { 1024 const char *field; 1025 1026 field = va_arg(args, const char *); 1027 if (!field) 1028 break; 1029 1030 if (++cmd->n_fields > MAX_TRACE_ARGS) { 1031 ret = -EINVAL; 1032 break; 1033 } 1034 1035 arg.str = field; 1036 ret = dynevent_arg_add(cmd, &arg, NULL); 1037 if (ret) 1038 break; 1039 } 1040 va_end(args); 1041 1042 return ret; 1043 } 1044 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields); 1045 1046 /** 1047 * kprobe_event_delete - Delete a kprobe event 1048 * @name: The name of the kprobe event to delete 1049 * 1050 * Delete a kprobe event with the give @name from kernel code rather 1051 * than directly from the command line. 1052 * 1053 * Return: 0 if successful, error otherwise. 1054 */ 1055 int kprobe_event_delete(const char *name) 1056 { 1057 char buf[MAX_EVENT_NAME_LEN]; 1058 1059 snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name); 1060 1061 return trace_run_command(buf, create_or_delete_trace_kprobe); 1062 } 1063 EXPORT_SYMBOL_GPL(kprobe_event_delete); 1064 1065 static int trace_kprobe_release(struct dyn_event *ev) 1066 { 1067 struct trace_kprobe *tk = to_trace_kprobe(ev); 1068 int ret = unregister_trace_kprobe(tk); 1069 1070 if (!ret) 1071 free_trace_kprobe(tk); 1072 return ret; 1073 } 1074 1075 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) 1076 { 1077 struct trace_kprobe *tk = to_trace_kprobe(ev); 1078 int i; 1079 1080 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 1081 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), 1082 trace_probe_name(&tk->tp)); 1083 1084 if (!tk->symbol) 1085 seq_printf(m, " 0x%p", tk->rp.kp.addr); 1086 else if (tk->rp.kp.offset) 1087 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 1088 tk->rp.kp.offset); 1089 else 1090 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 1091 1092 for (i = 0; i < tk->tp.nr_args; i++) 1093 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 1094 seq_putc(m, '\n'); 1095 1096 return 0; 1097 } 1098 1099 static int probes_seq_show(struct seq_file *m, void *v) 1100 { 1101 struct dyn_event *ev = v; 1102 1103 if (!is_trace_kprobe(ev)) 1104 return 0; 1105 1106 return trace_kprobe_show(m, ev); 1107 } 1108 1109 static const struct seq_operations probes_seq_op = { 1110 .start = dyn_event_seq_start, 1111 .next = dyn_event_seq_next, 1112 .stop = dyn_event_seq_stop, 1113 .show = probes_seq_show 1114 }; 1115 1116 static int probes_open(struct inode *inode, struct file *file) 1117 { 1118 int ret; 1119 1120 ret = security_locked_down(LOCKDOWN_TRACEFS); 1121 if (ret) 1122 return ret; 1123 1124 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 1125 ret = dyn_events_release_all(&trace_kprobe_ops); 1126 if (ret < 0) 1127 return ret; 1128 } 1129 1130 return seq_open(file, &probes_seq_op); 1131 } 1132 1133 static ssize_t probes_write(struct file *file, const char __user *buffer, 1134 size_t count, loff_t *ppos) 1135 { 1136 return trace_parse_run_command(file, buffer, count, ppos, 1137 create_or_delete_trace_kprobe); 1138 } 1139 1140 static const struct file_operations kprobe_events_ops = { 1141 .owner = THIS_MODULE, 1142 .open = probes_open, 1143 .read = seq_read, 1144 .llseek = seq_lseek, 1145 .release = seq_release, 1146 .write = probes_write, 1147 }; 1148 1149 /* Probes profiling interfaces */ 1150 static int probes_profile_seq_show(struct seq_file *m, void *v) 1151 { 1152 struct dyn_event *ev = v; 1153 struct trace_kprobe *tk; 1154 1155 if (!is_trace_kprobe(ev)) 1156 return 0; 1157 1158 tk = to_trace_kprobe(ev); 1159 seq_printf(m, " %-44s %15lu %15lu\n", 1160 trace_probe_name(&tk->tp), 1161 trace_kprobe_nhit(tk), 1162 tk->rp.kp.nmissed); 1163 1164 return 0; 1165 } 1166 1167 static const struct seq_operations profile_seq_op = { 1168 .start = dyn_event_seq_start, 1169 .next = dyn_event_seq_next, 1170 .stop = dyn_event_seq_stop, 1171 .show = probes_profile_seq_show 1172 }; 1173 1174 static int profile_open(struct inode *inode, struct file *file) 1175 { 1176 int ret; 1177 1178 ret = security_locked_down(LOCKDOWN_TRACEFS); 1179 if (ret) 1180 return ret; 1181 1182 return seq_open(file, &profile_seq_op); 1183 } 1184 1185 static const struct file_operations kprobe_profile_ops = { 1186 .owner = THIS_MODULE, 1187 .open = profile_open, 1188 .read = seq_read, 1189 .llseek = seq_lseek, 1190 .release = seq_release, 1191 }; 1192 1193 /* Kprobe specific fetch functions */ 1194 1195 /* Return the length of string -- including null terminal byte */ 1196 static nokprobe_inline int 1197 fetch_store_strlen(unsigned long addr) 1198 { 1199 int ret, len = 0; 1200 u8 c; 1201 1202 do { 1203 ret = probe_kernel_read(&c, (u8 *)addr + len, 1); 1204 len++; 1205 } while (c && ret == 0 && len < MAX_STRING_SIZE); 1206 1207 return (ret < 0) ? ret : len; 1208 } 1209 1210 /* Return the length of string -- including null terminal byte */ 1211 static nokprobe_inline int 1212 fetch_store_strlen_user(unsigned long addr) 1213 { 1214 const void __user *uaddr = (__force const void __user *)addr; 1215 1216 return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE); 1217 } 1218 1219 /* 1220 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max 1221 * length and relative data location. 1222 */ 1223 static nokprobe_inline int 1224 fetch_store_string(unsigned long addr, void *dest, void *base) 1225 { 1226 int maxlen = get_loc_len(*(u32 *)dest); 1227 void *__dest; 1228 long ret; 1229 1230 if (unlikely(!maxlen)) 1231 return -ENOMEM; 1232 1233 __dest = get_loc_data(dest, base); 1234 1235 /* 1236 * Try to get string again, since the string can be changed while 1237 * probing. 1238 */ 1239 ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen); 1240 if (ret >= 0) 1241 *(u32 *)dest = make_data_loc(ret, __dest - base); 1242 1243 return ret; 1244 } 1245 1246 /* 1247 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf 1248 * with max length and relative data location. 1249 */ 1250 static nokprobe_inline int 1251 fetch_store_string_user(unsigned long addr, void *dest, void *base) 1252 { 1253 const void __user *uaddr = (__force const void __user *)addr; 1254 int maxlen = get_loc_len(*(u32 *)dest); 1255 void *__dest; 1256 long ret; 1257 1258 if (unlikely(!maxlen)) 1259 return -ENOMEM; 1260 1261 __dest = get_loc_data(dest, base); 1262 1263 ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen); 1264 if (ret >= 0) 1265 *(u32 *)dest = make_data_loc(ret, __dest - base); 1266 1267 return ret; 1268 } 1269 1270 static nokprobe_inline int 1271 probe_mem_read(void *dest, void *src, size_t size) 1272 { 1273 return probe_kernel_read(dest, src, size); 1274 } 1275 1276 static nokprobe_inline int 1277 probe_mem_read_user(void *dest, void *src, size_t size) 1278 { 1279 const void __user *uaddr = (__force const void __user *)src; 1280 1281 return probe_user_read(dest, uaddr, size); 1282 } 1283 1284 /* Note that we don't verify it, since the code does not come from user space */ 1285 static int 1286 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 1287 void *base) 1288 { 1289 unsigned long val; 1290 1291 retry: 1292 /* 1st stage: get value from context */ 1293 switch (code->op) { 1294 case FETCH_OP_REG: 1295 val = regs_get_register(regs, code->param); 1296 break; 1297 case FETCH_OP_STACK: 1298 val = regs_get_kernel_stack_nth(regs, code->param); 1299 break; 1300 case FETCH_OP_STACKP: 1301 val = kernel_stack_pointer(regs); 1302 break; 1303 case FETCH_OP_RETVAL: 1304 val = regs_return_value(regs); 1305 break; 1306 case FETCH_OP_IMM: 1307 val = code->immediate; 1308 break; 1309 case FETCH_OP_COMM: 1310 val = (unsigned long)current->comm; 1311 break; 1312 case FETCH_OP_DATA: 1313 val = (unsigned long)code->data; 1314 break; 1315 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 1316 case FETCH_OP_ARG: 1317 val = regs_get_kernel_argument(regs, code->param); 1318 break; 1319 #endif 1320 case FETCH_NOP_SYMBOL: /* Ignore a place holder */ 1321 code++; 1322 goto retry; 1323 default: 1324 return -EILSEQ; 1325 } 1326 code++; 1327 1328 return process_fetch_insn_bottom(code, val, dest, base); 1329 } 1330 NOKPROBE_SYMBOL(process_fetch_insn) 1331 1332 /* Kprobe handler */ 1333 static nokprobe_inline void 1334 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 1335 struct trace_event_file *trace_file) 1336 { 1337 struct kprobe_trace_entry_head *entry; 1338 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1339 struct trace_event_buffer fbuffer; 1340 int dsize; 1341 1342 WARN_ON(call != trace_file->event_call); 1343 1344 if (trace_trigger_soft_disabled(trace_file)) 1345 return; 1346 1347 local_save_flags(fbuffer.flags); 1348 fbuffer.pc = preempt_count(); 1349 fbuffer.trace_file = trace_file; 1350 1351 dsize = __get_data_size(&tk->tp, regs); 1352 1353 fbuffer.event = 1354 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file, 1355 call->event.type, 1356 sizeof(*entry) + tk->tp.size + dsize, 1357 fbuffer.flags, fbuffer.pc); 1358 if (!fbuffer.event) 1359 return; 1360 1361 fbuffer.regs = regs; 1362 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); 1363 entry->ip = (unsigned long)tk->rp.kp.addr; 1364 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1365 1366 trace_event_buffer_commit(&fbuffer); 1367 } 1368 1369 static void 1370 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 1371 { 1372 struct event_file_link *link; 1373 1374 trace_probe_for_each_link_rcu(link, &tk->tp) 1375 __kprobe_trace_func(tk, regs, link->file); 1376 } 1377 NOKPROBE_SYMBOL(kprobe_trace_func); 1378 1379 /* Kretprobe handler */ 1380 static nokprobe_inline void 1381 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1382 struct pt_regs *regs, 1383 struct trace_event_file *trace_file) 1384 { 1385 struct kretprobe_trace_entry_head *entry; 1386 struct trace_event_buffer fbuffer; 1387 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1388 int dsize; 1389 1390 WARN_ON(call != trace_file->event_call); 1391 1392 if (trace_trigger_soft_disabled(trace_file)) 1393 return; 1394 1395 local_save_flags(fbuffer.flags); 1396 fbuffer.pc = preempt_count(); 1397 fbuffer.trace_file = trace_file; 1398 1399 dsize = __get_data_size(&tk->tp, regs); 1400 fbuffer.event = 1401 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file, 1402 call->event.type, 1403 sizeof(*entry) + tk->tp.size + dsize, 1404 fbuffer.flags, fbuffer.pc); 1405 if (!fbuffer.event) 1406 return; 1407 1408 fbuffer.regs = regs; 1409 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); 1410 entry->func = (unsigned long)tk->rp.kp.addr; 1411 entry->ret_ip = (unsigned long)ri->ret_addr; 1412 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1413 1414 trace_event_buffer_commit(&fbuffer); 1415 } 1416 1417 static void 1418 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1419 struct pt_regs *regs) 1420 { 1421 struct event_file_link *link; 1422 1423 trace_probe_for_each_link_rcu(link, &tk->tp) 1424 __kretprobe_trace_func(tk, ri, regs, link->file); 1425 } 1426 NOKPROBE_SYMBOL(kretprobe_trace_func); 1427 1428 /* Event entry printers */ 1429 static enum print_line_t 1430 print_kprobe_event(struct trace_iterator *iter, int flags, 1431 struct trace_event *event) 1432 { 1433 struct kprobe_trace_entry_head *field; 1434 struct trace_seq *s = &iter->seq; 1435 struct trace_probe *tp; 1436 1437 field = (struct kprobe_trace_entry_head *)iter->ent; 1438 tp = trace_probe_primary_from_call( 1439 container_of(event, struct trace_event_call, event)); 1440 if (WARN_ON_ONCE(!tp)) 1441 goto out; 1442 1443 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1444 1445 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) 1446 goto out; 1447 1448 trace_seq_putc(s, ')'); 1449 1450 if (print_probe_args(s, tp->args, tp->nr_args, 1451 (u8 *)&field[1], field) < 0) 1452 goto out; 1453 1454 trace_seq_putc(s, '\n'); 1455 out: 1456 return trace_handle_return(s); 1457 } 1458 1459 static enum print_line_t 1460 print_kretprobe_event(struct trace_iterator *iter, int flags, 1461 struct trace_event *event) 1462 { 1463 struct kretprobe_trace_entry_head *field; 1464 struct trace_seq *s = &iter->seq; 1465 struct trace_probe *tp; 1466 1467 field = (struct kretprobe_trace_entry_head *)iter->ent; 1468 tp = trace_probe_primary_from_call( 1469 container_of(event, struct trace_event_call, event)); 1470 if (WARN_ON_ONCE(!tp)) 1471 goto out; 1472 1473 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1474 1475 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) 1476 goto out; 1477 1478 trace_seq_puts(s, " <- "); 1479 1480 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) 1481 goto out; 1482 1483 trace_seq_putc(s, ')'); 1484 1485 if (print_probe_args(s, tp->args, tp->nr_args, 1486 (u8 *)&field[1], field) < 0) 1487 goto out; 1488 1489 trace_seq_putc(s, '\n'); 1490 1491 out: 1492 return trace_handle_return(s); 1493 } 1494 1495 1496 static int kprobe_event_define_fields(struct trace_event_call *event_call) 1497 { 1498 int ret; 1499 struct kprobe_trace_entry_head field; 1500 struct trace_probe *tp; 1501 1502 tp = trace_probe_primary_from_call(event_call); 1503 if (WARN_ON_ONCE(!tp)) 1504 return -ENOENT; 1505 1506 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1507 1508 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1509 } 1510 1511 static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1512 { 1513 int ret; 1514 struct kretprobe_trace_entry_head field; 1515 struct trace_probe *tp; 1516 1517 tp = trace_probe_primary_from_call(event_call); 1518 if (WARN_ON_ONCE(!tp)) 1519 return -ENOENT; 1520 1521 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1522 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1523 1524 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1525 } 1526 1527 #ifdef CONFIG_PERF_EVENTS 1528 1529 /* Kprobe profile handler */ 1530 static int 1531 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1532 { 1533 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1534 struct kprobe_trace_entry_head *entry; 1535 struct hlist_head *head; 1536 int size, __size, dsize; 1537 int rctx; 1538 1539 if (bpf_prog_array_valid(call)) { 1540 unsigned long orig_ip = instruction_pointer(regs); 1541 int ret; 1542 1543 ret = trace_call_bpf(call, regs); 1544 1545 /* 1546 * We need to check and see if we modified the pc of the 1547 * pt_regs, and if so return 1 so that we don't do the 1548 * single stepping. 1549 */ 1550 if (orig_ip != instruction_pointer(regs)) 1551 return 1; 1552 if (!ret) 1553 return 0; 1554 } 1555 1556 head = this_cpu_ptr(call->perf_events); 1557 if (hlist_empty(head)) 1558 return 0; 1559 1560 dsize = __get_data_size(&tk->tp, regs); 1561 __size = sizeof(*entry) + tk->tp.size + dsize; 1562 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1563 size -= sizeof(u32); 1564 1565 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1566 if (!entry) 1567 return 0; 1568 1569 entry->ip = (unsigned long)tk->rp.kp.addr; 1570 memset(&entry[1], 0, dsize); 1571 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1572 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1573 head, NULL); 1574 return 0; 1575 } 1576 NOKPROBE_SYMBOL(kprobe_perf_func); 1577 1578 /* Kretprobe profile handler */ 1579 static void 1580 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1581 struct pt_regs *regs) 1582 { 1583 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1584 struct kretprobe_trace_entry_head *entry; 1585 struct hlist_head *head; 1586 int size, __size, dsize; 1587 int rctx; 1588 1589 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1590 return; 1591 1592 head = this_cpu_ptr(call->perf_events); 1593 if (hlist_empty(head)) 1594 return; 1595 1596 dsize = __get_data_size(&tk->tp, regs); 1597 __size = sizeof(*entry) + tk->tp.size + dsize; 1598 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1599 size -= sizeof(u32); 1600 1601 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1602 if (!entry) 1603 return; 1604 1605 entry->func = (unsigned long)tk->rp.kp.addr; 1606 entry->ret_ip = (unsigned long)ri->ret_addr; 1607 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1608 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1609 head, NULL); 1610 } 1611 NOKPROBE_SYMBOL(kretprobe_perf_func); 1612 1613 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, 1614 const char **symbol, u64 *probe_offset, 1615 u64 *probe_addr, bool perf_type_tracepoint) 1616 { 1617 const char *pevent = trace_event_name(event->tp_event); 1618 const char *group = event->tp_event->class->system; 1619 struct trace_kprobe *tk; 1620 1621 if (perf_type_tracepoint) 1622 tk = find_trace_kprobe(pevent, group); 1623 else 1624 tk = event->tp_event->data; 1625 if (!tk) 1626 return -EINVAL; 1627 1628 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE 1629 : BPF_FD_TYPE_KPROBE; 1630 if (tk->symbol) { 1631 *symbol = tk->symbol; 1632 *probe_offset = tk->rp.kp.offset; 1633 *probe_addr = 0; 1634 } else { 1635 *symbol = NULL; 1636 *probe_offset = 0; 1637 *probe_addr = (unsigned long)tk->rp.kp.addr; 1638 } 1639 return 0; 1640 } 1641 #endif /* CONFIG_PERF_EVENTS */ 1642 1643 /* 1644 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1645 * 1646 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1647 * lockless, but we can't race with this __init function. 1648 */ 1649 static int kprobe_register(struct trace_event_call *event, 1650 enum trace_reg type, void *data) 1651 { 1652 struct trace_event_file *file = data; 1653 1654 switch (type) { 1655 case TRACE_REG_REGISTER: 1656 return enable_trace_kprobe(event, file); 1657 case TRACE_REG_UNREGISTER: 1658 return disable_trace_kprobe(event, file); 1659 1660 #ifdef CONFIG_PERF_EVENTS 1661 case TRACE_REG_PERF_REGISTER: 1662 return enable_trace_kprobe(event, NULL); 1663 case TRACE_REG_PERF_UNREGISTER: 1664 return disable_trace_kprobe(event, NULL); 1665 case TRACE_REG_PERF_OPEN: 1666 case TRACE_REG_PERF_CLOSE: 1667 case TRACE_REG_PERF_ADD: 1668 case TRACE_REG_PERF_DEL: 1669 return 0; 1670 #endif 1671 } 1672 return 0; 1673 } 1674 1675 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1676 { 1677 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1678 int ret = 0; 1679 1680 raw_cpu_inc(*tk->nhit); 1681 1682 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1683 kprobe_trace_func(tk, regs); 1684 #ifdef CONFIG_PERF_EVENTS 1685 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1686 ret = kprobe_perf_func(tk, regs); 1687 #endif 1688 return ret; 1689 } 1690 NOKPROBE_SYMBOL(kprobe_dispatcher); 1691 1692 static int 1693 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1694 { 1695 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp); 1696 1697 raw_cpu_inc(*tk->nhit); 1698 1699 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1700 kretprobe_trace_func(tk, ri, regs); 1701 #ifdef CONFIG_PERF_EVENTS 1702 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1703 kretprobe_perf_func(tk, ri, regs); 1704 #endif 1705 return 0; /* We don't tweek kernel, so just return 0 */ 1706 } 1707 NOKPROBE_SYMBOL(kretprobe_dispatcher); 1708 1709 static struct trace_event_functions kretprobe_funcs = { 1710 .trace = print_kretprobe_event 1711 }; 1712 1713 static struct trace_event_functions kprobe_funcs = { 1714 .trace = print_kprobe_event 1715 }; 1716 1717 static struct trace_event_fields kretprobe_fields_array[] = { 1718 { .type = TRACE_FUNCTION_TYPE, 1719 .define_fields = kretprobe_event_define_fields }, 1720 {} 1721 }; 1722 1723 static struct trace_event_fields kprobe_fields_array[] = { 1724 { .type = TRACE_FUNCTION_TYPE, 1725 .define_fields = kprobe_event_define_fields }, 1726 {} 1727 }; 1728 1729 static inline void init_trace_event_call(struct trace_kprobe *tk) 1730 { 1731 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1732 1733 if (trace_kprobe_is_return(tk)) { 1734 call->event.funcs = &kretprobe_funcs; 1735 call->class->fields_array = kretprobe_fields_array; 1736 } else { 1737 call->event.funcs = &kprobe_funcs; 1738 call->class->fields_array = kprobe_fields_array; 1739 } 1740 1741 call->flags = TRACE_EVENT_FL_KPROBE; 1742 call->class->reg = kprobe_register; 1743 } 1744 1745 static int register_kprobe_event(struct trace_kprobe *tk) 1746 { 1747 init_trace_event_call(tk); 1748 1749 return trace_probe_register_event_call(&tk->tp); 1750 } 1751 1752 static int unregister_kprobe_event(struct trace_kprobe *tk) 1753 { 1754 return trace_probe_unregister_event_call(&tk->tp); 1755 } 1756 1757 #ifdef CONFIG_PERF_EVENTS 1758 /* create a trace_kprobe, but don't add it to global lists */ 1759 struct trace_event_call * 1760 create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 1761 bool is_return) 1762 { 1763 struct trace_kprobe *tk; 1764 int ret; 1765 char *event; 1766 1767 /* 1768 * local trace_kprobes are not added to dyn_event, so they are never 1769 * searched in find_trace_kprobe(). Therefore, there is no concern of 1770 * duplicated name here. 1771 */ 1772 event = func ? func : "DUMMY_EVENT"; 1773 1774 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, 1775 offs, 0 /* maxactive */, 0 /* nargs */, 1776 is_return); 1777 1778 if (IS_ERR(tk)) { 1779 pr_info("Failed to allocate trace_probe.(%d)\n", 1780 (int)PTR_ERR(tk)); 1781 return ERR_CAST(tk); 1782 } 1783 1784 init_trace_event_call(tk); 1785 1786 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) { 1787 ret = -ENOMEM; 1788 goto error; 1789 } 1790 1791 ret = __register_trace_kprobe(tk); 1792 if (ret < 0) 1793 goto error; 1794 1795 return trace_probe_event_call(&tk->tp); 1796 error: 1797 free_trace_kprobe(tk); 1798 return ERR_PTR(ret); 1799 } 1800 1801 void destroy_local_trace_kprobe(struct trace_event_call *event_call) 1802 { 1803 struct trace_kprobe *tk; 1804 1805 tk = trace_kprobe_primary_from_call(event_call); 1806 if (unlikely(!tk)) 1807 return; 1808 1809 if (trace_probe_is_enabled(&tk->tp)) { 1810 WARN_ON(1); 1811 return; 1812 } 1813 1814 __unregister_trace_kprobe(tk); 1815 1816 free_trace_kprobe(tk); 1817 } 1818 #endif /* CONFIG_PERF_EVENTS */ 1819 1820 static __init void enable_boot_kprobe_events(void) 1821 { 1822 struct trace_array *tr = top_trace_array(); 1823 struct trace_event_file *file; 1824 struct trace_kprobe *tk; 1825 struct dyn_event *pos; 1826 1827 mutex_lock(&event_mutex); 1828 for_each_trace_kprobe(tk, pos) { 1829 list_for_each_entry(file, &tr->events, list) 1830 if (file->event_call == trace_probe_event_call(&tk->tp)) 1831 trace_event_enable_disable(file, 1, 0); 1832 } 1833 mutex_unlock(&event_mutex); 1834 } 1835 1836 static __init void setup_boot_kprobe_events(void) 1837 { 1838 char *p, *cmd = kprobe_boot_events_buf; 1839 int ret; 1840 1841 strreplace(kprobe_boot_events_buf, ',', ' '); 1842 1843 while (cmd && *cmd != '\0') { 1844 p = strchr(cmd, ';'); 1845 if (p) 1846 *p++ = '\0'; 1847 1848 ret = trace_run_command(cmd, create_or_delete_trace_kprobe); 1849 if (ret) 1850 pr_warn("Failed to add event(%d): %s\n", ret, cmd); 1851 else 1852 kprobe_boot_events_enabled = true; 1853 1854 cmd = p; 1855 } 1856 1857 enable_boot_kprobe_events(); 1858 } 1859 1860 /* 1861 * Register dynevent at subsys_initcall. This allows kernel to setup kprobe 1862 * events in fs_initcall without tracefs. 1863 */ 1864 static __init int init_kprobe_trace_early(void) 1865 { 1866 int ret; 1867 1868 ret = dyn_event_register(&trace_kprobe_ops); 1869 if (ret) 1870 return ret; 1871 1872 if (register_module_notifier(&trace_kprobe_module_nb)) 1873 return -EINVAL; 1874 1875 return 0; 1876 } 1877 subsys_initcall(init_kprobe_trace_early); 1878 1879 /* Make a tracefs interface for controlling probe points */ 1880 static __init int init_kprobe_trace(void) 1881 { 1882 struct dentry *d_tracer; 1883 struct dentry *entry; 1884 1885 d_tracer = tracing_init_dentry(); 1886 if (IS_ERR(d_tracer)) 1887 return 0; 1888 1889 entry = tracefs_create_file("kprobe_events", 0644, d_tracer, 1890 NULL, &kprobe_events_ops); 1891 1892 /* Event list interface */ 1893 if (!entry) 1894 pr_warn("Could not create tracefs 'kprobe_events' entry\n"); 1895 1896 /* Profile interface */ 1897 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer, 1898 NULL, &kprobe_profile_ops); 1899 1900 if (!entry) 1901 pr_warn("Could not create tracefs 'kprobe_profile' entry\n"); 1902 1903 setup_boot_kprobe_events(); 1904 1905 return 0; 1906 } 1907 fs_initcall(init_kprobe_trace); 1908 1909 1910 #ifdef CONFIG_FTRACE_STARTUP_TEST 1911 static __init struct trace_event_file * 1912 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 1913 { 1914 struct trace_event_file *file; 1915 1916 list_for_each_entry(file, &tr->events, list) 1917 if (file->event_call == trace_probe_event_call(&tk->tp)) 1918 return file; 1919 1920 return NULL; 1921 } 1922 1923 /* 1924 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 1925 * stage, we can do this lockless. 1926 */ 1927 static __init int kprobe_trace_self_tests_init(void) 1928 { 1929 int ret, warn = 0; 1930 int (*target)(int, int, int, int, int, int); 1931 struct trace_kprobe *tk; 1932 struct trace_event_file *file; 1933 1934 if (tracing_is_disabled()) 1935 return -ENODEV; 1936 1937 if (kprobe_boot_events_enabled) { 1938 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n"); 1939 return 0; 1940 } 1941 1942 target = kprobe_trace_selftest_target; 1943 1944 pr_info("Testing kprobe tracing: "); 1945 1946 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)", 1947 create_or_delete_trace_kprobe); 1948 if (WARN_ON_ONCE(ret)) { 1949 pr_warn("error on probing function entry.\n"); 1950 warn++; 1951 } else { 1952 /* Enable trace point */ 1953 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1954 if (WARN_ON_ONCE(tk == NULL)) { 1955 pr_warn("error on getting new probe.\n"); 1956 warn++; 1957 } else { 1958 file = find_trace_probe_file(tk, top_trace_array()); 1959 if (WARN_ON_ONCE(file == NULL)) { 1960 pr_warn("error on getting probe file.\n"); 1961 warn++; 1962 } else 1963 enable_trace_kprobe( 1964 trace_probe_event_call(&tk->tp), file); 1965 } 1966 } 1967 1968 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval", 1969 create_or_delete_trace_kprobe); 1970 if (WARN_ON_ONCE(ret)) { 1971 pr_warn("error on probing function return.\n"); 1972 warn++; 1973 } else { 1974 /* Enable trace point */ 1975 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1976 if (WARN_ON_ONCE(tk == NULL)) { 1977 pr_warn("error on getting 2nd new probe.\n"); 1978 warn++; 1979 } else { 1980 file = find_trace_probe_file(tk, top_trace_array()); 1981 if (WARN_ON_ONCE(file == NULL)) { 1982 pr_warn("error on getting probe file.\n"); 1983 warn++; 1984 } else 1985 enable_trace_kprobe( 1986 trace_probe_event_call(&tk->tp), file); 1987 } 1988 } 1989 1990 if (warn) 1991 goto end; 1992 1993 ret = target(1, 2, 3, 4, 5, 6); 1994 1995 /* 1996 * Not expecting an error here, the check is only to prevent the 1997 * optimizer from removing the call to target() as otherwise there 1998 * are no side-effects and the call is never performed. 1999 */ 2000 if (ret != 21) 2001 warn++; 2002 2003 /* Disable trace points before removing it */ 2004 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 2005 if (WARN_ON_ONCE(tk == NULL)) { 2006 pr_warn("error on getting test probe.\n"); 2007 warn++; 2008 } else { 2009 if (trace_kprobe_nhit(tk) != 1) { 2010 pr_warn("incorrect number of testprobe hits\n"); 2011 warn++; 2012 } 2013 2014 file = find_trace_probe_file(tk, top_trace_array()); 2015 if (WARN_ON_ONCE(file == NULL)) { 2016 pr_warn("error on getting probe file.\n"); 2017 warn++; 2018 } else 2019 disable_trace_kprobe( 2020 trace_probe_event_call(&tk->tp), file); 2021 } 2022 2023 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 2024 if (WARN_ON_ONCE(tk == NULL)) { 2025 pr_warn("error on getting 2nd test probe.\n"); 2026 warn++; 2027 } else { 2028 if (trace_kprobe_nhit(tk) != 1) { 2029 pr_warn("incorrect number of testprobe2 hits\n"); 2030 warn++; 2031 } 2032 2033 file = find_trace_probe_file(tk, top_trace_array()); 2034 if (WARN_ON_ONCE(file == NULL)) { 2035 pr_warn("error on getting probe file.\n"); 2036 warn++; 2037 } else 2038 disable_trace_kprobe( 2039 trace_probe_event_call(&tk->tp), file); 2040 } 2041 2042 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe); 2043 if (WARN_ON_ONCE(ret)) { 2044 pr_warn("error on deleting a probe.\n"); 2045 warn++; 2046 } 2047 2048 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe); 2049 if (WARN_ON_ONCE(ret)) { 2050 pr_warn("error on deleting a probe.\n"); 2051 warn++; 2052 } 2053 2054 end: 2055 ret = dyn_events_release_all(&trace_kprobe_ops); 2056 if (WARN_ON_ONCE(ret)) { 2057 pr_warn("error on cleaning up probes.\n"); 2058 warn++; 2059 } 2060 /* 2061 * Wait for the optimizer work to finish. Otherwise it might fiddle 2062 * with probes in already freed __init text. 2063 */ 2064 wait_for_kprobe_optimizer(); 2065 if (warn) 2066 pr_cont("NG: Some tests are failed. Please check them.\n"); 2067 else 2068 pr_cont("OK\n"); 2069 return 0; 2070 } 2071 2072 late_initcall(kprobe_trace_self_tests_init); 2073 2074 #endif 2075