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); 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 int trace_kprobe_run_command(const char *command) 905 { 906 return trace_run_command(command, create_or_delete_trace_kprobe); 907 } 908 909 static int trace_kprobe_release(struct dyn_event *ev) 910 { 911 struct trace_kprobe *tk = to_trace_kprobe(ev); 912 int ret = unregister_trace_kprobe(tk); 913 914 if (!ret) 915 free_trace_kprobe(tk); 916 return ret; 917 } 918 919 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) 920 { 921 struct trace_kprobe *tk = to_trace_kprobe(ev); 922 int i; 923 924 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 925 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), 926 trace_probe_name(&tk->tp)); 927 928 if (!tk->symbol) 929 seq_printf(m, " 0x%p", tk->rp.kp.addr); 930 else if (tk->rp.kp.offset) 931 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 932 tk->rp.kp.offset); 933 else 934 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 935 936 for (i = 0; i < tk->tp.nr_args; i++) 937 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 938 seq_putc(m, '\n'); 939 940 return 0; 941 } 942 943 static int probes_seq_show(struct seq_file *m, void *v) 944 { 945 struct dyn_event *ev = v; 946 947 if (!is_trace_kprobe(ev)) 948 return 0; 949 950 return trace_kprobe_show(m, ev); 951 } 952 953 static const struct seq_operations probes_seq_op = { 954 .start = dyn_event_seq_start, 955 .next = dyn_event_seq_next, 956 .stop = dyn_event_seq_stop, 957 .show = probes_seq_show 958 }; 959 960 static int probes_open(struct inode *inode, struct file *file) 961 { 962 int ret; 963 964 ret = security_locked_down(LOCKDOWN_TRACEFS); 965 if (ret) 966 return ret; 967 968 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 969 ret = dyn_events_release_all(&trace_kprobe_ops); 970 if (ret < 0) 971 return ret; 972 } 973 974 return seq_open(file, &probes_seq_op); 975 } 976 977 static ssize_t probes_write(struct file *file, const char __user *buffer, 978 size_t count, loff_t *ppos) 979 { 980 return trace_parse_run_command(file, buffer, count, ppos, 981 create_or_delete_trace_kprobe); 982 } 983 984 static const struct file_operations kprobe_events_ops = { 985 .owner = THIS_MODULE, 986 .open = probes_open, 987 .read = seq_read, 988 .llseek = seq_lseek, 989 .release = seq_release, 990 .write = probes_write, 991 }; 992 993 /* Probes profiling interfaces */ 994 static int probes_profile_seq_show(struct seq_file *m, void *v) 995 { 996 struct dyn_event *ev = v; 997 struct trace_kprobe *tk; 998 999 if (!is_trace_kprobe(ev)) 1000 return 0; 1001 1002 tk = to_trace_kprobe(ev); 1003 seq_printf(m, " %-44s %15lu %15lu\n", 1004 trace_probe_name(&tk->tp), 1005 trace_kprobe_nhit(tk), 1006 tk->rp.kp.nmissed); 1007 1008 return 0; 1009 } 1010 1011 static const struct seq_operations profile_seq_op = { 1012 .start = dyn_event_seq_start, 1013 .next = dyn_event_seq_next, 1014 .stop = dyn_event_seq_stop, 1015 .show = probes_profile_seq_show 1016 }; 1017 1018 static int profile_open(struct inode *inode, struct file *file) 1019 { 1020 int ret; 1021 1022 ret = security_locked_down(LOCKDOWN_TRACEFS); 1023 if (ret) 1024 return ret; 1025 1026 return seq_open(file, &profile_seq_op); 1027 } 1028 1029 static const struct file_operations kprobe_profile_ops = { 1030 .owner = THIS_MODULE, 1031 .open = profile_open, 1032 .read = seq_read, 1033 .llseek = seq_lseek, 1034 .release = seq_release, 1035 }; 1036 1037 /* Kprobe specific fetch functions */ 1038 1039 /* Return the length of string -- including null terminal byte */ 1040 static nokprobe_inline int 1041 fetch_store_strlen(unsigned long addr) 1042 { 1043 int ret, len = 0; 1044 u8 c; 1045 1046 do { 1047 ret = probe_kernel_read(&c, (u8 *)addr + len, 1); 1048 len++; 1049 } while (c && ret == 0 && len < MAX_STRING_SIZE); 1050 1051 return (ret < 0) ? ret : len; 1052 } 1053 1054 /* Return the length of string -- including null terminal byte */ 1055 static nokprobe_inline int 1056 fetch_store_strlen_user(unsigned long addr) 1057 { 1058 const void __user *uaddr = (__force const void __user *)addr; 1059 1060 return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE); 1061 } 1062 1063 /* 1064 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max 1065 * length and relative data location. 1066 */ 1067 static nokprobe_inline int 1068 fetch_store_string(unsigned long addr, void *dest, void *base) 1069 { 1070 int maxlen = get_loc_len(*(u32 *)dest); 1071 void *__dest; 1072 long ret; 1073 1074 if (unlikely(!maxlen)) 1075 return -ENOMEM; 1076 1077 __dest = get_loc_data(dest, base); 1078 1079 /* 1080 * Try to get string again, since the string can be changed while 1081 * probing. 1082 */ 1083 ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen); 1084 if (ret >= 0) 1085 *(u32 *)dest = make_data_loc(ret, __dest - base); 1086 1087 return ret; 1088 } 1089 1090 /* 1091 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf 1092 * with max length and relative data location. 1093 */ 1094 static nokprobe_inline int 1095 fetch_store_string_user(unsigned long addr, void *dest, void *base) 1096 { 1097 const void __user *uaddr = (__force const void __user *)addr; 1098 int maxlen = get_loc_len(*(u32 *)dest); 1099 void *__dest; 1100 long ret; 1101 1102 if (unlikely(!maxlen)) 1103 return -ENOMEM; 1104 1105 __dest = get_loc_data(dest, base); 1106 1107 ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen); 1108 if (ret >= 0) 1109 *(u32 *)dest = make_data_loc(ret, __dest - base); 1110 1111 return ret; 1112 } 1113 1114 static nokprobe_inline int 1115 probe_mem_read(void *dest, void *src, size_t size) 1116 { 1117 return probe_kernel_read(dest, src, size); 1118 } 1119 1120 static nokprobe_inline int 1121 probe_mem_read_user(void *dest, void *src, size_t size) 1122 { 1123 const void __user *uaddr = (__force const void __user *)src; 1124 1125 return probe_user_read(dest, uaddr, size); 1126 } 1127 1128 /* Note that we don't verify it, since the code does not come from user space */ 1129 static int 1130 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 1131 void *base) 1132 { 1133 unsigned long val; 1134 1135 retry: 1136 /* 1st stage: get value from context */ 1137 switch (code->op) { 1138 case FETCH_OP_REG: 1139 val = regs_get_register(regs, code->param); 1140 break; 1141 case FETCH_OP_STACK: 1142 val = regs_get_kernel_stack_nth(regs, code->param); 1143 break; 1144 case FETCH_OP_STACKP: 1145 val = kernel_stack_pointer(regs); 1146 break; 1147 case FETCH_OP_RETVAL: 1148 val = regs_return_value(regs); 1149 break; 1150 case FETCH_OP_IMM: 1151 val = code->immediate; 1152 break; 1153 case FETCH_OP_COMM: 1154 val = (unsigned long)current->comm; 1155 break; 1156 case FETCH_OP_DATA: 1157 val = (unsigned long)code->data; 1158 break; 1159 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 1160 case FETCH_OP_ARG: 1161 val = regs_get_kernel_argument(regs, code->param); 1162 break; 1163 #endif 1164 case FETCH_NOP_SYMBOL: /* Ignore a place holder */ 1165 code++; 1166 goto retry; 1167 default: 1168 return -EILSEQ; 1169 } 1170 code++; 1171 1172 return process_fetch_insn_bottom(code, val, dest, base); 1173 } 1174 NOKPROBE_SYMBOL(process_fetch_insn) 1175 1176 /* Kprobe handler */ 1177 static nokprobe_inline void 1178 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 1179 struct trace_event_file *trace_file) 1180 { 1181 struct kprobe_trace_entry_head *entry; 1182 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1183 struct trace_event_buffer fbuffer; 1184 int dsize; 1185 1186 WARN_ON(call != trace_file->event_call); 1187 1188 if (trace_trigger_soft_disabled(trace_file)) 1189 return; 1190 1191 local_save_flags(fbuffer.flags); 1192 fbuffer.pc = preempt_count(); 1193 fbuffer.trace_file = trace_file; 1194 1195 dsize = __get_data_size(&tk->tp, regs); 1196 1197 fbuffer.event = 1198 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file, 1199 call->event.type, 1200 sizeof(*entry) + tk->tp.size + dsize, 1201 fbuffer.flags, fbuffer.pc); 1202 if (!fbuffer.event) 1203 return; 1204 1205 fbuffer.regs = regs; 1206 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); 1207 entry->ip = (unsigned long)tk->rp.kp.addr; 1208 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1209 1210 trace_event_buffer_commit(&fbuffer); 1211 } 1212 1213 static void 1214 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 1215 { 1216 struct event_file_link *link; 1217 1218 trace_probe_for_each_link_rcu(link, &tk->tp) 1219 __kprobe_trace_func(tk, regs, link->file); 1220 } 1221 NOKPROBE_SYMBOL(kprobe_trace_func); 1222 1223 /* Kretprobe handler */ 1224 static nokprobe_inline void 1225 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1226 struct pt_regs *regs, 1227 struct trace_event_file *trace_file) 1228 { 1229 struct kretprobe_trace_entry_head *entry; 1230 struct trace_event_buffer fbuffer; 1231 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1232 int dsize; 1233 1234 WARN_ON(call != trace_file->event_call); 1235 1236 if (trace_trigger_soft_disabled(trace_file)) 1237 return; 1238 1239 local_save_flags(fbuffer.flags); 1240 fbuffer.pc = preempt_count(); 1241 fbuffer.trace_file = trace_file; 1242 1243 dsize = __get_data_size(&tk->tp, regs); 1244 fbuffer.event = 1245 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file, 1246 call->event.type, 1247 sizeof(*entry) + tk->tp.size + dsize, 1248 fbuffer.flags, fbuffer.pc); 1249 if (!fbuffer.event) 1250 return; 1251 1252 fbuffer.regs = regs; 1253 entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event); 1254 entry->func = (unsigned long)tk->rp.kp.addr; 1255 entry->ret_ip = (unsigned long)ri->ret_addr; 1256 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1257 1258 trace_event_buffer_commit(&fbuffer); 1259 } 1260 1261 static void 1262 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1263 struct pt_regs *regs) 1264 { 1265 struct event_file_link *link; 1266 1267 trace_probe_for_each_link_rcu(link, &tk->tp) 1268 __kretprobe_trace_func(tk, ri, regs, link->file); 1269 } 1270 NOKPROBE_SYMBOL(kretprobe_trace_func); 1271 1272 /* Event entry printers */ 1273 static enum print_line_t 1274 print_kprobe_event(struct trace_iterator *iter, int flags, 1275 struct trace_event *event) 1276 { 1277 struct kprobe_trace_entry_head *field; 1278 struct trace_seq *s = &iter->seq; 1279 struct trace_probe *tp; 1280 1281 field = (struct kprobe_trace_entry_head *)iter->ent; 1282 tp = trace_probe_primary_from_call( 1283 container_of(event, struct trace_event_call, event)); 1284 if (WARN_ON_ONCE(!tp)) 1285 goto out; 1286 1287 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1288 1289 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) 1290 goto out; 1291 1292 trace_seq_putc(s, ')'); 1293 1294 if (print_probe_args(s, tp->args, tp->nr_args, 1295 (u8 *)&field[1], field) < 0) 1296 goto out; 1297 1298 trace_seq_putc(s, '\n'); 1299 out: 1300 return trace_handle_return(s); 1301 } 1302 1303 static enum print_line_t 1304 print_kretprobe_event(struct trace_iterator *iter, int flags, 1305 struct trace_event *event) 1306 { 1307 struct kretprobe_trace_entry_head *field; 1308 struct trace_seq *s = &iter->seq; 1309 struct trace_probe *tp; 1310 1311 field = (struct kretprobe_trace_entry_head *)iter->ent; 1312 tp = trace_probe_primary_from_call( 1313 container_of(event, struct trace_event_call, event)); 1314 if (WARN_ON_ONCE(!tp)) 1315 goto out; 1316 1317 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1318 1319 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) 1320 goto out; 1321 1322 trace_seq_puts(s, " <- "); 1323 1324 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) 1325 goto out; 1326 1327 trace_seq_putc(s, ')'); 1328 1329 if (print_probe_args(s, tp->args, tp->nr_args, 1330 (u8 *)&field[1], field) < 0) 1331 goto out; 1332 1333 trace_seq_putc(s, '\n'); 1334 1335 out: 1336 return trace_handle_return(s); 1337 } 1338 1339 1340 static int kprobe_event_define_fields(struct trace_event_call *event_call) 1341 { 1342 int ret; 1343 struct kprobe_trace_entry_head field; 1344 struct trace_probe *tp; 1345 1346 tp = trace_probe_primary_from_call(event_call); 1347 if (WARN_ON_ONCE(!tp)) 1348 return -ENOENT; 1349 1350 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1351 1352 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1353 } 1354 1355 static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1356 { 1357 int ret; 1358 struct kretprobe_trace_entry_head field; 1359 struct trace_probe *tp; 1360 1361 tp = trace_probe_primary_from_call(event_call); 1362 if (WARN_ON_ONCE(!tp)) 1363 return -ENOENT; 1364 1365 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1366 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1367 1368 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1369 } 1370 1371 #ifdef CONFIG_PERF_EVENTS 1372 1373 /* Kprobe profile handler */ 1374 static int 1375 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1376 { 1377 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1378 struct kprobe_trace_entry_head *entry; 1379 struct hlist_head *head; 1380 int size, __size, dsize; 1381 int rctx; 1382 1383 if (bpf_prog_array_valid(call)) { 1384 unsigned long orig_ip = instruction_pointer(regs); 1385 int ret; 1386 1387 ret = trace_call_bpf(call, regs); 1388 1389 /* 1390 * We need to check and see if we modified the pc of the 1391 * pt_regs, and if so return 1 so that we don't do the 1392 * single stepping. 1393 */ 1394 if (orig_ip != instruction_pointer(regs)) 1395 return 1; 1396 if (!ret) 1397 return 0; 1398 } 1399 1400 head = this_cpu_ptr(call->perf_events); 1401 if (hlist_empty(head)) 1402 return 0; 1403 1404 dsize = __get_data_size(&tk->tp, regs); 1405 __size = sizeof(*entry) + tk->tp.size + dsize; 1406 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1407 size -= sizeof(u32); 1408 1409 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1410 if (!entry) 1411 return 0; 1412 1413 entry->ip = (unsigned long)tk->rp.kp.addr; 1414 memset(&entry[1], 0, dsize); 1415 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1416 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1417 head, NULL); 1418 return 0; 1419 } 1420 NOKPROBE_SYMBOL(kprobe_perf_func); 1421 1422 /* Kretprobe profile handler */ 1423 static void 1424 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1425 struct pt_regs *regs) 1426 { 1427 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1428 struct kretprobe_trace_entry_head *entry; 1429 struct hlist_head *head; 1430 int size, __size, dsize; 1431 int rctx; 1432 1433 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1434 return; 1435 1436 head = this_cpu_ptr(call->perf_events); 1437 if (hlist_empty(head)) 1438 return; 1439 1440 dsize = __get_data_size(&tk->tp, regs); 1441 __size = sizeof(*entry) + tk->tp.size + dsize; 1442 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1443 size -= sizeof(u32); 1444 1445 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1446 if (!entry) 1447 return; 1448 1449 entry->func = (unsigned long)tk->rp.kp.addr; 1450 entry->ret_ip = (unsigned long)ri->ret_addr; 1451 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1452 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1453 head, NULL); 1454 } 1455 NOKPROBE_SYMBOL(kretprobe_perf_func); 1456 1457 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, 1458 const char **symbol, u64 *probe_offset, 1459 u64 *probe_addr, bool perf_type_tracepoint) 1460 { 1461 const char *pevent = trace_event_name(event->tp_event); 1462 const char *group = event->tp_event->class->system; 1463 struct trace_kprobe *tk; 1464 1465 if (perf_type_tracepoint) 1466 tk = find_trace_kprobe(pevent, group); 1467 else 1468 tk = event->tp_event->data; 1469 if (!tk) 1470 return -EINVAL; 1471 1472 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE 1473 : BPF_FD_TYPE_KPROBE; 1474 if (tk->symbol) { 1475 *symbol = tk->symbol; 1476 *probe_offset = tk->rp.kp.offset; 1477 *probe_addr = 0; 1478 } else { 1479 *symbol = NULL; 1480 *probe_offset = 0; 1481 *probe_addr = (unsigned long)tk->rp.kp.addr; 1482 } 1483 return 0; 1484 } 1485 #endif /* CONFIG_PERF_EVENTS */ 1486 1487 /* 1488 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1489 * 1490 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1491 * lockless, but we can't race with this __init function. 1492 */ 1493 static int kprobe_register(struct trace_event_call *event, 1494 enum trace_reg type, void *data) 1495 { 1496 struct trace_event_file *file = data; 1497 1498 switch (type) { 1499 case TRACE_REG_REGISTER: 1500 return enable_trace_kprobe(event, file); 1501 case TRACE_REG_UNREGISTER: 1502 return disable_trace_kprobe(event, file); 1503 1504 #ifdef CONFIG_PERF_EVENTS 1505 case TRACE_REG_PERF_REGISTER: 1506 return enable_trace_kprobe(event, NULL); 1507 case TRACE_REG_PERF_UNREGISTER: 1508 return disable_trace_kprobe(event, NULL); 1509 case TRACE_REG_PERF_OPEN: 1510 case TRACE_REG_PERF_CLOSE: 1511 case TRACE_REG_PERF_ADD: 1512 case TRACE_REG_PERF_DEL: 1513 return 0; 1514 #endif 1515 } 1516 return 0; 1517 } 1518 1519 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1520 { 1521 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1522 int ret = 0; 1523 1524 raw_cpu_inc(*tk->nhit); 1525 1526 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1527 kprobe_trace_func(tk, regs); 1528 #ifdef CONFIG_PERF_EVENTS 1529 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1530 ret = kprobe_perf_func(tk, regs); 1531 #endif 1532 return ret; 1533 } 1534 NOKPROBE_SYMBOL(kprobe_dispatcher); 1535 1536 static int 1537 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1538 { 1539 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp); 1540 1541 raw_cpu_inc(*tk->nhit); 1542 1543 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1544 kretprobe_trace_func(tk, ri, regs); 1545 #ifdef CONFIG_PERF_EVENTS 1546 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1547 kretprobe_perf_func(tk, ri, regs); 1548 #endif 1549 return 0; /* We don't tweek kernel, so just return 0 */ 1550 } 1551 NOKPROBE_SYMBOL(kretprobe_dispatcher); 1552 1553 static struct trace_event_functions kretprobe_funcs = { 1554 .trace = print_kretprobe_event 1555 }; 1556 1557 static struct trace_event_functions kprobe_funcs = { 1558 .trace = print_kprobe_event 1559 }; 1560 1561 static inline void init_trace_event_call(struct trace_kprobe *tk) 1562 { 1563 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1564 1565 if (trace_kprobe_is_return(tk)) { 1566 call->event.funcs = &kretprobe_funcs; 1567 call->class->define_fields = kretprobe_event_define_fields; 1568 } else { 1569 call->event.funcs = &kprobe_funcs; 1570 call->class->define_fields = kprobe_event_define_fields; 1571 } 1572 1573 call->flags = TRACE_EVENT_FL_KPROBE; 1574 call->class->reg = kprobe_register; 1575 } 1576 1577 static int register_kprobe_event(struct trace_kprobe *tk) 1578 { 1579 init_trace_event_call(tk); 1580 1581 return trace_probe_register_event_call(&tk->tp); 1582 } 1583 1584 static int unregister_kprobe_event(struct trace_kprobe *tk) 1585 { 1586 return trace_probe_unregister_event_call(&tk->tp); 1587 } 1588 1589 #ifdef CONFIG_PERF_EVENTS 1590 /* create a trace_kprobe, but don't add it to global lists */ 1591 struct trace_event_call * 1592 create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 1593 bool is_return) 1594 { 1595 struct trace_kprobe *tk; 1596 int ret; 1597 char *event; 1598 1599 /* 1600 * local trace_kprobes are not added to dyn_event, so they are never 1601 * searched in find_trace_kprobe(). Therefore, there is no concern of 1602 * duplicated name here. 1603 */ 1604 event = func ? func : "DUMMY_EVENT"; 1605 1606 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, 1607 offs, 0 /* maxactive */, 0 /* nargs */, 1608 is_return); 1609 1610 if (IS_ERR(tk)) { 1611 pr_info("Failed to allocate trace_probe.(%d)\n", 1612 (int)PTR_ERR(tk)); 1613 return ERR_CAST(tk); 1614 } 1615 1616 init_trace_event_call(tk); 1617 1618 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) { 1619 ret = -ENOMEM; 1620 goto error; 1621 } 1622 1623 ret = __register_trace_kprobe(tk); 1624 if (ret < 0) 1625 goto error; 1626 1627 return trace_probe_event_call(&tk->tp); 1628 error: 1629 free_trace_kprobe(tk); 1630 return ERR_PTR(ret); 1631 } 1632 1633 void destroy_local_trace_kprobe(struct trace_event_call *event_call) 1634 { 1635 struct trace_kprobe *tk; 1636 1637 tk = trace_kprobe_primary_from_call(event_call); 1638 if (unlikely(!tk)) 1639 return; 1640 1641 if (trace_probe_is_enabled(&tk->tp)) { 1642 WARN_ON(1); 1643 return; 1644 } 1645 1646 __unregister_trace_kprobe(tk); 1647 1648 free_trace_kprobe(tk); 1649 } 1650 #endif /* CONFIG_PERF_EVENTS */ 1651 1652 static __init void enable_boot_kprobe_events(void) 1653 { 1654 struct trace_array *tr = top_trace_array(); 1655 struct trace_event_file *file; 1656 struct trace_kprobe *tk; 1657 struct dyn_event *pos; 1658 1659 mutex_lock(&event_mutex); 1660 for_each_trace_kprobe(tk, pos) { 1661 list_for_each_entry(file, &tr->events, list) 1662 if (file->event_call == trace_probe_event_call(&tk->tp)) 1663 trace_event_enable_disable(file, 1, 0); 1664 } 1665 mutex_unlock(&event_mutex); 1666 } 1667 1668 static __init void setup_boot_kprobe_events(void) 1669 { 1670 char *p, *cmd = kprobe_boot_events_buf; 1671 int ret; 1672 1673 strreplace(kprobe_boot_events_buf, ',', ' '); 1674 1675 while (cmd && *cmd != '\0') { 1676 p = strchr(cmd, ';'); 1677 if (p) 1678 *p++ = '\0'; 1679 1680 ret = trace_run_command(cmd, create_or_delete_trace_kprobe); 1681 if (ret) 1682 pr_warn("Failed to add event(%d): %s\n", ret, cmd); 1683 else 1684 kprobe_boot_events_enabled = true; 1685 1686 cmd = p; 1687 } 1688 1689 enable_boot_kprobe_events(); 1690 } 1691 1692 /* 1693 * Register dynevent at subsys_initcall. This allows kernel to setup kprobe 1694 * events in fs_initcall without tracefs. 1695 */ 1696 static __init int init_kprobe_trace_early(void) 1697 { 1698 int ret; 1699 1700 ret = dyn_event_register(&trace_kprobe_ops); 1701 if (ret) 1702 return ret; 1703 1704 if (register_module_notifier(&trace_kprobe_module_nb)) 1705 return -EINVAL; 1706 1707 return 0; 1708 } 1709 subsys_initcall(init_kprobe_trace_early); 1710 1711 /* Make a tracefs interface for controlling probe points */ 1712 static __init int init_kprobe_trace(void) 1713 { 1714 struct dentry *d_tracer; 1715 struct dentry *entry; 1716 1717 d_tracer = tracing_init_dentry(); 1718 if (IS_ERR(d_tracer)) 1719 return 0; 1720 1721 entry = tracefs_create_file("kprobe_events", 0644, d_tracer, 1722 NULL, &kprobe_events_ops); 1723 1724 /* Event list interface */ 1725 if (!entry) 1726 pr_warn("Could not create tracefs 'kprobe_events' entry\n"); 1727 1728 /* Profile interface */ 1729 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer, 1730 NULL, &kprobe_profile_ops); 1731 1732 if (!entry) 1733 pr_warn("Could not create tracefs 'kprobe_profile' entry\n"); 1734 1735 setup_boot_kprobe_events(); 1736 1737 return 0; 1738 } 1739 fs_initcall(init_kprobe_trace); 1740 1741 1742 #ifdef CONFIG_FTRACE_STARTUP_TEST 1743 static __init struct trace_event_file * 1744 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 1745 { 1746 struct trace_event_file *file; 1747 1748 list_for_each_entry(file, &tr->events, list) 1749 if (file->event_call == trace_probe_event_call(&tk->tp)) 1750 return file; 1751 1752 return NULL; 1753 } 1754 1755 /* 1756 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 1757 * stage, we can do this lockless. 1758 */ 1759 static __init int kprobe_trace_self_tests_init(void) 1760 { 1761 int ret, warn = 0; 1762 int (*target)(int, int, int, int, int, int); 1763 struct trace_kprobe *tk; 1764 struct trace_event_file *file; 1765 1766 if (tracing_is_disabled()) 1767 return -ENODEV; 1768 1769 if (kprobe_boot_events_enabled) { 1770 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n"); 1771 return 0; 1772 } 1773 1774 target = kprobe_trace_selftest_target; 1775 1776 pr_info("Testing kprobe tracing: "); 1777 1778 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)", 1779 create_or_delete_trace_kprobe); 1780 if (WARN_ON_ONCE(ret)) { 1781 pr_warn("error on probing function entry.\n"); 1782 warn++; 1783 } else { 1784 /* Enable trace point */ 1785 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1786 if (WARN_ON_ONCE(tk == NULL)) { 1787 pr_warn("error on getting new probe.\n"); 1788 warn++; 1789 } else { 1790 file = find_trace_probe_file(tk, top_trace_array()); 1791 if (WARN_ON_ONCE(file == NULL)) { 1792 pr_warn("error on getting probe file.\n"); 1793 warn++; 1794 } else 1795 enable_trace_kprobe( 1796 trace_probe_event_call(&tk->tp), file); 1797 } 1798 } 1799 1800 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval", 1801 create_or_delete_trace_kprobe); 1802 if (WARN_ON_ONCE(ret)) { 1803 pr_warn("error on probing function return.\n"); 1804 warn++; 1805 } else { 1806 /* Enable trace point */ 1807 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1808 if (WARN_ON_ONCE(tk == NULL)) { 1809 pr_warn("error on getting 2nd new probe.\n"); 1810 warn++; 1811 } else { 1812 file = find_trace_probe_file(tk, top_trace_array()); 1813 if (WARN_ON_ONCE(file == NULL)) { 1814 pr_warn("error on getting probe file.\n"); 1815 warn++; 1816 } else 1817 enable_trace_kprobe( 1818 trace_probe_event_call(&tk->tp), file); 1819 } 1820 } 1821 1822 if (warn) 1823 goto end; 1824 1825 ret = target(1, 2, 3, 4, 5, 6); 1826 1827 /* 1828 * Not expecting an error here, the check is only to prevent the 1829 * optimizer from removing the call to target() as otherwise there 1830 * are no side-effects and the call is never performed. 1831 */ 1832 if (ret != 21) 1833 warn++; 1834 1835 /* Disable trace points before removing it */ 1836 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1837 if (WARN_ON_ONCE(tk == NULL)) { 1838 pr_warn("error on getting test probe.\n"); 1839 warn++; 1840 } else { 1841 if (trace_kprobe_nhit(tk) != 1) { 1842 pr_warn("incorrect number of testprobe hits\n"); 1843 warn++; 1844 } 1845 1846 file = find_trace_probe_file(tk, top_trace_array()); 1847 if (WARN_ON_ONCE(file == NULL)) { 1848 pr_warn("error on getting probe file.\n"); 1849 warn++; 1850 } else 1851 disable_trace_kprobe( 1852 trace_probe_event_call(&tk->tp), file); 1853 } 1854 1855 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1856 if (WARN_ON_ONCE(tk == NULL)) { 1857 pr_warn("error on getting 2nd test probe.\n"); 1858 warn++; 1859 } else { 1860 if (trace_kprobe_nhit(tk) != 1) { 1861 pr_warn("incorrect number of testprobe2 hits\n"); 1862 warn++; 1863 } 1864 1865 file = find_trace_probe_file(tk, top_trace_array()); 1866 if (WARN_ON_ONCE(file == NULL)) { 1867 pr_warn("error on getting probe file.\n"); 1868 warn++; 1869 } else 1870 disable_trace_kprobe( 1871 trace_probe_event_call(&tk->tp), file); 1872 } 1873 1874 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe); 1875 if (WARN_ON_ONCE(ret)) { 1876 pr_warn("error on deleting a probe.\n"); 1877 warn++; 1878 } 1879 1880 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe); 1881 if (WARN_ON_ONCE(ret)) { 1882 pr_warn("error on deleting a probe.\n"); 1883 warn++; 1884 } 1885 1886 end: 1887 ret = dyn_events_release_all(&trace_kprobe_ops); 1888 if (WARN_ON_ONCE(ret)) { 1889 pr_warn("error on cleaning up probes.\n"); 1890 warn++; 1891 } 1892 /* 1893 * Wait for the optimizer work to finish. Otherwise it might fiddle 1894 * with probes in already freed __init text. 1895 */ 1896 wait_for_kprobe_optimizer(); 1897 if (warn) 1898 pr_cont("NG: Some tests are failed. Please check them.\n"); 1899 else 1900 pr_cont("OK\n"); 1901 return 0; 1902 } 1903 1904 late_initcall(kprobe_trace_self_tests_init); 1905 1906 #endif 1907