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