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/module.h> 11 #include <linux/uaccess.h> 12 #include <linux/rculist.h> 13 #include <linux/error-injection.h> 14 #include <linux/security.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(struct trace_kprobe *tk) 439 { 440 unsigned long offset, size, addr; 441 442 addr = trace_kprobe_address(tk); 443 if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset)) 444 return false; 445 446 /* Get the entry address of the target function */ 447 addr -= offset; 448 449 /* 450 * Since ftrace_location_range() does inclusive range check, we need 451 * to subtract 1 byte from the end address. 452 */ 453 return !ftrace_location_range(addr, addr + size - 1); 454 } 455 #else 456 #define within_notrace_func(tk) (false) 457 #endif 458 459 /* Internal register function - just handle k*probes and flags */ 460 static int __register_trace_kprobe(struct trace_kprobe *tk) 461 { 462 int i, ret; 463 464 ret = security_locked_down(LOCKDOWN_KPROBES); 465 if (ret) 466 return ret; 467 468 if (trace_kprobe_is_registered(tk)) 469 return -EINVAL; 470 471 if (within_notrace_func(tk)) { 472 pr_warn("Could not probe notrace function %s\n", 473 trace_kprobe_symbol(tk)); 474 return -EINVAL; 475 } 476 477 for (i = 0; i < tk->tp.nr_args; i++) { 478 ret = traceprobe_update_arg(&tk->tp.args[i]); 479 if (ret) 480 return ret; 481 } 482 483 /* Set/clear disabled flag according to tp->flag */ 484 if (trace_probe_is_enabled(&tk->tp)) 485 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; 486 else 487 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; 488 489 if (trace_kprobe_is_return(tk)) 490 ret = register_kretprobe(&tk->rp); 491 else 492 ret = register_kprobe(&tk->rp.kp); 493 494 return ret; 495 } 496 497 /* Internal unregister function - just handle k*probes and flags */ 498 static void __unregister_trace_kprobe(struct trace_kprobe *tk) 499 { 500 if (trace_kprobe_is_registered(tk)) { 501 if (trace_kprobe_is_return(tk)) 502 unregister_kretprobe(&tk->rp); 503 else 504 unregister_kprobe(&tk->rp.kp); 505 /* Cleanup kprobe for reuse and mark it unregistered */ 506 INIT_HLIST_NODE(&tk->rp.kp.hlist); 507 INIT_LIST_HEAD(&tk->rp.kp.list); 508 if (tk->rp.kp.symbol_name) 509 tk->rp.kp.addr = NULL; 510 } 511 } 512 513 /* Unregister a trace_probe and probe_event */ 514 static int unregister_trace_kprobe(struct trace_kprobe *tk) 515 { 516 /* If other probes are on the event, just unregister kprobe */ 517 if (trace_probe_has_sibling(&tk->tp)) 518 goto unreg; 519 520 /* Enabled event can not be unregistered */ 521 if (trace_probe_is_enabled(&tk->tp)) 522 return -EBUSY; 523 524 /* Will fail if probe is being used by ftrace or perf */ 525 if (unregister_kprobe_event(tk)) 526 return -EBUSY; 527 528 unreg: 529 __unregister_trace_kprobe(tk); 530 dyn_event_remove(&tk->devent); 531 trace_probe_unlink(&tk->tp); 532 533 return 0; 534 } 535 536 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig, 537 struct trace_kprobe *comp) 538 { 539 struct trace_probe_event *tpe = orig->tp.event; 540 struct trace_probe *pos; 541 int i; 542 543 list_for_each_entry(pos, &tpe->probes, list) { 544 orig = container_of(pos, struct trace_kprobe, tp); 545 if (strcmp(trace_kprobe_symbol(orig), 546 trace_kprobe_symbol(comp)) || 547 trace_kprobe_offset(orig) != trace_kprobe_offset(comp)) 548 continue; 549 550 /* 551 * trace_probe_compare_arg_type() ensured that nr_args and 552 * each argument name and type are same. Let's compare comm. 553 */ 554 for (i = 0; i < orig->tp.nr_args; i++) { 555 if (strcmp(orig->tp.args[i].comm, 556 comp->tp.args[i].comm)) 557 break; 558 } 559 560 if (i == orig->tp.nr_args) 561 return true; 562 } 563 564 return false; 565 } 566 567 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to) 568 { 569 int ret; 570 571 ret = trace_probe_compare_arg_type(&tk->tp, &to->tp); 572 if (ret) { 573 /* Note that argument starts index = 2 */ 574 trace_probe_log_set_index(ret + 1); 575 trace_probe_log_err(0, DIFF_ARG_TYPE); 576 return -EEXIST; 577 } 578 if (trace_kprobe_has_same_kprobe(to, tk)) { 579 trace_probe_log_set_index(0); 580 trace_probe_log_err(0, SAME_PROBE); 581 return -EEXIST; 582 } 583 584 /* Append to existing event */ 585 ret = trace_probe_append(&tk->tp, &to->tp); 586 if (ret) 587 return ret; 588 589 /* Register k*probe */ 590 ret = __register_trace_kprobe(tk); 591 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 592 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 593 ret = 0; 594 } 595 596 if (ret) 597 trace_probe_unlink(&tk->tp); 598 else 599 dyn_event_add(&tk->devent); 600 601 return ret; 602 } 603 604 /* Register a trace_probe and probe_event */ 605 static int register_trace_kprobe(struct trace_kprobe *tk) 606 { 607 struct trace_kprobe *old_tk; 608 int ret; 609 610 mutex_lock(&event_mutex); 611 612 old_tk = find_trace_kprobe(trace_probe_name(&tk->tp), 613 trace_probe_group_name(&tk->tp)); 614 if (old_tk) { 615 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) { 616 trace_probe_log_set_index(0); 617 trace_probe_log_err(0, DIFF_PROBE_TYPE); 618 ret = -EEXIST; 619 } else { 620 ret = append_trace_kprobe(tk, old_tk); 621 } 622 goto end; 623 } 624 625 /* Register new event */ 626 ret = register_kprobe_event(tk); 627 if (ret) { 628 pr_warn("Failed to register probe event(%d)\n", ret); 629 goto end; 630 } 631 632 /* Register k*probe */ 633 ret = __register_trace_kprobe(tk); 634 if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) { 635 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 636 ret = 0; 637 } 638 639 if (ret < 0) 640 unregister_kprobe_event(tk); 641 else 642 dyn_event_add(&tk->devent); 643 644 end: 645 mutex_unlock(&event_mutex); 646 return ret; 647 } 648 649 /* Module notifier call back, checking event on the module */ 650 static int trace_kprobe_module_callback(struct notifier_block *nb, 651 unsigned long val, void *data) 652 { 653 struct module *mod = data; 654 struct dyn_event *pos; 655 struct trace_kprobe *tk; 656 int ret; 657 658 if (val != MODULE_STATE_COMING) 659 return NOTIFY_DONE; 660 661 /* Update probes on coming module */ 662 mutex_lock(&event_mutex); 663 for_each_trace_kprobe(tk, pos) { 664 if (trace_kprobe_within_module(tk, mod)) { 665 /* Don't need to check busy - this should have gone. */ 666 __unregister_trace_kprobe(tk); 667 ret = __register_trace_kprobe(tk); 668 if (ret) 669 pr_warn("Failed to re-register probe %s on %s: %d\n", 670 trace_probe_name(&tk->tp), 671 mod->name, ret); 672 } 673 } 674 mutex_unlock(&event_mutex); 675 676 return NOTIFY_DONE; 677 } 678 679 static struct notifier_block trace_kprobe_module_nb = { 680 .notifier_call = trace_kprobe_module_callback, 681 .priority = 1 /* Invoked after kprobe module callback */ 682 }; 683 684 /* Convert certain expected symbols into '_' when generating event names */ 685 static inline void sanitize_event_name(char *name) 686 { 687 while (*name++ != '\0') 688 if (*name == ':' || *name == '.') 689 *name = '_'; 690 } 691 692 static int trace_kprobe_create(int argc, const char *argv[]) 693 { 694 /* 695 * Argument syntax: 696 * - Add kprobe: 697 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] 698 * - Add kretprobe: 699 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] 700 * Fetch args: 701 * $retval : fetch return value 702 * $stack : fetch stack address 703 * $stackN : fetch Nth of stack (N:0-) 704 * $comm : fetch current task comm 705 * @ADDR : fetch memory at ADDR (ADDR should be in kernel) 706 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) 707 * %REG : fetch register REG 708 * Dereferencing memory fetch: 709 * +|-offs(ARG) : fetch memory at ARG +|- offs address. 710 * Alias name of args: 711 * NAME=FETCHARG : set NAME as alias of FETCHARG. 712 * Type of args: 713 * FETCHARG:TYPE : use TYPE instead of unsigned long. 714 */ 715 struct trace_kprobe *tk = NULL; 716 int i, len, ret = 0; 717 bool is_return = false; 718 char *symbol = NULL, *tmp = NULL; 719 const char *event = NULL, *group = KPROBE_EVENT_SYSTEM; 720 int maxactive = 0; 721 long offset = 0; 722 void *addr = NULL; 723 char buf[MAX_EVENT_NAME_LEN]; 724 unsigned int flags = TPARG_FL_KERNEL; 725 726 switch (argv[0][0]) { 727 case 'r': 728 is_return = true; 729 flags |= TPARG_FL_RETURN; 730 break; 731 case 'p': 732 break; 733 default: 734 return -ECANCELED; 735 } 736 if (argc < 2) 737 return -ECANCELED; 738 739 trace_probe_log_init("trace_kprobe", argc, argv); 740 741 event = strchr(&argv[0][1], ':'); 742 if (event) 743 event++; 744 745 if (isdigit(argv[0][1])) { 746 if (!is_return) { 747 trace_probe_log_err(1, MAXACT_NO_KPROBE); 748 goto parse_error; 749 } 750 if (event) 751 len = event - &argv[0][1] - 1; 752 else 753 len = strlen(&argv[0][1]); 754 if (len > MAX_EVENT_NAME_LEN - 1) { 755 trace_probe_log_err(1, BAD_MAXACT); 756 goto parse_error; 757 } 758 memcpy(buf, &argv[0][1], len); 759 buf[len] = '\0'; 760 ret = kstrtouint(buf, 0, &maxactive); 761 if (ret || !maxactive) { 762 trace_probe_log_err(1, BAD_MAXACT); 763 goto parse_error; 764 } 765 /* kretprobes instances are iterated over via a list. The 766 * maximum should stay reasonable. 767 */ 768 if (maxactive > KRETPROBE_MAXACTIVE_MAX) { 769 trace_probe_log_err(1, MAXACT_TOO_BIG); 770 goto parse_error; 771 } 772 } 773 774 /* try to parse an address. if that fails, try to read the 775 * input as a symbol. */ 776 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { 777 trace_probe_log_set_index(1); 778 /* Check whether uprobe event specified */ 779 if (strchr(argv[1], '/') && strchr(argv[1], ':')) { 780 ret = -ECANCELED; 781 goto error; 782 } 783 /* a symbol specified */ 784 symbol = kstrdup(argv[1], GFP_KERNEL); 785 if (!symbol) 786 return -ENOMEM; 787 /* TODO: support .init module functions */ 788 ret = traceprobe_split_symbol_offset(symbol, &offset); 789 if (ret || offset < 0 || offset > UINT_MAX) { 790 trace_probe_log_err(0, BAD_PROBE_ADDR); 791 goto parse_error; 792 } 793 if (kprobe_on_func_entry(NULL, symbol, offset)) 794 flags |= TPARG_FL_FENTRY; 795 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) { 796 trace_probe_log_err(0, BAD_RETPROBE); 797 goto parse_error; 798 } 799 } 800 801 trace_probe_log_set_index(0); 802 if (event) { 803 ret = traceprobe_parse_event_name(&event, &group, buf, 804 event - argv[0]); 805 if (ret) 806 goto parse_error; 807 } else { 808 /* Make a new event name */ 809 if (symbol) 810 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", 811 is_return ? 'r' : 'p', symbol, offset); 812 else 813 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", 814 is_return ? 'r' : 'p', addr); 815 sanitize_event_name(buf); 816 event = buf; 817 } 818 819 /* setup a probe */ 820 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, 821 argc - 2, is_return); 822 if (IS_ERR(tk)) { 823 ret = PTR_ERR(tk); 824 /* This must return -ENOMEM, else there is a bug */ 825 WARN_ON_ONCE(ret != -ENOMEM); 826 goto out; /* We know tk is not allocated */ 827 } 828 argc -= 2; argv += 2; 829 830 /* parse arguments */ 831 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 832 tmp = kstrdup(argv[i], GFP_KERNEL); 833 if (!tmp) { 834 ret = -ENOMEM; 835 goto error; 836 } 837 838 trace_probe_log_set_index(i + 2); 839 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags); 840 kfree(tmp); 841 if (ret) 842 goto error; /* This can be -ENOMEM */ 843 } 844 845 ret = traceprobe_set_print_fmt(&tk->tp, is_return); 846 if (ret < 0) 847 goto error; 848 849 ret = register_trace_kprobe(tk); 850 if (ret) { 851 trace_probe_log_set_index(1); 852 if (ret == -EILSEQ) 853 trace_probe_log_err(0, BAD_INSN_BNDRY); 854 else if (ret == -ENOENT) 855 trace_probe_log_err(0, BAD_PROBE_ADDR); 856 else if (ret != -ENOMEM && ret != -EEXIST) 857 trace_probe_log_err(0, FAIL_REG_PROBE); 858 goto error; 859 } 860 861 out: 862 trace_probe_log_clear(); 863 kfree(symbol); 864 return ret; 865 866 parse_error: 867 ret = -EINVAL; 868 error: 869 free_trace_kprobe(tk); 870 goto out; 871 } 872 873 static int create_or_delete_trace_kprobe(int argc, char **argv) 874 { 875 int ret; 876 877 if (argv[0][0] == '-') 878 return dyn_event_release(argc, argv, &trace_kprobe_ops); 879 880 ret = trace_kprobe_create(argc, (const char **)argv); 881 return ret == -ECANCELED ? -EINVAL : ret; 882 } 883 884 static int trace_kprobe_release(struct dyn_event *ev) 885 { 886 struct trace_kprobe *tk = to_trace_kprobe(ev); 887 int ret = unregister_trace_kprobe(tk); 888 889 if (!ret) 890 free_trace_kprobe(tk); 891 return ret; 892 } 893 894 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev) 895 { 896 struct trace_kprobe *tk = to_trace_kprobe(ev); 897 int i; 898 899 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 900 seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp), 901 trace_probe_name(&tk->tp)); 902 903 if (!tk->symbol) 904 seq_printf(m, " 0x%p", tk->rp.kp.addr); 905 else if (tk->rp.kp.offset) 906 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 907 tk->rp.kp.offset); 908 else 909 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 910 911 for (i = 0; i < tk->tp.nr_args; i++) 912 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 913 seq_putc(m, '\n'); 914 915 return 0; 916 } 917 918 static int probes_seq_show(struct seq_file *m, void *v) 919 { 920 struct dyn_event *ev = v; 921 922 if (!is_trace_kprobe(ev)) 923 return 0; 924 925 return trace_kprobe_show(m, ev); 926 } 927 928 static const struct seq_operations probes_seq_op = { 929 .start = dyn_event_seq_start, 930 .next = dyn_event_seq_next, 931 .stop = dyn_event_seq_stop, 932 .show = probes_seq_show 933 }; 934 935 static int probes_open(struct inode *inode, struct file *file) 936 { 937 int ret; 938 939 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 940 ret = dyn_events_release_all(&trace_kprobe_ops); 941 if (ret < 0) 942 return ret; 943 } 944 945 return seq_open(file, &probes_seq_op); 946 } 947 948 static ssize_t probes_write(struct file *file, const char __user *buffer, 949 size_t count, loff_t *ppos) 950 { 951 return trace_parse_run_command(file, buffer, count, ppos, 952 create_or_delete_trace_kprobe); 953 } 954 955 static const struct file_operations kprobe_events_ops = { 956 .owner = THIS_MODULE, 957 .open = probes_open, 958 .read = seq_read, 959 .llseek = seq_lseek, 960 .release = seq_release, 961 .write = probes_write, 962 }; 963 964 /* Probes profiling interfaces */ 965 static int probes_profile_seq_show(struct seq_file *m, void *v) 966 { 967 struct dyn_event *ev = v; 968 struct trace_kprobe *tk; 969 970 if (!is_trace_kprobe(ev)) 971 return 0; 972 973 tk = to_trace_kprobe(ev); 974 seq_printf(m, " %-44s %15lu %15lu\n", 975 trace_probe_name(&tk->tp), 976 trace_kprobe_nhit(tk), 977 tk->rp.kp.nmissed); 978 979 return 0; 980 } 981 982 static const struct seq_operations profile_seq_op = { 983 .start = dyn_event_seq_start, 984 .next = dyn_event_seq_next, 985 .stop = dyn_event_seq_stop, 986 .show = probes_profile_seq_show 987 }; 988 989 static int profile_open(struct inode *inode, struct file *file) 990 { 991 return seq_open(file, &profile_seq_op); 992 } 993 994 static const struct file_operations kprobe_profile_ops = { 995 .owner = THIS_MODULE, 996 .open = profile_open, 997 .read = seq_read, 998 .llseek = seq_lseek, 999 .release = seq_release, 1000 }; 1001 1002 /* Kprobe specific fetch functions */ 1003 1004 /* Return the length of string -- including null terminal byte */ 1005 static nokprobe_inline int 1006 fetch_store_strlen(unsigned long addr) 1007 { 1008 int ret, len = 0; 1009 u8 c; 1010 1011 do { 1012 ret = probe_kernel_read(&c, (u8 *)addr + len, 1); 1013 len++; 1014 } while (c && ret == 0 && len < MAX_STRING_SIZE); 1015 1016 return (ret < 0) ? ret : len; 1017 } 1018 1019 /* Return the length of string -- including null terminal byte */ 1020 static nokprobe_inline int 1021 fetch_store_strlen_user(unsigned long addr) 1022 { 1023 const void __user *uaddr = (__force const void __user *)addr; 1024 1025 return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE); 1026 } 1027 1028 /* 1029 * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max 1030 * length and relative data location. 1031 */ 1032 static nokprobe_inline int 1033 fetch_store_string(unsigned long addr, void *dest, void *base) 1034 { 1035 int maxlen = get_loc_len(*(u32 *)dest); 1036 void *__dest; 1037 long ret; 1038 1039 if (unlikely(!maxlen)) 1040 return -ENOMEM; 1041 1042 __dest = get_loc_data(dest, base); 1043 1044 /* 1045 * Try to get string again, since the string can be changed while 1046 * probing. 1047 */ 1048 ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen); 1049 if (ret >= 0) 1050 *(u32 *)dest = make_data_loc(ret, __dest - base); 1051 1052 return ret; 1053 } 1054 1055 /* 1056 * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf 1057 * with max length and relative data location. 1058 */ 1059 static nokprobe_inline int 1060 fetch_store_string_user(unsigned long addr, void *dest, void *base) 1061 { 1062 const void __user *uaddr = (__force const void __user *)addr; 1063 int maxlen = get_loc_len(*(u32 *)dest); 1064 void *__dest; 1065 long ret; 1066 1067 if (unlikely(!maxlen)) 1068 return -ENOMEM; 1069 1070 __dest = get_loc_data(dest, base); 1071 1072 ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen); 1073 if (ret >= 0) 1074 *(u32 *)dest = make_data_loc(ret, __dest - base); 1075 1076 return ret; 1077 } 1078 1079 static nokprobe_inline int 1080 probe_mem_read(void *dest, void *src, size_t size) 1081 { 1082 return probe_kernel_read(dest, src, size); 1083 } 1084 1085 static nokprobe_inline int 1086 probe_mem_read_user(void *dest, void *src, size_t size) 1087 { 1088 const void __user *uaddr = (__force const void __user *)src; 1089 1090 return probe_user_read(dest, uaddr, size); 1091 } 1092 1093 /* Note that we don't verify it, since the code does not come from user space */ 1094 static int 1095 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, 1096 void *base) 1097 { 1098 unsigned long val; 1099 1100 retry: 1101 /* 1st stage: get value from context */ 1102 switch (code->op) { 1103 case FETCH_OP_REG: 1104 val = regs_get_register(regs, code->param); 1105 break; 1106 case FETCH_OP_STACK: 1107 val = regs_get_kernel_stack_nth(regs, code->param); 1108 break; 1109 case FETCH_OP_STACKP: 1110 val = kernel_stack_pointer(regs); 1111 break; 1112 case FETCH_OP_RETVAL: 1113 val = regs_return_value(regs); 1114 break; 1115 case FETCH_OP_IMM: 1116 val = code->immediate; 1117 break; 1118 case FETCH_OP_COMM: 1119 val = (unsigned long)current->comm; 1120 break; 1121 case FETCH_OP_DATA: 1122 val = (unsigned long)code->data; 1123 break; 1124 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 1125 case FETCH_OP_ARG: 1126 val = regs_get_kernel_argument(regs, code->param); 1127 break; 1128 #endif 1129 case FETCH_NOP_SYMBOL: /* Ignore a place holder */ 1130 code++; 1131 goto retry; 1132 default: 1133 return -EILSEQ; 1134 } 1135 code++; 1136 1137 return process_fetch_insn_bottom(code, val, dest, base); 1138 } 1139 NOKPROBE_SYMBOL(process_fetch_insn) 1140 1141 /* Kprobe handler */ 1142 static nokprobe_inline void 1143 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 1144 struct trace_event_file *trace_file) 1145 { 1146 struct kprobe_trace_entry_head *entry; 1147 struct ring_buffer_event *event; 1148 struct ring_buffer *buffer; 1149 int size, dsize, pc; 1150 unsigned long irq_flags; 1151 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1152 1153 WARN_ON(call != trace_file->event_call); 1154 1155 if (trace_trigger_soft_disabled(trace_file)) 1156 return; 1157 1158 local_save_flags(irq_flags); 1159 pc = preempt_count(); 1160 1161 dsize = __get_data_size(&tk->tp, regs); 1162 size = sizeof(*entry) + tk->tp.size + dsize; 1163 1164 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 1165 call->event.type, 1166 size, irq_flags, pc); 1167 if (!event) 1168 return; 1169 1170 entry = ring_buffer_event_data(event); 1171 entry->ip = (unsigned long)tk->rp.kp.addr; 1172 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1173 1174 event_trigger_unlock_commit_regs(trace_file, buffer, event, 1175 entry, irq_flags, pc, regs); 1176 } 1177 1178 static void 1179 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 1180 { 1181 struct event_file_link *link; 1182 1183 trace_probe_for_each_link_rcu(link, &tk->tp) 1184 __kprobe_trace_func(tk, regs, link->file); 1185 } 1186 NOKPROBE_SYMBOL(kprobe_trace_func); 1187 1188 /* Kretprobe handler */ 1189 static nokprobe_inline void 1190 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1191 struct pt_regs *regs, 1192 struct trace_event_file *trace_file) 1193 { 1194 struct kretprobe_trace_entry_head *entry; 1195 struct ring_buffer_event *event; 1196 struct ring_buffer *buffer; 1197 int size, pc, dsize; 1198 unsigned long irq_flags; 1199 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1200 1201 WARN_ON(call != trace_file->event_call); 1202 1203 if (trace_trigger_soft_disabled(trace_file)) 1204 return; 1205 1206 local_save_flags(irq_flags); 1207 pc = preempt_count(); 1208 1209 dsize = __get_data_size(&tk->tp, regs); 1210 size = sizeof(*entry) + tk->tp.size + dsize; 1211 1212 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 1213 call->event.type, 1214 size, irq_flags, pc); 1215 if (!event) 1216 return; 1217 1218 entry = ring_buffer_event_data(event); 1219 entry->func = (unsigned long)tk->rp.kp.addr; 1220 entry->ret_ip = (unsigned long)ri->ret_addr; 1221 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1222 1223 event_trigger_unlock_commit_regs(trace_file, buffer, event, 1224 entry, irq_flags, pc, regs); 1225 } 1226 1227 static void 1228 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1229 struct pt_regs *regs) 1230 { 1231 struct event_file_link *link; 1232 1233 trace_probe_for_each_link_rcu(link, &tk->tp) 1234 __kretprobe_trace_func(tk, ri, regs, link->file); 1235 } 1236 NOKPROBE_SYMBOL(kretprobe_trace_func); 1237 1238 /* Event entry printers */ 1239 static enum print_line_t 1240 print_kprobe_event(struct trace_iterator *iter, int flags, 1241 struct trace_event *event) 1242 { 1243 struct kprobe_trace_entry_head *field; 1244 struct trace_seq *s = &iter->seq; 1245 struct trace_probe *tp; 1246 1247 field = (struct kprobe_trace_entry_head *)iter->ent; 1248 tp = trace_probe_primary_from_call( 1249 container_of(event, struct trace_event_call, event)); 1250 if (WARN_ON_ONCE(!tp)) 1251 goto out; 1252 1253 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1254 1255 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) 1256 goto out; 1257 1258 trace_seq_putc(s, ')'); 1259 1260 if (print_probe_args(s, tp->args, tp->nr_args, 1261 (u8 *)&field[1], field) < 0) 1262 goto out; 1263 1264 trace_seq_putc(s, '\n'); 1265 out: 1266 return trace_handle_return(s); 1267 } 1268 1269 static enum print_line_t 1270 print_kretprobe_event(struct trace_iterator *iter, int flags, 1271 struct trace_event *event) 1272 { 1273 struct kretprobe_trace_entry_head *field; 1274 struct trace_seq *s = &iter->seq; 1275 struct trace_probe *tp; 1276 1277 field = (struct kretprobe_trace_entry_head *)iter->ent; 1278 tp = trace_probe_primary_from_call( 1279 container_of(event, struct trace_event_call, event)); 1280 if (WARN_ON_ONCE(!tp)) 1281 goto out; 1282 1283 trace_seq_printf(s, "%s: (", trace_probe_name(tp)); 1284 1285 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) 1286 goto out; 1287 1288 trace_seq_puts(s, " <- "); 1289 1290 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) 1291 goto out; 1292 1293 trace_seq_putc(s, ')'); 1294 1295 if (print_probe_args(s, tp->args, tp->nr_args, 1296 (u8 *)&field[1], field) < 0) 1297 goto out; 1298 1299 trace_seq_putc(s, '\n'); 1300 1301 out: 1302 return trace_handle_return(s); 1303 } 1304 1305 1306 static int kprobe_event_define_fields(struct trace_event_call *event_call) 1307 { 1308 int ret; 1309 struct kprobe_trace_entry_head field; 1310 struct trace_probe *tp; 1311 1312 tp = trace_probe_primary_from_call(event_call); 1313 if (WARN_ON_ONCE(!tp)) 1314 return -ENOENT; 1315 1316 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1317 1318 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1319 } 1320 1321 static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1322 { 1323 int ret; 1324 struct kretprobe_trace_entry_head field; 1325 struct trace_probe *tp; 1326 1327 tp = trace_probe_primary_from_call(event_call); 1328 if (WARN_ON_ONCE(!tp)) 1329 return -ENOENT; 1330 1331 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1332 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1333 1334 return traceprobe_define_arg_fields(event_call, sizeof(field), tp); 1335 } 1336 1337 #ifdef CONFIG_PERF_EVENTS 1338 1339 /* Kprobe profile handler */ 1340 static int 1341 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1342 { 1343 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1344 struct kprobe_trace_entry_head *entry; 1345 struct hlist_head *head; 1346 int size, __size, dsize; 1347 int rctx; 1348 1349 if (bpf_prog_array_valid(call)) { 1350 unsigned long orig_ip = instruction_pointer(regs); 1351 int ret; 1352 1353 ret = trace_call_bpf(call, regs); 1354 1355 /* 1356 * We need to check and see if we modified the pc of the 1357 * pt_regs, and if so return 1 so that we don't do the 1358 * single stepping. 1359 */ 1360 if (orig_ip != instruction_pointer(regs)) 1361 return 1; 1362 if (!ret) 1363 return 0; 1364 } 1365 1366 head = this_cpu_ptr(call->perf_events); 1367 if (hlist_empty(head)) 1368 return 0; 1369 1370 dsize = __get_data_size(&tk->tp, regs); 1371 __size = sizeof(*entry) + tk->tp.size + dsize; 1372 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1373 size -= sizeof(u32); 1374 1375 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1376 if (!entry) 1377 return 0; 1378 1379 entry->ip = (unsigned long)tk->rp.kp.addr; 1380 memset(&entry[1], 0, dsize); 1381 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1382 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1383 head, NULL); 1384 return 0; 1385 } 1386 NOKPROBE_SYMBOL(kprobe_perf_func); 1387 1388 /* Kretprobe profile handler */ 1389 static void 1390 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1391 struct pt_regs *regs) 1392 { 1393 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1394 struct kretprobe_trace_entry_head *entry; 1395 struct hlist_head *head; 1396 int size, __size, dsize; 1397 int rctx; 1398 1399 if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs)) 1400 return; 1401 1402 head = this_cpu_ptr(call->perf_events); 1403 if (hlist_empty(head)) 1404 return; 1405 1406 dsize = __get_data_size(&tk->tp, regs); 1407 __size = sizeof(*entry) + tk->tp.size + dsize; 1408 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1409 size -= sizeof(u32); 1410 1411 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1412 if (!entry) 1413 return; 1414 1415 entry->func = (unsigned long)tk->rp.kp.addr; 1416 entry->ret_ip = (unsigned long)ri->ret_addr; 1417 store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); 1418 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1419 head, NULL); 1420 } 1421 NOKPROBE_SYMBOL(kretprobe_perf_func); 1422 1423 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, 1424 const char **symbol, u64 *probe_offset, 1425 u64 *probe_addr, bool perf_type_tracepoint) 1426 { 1427 const char *pevent = trace_event_name(event->tp_event); 1428 const char *group = event->tp_event->class->system; 1429 struct trace_kprobe *tk; 1430 1431 if (perf_type_tracepoint) 1432 tk = find_trace_kprobe(pevent, group); 1433 else 1434 tk = event->tp_event->data; 1435 if (!tk) 1436 return -EINVAL; 1437 1438 *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE 1439 : BPF_FD_TYPE_KPROBE; 1440 if (tk->symbol) { 1441 *symbol = tk->symbol; 1442 *probe_offset = tk->rp.kp.offset; 1443 *probe_addr = 0; 1444 } else { 1445 *symbol = NULL; 1446 *probe_offset = 0; 1447 *probe_addr = (unsigned long)tk->rp.kp.addr; 1448 } 1449 return 0; 1450 } 1451 #endif /* CONFIG_PERF_EVENTS */ 1452 1453 /* 1454 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1455 * 1456 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1457 * lockless, but we can't race with this __init function. 1458 */ 1459 static int kprobe_register(struct trace_event_call *event, 1460 enum trace_reg type, void *data) 1461 { 1462 struct trace_event_file *file = data; 1463 1464 switch (type) { 1465 case TRACE_REG_REGISTER: 1466 return enable_trace_kprobe(event, file); 1467 case TRACE_REG_UNREGISTER: 1468 return disable_trace_kprobe(event, file); 1469 1470 #ifdef CONFIG_PERF_EVENTS 1471 case TRACE_REG_PERF_REGISTER: 1472 return enable_trace_kprobe(event, NULL); 1473 case TRACE_REG_PERF_UNREGISTER: 1474 return disable_trace_kprobe(event, NULL); 1475 case TRACE_REG_PERF_OPEN: 1476 case TRACE_REG_PERF_CLOSE: 1477 case TRACE_REG_PERF_ADD: 1478 case TRACE_REG_PERF_DEL: 1479 return 0; 1480 #endif 1481 } 1482 return 0; 1483 } 1484 1485 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1486 { 1487 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1488 int ret = 0; 1489 1490 raw_cpu_inc(*tk->nhit); 1491 1492 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1493 kprobe_trace_func(tk, regs); 1494 #ifdef CONFIG_PERF_EVENTS 1495 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1496 ret = kprobe_perf_func(tk, regs); 1497 #endif 1498 return ret; 1499 } 1500 NOKPROBE_SYMBOL(kprobe_dispatcher); 1501 1502 static int 1503 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1504 { 1505 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp); 1506 1507 raw_cpu_inc(*tk->nhit); 1508 1509 if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE)) 1510 kretprobe_trace_func(tk, ri, regs); 1511 #ifdef CONFIG_PERF_EVENTS 1512 if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE)) 1513 kretprobe_perf_func(tk, ri, regs); 1514 #endif 1515 return 0; /* We don't tweek kernel, so just return 0 */ 1516 } 1517 NOKPROBE_SYMBOL(kretprobe_dispatcher); 1518 1519 static struct trace_event_functions kretprobe_funcs = { 1520 .trace = print_kretprobe_event 1521 }; 1522 1523 static struct trace_event_functions kprobe_funcs = { 1524 .trace = print_kprobe_event 1525 }; 1526 1527 static inline void init_trace_event_call(struct trace_kprobe *tk) 1528 { 1529 struct trace_event_call *call = trace_probe_event_call(&tk->tp); 1530 1531 if (trace_kprobe_is_return(tk)) { 1532 call->event.funcs = &kretprobe_funcs; 1533 call->class->define_fields = kretprobe_event_define_fields; 1534 } else { 1535 call->event.funcs = &kprobe_funcs; 1536 call->class->define_fields = kprobe_event_define_fields; 1537 } 1538 1539 call->flags = TRACE_EVENT_FL_KPROBE; 1540 call->class->reg = kprobe_register; 1541 } 1542 1543 static int register_kprobe_event(struct trace_kprobe *tk) 1544 { 1545 init_trace_event_call(tk); 1546 1547 return trace_probe_register_event_call(&tk->tp); 1548 } 1549 1550 static int unregister_kprobe_event(struct trace_kprobe *tk) 1551 { 1552 return trace_probe_unregister_event_call(&tk->tp); 1553 } 1554 1555 #ifdef CONFIG_PERF_EVENTS 1556 /* create a trace_kprobe, but don't add it to global lists */ 1557 struct trace_event_call * 1558 create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 1559 bool is_return) 1560 { 1561 struct trace_kprobe *tk; 1562 int ret; 1563 char *event; 1564 1565 /* 1566 * local trace_kprobes are not added to dyn_event, so they are never 1567 * searched in find_trace_kprobe(). Therefore, there is no concern of 1568 * duplicated name here. 1569 */ 1570 event = func ? func : "DUMMY_EVENT"; 1571 1572 tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func, 1573 offs, 0 /* maxactive */, 0 /* nargs */, 1574 is_return); 1575 1576 if (IS_ERR(tk)) { 1577 pr_info("Failed to allocate trace_probe.(%d)\n", 1578 (int)PTR_ERR(tk)); 1579 return ERR_CAST(tk); 1580 } 1581 1582 init_trace_event_call(tk); 1583 1584 if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) { 1585 ret = -ENOMEM; 1586 goto error; 1587 } 1588 1589 ret = __register_trace_kprobe(tk); 1590 if (ret < 0) 1591 goto error; 1592 1593 return trace_probe_event_call(&tk->tp); 1594 error: 1595 free_trace_kprobe(tk); 1596 return ERR_PTR(ret); 1597 } 1598 1599 void destroy_local_trace_kprobe(struct trace_event_call *event_call) 1600 { 1601 struct trace_kprobe *tk; 1602 1603 tk = trace_kprobe_primary_from_call(event_call); 1604 if (unlikely(!tk)) 1605 return; 1606 1607 if (trace_probe_is_enabled(&tk->tp)) { 1608 WARN_ON(1); 1609 return; 1610 } 1611 1612 __unregister_trace_kprobe(tk); 1613 1614 free_trace_kprobe(tk); 1615 } 1616 #endif /* CONFIG_PERF_EVENTS */ 1617 1618 static __init void enable_boot_kprobe_events(void) 1619 { 1620 struct trace_array *tr = top_trace_array(); 1621 struct trace_event_file *file; 1622 struct trace_kprobe *tk; 1623 struct dyn_event *pos; 1624 1625 mutex_lock(&event_mutex); 1626 for_each_trace_kprobe(tk, pos) { 1627 list_for_each_entry(file, &tr->events, list) 1628 if (file->event_call == trace_probe_event_call(&tk->tp)) 1629 trace_event_enable_disable(file, 1, 0); 1630 } 1631 mutex_unlock(&event_mutex); 1632 } 1633 1634 static __init void setup_boot_kprobe_events(void) 1635 { 1636 char *p, *cmd = kprobe_boot_events_buf; 1637 int ret; 1638 1639 strreplace(kprobe_boot_events_buf, ',', ' '); 1640 1641 while (cmd && *cmd != '\0') { 1642 p = strchr(cmd, ';'); 1643 if (p) 1644 *p++ = '\0'; 1645 1646 ret = trace_run_command(cmd, create_or_delete_trace_kprobe); 1647 if (ret) 1648 pr_warn("Failed to add event(%d): %s\n", ret, cmd); 1649 else 1650 kprobe_boot_events_enabled = true; 1651 1652 cmd = p; 1653 } 1654 1655 enable_boot_kprobe_events(); 1656 } 1657 1658 /* Make a tracefs interface for controlling probe points */ 1659 static __init int init_kprobe_trace(void) 1660 { 1661 struct dentry *d_tracer; 1662 struct dentry *entry; 1663 int ret; 1664 1665 ret = dyn_event_register(&trace_kprobe_ops); 1666 if (ret) 1667 return ret; 1668 1669 if (register_module_notifier(&trace_kprobe_module_nb)) 1670 return -EINVAL; 1671 1672 d_tracer = tracing_init_dentry(); 1673 if (IS_ERR(d_tracer)) 1674 return 0; 1675 1676 entry = tracefs_create_file("kprobe_events", 0644, d_tracer, 1677 NULL, &kprobe_events_ops); 1678 1679 /* Event list interface */ 1680 if (!entry) 1681 pr_warn("Could not create tracefs 'kprobe_events' entry\n"); 1682 1683 /* Profile interface */ 1684 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer, 1685 NULL, &kprobe_profile_ops); 1686 1687 if (!entry) 1688 pr_warn("Could not create tracefs 'kprobe_profile' entry\n"); 1689 1690 setup_boot_kprobe_events(); 1691 1692 return 0; 1693 } 1694 fs_initcall(init_kprobe_trace); 1695 1696 1697 #ifdef CONFIG_FTRACE_STARTUP_TEST 1698 static __init struct trace_event_file * 1699 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 1700 { 1701 struct trace_event_file *file; 1702 1703 list_for_each_entry(file, &tr->events, list) 1704 if (file->event_call == trace_probe_event_call(&tk->tp)) 1705 return file; 1706 1707 return NULL; 1708 } 1709 1710 /* 1711 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 1712 * stage, we can do this lockless. 1713 */ 1714 static __init int kprobe_trace_self_tests_init(void) 1715 { 1716 int ret, warn = 0; 1717 int (*target)(int, int, int, int, int, int); 1718 struct trace_kprobe *tk; 1719 struct trace_event_file *file; 1720 1721 if (tracing_is_disabled()) 1722 return -ENODEV; 1723 1724 if (kprobe_boot_events_enabled) { 1725 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n"); 1726 return 0; 1727 } 1728 1729 target = kprobe_trace_selftest_target; 1730 1731 pr_info("Testing kprobe tracing: "); 1732 1733 ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)", 1734 create_or_delete_trace_kprobe); 1735 if (WARN_ON_ONCE(ret)) { 1736 pr_warn("error on probing function entry.\n"); 1737 warn++; 1738 } else { 1739 /* Enable trace point */ 1740 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1741 if (WARN_ON_ONCE(tk == NULL)) { 1742 pr_warn("error on getting new probe.\n"); 1743 warn++; 1744 } else { 1745 file = find_trace_probe_file(tk, top_trace_array()); 1746 if (WARN_ON_ONCE(file == NULL)) { 1747 pr_warn("error on getting probe file.\n"); 1748 warn++; 1749 } else 1750 enable_trace_kprobe( 1751 trace_probe_event_call(&tk->tp), file); 1752 } 1753 } 1754 1755 ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval", 1756 create_or_delete_trace_kprobe); 1757 if (WARN_ON_ONCE(ret)) { 1758 pr_warn("error on probing function return.\n"); 1759 warn++; 1760 } else { 1761 /* Enable trace point */ 1762 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1763 if (WARN_ON_ONCE(tk == NULL)) { 1764 pr_warn("error on getting 2nd new probe.\n"); 1765 warn++; 1766 } else { 1767 file = find_trace_probe_file(tk, top_trace_array()); 1768 if (WARN_ON_ONCE(file == NULL)) { 1769 pr_warn("error on getting probe file.\n"); 1770 warn++; 1771 } else 1772 enable_trace_kprobe( 1773 trace_probe_event_call(&tk->tp), file); 1774 } 1775 } 1776 1777 if (warn) 1778 goto end; 1779 1780 ret = target(1, 2, 3, 4, 5, 6); 1781 1782 /* 1783 * Not expecting an error here, the check is only to prevent the 1784 * optimizer from removing the call to target() as otherwise there 1785 * are no side-effects and the call is never performed. 1786 */ 1787 if (ret != 21) 1788 warn++; 1789 1790 /* Disable trace points before removing it */ 1791 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1792 if (WARN_ON_ONCE(tk == NULL)) { 1793 pr_warn("error on getting test probe.\n"); 1794 warn++; 1795 } else { 1796 if (trace_kprobe_nhit(tk) != 1) { 1797 pr_warn("incorrect number of testprobe hits\n"); 1798 warn++; 1799 } 1800 1801 file = find_trace_probe_file(tk, top_trace_array()); 1802 if (WARN_ON_ONCE(file == NULL)) { 1803 pr_warn("error on getting probe file.\n"); 1804 warn++; 1805 } else 1806 disable_trace_kprobe( 1807 trace_probe_event_call(&tk->tp), file); 1808 } 1809 1810 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1811 if (WARN_ON_ONCE(tk == NULL)) { 1812 pr_warn("error on getting 2nd test probe.\n"); 1813 warn++; 1814 } else { 1815 if (trace_kprobe_nhit(tk) != 1) { 1816 pr_warn("incorrect number of testprobe2 hits\n"); 1817 warn++; 1818 } 1819 1820 file = find_trace_probe_file(tk, top_trace_array()); 1821 if (WARN_ON_ONCE(file == NULL)) { 1822 pr_warn("error on getting probe file.\n"); 1823 warn++; 1824 } else 1825 disable_trace_kprobe( 1826 trace_probe_event_call(&tk->tp), file); 1827 } 1828 1829 ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe); 1830 if (WARN_ON_ONCE(ret)) { 1831 pr_warn("error on deleting a probe.\n"); 1832 warn++; 1833 } 1834 1835 ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe); 1836 if (WARN_ON_ONCE(ret)) { 1837 pr_warn("error on deleting a probe.\n"); 1838 warn++; 1839 } 1840 1841 end: 1842 ret = dyn_events_release_all(&trace_kprobe_ops); 1843 if (WARN_ON_ONCE(ret)) { 1844 pr_warn("error on cleaning up probes.\n"); 1845 warn++; 1846 } 1847 /* 1848 * Wait for the optimizer work to finish. Otherwise it might fiddle 1849 * with probes in already freed __init text. 1850 */ 1851 wait_for_kprobe_optimizer(); 1852 if (warn) 1853 pr_cont("NG: Some tests are failed. Please check them.\n"); 1854 else 1855 pr_cont("OK\n"); 1856 return 0; 1857 } 1858 1859 late_initcall(kprobe_trace_self_tests_init); 1860 1861 #endif 1862