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