1 /* 2 * Kprobes-based tracing events 3 * 4 * Created by Masami Hiramatsu <mhiramat@redhat.com> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 */ 19 #define pr_fmt(fmt) "trace_kprobe: " fmt 20 21 #include <linux/module.h> 22 #include <linux/uaccess.h> 23 #include <linux/rculist.h> 24 25 #include "trace_probe.h" 26 27 #define KPROBE_EVENT_SYSTEM "kprobes" 28 #define KRETPROBE_MAXACTIVE_MAX 4096 29 30 /** 31 * Kprobe event core functions 32 */ 33 struct trace_kprobe { 34 struct list_head list; 35 struct kretprobe rp; /* Use rp.kp for kprobe use */ 36 unsigned long __percpu *nhit; 37 const char *symbol; /* symbol name */ 38 struct trace_probe tp; 39 }; 40 41 #define SIZEOF_TRACE_KPROBE(n) \ 42 (offsetof(struct trace_kprobe, tp.args) + \ 43 (sizeof(struct probe_arg) * (n))) 44 45 46 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk) 47 { 48 return tk->rp.handler != NULL; 49 } 50 51 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk) 52 { 53 return tk->symbol ? tk->symbol : "unknown"; 54 } 55 56 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk) 57 { 58 return tk->rp.kp.offset; 59 } 60 61 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk) 62 { 63 return !!(kprobe_gone(&tk->rp.kp)); 64 } 65 66 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, 67 struct module *mod) 68 { 69 int len = strlen(mod->name); 70 const char *name = trace_kprobe_symbol(tk); 71 return strncmp(mod->name, name, len) == 0 && name[len] == ':'; 72 } 73 74 static nokprobe_inline bool trace_kprobe_is_on_module(struct trace_kprobe *tk) 75 { 76 return !!strchr(trace_kprobe_symbol(tk), ':'); 77 } 78 79 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk) 80 { 81 unsigned long nhit = 0; 82 int cpu; 83 84 for_each_possible_cpu(cpu) 85 nhit += *per_cpu_ptr(tk->nhit, cpu); 86 87 return nhit; 88 } 89 90 static int register_kprobe_event(struct trace_kprobe *tk); 91 static int unregister_kprobe_event(struct trace_kprobe *tk); 92 93 static DEFINE_MUTEX(probe_lock); 94 static LIST_HEAD(probe_list); 95 96 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); 97 static int kretprobe_dispatcher(struct kretprobe_instance *ri, 98 struct pt_regs *regs); 99 100 /* Memory fetching by symbol */ 101 struct symbol_cache { 102 char *symbol; 103 long offset; 104 unsigned long addr; 105 }; 106 107 unsigned long update_symbol_cache(struct symbol_cache *sc) 108 { 109 sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol); 110 111 if (sc->addr) 112 sc->addr += sc->offset; 113 114 return sc->addr; 115 } 116 117 void free_symbol_cache(struct symbol_cache *sc) 118 { 119 kfree(sc->symbol); 120 kfree(sc); 121 } 122 123 struct symbol_cache *alloc_symbol_cache(const char *sym, long offset) 124 { 125 struct symbol_cache *sc; 126 127 if (!sym || strlen(sym) == 0) 128 return NULL; 129 130 sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL); 131 if (!sc) 132 return NULL; 133 134 sc->symbol = kstrdup(sym, GFP_KERNEL); 135 if (!sc->symbol) { 136 kfree(sc); 137 return NULL; 138 } 139 sc->offset = offset; 140 update_symbol_cache(sc); 141 142 return sc; 143 } 144 145 /* 146 * Kprobes-specific fetch functions 147 */ 148 #define DEFINE_FETCH_stack(type) \ 149 static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \ 150 void *offset, void *dest) \ 151 { \ 152 *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \ 153 (unsigned int)((unsigned long)offset)); \ 154 } \ 155 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type)); 156 157 DEFINE_BASIC_FETCH_FUNCS(stack) 158 /* No string on the stack entry */ 159 #define fetch_stack_string NULL 160 #define fetch_stack_string_size NULL 161 162 #define DEFINE_FETCH_memory(type) \ 163 static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \ 164 void *addr, void *dest) \ 165 { \ 166 type retval; \ 167 if (probe_kernel_address(addr, retval)) \ 168 *(type *)dest = 0; \ 169 else \ 170 *(type *)dest = retval; \ 171 } \ 172 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type)); 173 174 DEFINE_BASIC_FETCH_FUNCS(memory) 175 /* 176 * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max 177 * length and relative data location. 178 */ 179 static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, 180 void *addr, void *dest) 181 { 182 int maxlen = get_rloc_len(*(u32 *)dest); 183 u8 *dst = get_rloc_data(dest); 184 long ret; 185 186 if (!maxlen) 187 return; 188 189 /* 190 * Try to get string again, since the string can be changed while 191 * probing. 192 */ 193 ret = strncpy_from_unsafe(dst, addr, maxlen); 194 195 if (ret < 0) { /* Failed to fetch string */ 196 dst[0] = '\0'; 197 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest)); 198 } else { 199 *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest)); 200 } 201 } 202 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string)); 203 204 /* Return the length of string -- including null terminal byte */ 205 static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs, 206 void *addr, void *dest) 207 { 208 mm_segment_t old_fs; 209 int ret, len = 0; 210 u8 c; 211 212 old_fs = get_fs(); 213 set_fs(KERNEL_DS); 214 pagefault_disable(); 215 216 do { 217 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1); 218 len++; 219 } while (c && ret == 0 && len < MAX_STRING_SIZE); 220 221 pagefault_enable(); 222 set_fs(old_fs); 223 224 if (ret < 0) /* Failed to check the length */ 225 *(u32 *)dest = 0; 226 else 227 *(u32 *)dest = len; 228 } 229 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size)); 230 231 #define DEFINE_FETCH_symbol(type) \ 232 void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\ 233 { \ 234 struct symbol_cache *sc = data; \ 235 if (sc->addr) \ 236 fetch_memory_##type(regs, (void *)sc->addr, dest); \ 237 else \ 238 *(type *)dest = 0; \ 239 } \ 240 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type)); 241 242 DEFINE_BASIC_FETCH_FUNCS(symbol) 243 DEFINE_FETCH_symbol(string) 244 DEFINE_FETCH_symbol(string_size) 245 246 /* kprobes don't support file_offset fetch methods */ 247 #define fetch_file_offset_u8 NULL 248 #define fetch_file_offset_u16 NULL 249 #define fetch_file_offset_u32 NULL 250 #define fetch_file_offset_u64 NULL 251 #define fetch_file_offset_string NULL 252 #define fetch_file_offset_string_size NULL 253 254 /* Fetch type information table */ 255 static const struct fetch_type kprobes_fetch_type_table[] = { 256 /* Special types */ 257 [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string, 258 sizeof(u32), 1, "__data_loc char[]"), 259 [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32, 260 string_size, sizeof(u32), 0, "u32"), 261 /* Basic types */ 262 ASSIGN_FETCH_TYPE(u8, u8, 0), 263 ASSIGN_FETCH_TYPE(u16, u16, 0), 264 ASSIGN_FETCH_TYPE(u32, u32, 0), 265 ASSIGN_FETCH_TYPE(u64, u64, 0), 266 ASSIGN_FETCH_TYPE(s8, u8, 1), 267 ASSIGN_FETCH_TYPE(s16, u16, 1), 268 ASSIGN_FETCH_TYPE(s32, u32, 1), 269 ASSIGN_FETCH_TYPE(s64, u64, 1), 270 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0), 271 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0), 272 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0), 273 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), 274 275 ASSIGN_FETCH_TYPE_END 276 }; 277 278 /* 279 * Allocate new trace_probe and initialize it (including kprobes). 280 */ 281 static struct trace_kprobe *alloc_trace_kprobe(const char *group, 282 const char *event, 283 void *addr, 284 const char *symbol, 285 unsigned long offs, 286 int maxactive, 287 int nargs, bool is_return) 288 { 289 struct trace_kprobe *tk; 290 int ret = -ENOMEM; 291 292 tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL); 293 if (!tk) 294 return ERR_PTR(ret); 295 296 tk->nhit = alloc_percpu(unsigned long); 297 if (!tk->nhit) 298 goto error; 299 300 if (symbol) { 301 tk->symbol = kstrdup(symbol, GFP_KERNEL); 302 if (!tk->symbol) 303 goto error; 304 tk->rp.kp.symbol_name = tk->symbol; 305 tk->rp.kp.offset = offs; 306 } else 307 tk->rp.kp.addr = addr; 308 309 if (is_return) 310 tk->rp.handler = kretprobe_dispatcher; 311 else 312 tk->rp.kp.pre_handler = kprobe_dispatcher; 313 314 tk->rp.maxactive = maxactive; 315 316 if (!event || !is_good_name(event)) { 317 ret = -EINVAL; 318 goto error; 319 } 320 321 tk->tp.call.class = &tk->tp.class; 322 tk->tp.call.name = kstrdup(event, GFP_KERNEL); 323 if (!tk->tp.call.name) 324 goto error; 325 326 if (!group || !is_good_name(group)) { 327 ret = -EINVAL; 328 goto error; 329 } 330 331 tk->tp.class.system = kstrdup(group, GFP_KERNEL); 332 if (!tk->tp.class.system) 333 goto error; 334 335 INIT_LIST_HEAD(&tk->list); 336 INIT_LIST_HEAD(&tk->tp.files); 337 return tk; 338 error: 339 kfree(tk->tp.call.name); 340 kfree(tk->symbol); 341 free_percpu(tk->nhit); 342 kfree(tk); 343 return ERR_PTR(ret); 344 } 345 346 static void free_trace_kprobe(struct trace_kprobe *tk) 347 { 348 int i; 349 350 for (i = 0; i < tk->tp.nr_args; i++) 351 traceprobe_free_probe_arg(&tk->tp.args[i]); 352 353 kfree(tk->tp.call.class->system); 354 kfree(tk->tp.call.name); 355 kfree(tk->symbol); 356 free_percpu(tk->nhit); 357 kfree(tk); 358 } 359 360 static struct trace_kprobe *find_trace_kprobe(const char *event, 361 const char *group) 362 { 363 struct trace_kprobe *tk; 364 365 list_for_each_entry(tk, &probe_list, list) 366 if (strcmp(trace_event_name(&tk->tp.call), event) == 0 && 367 strcmp(tk->tp.call.class->system, group) == 0) 368 return tk; 369 return NULL; 370 } 371 372 /* 373 * Enable trace_probe 374 * if the file is NULL, enable "perf" handler, or enable "trace" handler. 375 */ 376 static int 377 enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) 378 { 379 int ret = 0; 380 381 if (file) { 382 struct event_file_link *link; 383 384 link = kmalloc(sizeof(*link), GFP_KERNEL); 385 if (!link) { 386 ret = -ENOMEM; 387 goto out; 388 } 389 390 link->file = file; 391 list_add_tail_rcu(&link->list, &tk->tp.files); 392 393 tk->tp.flags |= TP_FLAG_TRACE; 394 } else 395 tk->tp.flags |= TP_FLAG_PROFILE; 396 397 if (trace_probe_is_registered(&tk->tp) && !trace_kprobe_has_gone(tk)) { 398 if (trace_kprobe_is_return(tk)) 399 ret = enable_kretprobe(&tk->rp); 400 else 401 ret = enable_kprobe(&tk->rp.kp); 402 } 403 out: 404 return ret; 405 } 406 407 /* 408 * Disable trace_probe 409 * if the file is NULL, disable "perf" handler, or disable "trace" handler. 410 */ 411 static int 412 disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) 413 { 414 struct event_file_link *link = NULL; 415 int wait = 0; 416 int ret = 0; 417 418 if (file) { 419 link = find_event_file_link(&tk->tp, file); 420 if (!link) { 421 ret = -EINVAL; 422 goto out; 423 } 424 425 list_del_rcu(&link->list); 426 wait = 1; 427 if (!list_empty(&tk->tp.files)) 428 goto out; 429 430 tk->tp.flags &= ~TP_FLAG_TRACE; 431 } else 432 tk->tp.flags &= ~TP_FLAG_PROFILE; 433 434 if (!trace_probe_is_enabled(&tk->tp) && trace_probe_is_registered(&tk->tp)) { 435 if (trace_kprobe_is_return(tk)) 436 disable_kretprobe(&tk->rp); 437 else 438 disable_kprobe(&tk->rp.kp); 439 wait = 1; 440 } 441 out: 442 if (wait) { 443 /* 444 * Synchronize with kprobe_trace_func/kretprobe_trace_func 445 * to ensure disabled (all running handlers are finished). 446 * This is not only for kfree(), but also the caller, 447 * trace_remove_event_call() supposes it for releasing 448 * event_call related objects, which will be accessed in 449 * the kprobe_trace_func/kretprobe_trace_func. 450 */ 451 synchronize_sched(); 452 kfree(link); /* Ignored if link == NULL */ 453 } 454 455 return ret; 456 } 457 458 /* Internal register function - just handle k*probes and flags */ 459 static int __register_trace_kprobe(struct trace_kprobe *tk) 460 { 461 int i, ret; 462 463 if (trace_probe_is_registered(&tk->tp)) 464 return -EINVAL; 465 466 for (i = 0; i < tk->tp.nr_args; i++) 467 traceprobe_update_arg(&tk->tp.args[i]); 468 469 /* Set/clear disabled flag according to tp->flag */ 470 if (trace_probe_is_enabled(&tk->tp)) 471 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; 472 else 473 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED; 474 475 if (trace_kprobe_is_return(tk)) 476 ret = register_kretprobe(&tk->rp); 477 else 478 ret = register_kprobe(&tk->rp.kp); 479 480 if (ret == 0) 481 tk->tp.flags |= TP_FLAG_REGISTERED; 482 else { 483 pr_warn("Could not insert probe at %s+%lu: %d\n", 484 trace_kprobe_symbol(tk), trace_kprobe_offset(tk), ret); 485 if (ret == -ENOENT && trace_kprobe_is_on_module(tk)) { 486 pr_warn("This probe might be able to register after target module is loaded. Continue.\n"); 487 ret = 0; 488 } else if (ret == -EILSEQ) { 489 pr_warn("Probing address(0x%p) is not an instruction boundary.\n", 490 tk->rp.kp.addr); 491 ret = -EINVAL; 492 } 493 } 494 495 return ret; 496 } 497 498 /* Internal unregister function - just handle k*probes and flags */ 499 static void __unregister_trace_kprobe(struct trace_kprobe *tk) 500 { 501 if (trace_probe_is_registered(&tk->tp)) { 502 if (trace_kprobe_is_return(tk)) 503 unregister_kretprobe(&tk->rp); 504 else 505 unregister_kprobe(&tk->rp.kp); 506 tk->tp.flags &= ~TP_FLAG_REGISTERED; 507 /* Cleanup kprobe for reuse */ 508 if (tk->rp.kp.symbol_name) 509 tk->rp.kp.addr = NULL; 510 } 511 } 512 513 /* Unregister a trace_probe and probe_event: call with locking probe_lock */ 514 static int unregister_trace_kprobe(struct trace_kprobe *tk) 515 { 516 /* Enabled event can not be unregistered */ 517 if (trace_probe_is_enabled(&tk->tp)) 518 return -EBUSY; 519 520 /* Will fail if probe is being used by ftrace or perf */ 521 if (unregister_kprobe_event(tk)) 522 return -EBUSY; 523 524 __unregister_trace_kprobe(tk); 525 list_del(&tk->list); 526 527 return 0; 528 } 529 530 /* Register a trace_probe and probe_event */ 531 static int register_trace_kprobe(struct trace_kprobe *tk) 532 { 533 struct trace_kprobe *old_tk; 534 int ret; 535 536 mutex_lock(&probe_lock); 537 538 /* Delete old (same name) event if exist */ 539 old_tk = find_trace_kprobe(trace_event_name(&tk->tp.call), 540 tk->tp.call.class->system); 541 if (old_tk) { 542 ret = unregister_trace_kprobe(old_tk); 543 if (ret < 0) 544 goto end; 545 free_trace_kprobe(old_tk); 546 } 547 548 /* Register new event */ 549 ret = register_kprobe_event(tk); 550 if (ret) { 551 pr_warn("Failed to register probe event(%d)\n", ret); 552 goto end; 553 } 554 555 /* Register k*probe */ 556 ret = __register_trace_kprobe(tk); 557 if (ret < 0) 558 unregister_kprobe_event(tk); 559 else 560 list_add_tail(&tk->list, &probe_list); 561 562 end: 563 mutex_unlock(&probe_lock); 564 return ret; 565 } 566 567 /* Module notifier call back, checking event on the module */ 568 static int trace_kprobe_module_callback(struct notifier_block *nb, 569 unsigned long val, void *data) 570 { 571 struct module *mod = data; 572 struct trace_kprobe *tk; 573 int ret; 574 575 if (val != MODULE_STATE_COMING) 576 return NOTIFY_DONE; 577 578 /* Update probes on coming module */ 579 mutex_lock(&probe_lock); 580 list_for_each_entry(tk, &probe_list, list) { 581 if (trace_kprobe_within_module(tk, mod)) { 582 /* Don't need to check busy - this should have gone. */ 583 __unregister_trace_kprobe(tk); 584 ret = __register_trace_kprobe(tk); 585 if (ret) 586 pr_warn("Failed to re-register probe %s on %s: %d\n", 587 trace_event_name(&tk->tp.call), 588 mod->name, ret); 589 } 590 } 591 mutex_unlock(&probe_lock); 592 593 return NOTIFY_DONE; 594 } 595 596 static struct notifier_block trace_kprobe_module_nb = { 597 .notifier_call = trace_kprobe_module_callback, 598 .priority = 1 /* Invoked after kprobe module callback */ 599 }; 600 601 /* Convert certain expected symbols into '_' when generating event names */ 602 static inline void sanitize_event_name(char *name) 603 { 604 while (*name++ != '\0') 605 if (*name == ':' || *name == '.') 606 *name = '_'; 607 } 608 609 static int create_trace_kprobe(int argc, char **argv) 610 { 611 /* 612 * Argument syntax: 613 * - Add kprobe: 614 * p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS] 615 * - Add kretprobe: 616 * r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS] 617 * Fetch args: 618 * $retval : fetch return value 619 * $stack : fetch stack address 620 * $stackN : fetch Nth of stack (N:0-) 621 * $comm : fetch current task comm 622 * @ADDR : fetch memory at ADDR (ADDR should be in kernel) 623 * @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol) 624 * %REG : fetch register REG 625 * Dereferencing memory fetch: 626 * +|-offs(ARG) : fetch memory at ARG +|- offs address. 627 * Alias name of args: 628 * NAME=FETCHARG : set NAME as alias of FETCHARG. 629 * Type of args: 630 * FETCHARG:TYPE : use TYPE instead of unsigned long. 631 */ 632 struct trace_kprobe *tk; 633 int i, ret = 0; 634 bool is_return = false, is_delete = false; 635 char *symbol = NULL, *event = NULL, *group = NULL; 636 int maxactive = 0; 637 char *arg; 638 unsigned long offset = 0; 639 void *addr = NULL; 640 char buf[MAX_EVENT_NAME_LEN]; 641 642 /* argc must be >= 1 */ 643 if (argv[0][0] == 'p') 644 is_return = false; 645 else if (argv[0][0] == 'r') 646 is_return = true; 647 else if (argv[0][0] == '-') 648 is_delete = true; 649 else { 650 pr_info("Probe definition must be started with 'p', 'r' or" 651 " '-'.\n"); 652 return -EINVAL; 653 } 654 655 event = strchr(&argv[0][1], ':'); 656 if (event) { 657 event[0] = '\0'; 658 event++; 659 } 660 if (is_return && isdigit(argv[0][1])) { 661 ret = kstrtouint(&argv[0][1], 0, &maxactive); 662 if (ret) { 663 pr_info("Failed to parse maxactive.\n"); 664 return ret; 665 } 666 /* kretprobes instances are iterated over via a list. The 667 * maximum should stay reasonable. 668 */ 669 if (maxactive > KRETPROBE_MAXACTIVE_MAX) { 670 pr_info("Maxactive is too big (%d > %d).\n", 671 maxactive, KRETPROBE_MAXACTIVE_MAX); 672 return -E2BIG; 673 } 674 } 675 676 if (event) { 677 if (strchr(event, '/')) { 678 group = event; 679 event = strchr(group, '/') + 1; 680 event[-1] = '\0'; 681 if (strlen(group) == 0) { 682 pr_info("Group name is not specified\n"); 683 return -EINVAL; 684 } 685 } 686 if (strlen(event) == 0) { 687 pr_info("Event name is not specified\n"); 688 return -EINVAL; 689 } 690 } 691 if (!group) 692 group = KPROBE_EVENT_SYSTEM; 693 694 if (is_delete) { 695 if (!event) { 696 pr_info("Delete command needs an event name.\n"); 697 return -EINVAL; 698 } 699 mutex_lock(&probe_lock); 700 tk = find_trace_kprobe(event, group); 701 if (!tk) { 702 mutex_unlock(&probe_lock); 703 pr_info("Event %s/%s doesn't exist.\n", group, event); 704 return -ENOENT; 705 } 706 /* delete an event */ 707 ret = unregister_trace_kprobe(tk); 708 if (ret == 0) 709 free_trace_kprobe(tk); 710 mutex_unlock(&probe_lock); 711 return ret; 712 } 713 714 if (argc < 2) { 715 pr_info("Probe point is not specified.\n"); 716 return -EINVAL; 717 } 718 719 /* try to parse an address. if that fails, try to read the 720 * input as a symbol. */ 721 if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) { 722 /* a symbol specified */ 723 symbol = argv[1]; 724 /* TODO: support .init module functions */ 725 ret = traceprobe_split_symbol_offset(symbol, &offset); 726 if (ret) { 727 pr_info("Failed to parse either an address or a symbol.\n"); 728 return ret; 729 } 730 if (offset && is_return && 731 !kprobe_on_func_entry(NULL, symbol, offset)) { 732 pr_info("Given offset is not valid for return probe.\n"); 733 return -EINVAL; 734 } 735 } 736 argc -= 2; argv += 2; 737 738 /* setup a probe */ 739 if (!event) { 740 /* Make a new event name */ 741 if (symbol) 742 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld", 743 is_return ? 'r' : 'p', symbol, offset); 744 else 745 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p", 746 is_return ? 'r' : 'p', addr); 747 sanitize_event_name(buf); 748 event = buf; 749 } 750 tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive, 751 argc, is_return); 752 if (IS_ERR(tk)) { 753 pr_info("Failed to allocate trace_probe.(%d)\n", 754 (int)PTR_ERR(tk)); 755 return PTR_ERR(tk); 756 } 757 758 /* parse arguments */ 759 ret = 0; 760 for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) { 761 struct probe_arg *parg = &tk->tp.args[i]; 762 763 /* Increment count for freeing args in error case */ 764 tk->tp.nr_args++; 765 766 /* Parse argument name */ 767 arg = strchr(argv[i], '='); 768 if (arg) { 769 *arg++ = '\0'; 770 parg->name = kstrdup(argv[i], GFP_KERNEL); 771 } else { 772 arg = argv[i]; 773 /* If argument name is omitted, set "argN" */ 774 snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1); 775 parg->name = kstrdup(buf, GFP_KERNEL); 776 } 777 778 if (!parg->name) { 779 pr_info("Failed to allocate argument[%d] name.\n", i); 780 ret = -ENOMEM; 781 goto error; 782 } 783 784 if (!is_good_name(parg->name)) { 785 pr_info("Invalid argument[%d] name: %s\n", 786 i, parg->name); 787 ret = -EINVAL; 788 goto error; 789 } 790 791 if (traceprobe_conflict_field_name(parg->name, 792 tk->tp.args, i)) { 793 pr_info("Argument[%d] name '%s' conflicts with " 794 "another field.\n", i, argv[i]); 795 ret = -EINVAL; 796 goto error; 797 } 798 799 /* Parse fetch argument */ 800 ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg, 801 is_return, true, 802 kprobes_fetch_type_table); 803 if (ret) { 804 pr_info("Parse error at argument[%d]. (%d)\n", i, ret); 805 goto error; 806 } 807 } 808 809 ret = register_trace_kprobe(tk); 810 if (ret) 811 goto error; 812 return 0; 813 814 error: 815 free_trace_kprobe(tk); 816 return ret; 817 } 818 819 static int release_all_trace_kprobes(void) 820 { 821 struct trace_kprobe *tk; 822 int ret = 0; 823 824 mutex_lock(&probe_lock); 825 /* Ensure no probe is in use. */ 826 list_for_each_entry(tk, &probe_list, list) 827 if (trace_probe_is_enabled(&tk->tp)) { 828 ret = -EBUSY; 829 goto end; 830 } 831 /* TODO: Use batch unregistration */ 832 while (!list_empty(&probe_list)) { 833 tk = list_entry(probe_list.next, struct trace_kprobe, list); 834 ret = unregister_trace_kprobe(tk); 835 if (ret) 836 goto end; 837 free_trace_kprobe(tk); 838 } 839 840 end: 841 mutex_unlock(&probe_lock); 842 843 return ret; 844 } 845 846 /* Probes listing interfaces */ 847 static void *probes_seq_start(struct seq_file *m, loff_t *pos) 848 { 849 mutex_lock(&probe_lock); 850 return seq_list_start(&probe_list, *pos); 851 } 852 853 static void *probes_seq_next(struct seq_file *m, void *v, loff_t *pos) 854 { 855 return seq_list_next(v, &probe_list, pos); 856 } 857 858 static void probes_seq_stop(struct seq_file *m, void *v) 859 { 860 mutex_unlock(&probe_lock); 861 } 862 863 static int probes_seq_show(struct seq_file *m, void *v) 864 { 865 struct trace_kprobe *tk = v; 866 int i; 867 868 seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p'); 869 seq_printf(m, ":%s/%s", tk->tp.call.class->system, 870 trace_event_name(&tk->tp.call)); 871 872 if (!tk->symbol) 873 seq_printf(m, " 0x%p", tk->rp.kp.addr); 874 else if (tk->rp.kp.offset) 875 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk), 876 tk->rp.kp.offset); 877 else 878 seq_printf(m, " %s", trace_kprobe_symbol(tk)); 879 880 for (i = 0; i < tk->tp.nr_args; i++) 881 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm); 882 seq_putc(m, '\n'); 883 884 return 0; 885 } 886 887 static const struct seq_operations probes_seq_op = { 888 .start = probes_seq_start, 889 .next = probes_seq_next, 890 .stop = probes_seq_stop, 891 .show = probes_seq_show 892 }; 893 894 static int probes_open(struct inode *inode, struct file *file) 895 { 896 int ret; 897 898 if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { 899 ret = release_all_trace_kprobes(); 900 if (ret < 0) 901 return ret; 902 } 903 904 return seq_open(file, &probes_seq_op); 905 } 906 907 static ssize_t probes_write(struct file *file, const char __user *buffer, 908 size_t count, loff_t *ppos) 909 { 910 return traceprobe_probes_write(file, buffer, count, ppos, 911 create_trace_kprobe); 912 } 913 914 static const struct file_operations kprobe_events_ops = { 915 .owner = THIS_MODULE, 916 .open = probes_open, 917 .read = seq_read, 918 .llseek = seq_lseek, 919 .release = seq_release, 920 .write = probes_write, 921 }; 922 923 /* Probes profiling interfaces */ 924 static int probes_profile_seq_show(struct seq_file *m, void *v) 925 { 926 struct trace_kprobe *tk = v; 927 928 seq_printf(m, " %-44s %15lu %15lu\n", 929 trace_event_name(&tk->tp.call), 930 trace_kprobe_nhit(tk), 931 tk->rp.kp.nmissed); 932 933 return 0; 934 } 935 936 static const struct seq_operations profile_seq_op = { 937 .start = probes_seq_start, 938 .next = probes_seq_next, 939 .stop = probes_seq_stop, 940 .show = probes_profile_seq_show 941 }; 942 943 static int profile_open(struct inode *inode, struct file *file) 944 { 945 return seq_open(file, &profile_seq_op); 946 } 947 948 static const struct file_operations kprobe_profile_ops = { 949 .owner = THIS_MODULE, 950 .open = profile_open, 951 .read = seq_read, 952 .llseek = seq_lseek, 953 .release = seq_release, 954 }; 955 956 /* Kprobe handler */ 957 static nokprobe_inline void 958 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, 959 struct trace_event_file *trace_file) 960 { 961 struct kprobe_trace_entry_head *entry; 962 struct ring_buffer_event *event; 963 struct ring_buffer *buffer; 964 int size, dsize, pc; 965 unsigned long irq_flags; 966 struct trace_event_call *call = &tk->tp.call; 967 968 WARN_ON(call != trace_file->event_call); 969 970 if (trace_trigger_soft_disabled(trace_file)) 971 return; 972 973 local_save_flags(irq_flags); 974 pc = preempt_count(); 975 976 dsize = __get_data_size(&tk->tp, regs); 977 size = sizeof(*entry) + tk->tp.size + dsize; 978 979 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 980 call->event.type, 981 size, irq_flags, pc); 982 if (!event) 983 return; 984 985 entry = ring_buffer_event_data(event); 986 entry->ip = (unsigned long)tk->rp.kp.addr; 987 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); 988 989 event_trigger_unlock_commit_regs(trace_file, buffer, event, 990 entry, irq_flags, pc, regs); 991 } 992 993 static void 994 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs) 995 { 996 struct event_file_link *link; 997 998 list_for_each_entry_rcu(link, &tk->tp.files, list) 999 __kprobe_trace_func(tk, regs, link->file); 1000 } 1001 NOKPROBE_SYMBOL(kprobe_trace_func); 1002 1003 /* Kretprobe handler */ 1004 static nokprobe_inline void 1005 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1006 struct pt_regs *regs, 1007 struct trace_event_file *trace_file) 1008 { 1009 struct kretprobe_trace_entry_head *entry; 1010 struct ring_buffer_event *event; 1011 struct ring_buffer *buffer; 1012 int size, pc, dsize; 1013 unsigned long irq_flags; 1014 struct trace_event_call *call = &tk->tp.call; 1015 1016 WARN_ON(call != trace_file->event_call); 1017 1018 if (trace_trigger_soft_disabled(trace_file)) 1019 return; 1020 1021 local_save_flags(irq_flags); 1022 pc = preempt_count(); 1023 1024 dsize = __get_data_size(&tk->tp, regs); 1025 size = sizeof(*entry) + tk->tp.size + dsize; 1026 1027 event = trace_event_buffer_lock_reserve(&buffer, trace_file, 1028 call->event.type, 1029 size, irq_flags, pc); 1030 if (!event) 1031 return; 1032 1033 entry = ring_buffer_event_data(event); 1034 entry->func = (unsigned long)tk->rp.kp.addr; 1035 entry->ret_ip = (unsigned long)ri->ret_addr; 1036 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); 1037 1038 event_trigger_unlock_commit_regs(trace_file, buffer, event, 1039 entry, irq_flags, pc, regs); 1040 } 1041 1042 static void 1043 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1044 struct pt_regs *regs) 1045 { 1046 struct event_file_link *link; 1047 1048 list_for_each_entry_rcu(link, &tk->tp.files, list) 1049 __kretprobe_trace_func(tk, ri, regs, link->file); 1050 } 1051 NOKPROBE_SYMBOL(kretprobe_trace_func); 1052 1053 /* Event entry printers */ 1054 static enum print_line_t 1055 print_kprobe_event(struct trace_iterator *iter, int flags, 1056 struct trace_event *event) 1057 { 1058 struct kprobe_trace_entry_head *field; 1059 struct trace_seq *s = &iter->seq; 1060 struct trace_probe *tp; 1061 u8 *data; 1062 int i; 1063 1064 field = (struct kprobe_trace_entry_head *)iter->ent; 1065 tp = container_of(event, struct trace_probe, call.event); 1066 1067 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call)); 1068 1069 if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET)) 1070 goto out; 1071 1072 trace_seq_putc(s, ')'); 1073 1074 data = (u8 *)&field[1]; 1075 for (i = 0; i < tp->nr_args; i++) 1076 if (!tp->args[i].type->print(s, tp->args[i].name, 1077 data + tp->args[i].offset, field)) 1078 goto out; 1079 1080 trace_seq_putc(s, '\n'); 1081 out: 1082 return trace_handle_return(s); 1083 } 1084 1085 static enum print_line_t 1086 print_kretprobe_event(struct trace_iterator *iter, int flags, 1087 struct trace_event *event) 1088 { 1089 struct kretprobe_trace_entry_head *field; 1090 struct trace_seq *s = &iter->seq; 1091 struct trace_probe *tp; 1092 u8 *data; 1093 int i; 1094 1095 field = (struct kretprobe_trace_entry_head *)iter->ent; 1096 tp = container_of(event, struct trace_probe, call.event); 1097 1098 trace_seq_printf(s, "%s: (", trace_event_name(&tp->call)); 1099 1100 if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET)) 1101 goto out; 1102 1103 trace_seq_puts(s, " <- "); 1104 1105 if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET)) 1106 goto out; 1107 1108 trace_seq_putc(s, ')'); 1109 1110 data = (u8 *)&field[1]; 1111 for (i = 0; i < tp->nr_args; i++) 1112 if (!tp->args[i].type->print(s, tp->args[i].name, 1113 data + tp->args[i].offset, field)) 1114 goto out; 1115 1116 trace_seq_putc(s, '\n'); 1117 1118 out: 1119 return trace_handle_return(s); 1120 } 1121 1122 1123 static int kprobe_event_define_fields(struct trace_event_call *event_call) 1124 { 1125 int ret, i; 1126 struct kprobe_trace_entry_head field; 1127 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data; 1128 1129 DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); 1130 /* Set argument names as fields */ 1131 for (i = 0; i < tk->tp.nr_args; i++) { 1132 struct probe_arg *parg = &tk->tp.args[i]; 1133 1134 ret = trace_define_field(event_call, parg->type->fmttype, 1135 parg->name, 1136 sizeof(field) + parg->offset, 1137 parg->type->size, 1138 parg->type->is_signed, 1139 FILTER_OTHER); 1140 if (ret) 1141 return ret; 1142 } 1143 return 0; 1144 } 1145 1146 static int kretprobe_event_define_fields(struct trace_event_call *event_call) 1147 { 1148 int ret, i; 1149 struct kretprobe_trace_entry_head field; 1150 struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data; 1151 1152 DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); 1153 DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); 1154 /* Set argument names as fields */ 1155 for (i = 0; i < tk->tp.nr_args; i++) { 1156 struct probe_arg *parg = &tk->tp.args[i]; 1157 1158 ret = trace_define_field(event_call, parg->type->fmttype, 1159 parg->name, 1160 sizeof(field) + parg->offset, 1161 parg->type->size, 1162 parg->type->is_signed, 1163 FILTER_OTHER); 1164 if (ret) 1165 return ret; 1166 } 1167 return 0; 1168 } 1169 1170 #ifdef CONFIG_PERF_EVENTS 1171 1172 /* Kprobe profile handler */ 1173 static void 1174 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs) 1175 { 1176 struct trace_event_call *call = &tk->tp.call; 1177 struct bpf_prog *prog = call->prog; 1178 struct kprobe_trace_entry_head *entry; 1179 struct hlist_head *head; 1180 int size, __size, dsize; 1181 int rctx; 1182 1183 if (prog && !trace_call_bpf(prog, regs)) 1184 return; 1185 1186 head = this_cpu_ptr(call->perf_events); 1187 if (hlist_empty(head)) 1188 return; 1189 1190 dsize = __get_data_size(&tk->tp, regs); 1191 __size = sizeof(*entry) + tk->tp.size + dsize; 1192 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1193 size -= sizeof(u32); 1194 1195 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1196 if (!entry) 1197 return; 1198 1199 entry->ip = (unsigned long)tk->rp.kp.addr; 1200 memset(&entry[1], 0, dsize); 1201 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); 1202 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1203 head, NULL, NULL); 1204 } 1205 NOKPROBE_SYMBOL(kprobe_perf_func); 1206 1207 /* Kretprobe profile handler */ 1208 static void 1209 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, 1210 struct pt_regs *regs) 1211 { 1212 struct trace_event_call *call = &tk->tp.call; 1213 struct bpf_prog *prog = call->prog; 1214 struct kretprobe_trace_entry_head *entry; 1215 struct hlist_head *head; 1216 int size, __size, dsize; 1217 int rctx; 1218 1219 if (prog && !trace_call_bpf(prog, regs)) 1220 return; 1221 1222 head = this_cpu_ptr(call->perf_events); 1223 if (hlist_empty(head)) 1224 return; 1225 1226 dsize = __get_data_size(&tk->tp, regs); 1227 __size = sizeof(*entry) + tk->tp.size + dsize; 1228 size = ALIGN(__size + sizeof(u32), sizeof(u64)); 1229 size -= sizeof(u32); 1230 1231 entry = perf_trace_buf_alloc(size, NULL, &rctx); 1232 if (!entry) 1233 return; 1234 1235 entry->func = (unsigned long)tk->rp.kp.addr; 1236 entry->ret_ip = (unsigned long)ri->ret_addr; 1237 store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); 1238 perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, 1239 head, NULL, NULL); 1240 } 1241 NOKPROBE_SYMBOL(kretprobe_perf_func); 1242 #endif /* CONFIG_PERF_EVENTS */ 1243 1244 /* 1245 * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex. 1246 * 1247 * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe 1248 * lockless, but we can't race with this __init function. 1249 */ 1250 static int kprobe_register(struct trace_event_call *event, 1251 enum trace_reg type, void *data) 1252 { 1253 struct trace_kprobe *tk = (struct trace_kprobe *)event->data; 1254 struct trace_event_file *file = data; 1255 1256 switch (type) { 1257 case TRACE_REG_REGISTER: 1258 return enable_trace_kprobe(tk, file); 1259 case TRACE_REG_UNREGISTER: 1260 return disable_trace_kprobe(tk, file); 1261 1262 #ifdef CONFIG_PERF_EVENTS 1263 case TRACE_REG_PERF_REGISTER: 1264 return enable_trace_kprobe(tk, NULL); 1265 case TRACE_REG_PERF_UNREGISTER: 1266 return disable_trace_kprobe(tk, NULL); 1267 case TRACE_REG_PERF_OPEN: 1268 case TRACE_REG_PERF_CLOSE: 1269 case TRACE_REG_PERF_ADD: 1270 case TRACE_REG_PERF_DEL: 1271 return 0; 1272 #endif 1273 } 1274 return 0; 1275 } 1276 1277 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs) 1278 { 1279 struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp); 1280 1281 raw_cpu_inc(*tk->nhit); 1282 1283 if (tk->tp.flags & TP_FLAG_TRACE) 1284 kprobe_trace_func(tk, regs); 1285 #ifdef CONFIG_PERF_EVENTS 1286 if (tk->tp.flags & TP_FLAG_PROFILE) 1287 kprobe_perf_func(tk, regs); 1288 #endif 1289 return 0; /* We don't tweek kernel, so just return 0 */ 1290 } 1291 NOKPROBE_SYMBOL(kprobe_dispatcher); 1292 1293 static int 1294 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs) 1295 { 1296 struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp); 1297 1298 raw_cpu_inc(*tk->nhit); 1299 1300 if (tk->tp.flags & TP_FLAG_TRACE) 1301 kretprobe_trace_func(tk, ri, regs); 1302 #ifdef CONFIG_PERF_EVENTS 1303 if (tk->tp.flags & TP_FLAG_PROFILE) 1304 kretprobe_perf_func(tk, ri, regs); 1305 #endif 1306 return 0; /* We don't tweek kernel, so just return 0 */ 1307 } 1308 NOKPROBE_SYMBOL(kretprobe_dispatcher); 1309 1310 static struct trace_event_functions kretprobe_funcs = { 1311 .trace = print_kretprobe_event 1312 }; 1313 1314 static struct trace_event_functions kprobe_funcs = { 1315 .trace = print_kprobe_event 1316 }; 1317 1318 static int register_kprobe_event(struct trace_kprobe *tk) 1319 { 1320 struct trace_event_call *call = &tk->tp.call; 1321 int ret; 1322 1323 /* Initialize trace_event_call */ 1324 INIT_LIST_HEAD(&call->class->fields); 1325 if (trace_kprobe_is_return(tk)) { 1326 call->event.funcs = &kretprobe_funcs; 1327 call->class->define_fields = kretprobe_event_define_fields; 1328 } else { 1329 call->event.funcs = &kprobe_funcs; 1330 call->class->define_fields = kprobe_event_define_fields; 1331 } 1332 if (set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) 1333 return -ENOMEM; 1334 ret = register_trace_event(&call->event); 1335 if (!ret) { 1336 kfree(call->print_fmt); 1337 return -ENODEV; 1338 } 1339 call->flags = TRACE_EVENT_FL_KPROBE; 1340 call->class->reg = kprobe_register; 1341 call->data = tk; 1342 ret = trace_add_event_call(call); 1343 if (ret) { 1344 pr_info("Failed to register kprobe event: %s\n", 1345 trace_event_name(call)); 1346 kfree(call->print_fmt); 1347 unregister_trace_event(&call->event); 1348 } 1349 return ret; 1350 } 1351 1352 static int unregister_kprobe_event(struct trace_kprobe *tk) 1353 { 1354 int ret; 1355 1356 /* tp->event is unregistered in trace_remove_event_call() */ 1357 ret = trace_remove_event_call(&tk->tp.call); 1358 if (!ret) 1359 kfree(tk->tp.call.print_fmt); 1360 return ret; 1361 } 1362 1363 /* Make a tracefs interface for controlling probe points */ 1364 static __init int init_kprobe_trace(void) 1365 { 1366 struct dentry *d_tracer; 1367 struct dentry *entry; 1368 1369 if (register_module_notifier(&trace_kprobe_module_nb)) 1370 return -EINVAL; 1371 1372 d_tracer = tracing_init_dentry(); 1373 if (IS_ERR(d_tracer)) 1374 return 0; 1375 1376 entry = tracefs_create_file("kprobe_events", 0644, d_tracer, 1377 NULL, &kprobe_events_ops); 1378 1379 /* Event list interface */ 1380 if (!entry) 1381 pr_warn("Could not create tracefs 'kprobe_events' entry\n"); 1382 1383 /* Profile interface */ 1384 entry = tracefs_create_file("kprobe_profile", 0444, d_tracer, 1385 NULL, &kprobe_profile_ops); 1386 1387 if (!entry) 1388 pr_warn("Could not create tracefs 'kprobe_profile' entry\n"); 1389 return 0; 1390 } 1391 fs_initcall(init_kprobe_trace); 1392 1393 1394 #ifdef CONFIG_FTRACE_STARTUP_TEST 1395 /* 1396 * The "__used" keeps gcc from removing the function symbol 1397 * from the kallsyms table. 'noinline' makes sure that there 1398 * isn't an inlined version used by the test method below 1399 */ 1400 static __used __init noinline int 1401 kprobe_trace_selftest_target(int a1, int a2, int a3, int a4, int a5, int a6) 1402 { 1403 return a1 + a2 + a3 + a4 + a5 + a6; 1404 } 1405 1406 static __init struct trace_event_file * 1407 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr) 1408 { 1409 struct trace_event_file *file; 1410 1411 list_for_each_entry(file, &tr->events, list) 1412 if (file->event_call == &tk->tp.call) 1413 return file; 1414 1415 return NULL; 1416 } 1417 1418 /* 1419 * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this 1420 * stage, we can do this lockless. 1421 */ 1422 static __init int kprobe_trace_self_tests_init(void) 1423 { 1424 int ret, warn = 0; 1425 int (*target)(int, int, int, int, int, int); 1426 struct trace_kprobe *tk; 1427 struct trace_event_file *file; 1428 1429 if (tracing_is_disabled()) 1430 return -ENODEV; 1431 1432 target = kprobe_trace_selftest_target; 1433 1434 pr_info("Testing kprobe tracing: "); 1435 1436 ret = traceprobe_command("p:testprobe kprobe_trace_selftest_target " 1437 "$stack $stack0 +0($stack)", 1438 create_trace_kprobe); 1439 if (WARN_ON_ONCE(ret)) { 1440 pr_warn("error on probing function entry.\n"); 1441 warn++; 1442 } else { 1443 /* Enable trace point */ 1444 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1445 if (WARN_ON_ONCE(tk == NULL)) { 1446 pr_warn("error on getting new probe.\n"); 1447 warn++; 1448 } else { 1449 file = find_trace_probe_file(tk, top_trace_array()); 1450 if (WARN_ON_ONCE(file == NULL)) { 1451 pr_warn("error on getting probe file.\n"); 1452 warn++; 1453 } else 1454 enable_trace_kprobe(tk, file); 1455 } 1456 } 1457 1458 ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target " 1459 "$retval", create_trace_kprobe); 1460 if (WARN_ON_ONCE(ret)) { 1461 pr_warn("error on probing function return.\n"); 1462 warn++; 1463 } else { 1464 /* Enable trace point */ 1465 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1466 if (WARN_ON_ONCE(tk == NULL)) { 1467 pr_warn("error on getting 2nd new probe.\n"); 1468 warn++; 1469 } else { 1470 file = find_trace_probe_file(tk, top_trace_array()); 1471 if (WARN_ON_ONCE(file == NULL)) { 1472 pr_warn("error on getting probe file.\n"); 1473 warn++; 1474 } else 1475 enable_trace_kprobe(tk, file); 1476 } 1477 } 1478 1479 if (warn) 1480 goto end; 1481 1482 ret = target(1, 2, 3, 4, 5, 6); 1483 1484 /* 1485 * Not expecting an error here, the check is only to prevent the 1486 * optimizer from removing the call to target() as otherwise there 1487 * are no side-effects and the call is never performed. 1488 */ 1489 if (ret != 21) 1490 warn++; 1491 1492 /* Disable trace points before removing it */ 1493 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM); 1494 if (WARN_ON_ONCE(tk == NULL)) { 1495 pr_warn("error on getting test probe.\n"); 1496 warn++; 1497 } else { 1498 if (trace_kprobe_nhit(tk) != 1) { 1499 pr_warn("incorrect number of testprobe hits\n"); 1500 warn++; 1501 } 1502 1503 file = find_trace_probe_file(tk, top_trace_array()); 1504 if (WARN_ON_ONCE(file == NULL)) { 1505 pr_warn("error on getting probe file.\n"); 1506 warn++; 1507 } else 1508 disable_trace_kprobe(tk, file); 1509 } 1510 1511 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM); 1512 if (WARN_ON_ONCE(tk == NULL)) { 1513 pr_warn("error on getting 2nd test probe.\n"); 1514 warn++; 1515 } else { 1516 if (trace_kprobe_nhit(tk) != 1) { 1517 pr_warn("incorrect number of testprobe2 hits\n"); 1518 warn++; 1519 } 1520 1521 file = find_trace_probe_file(tk, top_trace_array()); 1522 if (WARN_ON_ONCE(file == NULL)) { 1523 pr_warn("error on getting probe file.\n"); 1524 warn++; 1525 } else 1526 disable_trace_kprobe(tk, file); 1527 } 1528 1529 ret = traceprobe_command("-:testprobe", create_trace_kprobe); 1530 if (WARN_ON_ONCE(ret)) { 1531 pr_warn("error on deleting a probe.\n"); 1532 warn++; 1533 } 1534 1535 ret = traceprobe_command("-:testprobe2", create_trace_kprobe); 1536 if (WARN_ON_ONCE(ret)) { 1537 pr_warn("error on deleting a probe.\n"); 1538 warn++; 1539 } 1540 1541 end: 1542 release_all_trace_kprobes(); 1543 /* 1544 * Wait for the optimizer work to finish. Otherwise it might fiddle 1545 * with probes in already freed __init text. 1546 */ 1547 wait_for_kprobe_optimizer(); 1548 if (warn) 1549 pr_cont("NG: Some tests are failed. Please check them.\n"); 1550 else 1551 pr_cont("OK\n"); 1552 return 0; 1553 } 1554 1555 late_initcall(kprobe_trace_self_tests_init); 1556 1557 #endif 1558