kernel/trace/trace_kprobe.c

   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/bpf-cgroup.h>
  11 #include <linux/security.h>
  12 #include <linux/module.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/rculist.h>
  15 #include <linux/error-injection.h>
  16
  17 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
  18
  19 #include "trace_dynevent.h"
  20 #include "trace_kprobe_selftest.h"
  21 #include "trace_probe.h"
  22 #include "trace_probe_tmpl.h"
  23 #include "trace_probe_kernel.h"
  24
  25 #define KPROBE_EVENT_SYSTEM "kprobes"
  26 #define KRETPROBE_MAXACTIVE_MAX 4096
  27
  28 /* Kprobe early definition from command line */
  29 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
  30
  31 static int __init set_kprobe_boot_events(char *str)
  32 {
  33         strscpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
  34         disable_tracing_selftest("running kprobe events");
  35
  36         return 1;
  37 }
  38 __setup("kprobe_event=", set_kprobe_boot_events);
  39
  40 static int trace_kprobe_create(const char *raw_command);
  41 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
  42 static int trace_kprobe_release(struct dyn_event *ev);
  43 static bool trace_kprobe_is_busy(struct dyn_event *ev);
  44 static bool trace_kprobe_match(const char *system, const char *event,
  45                         int argc, const char **argv, struct dyn_event *ev);
  46
  47 static struct dyn_event_operations trace_kprobe_ops = {
  48         .create = trace_kprobe_create,
  49         .show = trace_kprobe_show,
  50         .is_busy = trace_kprobe_is_busy,
  51         .free = trace_kprobe_release,
  52         .match = trace_kprobe_match,
  53 };
  54
  55 /*
  56  * Kprobe event core functions
  57  */
  58 struct trace_kprobe {
  59         struct dyn_event        devent;
  60         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
  61         unsigned long __percpu *nhit;
  62         const char              *symbol;        /* symbol name */
  63         struct trace_probe      tp;
  64 };
  65
  66 static bool is_trace_kprobe(struct dyn_event *ev)
  67 {
  68         return ev->ops == &trace_kprobe_ops;
  69 }
  70
  71 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
  72 {
  73         return container_of(ev, struct trace_kprobe, devent);
  74 }
  75
  76 /**
  77  * for_each_trace_kprobe - iterate over the trace_kprobe list
  78  * @pos:        the struct trace_kprobe * for each entry
  79  * @dpos:       the struct dyn_event * to use as a loop cursor
  80  */
  81 #define for_each_trace_kprobe(pos, dpos)        \
  82         for_each_dyn_event(dpos)                \
  83                 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
  84
  85 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
  86 {
  87         return tk->rp.handler != NULL;
  88 }
  89
  90 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  91 {
  92         return tk->symbol ? tk->symbol : "unknown";
  93 }
  94
  95 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  96 {
  97         return tk->rp.kp.offset;
  98 }
  99
 100 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
 101 {
 102         return kprobe_gone(&tk->rp.kp);
 103 }
 104
 105 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
 106                                                  struct module *mod)
 107 {
 108         int len = strlen(module_name(mod));
 109         const char *name = trace_kprobe_symbol(tk);
 110
 111         return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
 112 }
 113
 114 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 115 {
 116         char *p;
 117         bool ret;
 118
 119         if (!tk->symbol)
 120                 return false;
 121         p = strchr(tk->symbol, ':');
 122         if (!p)
 123                 return true;
 124         *p = '\0';
 125         rcu_read_lock_sched();
 126         ret = !!find_module(tk->symbol);
 127         rcu_read_unlock_sched();
 128         *p = ':';
 129
 130         return ret;
 131 }
 132
 133 static bool trace_kprobe_is_busy(struct dyn_event *ev)
 134 {
 135         struct trace_kprobe *tk = to_trace_kprobe(ev);
 136
 137         return trace_probe_is_enabled(&tk->tp);
 138 }
 139
 140 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
 141                                             int argc, const char **argv)
 142 {
 143         char buf[MAX_ARGSTR_LEN + 1];
 144
 145         if (!argc)
 146                 return true;
 147
 148         if (!tk->symbol)
 149                 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
 150         else if (tk->rp.kp.offset)
 151                 snprintf(buf, sizeof(buf), "%s+%u",
 152                          trace_kprobe_symbol(tk), tk->rp.kp.offset);
 153         else
 154                 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
 155         if (strcmp(buf, argv[0]))
 156                 return false;
 157         argc--; argv++;
 158
 159         return trace_probe_match_command_args(&tk->tp, argc, argv);
 160 }
 161
 162 static bool trace_kprobe_match(const char *system, const char *event,
 163                         int argc, const char **argv, struct dyn_event *ev)
 164 {
 165         struct trace_kprobe *tk = to_trace_kprobe(ev);
 166
 167         return (event[0] == '\0' ||
 168                 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) == 0) : 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(struct_size(tk, tp.args, 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, false);
 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_kprobe *tk;
 334
 335         list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
 336                 if (!trace_kprobe_is_registered(tk))
 337                         continue;
 338                 if (trace_kprobe_is_return(tk))
 339                         disable_kretprobe(&tk->rp);
 340                 else
 341                         disable_kprobe(&tk->rp.kp);
 342         }
 343 }
 344
 345 /*
 346  * Enable trace_probe
 347  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 348  */
 349 static int enable_trace_kprobe(struct trace_event_call *call,
 350                                 struct trace_event_file *file)
 351 {
 352         struct trace_probe *tp;
 353         struct trace_kprobe *tk;
 354         bool enabled;
 355         int ret = 0;
 356
 357         tp = trace_probe_primary_from_call(call);
 358         if (WARN_ON_ONCE(!tp))
 359                 return -ENODEV;
 360         enabled = trace_probe_is_enabled(tp);
 361
 362         /* This also changes "enabled" state */
 363         if (file) {
 364                 ret = trace_probe_add_file(tp, file);
 365                 if (ret)
 366                         return ret;
 367         } else
 368                 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
 369
 370         if (enabled)
 371                 return 0;
 372
 373         list_for_each_entry(tk, trace_probe_probe_list(tp), tp.list) {
 374                 if (trace_kprobe_has_gone(tk))
 375                         continue;
 376                 ret = __enable_trace_kprobe(tk);
 377                 if (ret)
 378                         break;
 379                 enabled = true;
 380         }
 381
 382         if (ret) {
 383                 /* Failed to enable one of them. Roll back all */
 384                 if (enabled)
 385                         __disable_trace_kprobe(tp);
 386                 if (file)
 387                         trace_probe_remove_file(tp, file);
 388                 else
 389                         trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 390         }
 391
 392         return ret;
 393 }
 394
 395 /*
 396  * Disable trace_probe
 397  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 398  */
 399 static int disable_trace_kprobe(struct trace_event_call *call,
 400                                 struct trace_event_file *file)
 401 {
 402         struct trace_probe *tp;
 403
 404         tp = trace_probe_primary_from_call(call);
 405         if (WARN_ON_ONCE(!tp))
 406                 return -ENODEV;
 407
 408         if (file) {
 409                 if (!trace_probe_get_file_link(tp, file))
 410                         return -ENOENT;
 411                 if (!trace_probe_has_single_file(tp))
 412                         goto out;
 413                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
 414         } else
 415                 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 416
 417         if (!trace_probe_is_enabled(tp))
 418                 __disable_trace_kprobe(tp);
 419
 420  out:
 421         if (file)
 422                 /*
 423                  * Synchronization is done in below function. For perf event,
 424                  * file == NULL and perf_trace_event_unreg() calls
 425                  * tracepoint_synchronize_unregister() to ensure synchronize
 426                  * event. We don't need to care about it.
 427                  */
 428                 trace_probe_remove_file(tp, file);
 429
 430         return 0;
 431 }
 432
 433 #if defined(CONFIG_DYNAMIC_FTRACE) && \
 434         !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
 435 static bool __within_notrace_func(unsigned long addr)
 436 {
 437         unsigned long offset, size;
 438
 439         if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
 440                 return false;
 441
 442         /* Get the entry address of the target function */
 443         addr -= offset;
 444
 445         /*
 446          * Since ftrace_location_range() does inclusive range check, we need
 447          * to subtract 1 byte from the end address.
 448          */
 449         return !ftrace_location_range(addr, addr + size - 1);
 450 }
 451
 452 static bool within_notrace_func(struct trace_kprobe *tk)
 453 {
 454         unsigned long addr = trace_kprobe_address(tk);
 455         char symname[KSYM_NAME_LEN], *p;
 456
 457         if (!__within_notrace_func(addr))
 458                 return false;
 459
 460         /* Check if the address is on a suffixed-symbol */
 461         if (!lookup_symbol_name(addr, symname)) {
 462                 p = strchr(symname, '.');
 463                 if (!p)
 464                         return true;
 465                 *p = '\0';
 466                 addr = (unsigned long)kprobe_lookup_name(symname, 0);
 467                 if (addr)
 468                         return __within_notrace_func(addr);
 469         }
 470
 471         return true;
 472 }
 473 #else
 474 #define within_notrace_func(tk) (false)
 475 #endif
 476
 477 /* Internal register function - just handle k*probes and flags */
 478 static int __register_trace_kprobe(struct trace_kprobe *tk)
 479 {
 480         int i, ret;
 481
 482         ret = security_locked_down(LOCKDOWN_KPROBES);
 483         if (ret)
 484                 return ret;
 485
 486         if (trace_kprobe_is_registered(tk))
 487                 return -EINVAL;
 488
 489         if (within_notrace_func(tk)) {
 490                 pr_warn("Could not probe notrace function %s\n",
 491                         trace_kprobe_symbol(tk));
 492                 return -EINVAL;
 493         }
 494
 495         for (i = 0; i < tk->tp.nr_args; i++) {
 496                 ret = traceprobe_update_arg(&tk->tp.args[i]);
 497                 if (ret)
 498                         return ret;
 499         }
 500
 501         /* Set/clear disabled flag according to tp->flag */
 502         if (trace_probe_is_enabled(&tk->tp))
 503                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 504         else
 505                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 506
 507         if (trace_kprobe_is_return(tk))
 508                 ret = register_kretprobe(&tk->rp);
 509         else
 510                 ret = register_kprobe(&tk->rp.kp);
 511
 512         return ret;
 513 }
 514
 515 /* Internal unregister function - just handle k*probes and flags */
 516 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 517 {
 518         if (trace_kprobe_is_registered(tk)) {
 519                 if (trace_kprobe_is_return(tk))
 520                         unregister_kretprobe(&tk->rp);
 521                 else
 522                         unregister_kprobe(&tk->rp.kp);
 523                 /* Cleanup kprobe for reuse and mark it unregistered */
 524                 INIT_HLIST_NODE(&tk->rp.kp.hlist);
 525                 INIT_LIST_HEAD(&tk->rp.kp.list);
 526                 if (tk->rp.kp.symbol_name)
 527                         tk->rp.kp.addr = NULL;
 528         }
 529 }
 530
 531 /* Unregister a trace_probe and probe_event */
 532 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 533 {
 534         /* If other probes are on the event, just unregister kprobe */
 535         if (trace_probe_has_sibling(&tk->tp))
 536                 goto unreg;
 537
 538         /* Enabled event can not be unregistered */
 539         if (trace_probe_is_enabled(&tk->tp))
 540                 return -EBUSY;
 541
 542         /* If there's a reference to the dynamic event */
 543         if (trace_event_dyn_busy(trace_probe_event_call(&tk->tp)))
 544                 return -EBUSY;
 545
 546         /* Will fail if probe is being used by ftrace or perf */
 547         if (unregister_kprobe_event(tk))
 548                 return -EBUSY;
 549
 550 unreg:
 551         __unregister_trace_kprobe(tk);
 552         dyn_event_remove(&tk->devent);
 553         trace_probe_unlink(&tk->tp);
 554
 555         return 0;
 556 }
 557
 558 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
 559                                          struct trace_kprobe *comp)
 560 {
 561         struct trace_probe_event *tpe = orig->tp.event;
 562         int i;
 563
 564         list_for_each_entry(orig, &tpe->probes, tp.list) {
 565                 if (strcmp(trace_kprobe_symbol(orig),
 566                            trace_kprobe_symbol(comp)) ||
 567                     trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
 568                         continue;
 569
 570                 /*
 571                  * trace_probe_compare_arg_type() ensured that nr_args and
 572                  * each argument name and type are same. Let's compare comm.
 573                  */
 574                 for (i = 0; i < orig->tp.nr_args; i++) {
 575                         if (strcmp(orig->tp.args[i].comm,
 576                                    comp->tp.args[i].comm))
 577                                 break;
 578                 }
 579
 580                 if (i == orig->tp.nr_args)
 581                         return true;
 582         }
 583
 584         return false;
 585 }
 586
 587 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
 588 {
 589         int ret;
 590
 591         ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
 592         if (ret) {
 593                 /* Note that argument starts index = 2 */
 594                 trace_probe_log_set_index(ret + 1);
 595                 trace_probe_log_err(0, DIFF_ARG_TYPE);
 596                 return -EEXIST;
 597         }
 598         if (trace_kprobe_has_same_kprobe(to, tk)) {
 599                 trace_probe_log_set_index(0);
 600                 trace_probe_log_err(0, SAME_PROBE);
 601                 return -EEXIST;
 602         }
 603
 604         /* Append to existing event */
 605         ret = trace_probe_append(&tk->tp, &to->tp);
 606         if (ret)
 607                 return ret;
 608
 609         /* Register k*probe */
 610         ret = __register_trace_kprobe(tk);
 611         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 612                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 613                 ret = 0;
 614         }
 615
 616         if (ret)
 617                 trace_probe_unlink(&tk->tp);
 618         else
 619                 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
 620
 621         return ret;
 622 }
 623
 624 /* Register a trace_probe and probe_event */
 625 static int register_trace_kprobe(struct trace_kprobe *tk)
 626 {
 627         struct trace_kprobe *old_tk;
 628         int ret;
 629
 630         mutex_lock(&event_mutex);
 631
 632         old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
 633                                    trace_probe_group_name(&tk->tp));
 634         if (old_tk) {
 635                 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
 636                         trace_probe_log_set_index(0);
 637                         trace_probe_log_err(0, DIFF_PROBE_TYPE);
 638                         ret = -EEXIST;
 639                 } else {
 640                         ret = append_trace_kprobe(tk, old_tk);
 641                 }
 642                 goto end;
 643         }
 644
 645         /* Register new event */
 646         ret = register_kprobe_event(tk);
 647         if (ret) {
 648                 if (ret == -EEXIST) {
 649                         trace_probe_log_set_index(0);
 650                         trace_probe_log_err(0, EVENT_EXIST);
 651                 } else
 652                         pr_warn("Failed to register probe event(%d)\n", ret);
 653                 goto end;
 654         }
 655
 656         /* Register k*probe */
 657         ret = __register_trace_kprobe(tk);
 658         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 659                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 660                 ret = 0;
 661         }
 662
 663         if (ret < 0)
 664                 unregister_kprobe_event(tk);
 665         else
 666                 dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
 667
 668 end:
 669         mutex_unlock(&event_mutex);
 670         return ret;
 671 }
 672
 673 /* Module notifier call back, checking event on the module */
 674 static int trace_kprobe_module_callback(struct notifier_block *nb,
 675                                        unsigned long val, void *data)
 676 {
 677         struct module *mod = data;
 678         struct dyn_event *pos;
 679         struct trace_kprobe *tk;
 680         int ret;
 681
 682         if (val != MODULE_STATE_COMING)
 683                 return NOTIFY_DONE;
 684
 685         /* Update probes on coming module */
 686         mutex_lock(&event_mutex);
 687         for_each_trace_kprobe(tk, pos) {
 688                 if (trace_kprobe_within_module(tk, mod)) {
 689                         /* Don't need to check busy - this should have gone. */
 690                         __unregister_trace_kprobe(tk);
 691                         ret = __register_trace_kprobe(tk);
 692                         if (ret)
 693                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 694                                         trace_probe_name(&tk->tp),
 695                                         module_name(mod), ret);
 696                 }
 697         }
 698         mutex_unlock(&event_mutex);
 699
 700         return NOTIFY_DONE;
 701 }
 702
 703 static struct notifier_block trace_kprobe_module_nb = {
 704         .notifier_call = trace_kprobe_module_callback,
 705         .priority = 1   /* Invoked after kprobe module callback */
 706 };
 707
 708 static int __trace_kprobe_create(int argc, const char *argv[])
 709 {
 710         /*
 711          * Argument syntax:
 712          *  - Add kprobe:
 713          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 714          *  - Add kretprobe:
 715          *      r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
 716          *    Or
 717          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
 718          *
 719          * Fetch args:
 720          *  $retval     : fetch return value
 721          *  $stack      : fetch stack address
 722          *  $stackN     : fetch Nth of stack (N:0-)
 723          *  $comm       : fetch current task comm
 724          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 725          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 726          *  %REG        : fetch register REG
 727          * Dereferencing memory fetch:
 728          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 729          * Alias name of args:
 730          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 731          * Type of args:
 732          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 733          */
 734         struct trace_kprobe *tk = NULL;
 735         int i, len, new_argc = 0, ret = 0;
 736         bool is_return = false;
 737         char *symbol = NULL, *tmp = NULL;
 738         const char **new_argv = NULL;
 739         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 740         enum probe_print_type ptype;
 741         int maxactive = 0;
 742         long offset = 0;
 743         void *addr = NULL;
 744         char buf[MAX_EVENT_NAME_LEN];
 745         char gbuf[MAX_EVENT_NAME_LEN];
 746         char abuf[MAX_BTF_ARGS_LEN];
 747         struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
 748
 749         switch (argv[0][0]) {
 750         case 'r':
 751                 is_return = true;
 752                 break;
 753         case 'p':
 754                 break;
 755         default:
 756                 return -ECANCELED;
 757         }
 758         if (argc < 2)
 759                 return -ECANCELED;
 760
 761         trace_probe_log_init("trace_kprobe", argc, argv);
 762
 763         event = strchr(&argv[0][1], ':');
 764         if (event)
 765                 event++;
 766
 767         if (isdigit(argv[0][1])) {
 768                 if (!is_return) {
 769                         trace_probe_log_err(1, BAD_MAXACT_TYPE);
 770                         goto parse_error;
 771                 }
 772                 if (event)
 773                         len = event - &argv[0][1] - 1;
 774                 else
 775                         len = strlen(&argv[0][1]);
 776                 if (len > MAX_EVENT_NAME_LEN - 1) {
 777                         trace_probe_log_err(1, BAD_MAXACT);
 778                         goto parse_error;
 779                 }
 780                 memcpy(buf, &argv[0][1], len);
 781                 buf[len] = '\0';
 782                 ret = kstrtouint(buf, 0, &maxactive);
 783                 if (ret || !maxactive) {
 784                         trace_probe_log_err(1, BAD_MAXACT);
 785                         goto parse_error;
 786                 }
 787                 /* kretprobes instances are iterated over via a list. The
 788                  * maximum should stay reasonable.
 789                  */
 790                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 791                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 792                         goto parse_error;
 793                 }
 794         }
 795
 796         /* try to parse an address. if that fails, try to read the
 797          * input as a symbol. */
 798         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 799                 trace_probe_log_set_index(1);
 800                 /* Check whether uprobe event specified */
 801                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 802                         ret = -ECANCELED;
 803                         goto error;
 804                 }
 805                 /* a symbol specified */
 806                 symbol = kstrdup(argv[1], GFP_KERNEL);
 807                 if (!symbol)
 808                         return -ENOMEM;
 809
 810                 tmp = strchr(symbol, '%');
 811                 if (tmp) {
 812                         if (!strcmp(tmp, "%return")) {
 813                                 *tmp = '\0';
 814                                 is_return = true;
 815                         } else {
 816                                 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
 817                                 goto parse_error;
 818                         }
 819                 }
 820
 821                 /* TODO: support .init module functions */
 822                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 823                 if (ret || offset < 0 || offset > UINT_MAX) {
 824                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 825                         goto parse_error;
 826                 }
 827                 if (is_return)
 828                         ctx.flags |= TPARG_FL_RETURN;
 829                 ret = kprobe_on_func_entry(NULL, symbol, offset);
 830                 if (ret == 0 && !is_return)
 831                         ctx.flags |= TPARG_FL_FENTRY;
 832                 /* Defer the ENOENT case until register kprobe */
 833                 if (ret == -EINVAL && is_return) {
 834                         trace_probe_log_err(0, BAD_RETPROBE);
 835                         goto parse_error;
 836                 }
 837         }
 838
 839         trace_probe_log_set_index(0);
 840         if (event) {
 841                 ret = traceprobe_parse_event_name(&event, &group, gbuf,
 842                                                   event - argv[0]);
 843                 if (ret)
 844                         goto parse_error;
 845         }
 846
 847         if (!event) {
 848                 /* Make a new event name */
 849                 if (symbol)
 850                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 851                                  is_return ? 'r' : 'p', symbol, offset);
 852                 else
 853                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 854                                  is_return ? 'r' : 'p', addr);
 855                 sanitize_event_name(buf);
 856                 event = buf;
 857         }
 858
 859         argc -= 2; argv += 2;
 860         ctx.funcname = symbol;
 861         new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
 862                                                abuf, MAX_BTF_ARGS_LEN, &ctx);
 863         if (IS_ERR(new_argv)) {
 864                 ret = PTR_ERR(new_argv);
 865                 new_argv = NULL;
 866                 goto out;
 867         }
 868         if (new_argv) {
 869                 argc = new_argc;
 870                 argv = new_argv;
 871         }
 872
 873         /* setup a probe */
 874         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 875                                 argc, is_return);
 876         if (IS_ERR(tk)) {
 877                 ret = PTR_ERR(tk);
 878                 /* This must return -ENOMEM, else there is a bug */
 879                 WARN_ON_ONCE(ret != -ENOMEM);
 880                 goto out;       /* We know tk is not allocated */
 881         }
 882
 883         /* parse arguments */
 884         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 885                 trace_probe_log_set_index(i + 2);
 886                 ctx.offset = 0;
 887                 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);
 888                 if (ret)
 889                         goto error;     /* This can be -ENOMEM */
 890         }
 891
 892         ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
 893         ret = traceprobe_set_print_fmt(&tk->tp, ptype);
 894         if (ret < 0)
 895                 goto error;
 896
 897         ret = register_trace_kprobe(tk);
 898         if (ret) {
 899                 trace_probe_log_set_index(1);
 900                 if (ret == -EILSEQ)
 901                         trace_probe_log_err(0, BAD_INSN_BNDRY);
 902                 else if (ret == -ENOENT)
 903                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 904                 else if (ret != -ENOMEM && ret != -EEXIST)
 905                         trace_probe_log_err(0, FAIL_REG_PROBE);
 906                 goto error;
 907         }
 908
 909 out:
 910         traceprobe_finish_parse(&ctx);
 911         trace_probe_log_clear();
 912         kfree(new_argv);
 913         kfree(symbol);
 914         return ret;
 915
 916 parse_error:
 917         ret = -EINVAL;
 918 error:
 919         free_trace_kprobe(tk);
 920         goto out;
 921 }
 922
 923 static int trace_kprobe_create(const char *raw_command)
 924 {
 925         return trace_probe_create(raw_command, __trace_kprobe_create);
 926 }
 927
 928 static int create_or_delete_trace_kprobe(const char *raw_command)
 929 {
 930         int ret;
 931
 932         if (raw_command[0] == '-')
 933                 return dyn_event_release(raw_command, &trace_kprobe_ops);
 934
 935         ret = trace_kprobe_create(raw_command);
 936         return ret == -ECANCELED ? -EINVAL : ret;
 937 }
 938
 939 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
 940 {
 941         return create_or_delete_trace_kprobe(cmd->seq.buffer);
 942 }
 943
 944 /**
 945  * kprobe_event_cmd_init - Initialize a kprobe event command object
 946  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 947  * @buf: A pointer to the buffer used to build the command
 948  * @maxlen: The length of the buffer passed in @buf
 949  *
 950  * Initialize a synthetic event command object.  Use this before
 951  * calling any of the other kprobe_event functions.
 952  */
 953 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
 954 {
 955         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
 956                           trace_kprobe_run_command);
 957 }
 958 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
 959
 960 /**
 961  * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
 962  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 963  * @name: The name of the kprobe event
 964  * @loc: The location of the kprobe event
 965  * @kretprobe: Is this a return probe?
 966  * @args: Variable number of arg (pairs), one pair for each field
 967  *
 968  * NOTE: Users normally won't want to call this function directly, but
 969  * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
 970  * adds a NULL to the end of the arg list.  If this function is used
 971  * directly, make sure the last arg in the variable arg list is NULL.
 972  *
 973  * Generate a kprobe event command to be executed by
 974  * kprobe_event_gen_cmd_end().  This function can be used to generate the
 975  * complete command or only the first part of it; in the latter case,
 976  * kprobe_event_add_fields() can be used to add more fields following this.
 977  *
 978  * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
 979  * returns -EINVAL if @loc == NULL.
 980  *
 981  * Return: 0 if successful, error otherwise.
 982  */
 983 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
 984                                  const char *name, const char *loc, ...)
 985 {
 986         char buf[MAX_EVENT_NAME_LEN];
 987         struct dynevent_arg arg;
 988         va_list args;
 989         int ret;
 990
 991         if (cmd->type != DYNEVENT_TYPE_KPROBE)
 992                 return -EINVAL;
 993
 994         if (!loc)
 995                 return -EINVAL;
 996
 997         if (kretprobe)
 998                 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
 999         else
1000                 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
1001
1002         ret = dynevent_str_add(cmd, buf);
1003         if (ret)
1004                 return ret;
1005
1006         dynevent_arg_init(&arg, 0);
1007         arg.str = loc;
1008         ret = dynevent_arg_add(cmd, &arg, NULL);
1009         if (ret)
1010                 return ret;
1011
1012         va_start(args, loc);
1013         for (;;) {
1014                 const char *field;
1015
1016                 field = va_arg(args, const char *);
1017                 if (!field)
1018                         break;
1019
1020                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1021                         ret = -EINVAL;
1022                         break;
1023                 }
1024
1025                 arg.str = field;
1026                 ret = dynevent_arg_add(cmd, &arg, NULL);
1027                 if (ret)
1028                         break;
1029         }
1030         va_end(args);
1031
1032         return ret;
1033 }
1034 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1035
1036 /**
1037  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1038  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1039  * @args: Variable number of arg (pairs), one pair for each field
1040  *
1041  * NOTE: Users normally won't want to call this function directly, but
1042  * rather use the kprobe_event_add_fields() wrapper, which
1043  * automatically adds a NULL to the end of the arg list.  If this
1044  * function is used directly, make sure the last arg in the variable
1045  * arg list is NULL.
1046  *
1047  * Add probe fields to an existing kprobe command using a variable
1048  * list of args.  Fields are added in the same order they're listed.
1049  *
1050  * Return: 0 if successful, error otherwise.
1051  */
1052 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1053 {
1054         struct dynevent_arg arg;
1055         va_list args;
1056         int ret = 0;
1057
1058         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1059                 return -EINVAL;
1060
1061         dynevent_arg_init(&arg, 0);
1062
1063         va_start(args, cmd);
1064         for (;;) {
1065                 const char *field;
1066
1067                 field = va_arg(args, const char *);
1068                 if (!field)
1069                         break;
1070
1071                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1072                         ret = -EINVAL;
1073                         break;
1074                 }
1075
1076                 arg.str = field;
1077                 ret = dynevent_arg_add(cmd, &arg, NULL);
1078                 if (ret)
1079                         break;
1080         }
1081         va_end(args);
1082
1083         return ret;
1084 }
1085 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1086
1087 /**
1088  * kprobe_event_delete - Delete a kprobe event
1089  * @name: The name of the kprobe event to delete
1090  *
1091  * Delete a kprobe event with the give @name from kernel code rather
1092  * than directly from the command line.
1093  *
1094  * Return: 0 if successful, error otherwise.
1095  */
1096 int kprobe_event_delete(const char *name)
1097 {
1098         char buf[MAX_EVENT_NAME_LEN];
1099
1100         snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1101
1102         return create_or_delete_trace_kprobe(buf);
1103 }
1104 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1105
1106 static int trace_kprobe_release(struct dyn_event *ev)
1107 {
1108         struct trace_kprobe *tk = to_trace_kprobe(ev);
1109         int ret = unregister_trace_kprobe(tk);
1110
1111         if (!ret)
1112                 free_trace_kprobe(tk);
1113         return ret;
1114 }
1115
1116 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1117 {
1118         struct trace_kprobe *tk = to_trace_kprobe(ev);
1119         int i;
1120
1121         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1122         if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1123                 seq_printf(m, "%d", tk->rp.maxactive);
1124         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1125                                 trace_probe_name(&tk->tp));
1126
1127         if (!tk->symbol)
1128                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1129         else if (tk->rp.kp.offset)
1130                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1131                            tk->rp.kp.offset);
1132         else
1133                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1134
1135         for (i = 0; i < tk->tp.nr_args; i++)
1136                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1137         seq_putc(m, '\n');
1138
1139         return 0;
1140 }
1141
1142 static int probes_seq_show(struct seq_file *m, void *v)
1143 {
1144         struct dyn_event *ev = v;
1145
1146         if (!is_trace_kprobe(ev))
1147                 return 0;
1148
1149         return trace_kprobe_show(m, ev);
1150 }
1151
1152 static const struct seq_operations probes_seq_op = {
1153         .start  = dyn_event_seq_start,
1154         .next   = dyn_event_seq_next,
1155         .stop   = dyn_event_seq_stop,
1156         .show   = probes_seq_show
1157 };
1158
1159 static int probes_open(struct inode *inode, struct file *file)
1160 {
1161         int ret;
1162
1163         ret = security_locked_down(LOCKDOWN_TRACEFS);
1164         if (ret)
1165                 return ret;
1166
1167         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1168                 ret = dyn_events_release_all(&trace_kprobe_ops);
1169                 if (ret < 0)
1170                         return ret;
1171         }
1172
1173         return seq_open(file, &probes_seq_op);
1174 }
1175
1176 static ssize_t probes_write(struct file *file, const char __user *buffer,
1177                             size_t count, loff_t *ppos)
1178 {
1179         return trace_parse_run_command(file, buffer, count, ppos,
1180                                        create_or_delete_trace_kprobe);
1181 }
1182
1183 static const struct file_operations kprobe_events_ops = {
1184         .owner          = THIS_MODULE,
1185         .open           = probes_open,
1186         .read           = seq_read,
1187         .llseek         = seq_lseek,
1188         .release        = seq_release,
1189         .write          = probes_write,
1190 };
1191
1192 /* Probes profiling interfaces */
1193 static int probes_profile_seq_show(struct seq_file *m, void *v)
1194 {
1195         struct dyn_event *ev = v;
1196         struct trace_kprobe *tk;
1197         unsigned long nmissed;
1198
1199         if (!is_trace_kprobe(ev))
1200                 return 0;
1201
1202         tk = to_trace_kprobe(ev);
1203         nmissed = trace_kprobe_is_return(tk) ?
1204                 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1205         seq_printf(m, "  %-44s %15lu %15lu\n",
1206                    trace_probe_name(&tk->tp),
1207                    trace_kprobe_nhit(tk),
1208                    nmissed);
1209
1210         return 0;
1211 }
1212
1213 static const struct seq_operations profile_seq_op = {
1214         .start  = dyn_event_seq_start,
1215         .next   = dyn_event_seq_next,
1216         .stop   = dyn_event_seq_stop,
1217         .show   = probes_profile_seq_show
1218 };
1219
1220 static int profile_open(struct inode *inode, struct file *file)
1221 {
1222         int ret;
1223
1224         ret = security_locked_down(LOCKDOWN_TRACEFS);
1225         if (ret)
1226                 return ret;
1227
1228         return seq_open(file, &profile_seq_op);
1229 }
1230
1231 static const struct file_operations kprobe_profile_ops = {
1232         .owner          = THIS_MODULE,
1233         .open           = profile_open,
1234         .read           = seq_read,
1235         .llseek         = seq_lseek,
1236         .release        = seq_release,
1237 };
1238
1239 /* Note that we don't verify it, since the code does not come from user space */
1240 static int
1241 process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
1242                    void *base)
1243 {
1244         struct pt_regs *regs = rec;
1245         unsigned long val;
1246         int ret;
1247
1248 retry:
1249         /* 1st stage: get value from context */
1250         switch (code->op) {
1251         case FETCH_OP_REG:
1252                 val = regs_get_register(regs, code->param);
1253                 break;
1254         case FETCH_OP_STACK:
1255                 val = regs_get_kernel_stack_nth(regs, code->param);
1256                 break;
1257         case FETCH_OP_STACKP:
1258                 val = kernel_stack_pointer(regs);
1259                 break;
1260         case FETCH_OP_RETVAL:
1261                 val = regs_return_value(regs);
1262                 break;
1263 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1264         case FETCH_OP_ARG:
1265                 val = regs_get_kernel_argument(regs, code->param);
1266                 break;
1267 #endif
1268         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1269                 code++;
1270                 goto retry;
1271         default:
1272                 ret = process_common_fetch_insn(code, &val);
1273                 if (ret < 0)
1274                         return ret;
1275         }
1276         code++;
1277
1278         return process_fetch_insn_bottom(code, val, dest, base);
1279 }
1280 NOKPROBE_SYMBOL(process_fetch_insn)
1281
1282 /* Kprobe handler */
1283 static nokprobe_inline void
1284 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1285                     struct trace_event_file *trace_file)
1286 {
1287         struct kprobe_trace_entry_head *entry;
1288         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1289         struct trace_event_buffer fbuffer;
1290         int dsize;
1291
1292         WARN_ON(call != trace_file->event_call);
1293
1294         if (trace_trigger_soft_disabled(trace_file))
1295                 return;
1296
1297         dsize = __get_data_size(&tk->tp, regs);
1298
1299         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1300                                            sizeof(*entry) + tk->tp.size + dsize);
1301         if (!entry)
1302                 return;
1303
1304         fbuffer.regs = regs;
1305         entry->ip = (unsigned long)tk->rp.kp.addr;
1306         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1307
1308         trace_event_buffer_commit(&fbuffer);
1309 }
1310
1311 static void
1312 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1313 {
1314         struct event_file_link *link;
1315
1316         trace_probe_for_each_link_rcu(link, &tk->tp)
1317                 __kprobe_trace_func(tk, regs, link->file);
1318 }
1319 NOKPROBE_SYMBOL(kprobe_trace_func);
1320
1321 /* Kretprobe handler */
1322 static nokprobe_inline void
1323 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1324                        struct pt_regs *regs,
1325                        struct trace_event_file *trace_file)
1326 {
1327         struct kretprobe_trace_entry_head *entry;
1328         struct trace_event_buffer fbuffer;
1329         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1330         int dsize;
1331
1332         WARN_ON(call != trace_file->event_call);
1333
1334         if (trace_trigger_soft_disabled(trace_file))
1335                 return;
1336
1337         dsize = __get_data_size(&tk->tp, regs);
1338
1339         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1340                                            sizeof(*entry) + tk->tp.size + dsize);
1341         if (!entry)
1342                 return;
1343
1344         fbuffer.regs = regs;
1345         entry->func = (unsigned long)tk->rp.kp.addr;
1346         entry->ret_ip = get_kretprobe_retaddr(ri);
1347         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1348
1349         trace_event_buffer_commit(&fbuffer);
1350 }
1351
1352 static void
1353 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1354                      struct pt_regs *regs)
1355 {
1356         struct event_file_link *link;
1357
1358         trace_probe_for_each_link_rcu(link, &tk->tp)
1359                 __kretprobe_trace_func(tk, ri, regs, link->file);
1360 }
1361 NOKPROBE_SYMBOL(kretprobe_trace_func);
1362
1363 /* Event entry printers */
1364 static enum print_line_t
1365 print_kprobe_event(struct trace_iterator *iter, int flags,
1366                    struct trace_event *event)
1367 {
1368         struct kprobe_trace_entry_head *field;
1369         struct trace_seq *s = &iter->seq;
1370         struct trace_probe *tp;
1371
1372         field = (struct kprobe_trace_entry_head *)iter->ent;
1373         tp = trace_probe_primary_from_call(
1374                 container_of(event, struct trace_event_call, event));
1375         if (WARN_ON_ONCE(!tp))
1376                 goto out;
1377
1378         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1379
1380         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1381                 goto out;
1382
1383         trace_seq_putc(s, ')');
1384
1385         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1386                              (u8 *)&field[1], field) < 0)
1387                 goto out;
1388
1389         trace_seq_putc(s, '\n');
1390  out:
1391         return trace_handle_return(s);
1392 }
1393
1394 static enum print_line_t
1395 print_kretprobe_event(struct trace_iterator *iter, int flags,
1396                       struct trace_event *event)
1397 {
1398         struct kretprobe_trace_entry_head *field;
1399         struct trace_seq *s = &iter->seq;
1400         struct trace_probe *tp;
1401
1402         field = (struct kretprobe_trace_entry_head *)iter->ent;
1403         tp = trace_probe_primary_from_call(
1404                 container_of(event, struct trace_event_call, event));
1405         if (WARN_ON_ONCE(!tp))
1406                 goto out;
1407
1408         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1409
1410         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1411                 goto out;
1412
1413         trace_seq_puts(s, " <- ");
1414
1415         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1416                 goto out;
1417
1418         trace_seq_putc(s, ')');
1419
1420         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1421                              (u8 *)&field[1], field) < 0)
1422                 goto out;
1423
1424         trace_seq_putc(s, '\n');
1425
1426  out:
1427         return trace_handle_return(s);
1428 }
1429
1430
1431 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1432 {
1433         int ret;
1434         struct kprobe_trace_entry_head field;
1435         struct trace_probe *tp;
1436
1437         tp = trace_probe_primary_from_call(event_call);
1438         if (WARN_ON_ONCE(!tp))
1439                 return -ENOENT;
1440
1441         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1442
1443         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1444 }
1445
1446 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1447 {
1448         int ret;
1449         struct kretprobe_trace_entry_head field;
1450         struct trace_probe *tp;
1451
1452         tp = trace_probe_primary_from_call(event_call);
1453         if (WARN_ON_ONCE(!tp))
1454                 return -ENOENT;
1455
1456         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1457         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1458
1459         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1460 }
1461
1462 #ifdef CONFIG_PERF_EVENTS
1463
1464 /* Kprobe profile handler */
1465 static int
1466 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1467 {
1468         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1469         struct kprobe_trace_entry_head *entry;
1470         struct hlist_head *head;
1471         int size, __size, dsize;
1472         int rctx;
1473
1474         if (bpf_prog_array_valid(call)) {
1475                 unsigned long orig_ip = instruction_pointer(regs);
1476                 int ret;
1477
1478                 ret = trace_call_bpf(call, regs);
1479
1480                 /*
1481                  * We need to check and see if we modified the pc of the
1482                  * pt_regs, and if so return 1 so that we don't do the
1483                  * single stepping.
1484                  */
1485                 if (orig_ip != instruction_pointer(regs))
1486                         return 1;
1487                 if (!ret)
1488                         return 0;
1489         }
1490
1491         head = this_cpu_ptr(call->perf_events);
1492         if (hlist_empty(head))
1493                 return 0;
1494
1495         dsize = __get_data_size(&tk->tp, regs);
1496         __size = sizeof(*entry) + tk->tp.size + dsize;
1497         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1498         size -= sizeof(u32);
1499
1500         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1501         if (!entry)
1502                 return 0;
1503
1504         entry->ip = (unsigned long)tk->rp.kp.addr;
1505         memset(&entry[1], 0, dsize);
1506         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1507         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1508                               head, NULL);
1509         return 0;
1510 }
1511 NOKPROBE_SYMBOL(kprobe_perf_func);
1512
1513 /* Kretprobe profile handler */
1514 static void
1515 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1516                     struct pt_regs *regs)
1517 {
1518         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1519         struct kretprobe_trace_entry_head *entry;
1520         struct hlist_head *head;
1521         int size, __size, dsize;
1522         int rctx;
1523
1524         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1525                 return;
1526
1527         head = this_cpu_ptr(call->perf_events);
1528         if (hlist_empty(head))
1529                 return;
1530
1531         dsize = __get_data_size(&tk->tp, regs);
1532         __size = sizeof(*entry) + tk->tp.size + dsize;
1533         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1534         size -= sizeof(u32);
1535
1536         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1537         if (!entry)
1538                 return;
1539
1540         entry->func = (unsigned long)tk->rp.kp.addr;
1541         entry->ret_ip = get_kretprobe_retaddr(ri);
1542         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1543         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1544                               head, NULL);
1545 }
1546 NOKPROBE_SYMBOL(kretprobe_perf_func);
1547
1548 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1549                         const char **symbol, u64 *probe_offset,
1550                         u64 *probe_addr, bool perf_type_tracepoint)
1551 {
1552         const char *pevent = trace_event_name(event->tp_event);
1553         const char *group = event->tp_event->class->system;
1554         struct trace_kprobe *tk;
1555
1556         if (perf_type_tracepoint)
1557                 tk = find_trace_kprobe(pevent, group);
1558         else
1559                 tk = trace_kprobe_primary_from_call(event->tp_event);
1560         if (!tk)
1561                 return -EINVAL;
1562
1563         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1564                                               : BPF_FD_TYPE_KPROBE;
1565         *probe_offset = tk->rp.kp.offset;
1566         *probe_addr = kallsyms_show_value(current_cred()) ?
1567                       (unsigned long)tk->rp.kp.addr : 0;
1568         *symbol = tk->symbol;
1569         return 0;
1570 }
1571 #endif  /* CONFIG_PERF_EVENTS */
1572
1573 /*
1574  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1575  *
1576  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1577  * lockless, but we can't race with this __init function.
1578  */
1579 static int kprobe_register(struct trace_event_call *event,
1580                            enum trace_reg type, void *data)
1581 {
1582         struct trace_event_file *file = data;
1583
1584         switch (type) {
1585         case TRACE_REG_REGISTER:
1586                 return enable_trace_kprobe(event, file);
1587         case TRACE_REG_UNREGISTER:
1588                 return disable_trace_kprobe(event, file);
1589
1590 #ifdef CONFIG_PERF_EVENTS
1591         case TRACE_REG_PERF_REGISTER:
1592                 return enable_trace_kprobe(event, NULL);
1593         case TRACE_REG_PERF_UNREGISTER:
1594                 return disable_trace_kprobe(event, NULL);
1595         case TRACE_REG_PERF_OPEN:
1596         case TRACE_REG_PERF_CLOSE:
1597         case TRACE_REG_PERF_ADD:
1598         case TRACE_REG_PERF_DEL:
1599                 return 0;
1600 #endif
1601         }
1602         return 0;
1603 }
1604
1605 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1606 {
1607         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1608         int ret = 0;
1609
1610         raw_cpu_inc(*tk->nhit);
1611
1612         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1613                 kprobe_trace_func(tk, regs);
1614 #ifdef CONFIG_PERF_EVENTS
1615         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1616                 ret = kprobe_perf_func(tk, regs);
1617 #endif
1618         return ret;
1619 }
1620 NOKPROBE_SYMBOL(kprobe_dispatcher);
1621
1622 static int
1623 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1624 {
1625         struct kretprobe *rp = get_kretprobe(ri);
1626         struct trace_kprobe *tk;
1627
1628         /*
1629          * There is a small chance that get_kretprobe(ri) returns NULL when
1630          * the kretprobe is unregister on another CPU between kretprobe's
1631          * trampoline_handler and this function.
1632          */
1633         if (unlikely(!rp))
1634                 return 0;
1635
1636         tk = container_of(rp, struct trace_kprobe, rp);
1637         raw_cpu_inc(*tk->nhit);
1638
1639         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1640                 kretprobe_trace_func(tk, ri, regs);
1641 #ifdef CONFIG_PERF_EVENTS
1642         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1643                 kretprobe_perf_func(tk, ri, regs);
1644 #endif
1645         return 0;       /* We don't tweak kernel, so just return 0 */
1646 }
1647 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1648
1649 static struct trace_event_functions kretprobe_funcs = {
1650         .trace          = print_kretprobe_event
1651 };
1652
1653 static struct trace_event_functions kprobe_funcs = {
1654         .trace          = print_kprobe_event
1655 };
1656
1657 static struct trace_event_fields kretprobe_fields_array[] = {
1658         { .type = TRACE_FUNCTION_TYPE,
1659           .define_fields = kretprobe_event_define_fields },
1660         {}
1661 };
1662
1663 static struct trace_event_fields kprobe_fields_array[] = {
1664         { .type = TRACE_FUNCTION_TYPE,
1665           .define_fields = kprobe_event_define_fields },
1666         {}
1667 };
1668
1669 static inline void init_trace_event_call(struct trace_kprobe *tk)
1670 {
1671         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1672
1673         if (trace_kprobe_is_return(tk)) {
1674                 call->event.funcs = &kretprobe_funcs;
1675                 call->class->fields_array = kretprobe_fields_array;
1676         } else {
1677                 call->event.funcs = &kprobe_funcs;
1678                 call->class->fields_array = kprobe_fields_array;
1679         }
1680
1681         call->flags = TRACE_EVENT_FL_KPROBE;
1682         call->class->reg = kprobe_register;
1683 }
1684
1685 static int register_kprobe_event(struct trace_kprobe *tk)
1686 {
1687         init_trace_event_call(tk);
1688
1689         return trace_probe_register_event_call(&tk->tp);
1690 }
1691
1692 static int unregister_kprobe_event(struct trace_kprobe *tk)
1693 {
1694         return trace_probe_unregister_event_call(&tk->tp);
1695 }
1696
1697 #ifdef CONFIG_PERF_EVENTS
1698 /* create a trace_kprobe, but don't add it to global lists */
1699 struct trace_event_call *
1700 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1701                           bool is_return)
1702 {
1703         enum probe_print_type ptype;
1704         struct trace_kprobe *tk;
1705         int ret;
1706         char *event;
1707
1708         /*
1709          * local trace_kprobes are not added to dyn_event, so they are never
1710          * searched in find_trace_kprobe(). Therefore, there is no concern of
1711          * duplicated name here.
1712          */
1713         event = func ? func : "DUMMY_EVENT";
1714
1715         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1716                                 offs, 0 /* maxactive */, 0 /* nargs */,
1717                                 is_return);
1718
1719         if (IS_ERR(tk)) {
1720                 pr_info("Failed to allocate trace_probe.(%d)\n",
1721                         (int)PTR_ERR(tk));
1722                 return ERR_CAST(tk);
1723         }
1724
1725         init_trace_event_call(tk);
1726
1727         ptype = trace_kprobe_is_return(tk) ?
1728                 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1729         if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
1730                 ret = -ENOMEM;
1731                 goto error;
1732         }
1733
1734         ret = __register_trace_kprobe(tk);
1735         if (ret < 0)
1736                 goto error;
1737
1738         return trace_probe_event_call(&tk->tp);
1739 error:
1740         free_trace_kprobe(tk);
1741         return ERR_PTR(ret);
1742 }
1743
1744 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1745 {
1746         struct trace_kprobe *tk;
1747
1748         tk = trace_kprobe_primary_from_call(event_call);
1749         if (unlikely(!tk))
1750                 return;
1751
1752         if (trace_probe_is_enabled(&tk->tp)) {
1753                 WARN_ON(1);
1754                 return;
1755         }
1756
1757         __unregister_trace_kprobe(tk);
1758
1759         free_trace_kprobe(tk);
1760 }
1761 #endif /* CONFIG_PERF_EVENTS */
1762
1763 static __init void enable_boot_kprobe_events(void)
1764 {
1765         struct trace_array *tr = top_trace_array();
1766         struct trace_event_file *file;
1767         struct trace_kprobe *tk;
1768         struct dyn_event *pos;
1769
1770         mutex_lock(&event_mutex);
1771         for_each_trace_kprobe(tk, pos) {
1772                 list_for_each_entry(file, &tr->events, list)
1773                         if (file->event_call == trace_probe_event_call(&tk->tp))
1774                                 trace_event_enable_disable(file, 1, 0);
1775         }
1776         mutex_unlock(&event_mutex);
1777 }
1778
1779 static __init void setup_boot_kprobe_events(void)
1780 {
1781         char *p, *cmd = kprobe_boot_events_buf;
1782         int ret;
1783
1784         strreplace(kprobe_boot_events_buf, ',', ' ');
1785
1786         while (cmd && *cmd != '\0') {
1787                 p = strchr(cmd, ';');
1788                 if (p)
1789                         *p++ = '\0';
1790
1791                 ret = create_or_delete_trace_kprobe(cmd);
1792                 if (ret)
1793                         pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1794
1795                 cmd = p;
1796         }
1797
1798         enable_boot_kprobe_events();
1799 }
1800
1801 /*
1802  * Register dynevent at core_initcall. This allows kernel to setup kprobe
1803  * events in postcore_initcall without tracefs.
1804  */
1805 static __init int init_kprobe_trace_early(void)
1806 {
1807         int ret;
1808
1809         ret = dyn_event_register(&trace_kprobe_ops);
1810         if (ret)
1811                 return ret;
1812
1813         if (register_module_notifier(&trace_kprobe_module_nb))
1814                 return -EINVAL;
1815
1816         return 0;
1817 }
1818 core_initcall(init_kprobe_trace_early);
1819
1820 /* Make a tracefs interface for controlling probe points */
1821 static __init int init_kprobe_trace(void)
1822 {
1823         int ret;
1824
1825         ret = tracing_init_dentry();
1826         if (ret)
1827                 return 0;
1828
1829         /* Event list interface */
1830         trace_create_file("kprobe_events", TRACE_MODE_WRITE,
1831                           NULL, NULL, &kprobe_events_ops);
1832
1833         /* Profile interface */
1834         trace_create_file("kprobe_profile", TRACE_MODE_READ,
1835                           NULL, NULL, &kprobe_profile_ops);
1836
1837         setup_boot_kprobe_events();
1838
1839         return 0;
1840 }
1841 fs_initcall(init_kprobe_trace);
1842
1843
1844 #ifdef CONFIG_FTRACE_STARTUP_TEST
1845 static __init struct trace_event_file *
1846 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1847 {
1848         struct trace_event_file *file;
1849
1850         list_for_each_entry(file, &tr->events, list)
1851                 if (file->event_call == trace_probe_event_call(&tk->tp))
1852                         return file;
1853
1854         return NULL;
1855 }
1856
1857 /*
1858  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1859  * stage, we can do this lockless.
1860  */
1861 static __init int kprobe_trace_self_tests_init(void)
1862 {
1863         int ret, warn = 0;
1864         int (*target)(int, int, int, int, int, int);
1865         struct trace_kprobe *tk;
1866         struct trace_event_file *file;
1867
1868         if (tracing_is_disabled())
1869                 return -ENODEV;
1870
1871         if (tracing_selftest_disabled)
1872                 return 0;
1873
1874         target = kprobe_trace_selftest_target;
1875
1876         pr_info("Testing kprobe tracing: ");
1877
1878         ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
1879         if (WARN_ON_ONCE(ret)) {
1880                 pr_warn("error on probing function entry.\n");
1881                 warn++;
1882         } else {
1883                 /* Enable trace point */
1884                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1885                 if (WARN_ON_ONCE(tk == NULL)) {
1886                         pr_warn("error on getting new probe.\n");
1887                         warn++;
1888                 } else {
1889                         file = find_trace_probe_file(tk, top_trace_array());
1890                         if (WARN_ON_ONCE(file == NULL)) {
1891                                 pr_warn("error on getting probe file.\n");
1892                                 warn++;
1893                         } else
1894                                 enable_trace_kprobe(
1895                                         trace_probe_event_call(&tk->tp), file);
1896                 }
1897         }
1898
1899         ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
1900         if (WARN_ON_ONCE(ret)) {
1901                 pr_warn("error on probing function return.\n");
1902                 warn++;
1903         } else {
1904                 /* Enable trace point */
1905                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1906                 if (WARN_ON_ONCE(tk == NULL)) {
1907                         pr_warn("error on getting 2nd new probe.\n");
1908                         warn++;
1909                 } else {
1910                         file = find_trace_probe_file(tk, top_trace_array());
1911                         if (WARN_ON_ONCE(file == NULL)) {
1912                                 pr_warn("error on getting probe file.\n");
1913                                 warn++;
1914                         } else
1915                                 enable_trace_kprobe(
1916                                         trace_probe_event_call(&tk->tp), file);
1917                 }
1918         }
1919
1920         if (warn)
1921                 goto end;
1922
1923         ret = target(1, 2, 3, 4, 5, 6);
1924
1925         /*
1926          * Not expecting an error here, the check is only to prevent the
1927          * optimizer from removing the call to target() as otherwise there
1928          * are no side-effects and the call is never performed.
1929          */
1930         if (ret != 21)
1931                 warn++;
1932
1933         /* Disable trace points before removing it */
1934         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1935         if (WARN_ON_ONCE(tk == NULL)) {
1936                 pr_warn("error on getting test probe.\n");
1937                 warn++;
1938         } else {
1939                 if (trace_kprobe_nhit(tk) != 1) {
1940                         pr_warn("incorrect number of testprobe hits\n");
1941                         warn++;
1942                 }
1943
1944                 file = find_trace_probe_file(tk, top_trace_array());
1945                 if (WARN_ON_ONCE(file == NULL)) {
1946                         pr_warn("error on getting probe file.\n");
1947                         warn++;
1948                 } else
1949                         disable_trace_kprobe(
1950                                 trace_probe_event_call(&tk->tp), file);
1951         }
1952
1953         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1954         if (WARN_ON_ONCE(tk == NULL)) {
1955                 pr_warn("error on getting 2nd test probe.\n");
1956                 warn++;
1957         } else {
1958                 if (trace_kprobe_nhit(tk) != 1) {
1959                         pr_warn("incorrect number of testprobe2 hits\n");
1960                         warn++;
1961                 }
1962
1963                 file = find_trace_probe_file(tk, top_trace_array());
1964                 if (WARN_ON_ONCE(file == NULL)) {
1965                         pr_warn("error on getting probe file.\n");
1966                         warn++;
1967                 } else
1968                         disable_trace_kprobe(
1969                                 trace_probe_event_call(&tk->tp), file);
1970         }
1971
1972         ret = create_or_delete_trace_kprobe("-:testprobe");
1973         if (WARN_ON_ONCE(ret)) {
1974                 pr_warn("error on deleting a probe.\n");
1975                 warn++;
1976         }
1977
1978         ret = create_or_delete_trace_kprobe("-:testprobe2");
1979         if (WARN_ON_ONCE(ret)) {
1980                 pr_warn("error on deleting a probe.\n");
1981                 warn++;
1982         }
1983
1984 end:
1985         ret = dyn_events_release_all(&trace_kprobe_ops);
1986         if (WARN_ON_ONCE(ret)) {
1987                 pr_warn("error on cleaning up probes.\n");
1988                 warn++;
1989         }
1990         /*
1991          * Wait for the optimizer work to finish. Otherwise it might fiddle
1992          * with probes in already freed __init text.
1993          */
1994         wait_for_kprobe_optimizer();
1995         if (warn)
1996                 pr_cont("NG: Some tests are failed. Please check them.\n");
1997         else
1998                 pr_cont("OK\n");
1999         return 0;
2000 }
2001
2002 late_initcall(kprobe_trace_self_tests_init);
2003
2004 #endif