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 count_symbols(void *data, unsigned long unused)
 709 {
 710         unsigned int *count = data;
 711
 712         (*count)++;
 713
 714         return 0;
 715 }
 716
 717 struct sym_count_ctx {
 718         unsigned int count;
 719         const char *name;
 720 };
 721
 722 static int count_mod_symbols(void *data, const char *name, unsigned long unused)
 723 {
 724         struct sym_count_ctx *ctx = data;
 725
 726         if (strcmp(name, ctx->name) == 0)
 727                 ctx->count++;
 728
 729         return 0;
 730 }
 731
 732 static unsigned int number_of_same_symbols(char *func_name)
 733 {
 734         struct sym_count_ctx ctx = { .count = 0, .name = func_name };
 735
 736         kallsyms_on_each_match_symbol(count_symbols, func_name, &ctx.count);
 737
 738         module_kallsyms_on_each_symbol(NULL, count_mod_symbols, &ctx);
 739
 740         return ctx.count;
 741 }
 742
 743 static int __trace_kprobe_create(int argc, const char *argv[])
 744 {
 745         /*
 746          * Argument syntax:
 747          *  - Add kprobe:
 748          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 749          *  - Add kretprobe:
 750          *      r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
 751          *    Or
 752          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
 753          *
 754          * Fetch args:
 755          *  $retval     : fetch return value
 756          *  $stack      : fetch stack address
 757          *  $stackN     : fetch Nth of stack (N:0-)
 758          *  $comm       : fetch current task comm
 759          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 760          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 761          *  %REG        : fetch register REG
 762          * Dereferencing memory fetch:
 763          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 764          * Alias name of args:
 765          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 766          * Type of args:
 767          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 768          */
 769         struct trace_kprobe *tk = NULL;
 770         int i, len, new_argc = 0, ret = 0;
 771         bool is_return = false;
 772         char *symbol = NULL, *tmp = NULL;
 773         const char **new_argv = NULL;
 774         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 775         enum probe_print_type ptype;
 776         int maxactive = 0;
 777         long offset = 0;
 778         void *addr = NULL;
 779         char buf[MAX_EVENT_NAME_LEN];
 780         char gbuf[MAX_EVENT_NAME_LEN];
 781         char abuf[MAX_BTF_ARGS_LEN];
 782         struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
 783
 784         switch (argv[0][0]) {
 785         case 'r':
 786                 is_return = true;
 787                 break;
 788         case 'p':
 789                 break;
 790         default:
 791                 return -ECANCELED;
 792         }
 793         if (argc < 2)
 794                 return -ECANCELED;
 795
 796         trace_probe_log_init("trace_kprobe", argc, argv);
 797
 798         event = strchr(&argv[0][1], ':');
 799         if (event)
 800                 event++;
 801
 802         if (isdigit(argv[0][1])) {
 803                 if (!is_return) {
 804                         trace_probe_log_err(1, BAD_MAXACT_TYPE);
 805                         goto parse_error;
 806                 }
 807                 if (event)
 808                         len = event - &argv[0][1] - 1;
 809                 else
 810                         len = strlen(&argv[0][1]);
 811                 if (len > MAX_EVENT_NAME_LEN - 1) {
 812                         trace_probe_log_err(1, BAD_MAXACT);
 813                         goto parse_error;
 814                 }
 815                 memcpy(buf, &argv[0][1], len);
 816                 buf[len] = '\0';
 817                 ret = kstrtouint(buf, 0, &maxactive);
 818                 if (ret || !maxactive) {
 819                         trace_probe_log_err(1, BAD_MAXACT);
 820                         goto parse_error;
 821                 }
 822                 /* kretprobes instances are iterated over via a list. The
 823                  * maximum should stay reasonable.
 824                  */
 825                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 826                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 827                         goto parse_error;
 828                 }
 829         }
 830
 831         /* try to parse an address. if that fails, try to read the
 832          * input as a symbol. */
 833         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 834                 trace_probe_log_set_index(1);
 835                 /* Check whether uprobe event specified */
 836                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 837                         ret = -ECANCELED;
 838                         goto error;
 839                 }
 840                 /* a symbol specified */
 841                 symbol = kstrdup(argv[1], GFP_KERNEL);
 842                 if (!symbol)
 843                         return -ENOMEM;
 844
 845                 tmp = strchr(symbol, '%');
 846                 if (tmp) {
 847                         if (!strcmp(tmp, "%return")) {
 848                                 *tmp = '\0';
 849                                 is_return = true;
 850                         } else {
 851                                 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
 852                                 goto parse_error;
 853                         }
 854                 }
 855
 856                 /* TODO: support .init module functions */
 857                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 858                 if (ret || offset < 0 || offset > UINT_MAX) {
 859                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 860                         goto parse_error;
 861                 }
 862                 if (is_return)
 863                         ctx.flags |= TPARG_FL_RETURN;
 864                 ret = kprobe_on_func_entry(NULL, symbol, offset);
 865                 if (ret == 0 && !is_return)
 866                         ctx.flags |= TPARG_FL_FENTRY;
 867                 /* Defer the ENOENT case until register kprobe */
 868                 if (ret == -EINVAL && is_return) {
 869                         trace_probe_log_err(0, BAD_RETPROBE);
 870                         goto parse_error;
 871                 }
 872         }
 873
 874         if (symbol && !strchr(symbol, ':')) {
 875                 unsigned int count;
 876
 877                 count = number_of_same_symbols(symbol);
 878                 if (count > 1) {
 879                         /*
 880                          * Users should use ADDR to remove the ambiguity of
 881                          * using KSYM only.
 882                          */
 883                         trace_probe_log_err(0, NON_UNIQ_SYMBOL);
 884                         ret = -EADDRNOTAVAIL;
 885
 886                         goto error;
 887                 } else if (count == 0) {
 888                         /*
 889                          * We can return ENOENT earlier than when register the
 890                          * kprobe.
 891                          */
 892                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 893                         ret = -ENOENT;
 894
 895                         goto error;
 896                 }
 897         }
 898
 899         trace_probe_log_set_index(0);
 900         if (event) {
 901                 ret = traceprobe_parse_event_name(&event, &group, gbuf,
 902                                                   event - argv[0]);
 903                 if (ret)
 904                         goto parse_error;
 905         }
 906
 907         if (!event) {
 908                 /* Make a new event name */
 909                 if (symbol)
 910                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 911                                  is_return ? 'r' : 'p', symbol, offset);
 912                 else
 913                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 914                                  is_return ? 'r' : 'p', addr);
 915                 sanitize_event_name(buf);
 916                 event = buf;
 917         }
 918
 919         argc -= 2; argv += 2;
 920         ctx.funcname = symbol;
 921         new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
 922                                                abuf, MAX_BTF_ARGS_LEN, &ctx);
 923         if (IS_ERR(new_argv)) {
 924                 ret = PTR_ERR(new_argv);
 925                 new_argv = NULL;
 926                 goto out;
 927         }
 928         if (new_argv) {
 929                 argc = new_argc;
 930                 argv = new_argv;
 931         }
 932
 933         /* setup a probe */
 934         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 935                                 argc, is_return);
 936         if (IS_ERR(tk)) {
 937                 ret = PTR_ERR(tk);
 938                 /* This must return -ENOMEM, else there is a bug */
 939                 WARN_ON_ONCE(ret != -ENOMEM);
 940                 goto out;       /* We know tk is not allocated */
 941         }
 942
 943         /* parse arguments */
 944         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 945                 trace_probe_log_set_index(i + 2);
 946                 ctx.offset = 0;
 947                 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);
 948                 if (ret)
 949                         goto error;     /* This can be -ENOMEM */
 950         }
 951
 952         ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
 953         ret = traceprobe_set_print_fmt(&tk->tp, ptype);
 954         if (ret < 0)
 955                 goto error;
 956
 957         ret = register_trace_kprobe(tk);
 958         if (ret) {
 959                 trace_probe_log_set_index(1);
 960                 if (ret == -EILSEQ)
 961                         trace_probe_log_err(0, BAD_INSN_BNDRY);
 962                 else if (ret == -ENOENT)
 963                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 964                 else if (ret != -ENOMEM && ret != -EEXIST)
 965                         trace_probe_log_err(0, FAIL_REG_PROBE);
 966                 goto error;
 967         }
 968
 969 out:
 970         traceprobe_finish_parse(&ctx);
 971         trace_probe_log_clear();
 972         kfree(new_argv);
 973         kfree(symbol);
 974         return ret;
 975
 976 parse_error:
 977         ret = -EINVAL;
 978 error:
 979         free_trace_kprobe(tk);
 980         goto out;
 981 }
 982
 983 static int trace_kprobe_create(const char *raw_command)
 984 {
 985         return trace_probe_create(raw_command, __trace_kprobe_create);
 986 }
 987
 988 static int create_or_delete_trace_kprobe(const char *raw_command)
 989 {
 990         int ret;
 991
 992         if (raw_command[0] == '-')
 993                 return dyn_event_release(raw_command, &trace_kprobe_ops);
 994
 995         ret = trace_kprobe_create(raw_command);
 996         return ret == -ECANCELED ? -EINVAL : ret;
 997 }
 998
 999 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
1000 {
1001         return create_or_delete_trace_kprobe(cmd->seq.buffer);
1002 }
1003
1004 /**
1005  * kprobe_event_cmd_init - Initialize a kprobe event command object
1006  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1007  * @buf: A pointer to the buffer used to build the command
1008  * @maxlen: The length of the buffer passed in @buf
1009  *
1010  * Initialize a synthetic event command object.  Use this before
1011  * calling any of the other kprobe_event functions.
1012  */
1013 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1014 {
1015         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
1016                           trace_kprobe_run_command);
1017 }
1018 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
1019
1020 /**
1021  * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
1022  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1023  * @kretprobe: Is this a return probe?
1024  * @name: The name of the kprobe event
1025  * @loc: The location of the kprobe event
1026  * @...: Variable number of arg (pairs), one pair for each field
1027  *
1028  * NOTE: Users normally won't want to call this function directly, but
1029  * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
1030  * adds a NULL to the end of the arg list.  If this function is used
1031  * directly, make sure the last arg in the variable arg list is NULL.
1032  *
1033  * Generate a kprobe event command to be executed by
1034  * kprobe_event_gen_cmd_end().  This function can be used to generate the
1035  * complete command or only the first part of it; in the latter case,
1036  * kprobe_event_add_fields() can be used to add more fields following this.
1037  *
1038  * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
1039  * returns -EINVAL if @loc == NULL.
1040  *
1041  * Return: 0 if successful, error otherwise.
1042  */
1043 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
1044                                  const char *name, const char *loc, ...)
1045 {
1046         char buf[MAX_EVENT_NAME_LEN];
1047         struct dynevent_arg arg;
1048         va_list args;
1049         int ret;
1050
1051         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1052                 return -EINVAL;
1053
1054         if (!loc)
1055                 return -EINVAL;
1056
1057         if (kretprobe)
1058                 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
1059         else
1060                 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
1061
1062         ret = dynevent_str_add(cmd, buf);
1063         if (ret)
1064                 return ret;
1065
1066         dynevent_arg_init(&arg, 0);
1067         arg.str = loc;
1068         ret = dynevent_arg_add(cmd, &arg, NULL);
1069         if (ret)
1070                 return ret;
1071
1072         va_start(args, loc);
1073         for (;;) {
1074                 const char *field;
1075
1076                 field = va_arg(args, const char *);
1077                 if (!field)
1078                         break;
1079
1080                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1081                         ret = -EINVAL;
1082                         break;
1083                 }
1084
1085                 arg.str = field;
1086                 ret = dynevent_arg_add(cmd, &arg, NULL);
1087                 if (ret)
1088                         break;
1089         }
1090         va_end(args);
1091
1092         return ret;
1093 }
1094 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1095
1096 /**
1097  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1098  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1099  * @...: Variable number of arg (pairs), one pair for each field
1100  *
1101  * NOTE: Users normally won't want to call this function directly, but
1102  * rather use the kprobe_event_add_fields() wrapper, which
1103  * automatically adds a NULL to the end of the arg list.  If this
1104  * function is used directly, make sure the last arg in the variable
1105  * arg list is NULL.
1106  *
1107  * Add probe fields to an existing kprobe command using a variable
1108  * list of args.  Fields are added in the same order they're listed.
1109  *
1110  * Return: 0 if successful, error otherwise.
1111  */
1112 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1113 {
1114         struct dynevent_arg arg;
1115         va_list args;
1116         int ret = 0;
1117
1118         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1119                 return -EINVAL;
1120
1121         dynevent_arg_init(&arg, 0);
1122
1123         va_start(args, cmd);
1124         for (;;) {
1125                 const char *field;
1126
1127                 field = va_arg(args, const char *);
1128                 if (!field)
1129                         break;
1130
1131                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1132                         ret = -EINVAL;
1133                         break;
1134                 }
1135
1136                 arg.str = field;
1137                 ret = dynevent_arg_add(cmd, &arg, NULL);
1138                 if (ret)
1139                         break;
1140         }
1141         va_end(args);
1142
1143         return ret;
1144 }
1145 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1146
1147 /**
1148  * kprobe_event_delete - Delete a kprobe event
1149  * @name: The name of the kprobe event to delete
1150  *
1151  * Delete a kprobe event with the give @name from kernel code rather
1152  * than directly from the command line.
1153  *
1154  * Return: 0 if successful, error otherwise.
1155  */
1156 int kprobe_event_delete(const char *name)
1157 {
1158         char buf[MAX_EVENT_NAME_LEN];
1159
1160         snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1161
1162         return create_or_delete_trace_kprobe(buf);
1163 }
1164 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1165
1166 static int trace_kprobe_release(struct dyn_event *ev)
1167 {
1168         struct trace_kprobe *tk = to_trace_kprobe(ev);
1169         int ret = unregister_trace_kprobe(tk);
1170
1171         if (!ret)
1172                 free_trace_kprobe(tk);
1173         return ret;
1174 }
1175
1176 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1177 {
1178         struct trace_kprobe *tk = to_trace_kprobe(ev);
1179         int i;
1180
1181         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1182         if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1183                 seq_printf(m, "%d", tk->rp.maxactive);
1184         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1185                                 trace_probe_name(&tk->tp));
1186
1187         if (!tk->symbol)
1188                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1189         else if (tk->rp.kp.offset)
1190                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1191                            tk->rp.kp.offset);
1192         else
1193                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1194
1195         for (i = 0; i < tk->tp.nr_args; i++)
1196                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1197         seq_putc(m, '\n');
1198
1199         return 0;
1200 }
1201
1202 static int probes_seq_show(struct seq_file *m, void *v)
1203 {
1204         struct dyn_event *ev = v;
1205
1206         if (!is_trace_kprobe(ev))
1207                 return 0;
1208
1209         return trace_kprobe_show(m, ev);
1210 }
1211
1212 static const struct seq_operations probes_seq_op = {
1213         .start  = dyn_event_seq_start,
1214         .next   = dyn_event_seq_next,
1215         .stop   = dyn_event_seq_stop,
1216         .show   = probes_seq_show
1217 };
1218
1219 static int probes_open(struct inode *inode, struct file *file)
1220 {
1221         int ret;
1222
1223         ret = security_locked_down(LOCKDOWN_TRACEFS);
1224         if (ret)
1225                 return ret;
1226
1227         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1228                 ret = dyn_events_release_all(&trace_kprobe_ops);
1229                 if (ret < 0)
1230                         return ret;
1231         }
1232
1233         return seq_open(file, &probes_seq_op);
1234 }
1235
1236 static ssize_t probes_write(struct file *file, const char __user *buffer,
1237                             size_t count, loff_t *ppos)
1238 {
1239         return trace_parse_run_command(file, buffer, count, ppos,
1240                                        create_or_delete_trace_kprobe);
1241 }
1242
1243 static const struct file_operations kprobe_events_ops = {
1244         .owner          = THIS_MODULE,
1245         .open           = probes_open,
1246         .read           = seq_read,
1247         .llseek         = seq_lseek,
1248         .release        = seq_release,
1249         .write          = probes_write,
1250 };
1251
1252 /* Probes profiling interfaces */
1253 static int probes_profile_seq_show(struct seq_file *m, void *v)
1254 {
1255         struct dyn_event *ev = v;
1256         struct trace_kprobe *tk;
1257         unsigned long nmissed;
1258
1259         if (!is_trace_kprobe(ev))
1260                 return 0;
1261
1262         tk = to_trace_kprobe(ev);
1263         nmissed = trace_kprobe_is_return(tk) ?
1264                 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1265         seq_printf(m, "  %-44s %15lu %15lu\n",
1266                    trace_probe_name(&tk->tp),
1267                    trace_kprobe_nhit(tk),
1268                    nmissed);
1269
1270         return 0;
1271 }
1272
1273 static const struct seq_operations profile_seq_op = {
1274         .start  = dyn_event_seq_start,
1275         .next   = dyn_event_seq_next,
1276         .stop   = dyn_event_seq_stop,
1277         .show   = probes_profile_seq_show
1278 };
1279
1280 static int profile_open(struct inode *inode, struct file *file)
1281 {
1282         int ret;
1283
1284         ret = security_locked_down(LOCKDOWN_TRACEFS);
1285         if (ret)
1286                 return ret;
1287
1288         return seq_open(file, &profile_seq_op);
1289 }
1290
1291 static const struct file_operations kprobe_profile_ops = {
1292         .owner          = THIS_MODULE,
1293         .open           = profile_open,
1294         .read           = seq_read,
1295         .llseek         = seq_lseek,
1296         .release        = seq_release,
1297 };
1298
1299 /* Note that we don't verify it, since the code does not come from user space */
1300 static int
1301 process_fetch_insn(struct fetch_insn *code, void *rec, void *dest,
1302                    void *base)
1303 {
1304         struct pt_regs *regs = rec;
1305         unsigned long val;
1306         int ret;
1307
1308 retry:
1309         /* 1st stage: get value from context */
1310         switch (code->op) {
1311         case FETCH_OP_REG:
1312                 val = regs_get_register(regs, code->param);
1313                 break;
1314         case FETCH_OP_STACK:
1315                 val = regs_get_kernel_stack_nth(regs, code->param);
1316                 break;
1317         case FETCH_OP_STACKP:
1318                 val = kernel_stack_pointer(regs);
1319                 break;
1320         case FETCH_OP_RETVAL:
1321                 val = regs_return_value(regs);
1322                 break;
1323 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1324         case FETCH_OP_ARG:
1325                 val = regs_get_kernel_argument(regs, code->param);
1326                 break;
1327 #endif
1328         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1329                 code++;
1330                 goto retry;
1331         default:
1332                 ret = process_common_fetch_insn(code, &val);
1333                 if (ret < 0)
1334                         return ret;
1335         }
1336         code++;
1337
1338         return process_fetch_insn_bottom(code, val, dest, base);
1339 }
1340 NOKPROBE_SYMBOL(process_fetch_insn)
1341
1342 /* Kprobe handler */
1343 static nokprobe_inline void
1344 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1345                     struct trace_event_file *trace_file)
1346 {
1347         struct kprobe_trace_entry_head *entry;
1348         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1349         struct trace_event_buffer fbuffer;
1350         int dsize;
1351
1352         WARN_ON(call != trace_file->event_call);
1353
1354         if (trace_trigger_soft_disabled(trace_file))
1355                 return;
1356
1357         dsize = __get_data_size(&tk->tp, regs);
1358
1359         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1360                                            sizeof(*entry) + tk->tp.size + dsize);
1361         if (!entry)
1362                 return;
1363
1364         fbuffer.regs = regs;
1365         entry->ip = (unsigned long)tk->rp.kp.addr;
1366         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1367
1368         trace_event_buffer_commit(&fbuffer);
1369 }
1370
1371 static void
1372 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1373 {
1374         struct event_file_link *link;
1375
1376         trace_probe_for_each_link_rcu(link, &tk->tp)
1377                 __kprobe_trace_func(tk, regs, link->file);
1378 }
1379 NOKPROBE_SYMBOL(kprobe_trace_func);
1380
1381 /* Kretprobe handler */
1382 static nokprobe_inline void
1383 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1384                        struct pt_regs *regs,
1385                        struct trace_event_file *trace_file)
1386 {
1387         struct kretprobe_trace_entry_head *entry;
1388         struct trace_event_buffer fbuffer;
1389         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1390         int dsize;
1391
1392         WARN_ON(call != trace_file->event_call);
1393
1394         if (trace_trigger_soft_disabled(trace_file))
1395                 return;
1396
1397         dsize = __get_data_size(&tk->tp, regs);
1398
1399         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1400                                            sizeof(*entry) + tk->tp.size + dsize);
1401         if (!entry)
1402                 return;
1403
1404         fbuffer.regs = regs;
1405         entry->func = (unsigned long)tk->rp.kp.addr;
1406         entry->ret_ip = get_kretprobe_retaddr(ri);
1407         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1408
1409         trace_event_buffer_commit(&fbuffer);
1410 }
1411
1412 static void
1413 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1414                      struct pt_regs *regs)
1415 {
1416         struct event_file_link *link;
1417
1418         trace_probe_for_each_link_rcu(link, &tk->tp)
1419                 __kretprobe_trace_func(tk, ri, regs, link->file);
1420 }
1421 NOKPROBE_SYMBOL(kretprobe_trace_func);
1422
1423 /* Event entry printers */
1424 static enum print_line_t
1425 print_kprobe_event(struct trace_iterator *iter, int flags,
1426                    struct trace_event *event)
1427 {
1428         struct kprobe_trace_entry_head *field;
1429         struct trace_seq *s = &iter->seq;
1430         struct trace_probe *tp;
1431
1432         field = (struct kprobe_trace_entry_head *)iter->ent;
1433         tp = trace_probe_primary_from_call(
1434                 container_of(event, struct trace_event_call, event));
1435         if (WARN_ON_ONCE(!tp))
1436                 goto out;
1437
1438         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1439
1440         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1441                 goto out;
1442
1443         trace_seq_putc(s, ')');
1444
1445         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1446                              (u8 *)&field[1], field) < 0)
1447                 goto out;
1448
1449         trace_seq_putc(s, '\n');
1450  out:
1451         return trace_handle_return(s);
1452 }
1453
1454 static enum print_line_t
1455 print_kretprobe_event(struct trace_iterator *iter, int flags,
1456                       struct trace_event *event)
1457 {
1458         struct kretprobe_trace_entry_head *field;
1459         struct trace_seq *s = &iter->seq;
1460         struct trace_probe *tp;
1461
1462         field = (struct kretprobe_trace_entry_head *)iter->ent;
1463         tp = trace_probe_primary_from_call(
1464                 container_of(event, struct trace_event_call, event));
1465         if (WARN_ON_ONCE(!tp))
1466                 goto out;
1467
1468         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1469
1470         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1471                 goto out;
1472
1473         trace_seq_puts(s, " <- ");
1474
1475         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1476                 goto out;
1477
1478         trace_seq_putc(s, ')');
1479
1480         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1481                              (u8 *)&field[1], field) < 0)
1482                 goto out;
1483
1484         trace_seq_putc(s, '\n');
1485
1486  out:
1487         return trace_handle_return(s);
1488 }
1489
1490
1491 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1492 {
1493         int ret;
1494         struct kprobe_trace_entry_head field;
1495         struct trace_probe *tp;
1496
1497         tp = trace_probe_primary_from_call(event_call);
1498         if (WARN_ON_ONCE(!tp))
1499                 return -ENOENT;
1500
1501         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1502
1503         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1504 }
1505
1506 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1507 {
1508         int ret;
1509         struct kretprobe_trace_entry_head field;
1510         struct trace_probe *tp;
1511
1512         tp = trace_probe_primary_from_call(event_call);
1513         if (WARN_ON_ONCE(!tp))
1514                 return -ENOENT;
1515
1516         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1517         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1518
1519         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1520 }
1521
1522 #ifdef CONFIG_PERF_EVENTS
1523
1524 /* Kprobe profile handler */
1525 static int
1526 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1527 {
1528         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1529         struct kprobe_trace_entry_head *entry;
1530         struct hlist_head *head;
1531         int size, __size, dsize;
1532         int rctx;
1533
1534         if (bpf_prog_array_valid(call)) {
1535                 unsigned long orig_ip = instruction_pointer(regs);
1536                 int ret;
1537
1538                 ret = trace_call_bpf(call, regs);
1539
1540                 /*
1541                  * We need to check and see if we modified the pc of the
1542                  * pt_regs, and if so return 1 so that we don't do the
1543                  * single stepping.
1544                  */
1545                 if (orig_ip != instruction_pointer(regs))
1546                         return 1;
1547                 if (!ret)
1548                         return 0;
1549         }
1550
1551         head = this_cpu_ptr(call->perf_events);
1552         if (hlist_empty(head))
1553                 return 0;
1554
1555         dsize = __get_data_size(&tk->tp, regs);
1556         __size = sizeof(*entry) + tk->tp.size + dsize;
1557         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1558         size -= sizeof(u32);
1559
1560         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1561         if (!entry)
1562                 return 0;
1563
1564         entry->ip = (unsigned long)tk->rp.kp.addr;
1565         memset(&entry[1], 0, dsize);
1566         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1567         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1568                               head, NULL);
1569         return 0;
1570 }
1571 NOKPROBE_SYMBOL(kprobe_perf_func);
1572
1573 /* Kretprobe profile handler */
1574 static void
1575 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1576                     struct pt_regs *regs)
1577 {
1578         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1579         struct kretprobe_trace_entry_head *entry;
1580         struct hlist_head *head;
1581         int size, __size, dsize;
1582         int rctx;
1583
1584         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1585                 return;
1586
1587         head = this_cpu_ptr(call->perf_events);
1588         if (hlist_empty(head))
1589                 return;
1590
1591         dsize = __get_data_size(&tk->tp, regs);
1592         __size = sizeof(*entry) + tk->tp.size + dsize;
1593         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1594         size -= sizeof(u32);
1595
1596         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1597         if (!entry)
1598                 return;
1599
1600         entry->func = (unsigned long)tk->rp.kp.addr;
1601         entry->ret_ip = get_kretprobe_retaddr(ri);
1602         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1603         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1604                               head, NULL);
1605 }
1606 NOKPROBE_SYMBOL(kretprobe_perf_func);
1607
1608 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1609                         const char **symbol, u64 *probe_offset,
1610                         u64 *probe_addr, bool perf_type_tracepoint)
1611 {
1612         const char *pevent = trace_event_name(event->tp_event);
1613         const char *group = event->tp_event->class->system;
1614         struct trace_kprobe *tk;
1615
1616         if (perf_type_tracepoint)
1617                 tk = find_trace_kprobe(pevent, group);
1618         else
1619                 tk = trace_kprobe_primary_from_call(event->tp_event);
1620         if (!tk)
1621                 return -EINVAL;
1622
1623         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1624                                               : BPF_FD_TYPE_KPROBE;
1625         *probe_offset = tk->rp.kp.offset;
1626         *probe_addr = kallsyms_show_value(current_cred()) ?
1627                       (unsigned long)tk->rp.kp.addr : 0;
1628         *symbol = tk->symbol;
1629         return 0;
1630 }
1631 #endif  /* CONFIG_PERF_EVENTS */
1632
1633 /*
1634  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1635  *
1636  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1637  * lockless, but we can't race with this __init function.
1638  */
1639 static int kprobe_register(struct trace_event_call *event,
1640                            enum trace_reg type, void *data)
1641 {
1642         struct trace_event_file *file = data;
1643
1644         switch (type) {
1645         case TRACE_REG_REGISTER:
1646                 return enable_trace_kprobe(event, file);
1647         case TRACE_REG_UNREGISTER:
1648                 return disable_trace_kprobe(event, file);
1649
1650 #ifdef CONFIG_PERF_EVENTS
1651         case TRACE_REG_PERF_REGISTER:
1652                 return enable_trace_kprobe(event, NULL);
1653         case TRACE_REG_PERF_UNREGISTER:
1654                 return disable_trace_kprobe(event, NULL);
1655         case TRACE_REG_PERF_OPEN:
1656         case TRACE_REG_PERF_CLOSE:
1657         case TRACE_REG_PERF_ADD:
1658         case TRACE_REG_PERF_DEL:
1659                 return 0;
1660 #endif
1661         }
1662         return 0;
1663 }
1664
1665 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1666 {
1667         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1668         int ret = 0;
1669
1670         raw_cpu_inc(*tk->nhit);
1671
1672         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1673                 kprobe_trace_func(tk, regs);
1674 #ifdef CONFIG_PERF_EVENTS
1675         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1676                 ret = kprobe_perf_func(tk, regs);
1677 #endif
1678         return ret;
1679 }
1680 NOKPROBE_SYMBOL(kprobe_dispatcher);
1681
1682 static int
1683 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1684 {
1685         struct kretprobe *rp = get_kretprobe(ri);
1686         struct trace_kprobe *tk;
1687
1688         /*
1689          * There is a small chance that get_kretprobe(ri) returns NULL when
1690          * the kretprobe is unregister on another CPU between kretprobe's
1691          * trampoline_handler and this function.
1692          */
1693         if (unlikely(!rp))
1694                 return 0;
1695
1696         tk = container_of(rp, struct trace_kprobe, rp);
1697         raw_cpu_inc(*tk->nhit);
1698
1699         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1700                 kretprobe_trace_func(tk, ri, regs);
1701 #ifdef CONFIG_PERF_EVENTS
1702         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1703                 kretprobe_perf_func(tk, ri, regs);
1704 #endif
1705         return 0;       /* We don't tweak kernel, so just return 0 */
1706 }
1707 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1708
1709 static struct trace_event_functions kretprobe_funcs = {
1710         .trace          = print_kretprobe_event
1711 };
1712
1713 static struct trace_event_functions kprobe_funcs = {
1714         .trace          = print_kprobe_event
1715 };
1716
1717 static struct trace_event_fields kretprobe_fields_array[] = {
1718         { .type = TRACE_FUNCTION_TYPE,
1719           .define_fields = kretprobe_event_define_fields },
1720         {}
1721 };
1722
1723 static struct trace_event_fields kprobe_fields_array[] = {
1724         { .type = TRACE_FUNCTION_TYPE,
1725           .define_fields = kprobe_event_define_fields },
1726         {}
1727 };
1728
1729 static inline void init_trace_event_call(struct trace_kprobe *tk)
1730 {
1731         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1732
1733         if (trace_kprobe_is_return(tk)) {
1734                 call->event.funcs = &kretprobe_funcs;
1735                 call->class->fields_array = kretprobe_fields_array;
1736         } else {
1737                 call->event.funcs = &kprobe_funcs;
1738                 call->class->fields_array = kprobe_fields_array;
1739         }
1740
1741         call->flags = TRACE_EVENT_FL_KPROBE;
1742         call->class->reg = kprobe_register;
1743 }
1744
1745 static int register_kprobe_event(struct trace_kprobe *tk)
1746 {
1747         init_trace_event_call(tk);
1748
1749         return trace_probe_register_event_call(&tk->tp);
1750 }
1751
1752 static int unregister_kprobe_event(struct trace_kprobe *tk)
1753 {
1754         return trace_probe_unregister_event_call(&tk->tp);
1755 }
1756
1757 #ifdef CONFIG_PERF_EVENTS
1758
1759 /* create a trace_kprobe, but don't add it to global lists */
1760 struct trace_event_call *
1761 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1762                           bool is_return)
1763 {
1764         enum probe_print_type ptype;
1765         struct trace_kprobe *tk;
1766         int ret;
1767         char *event;
1768
1769         if (func) {
1770                 unsigned int count;
1771
1772                 count = number_of_same_symbols(func);
1773                 if (count > 1)
1774                         /*
1775                          * Users should use addr to remove the ambiguity of
1776                          * using func only.
1777                          */
1778                         return ERR_PTR(-EADDRNOTAVAIL);
1779                 else if (count == 0)
1780                         /*
1781                          * We can return ENOENT earlier than when register the
1782                          * kprobe.
1783                          */
1784                         return ERR_PTR(-ENOENT);
1785         }
1786
1787         /*
1788          * local trace_kprobes are not added to dyn_event, so they are never
1789          * searched in find_trace_kprobe(). Therefore, there is no concern of
1790          * duplicated name here.
1791          */
1792         event = func ? func : "DUMMY_EVENT";
1793
1794         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1795                                 offs, 0 /* maxactive */, 0 /* nargs */,
1796                                 is_return);
1797
1798         if (IS_ERR(tk)) {
1799                 pr_info("Failed to allocate trace_probe.(%d)\n",
1800                         (int)PTR_ERR(tk));
1801                 return ERR_CAST(tk);
1802         }
1803
1804         init_trace_event_call(tk);
1805
1806         ptype = trace_kprobe_is_return(tk) ?
1807                 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1808         if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
1809                 ret = -ENOMEM;
1810                 goto error;
1811         }
1812
1813         ret = __register_trace_kprobe(tk);
1814         if (ret < 0)
1815                 goto error;
1816
1817         return trace_probe_event_call(&tk->tp);
1818 error:
1819         free_trace_kprobe(tk);
1820         return ERR_PTR(ret);
1821 }
1822
1823 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1824 {
1825         struct trace_kprobe *tk;
1826
1827         tk = trace_kprobe_primary_from_call(event_call);
1828         if (unlikely(!tk))
1829                 return;
1830
1831         if (trace_probe_is_enabled(&tk->tp)) {
1832                 WARN_ON(1);
1833                 return;
1834         }
1835
1836         __unregister_trace_kprobe(tk);
1837
1838         free_trace_kprobe(tk);
1839 }
1840 #endif /* CONFIG_PERF_EVENTS */
1841
1842 static __init void enable_boot_kprobe_events(void)
1843 {
1844         struct trace_array *tr = top_trace_array();
1845         struct trace_event_file *file;
1846         struct trace_kprobe *tk;
1847         struct dyn_event *pos;
1848
1849         mutex_lock(&event_mutex);
1850         for_each_trace_kprobe(tk, pos) {
1851                 list_for_each_entry(file, &tr->events, list)
1852                         if (file->event_call == trace_probe_event_call(&tk->tp))
1853                                 trace_event_enable_disable(file, 1, 0);
1854         }
1855         mutex_unlock(&event_mutex);
1856 }
1857
1858 static __init void setup_boot_kprobe_events(void)
1859 {
1860         char *p, *cmd = kprobe_boot_events_buf;
1861         int ret;
1862
1863         strreplace(kprobe_boot_events_buf, ',', ' ');
1864
1865         while (cmd && *cmd != '\0') {
1866                 p = strchr(cmd, ';');
1867                 if (p)
1868                         *p++ = '\0';
1869
1870                 ret = create_or_delete_trace_kprobe(cmd);
1871                 if (ret)
1872                         pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1873
1874                 cmd = p;
1875         }
1876
1877         enable_boot_kprobe_events();
1878 }
1879
1880 /*
1881  * Register dynevent at core_initcall. This allows kernel to setup kprobe
1882  * events in postcore_initcall without tracefs.
1883  */
1884 static __init int init_kprobe_trace_early(void)
1885 {
1886         int ret;
1887
1888         ret = dyn_event_register(&trace_kprobe_ops);
1889         if (ret)
1890                 return ret;
1891
1892         if (register_module_notifier(&trace_kprobe_module_nb))
1893                 return -EINVAL;
1894
1895         return 0;
1896 }
1897 core_initcall(init_kprobe_trace_early);
1898
1899 /* Make a tracefs interface for controlling probe points */
1900 static __init int init_kprobe_trace(void)
1901 {
1902         int ret;
1903
1904         ret = tracing_init_dentry();
1905         if (ret)
1906                 return 0;
1907
1908         /* Event list interface */
1909         trace_create_file("kprobe_events", TRACE_MODE_WRITE,
1910                           NULL, NULL, &kprobe_events_ops);
1911
1912         /* Profile interface */
1913         trace_create_file("kprobe_profile", TRACE_MODE_READ,
1914                           NULL, NULL, &kprobe_profile_ops);
1915
1916         setup_boot_kprobe_events();
1917
1918         return 0;
1919 }
1920 fs_initcall(init_kprobe_trace);
1921
1922
1923 #ifdef CONFIG_FTRACE_STARTUP_TEST
1924 static __init struct trace_event_file *
1925 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1926 {
1927         struct trace_event_file *file;
1928
1929         list_for_each_entry(file, &tr->events, list)
1930                 if (file->event_call == trace_probe_event_call(&tk->tp))
1931                         return file;
1932
1933         return NULL;
1934 }
1935
1936 /*
1937  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1938  * stage, we can do this lockless.
1939  */
1940 static __init int kprobe_trace_self_tests_init(void)
1941 {
1942         int ret, warn = 0;
1943         int (*target)(int, int, int, int, int, int);
1944         struct trace_kprobe *tk;
1945         struct trace_event_file *file;
1946
1947         if (tracing_is_disabled())
1948                 return -ENODEV;
1949
1950         if (tracing_selftest_disabled)
1951                 return 0;
1952
1953         target = kprobe_trace_selftest_target;
1954
1955         pr_info("Testing kprobe tracing: ");
1956
1957         ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
1958         if (WARN_ON_ONCE(ret)) {
1959                 pr_warn("error on probing function entry.\n");
1960                 warn++;
1961         } else {
1962                 /* Enable trace point */
1963                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1964                 if (WARN_ON_ONCE(tk == NULL)) {
1965                         pr_warn("error on getting new probe.\n");
1966                         warn++;
1967                 } else {
1968                         file = find_trace_probe_file(tk, top_trace_array());
1969                         if (WARN_ON_ONCE(file == NULL)) {
1970                                 pr_warn("error on getting probe file.\n");
1971                                 warn++;
1972                         } else
1973                                 enable_trace_kprobe(
1974                                         trace_probe_event_call(&tk->tp), file);
1975                 }
1976         }
1977
1978         ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
1979         if (WARN_ON_ONCE(ret)) {
1980                 pr_warn("error on probing function return.\n");
1981                 warn++;
1982         } else {
1983                 /* Enable trace point */
1984                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1985                 if (WARN_ON_ONCE(tk == NULL)) {
1986                         pr_warn("error on getting 2nd new probe.\n");
1987                         warn++;
1988                 } else {
1989                         file = find_trace_probe_file(tk, top_trace_array());
1990                         if (WARN_ON_ONCE(file == NULL)) {
1991                                 pr_warn("error on getting probe file.\n");
1992                                 warn++;
1993                         } else
1994                                 enable_trace_kprobe(
1995                                         trace_probe_event_call(&tk->tp), file);
1996                 }
1997         }
1998
1999         if (warn)
2000                 goto end;
2001
2002         ret = target(1, 2, 3, 4, 5, 6);
2003
2004         /*
2005          * Not expecting an error here, the check is only to prevent the
2006          * optimizer from removing the call to target() as otherwise there
2007          * are no side-effects and the call is never performed.
2008          */
2009         if (ret != 21)
2010                 warn++;
2011
2012         /* Disable trace points before removing it */
2013         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2014         if (WARN_ON_ONCE(tk == NULL)) {
2015                 pr_warn("error on getting test probe.\n");
2016                 warn++;
2017         } else {
2018                 if (trace_kprobe_nhit(tk) != 1) {
2019                         pr_warn("incorrect number of testprobe hits\n");
2020                         warn++;
2021                 }
2022
2023                 file = find_trace_probe_file(tk, top_trace_array());
2024                 if (WARN_ON_ONCE(file == NULL)) {
2025                         pr_warn("error on getting probe file.\n");
2026                         warn++;
2027                 } else
2028                         disable_trace_kprobe(
2029                                 trace_probe_event_call(&tk->tp), file);
2030         }
2031
2032         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2033         if (WARN_ON_ONCE(tk == NULL)) {
2034                 pr_warn("error on getting 2nd test probe.\n");
2035                 warn++;
2036         } else {
2037                 if (trace_kprobe_nhit(tk) != 1) {
2038                         pr_warn("incorrect number of testprobe2 hits\n");
2039                         warn++;
2040                 }
2041
2042                 file = find_trace_probe_file(tk, top_trace_array());
2043                 if (WARN_ON_ONCE(file == NULL)) {
2044                         pr_warn("error on getting probe file.\n");
2045                         warn++;
2046                 } else
2047                         disable_trace_kprobe(
2048                                 trace_probe_event_call(&tk->tp), file);
2049         }
2050
2051         ret = create_or_delete_trace_kprobe("-:testprobe");
2052         if (WARN_ON_ONCE(ret)) {
2053                 pr_warn("error on deleting a probe.\n");
2054                 warn++;
2055         }
2056
2057         ret = create_or_delete_trace_kprobe("-:testprobe2");
2058         if (WARN_ON_ONCE(ret)) {
2059                 pr_warn("error on deleting a probe.\n");
2060                 warn++;
2061         }
2062
2063 end:
2064         ret = dyn_events_release_all(&trace_kprobe_ops);
2065         if (WARN_ON_ONCE(ret)) {
2066                 pr_warn("error on cleaning up probes.\n");
2067                 warn++;
2068         }
2069         /*
2070          * Wait for the optimizer work to finish. Otherwise it might fiddle
2071          * with probes in already freed __init text.
2072          */
2073         wait_for_kprobe_optimizer();
2074         if (warn)
2075                 pr_cont("NG: Some tests are failed. Please check them.\n");
2076         else
2077                 pr_cont("OK\n");
2078         return 0;
2079 }
2080
2081 late_initcall(kprobe_trace_self_tests_init);
2082
2083 #endif