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, nargs);
 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 %ps\n",
 491                         (void *)trace_kprobe_address(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_entry_handler(struct kretprobe_instance *ri,
 744                                       struct pt_regs *regs);
 745
 746 static int __trace_kprobe_create(int argc, const char *argv[])
 747 {
 748         /*
 749          * Argument syntax:
 750          *  - Add kprobe:
 751          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 752          *  - Add kretprobe:
 753          *      r[MAXACTIVE][:[GRP/][EVENT]] [MOD:]KSYM[+0] [FETCHARGS]
 754          *    Or
 755          *      p[:[GRP/][EVENT]] [MOD:]KSYM[+0]%return [FETCHARGS]
 756          *
 757          * Fetch args:
 758          *  $retval     : fetch return value
 759          *  $stack      : fetch stack address
 760          *  $stackN     : fetch Nth of stack (N:0-)
 761          *  $comm       : fetch current task comm
 762          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 763          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 764          *  %REG        : fetch register REG
 765          * Dereferencing memory fetch:
 766          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 767          * Alias name of args:
 768          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 769          * Type of args:
 770          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 771          */
 772         struct trace_kprobe *tk = NULL;
 773         int i, len, new_argc = 0, ret = 0;
 774         bool is_return = false;
 775         char *symbol = NULL, *tmp = NULL;
 776         const char **new_argv = NULL;
 777         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 778         enum probe_print_type ptype;
 779         int maxactive = 0;
 780         long offset = 0;
 781         void *addr = NULL;
 782         char buf[MAX_EVENT_NAME_LEN];
 783         char gbuf[MAX_EVENT_NAME_LEN];
 784         char abuf[MAX_BTF_ARGS_LEN];
 785         struct traceprobe_parse_context ctx = { .flags = TPARG_FL_KERNEL };
 786
 787         switch (argv[0][0]) {
 788         case 'r':
 789                 is_return = true;
 790                 break;
 791         case 'p':
 792                 break;
 793         default:
 794                 return -ECANCELED;
 795         }
 796         if (argc < 2)
 797                 return -ECANCELED;
 798
 799         trace_probe_log_init("trace_kprobe", argc, argv);
 800
 801         event = strchr(&argv[0][1], ':');
 802         if (event)
 803                 event++;
 804
 805         if (isdigit(argv[0][1])) {
 806                 if (!is_return) {
 807                         trace_probe_log_err(1, BAD_MAXACT_TYPE);
 808                         goto parse_error;
 809                 }
 810                 if (event)
 811                         len = event - &argv[0][1] - 1;
 812                 else
 813                         len = strlen(&argv[0][1]);
 814                 if (len > MAX_EVENT_NAME_LEN - 1) {
 815                         trace_probe_log_err(1, BAD_MAXACT);
 816                         goto parse_error;
 817                 }
 818                 memcpy(buf, &argv[0][1], len);
 819                 buf[len] = '\0';
 820                 ret = kstrtouint(buf, 0, &maxactive);
 821                 if (ret || !maxactive) {
 822                         trace_probe_log_err(1, BAD_MAXACT);
 823                         goto parse_error;
 824                 }
 825                 /* kretprobes instances are iterated over via a list. The
 826                  * maximum should stay reasonable.
 827                  */
 828                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 829                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 830                         goto parse_error;
 831                 }
 832         }
 833
 834         /* try to parse an address. if that fails, try to read the
 835          * input as a symbol. */
 836         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 837                 trace_probe_log_set_index(1);
 838                 /* Check whether uprobe event specified */
 839                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 840                         ret = -ECANCELED;
 841                         goto error;
 842                 }
 843                 /* a symbol specified */
 844                 symbol = kstrdup(argv[1], GFP_KERNEL);
 845                 if (!symbol)
 846                         return -ENOMEM;
 847
 848                 tmp = strchr(symbol, '%');
 849                 if (tmp) {
 850                         if (!strcmp(tmp, "%return")) {
 851                                 *tmp = '\0';
 852                                 is_return = true;
 853                         } else {
 854                                 trace_probe_log_err(tmp - symbol, BAD_ADDR_SUFFIX);
 855                                 goto parse_error;
 856                         }
 857                 }
 858
 859                 /* TODO: support .init module functions */
 860                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 861                 if (ret || offset < 0 || offset > UINT_MAX) {
 862                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 863                         goto parse_error;
 864                 }
 865                 if (is_return)
 866                         ctx.flags |= TPARG_FL_RETURN;
 867                 ret = kprobe_on_func_entry(NULL, symbol, offset);
 868                 if (ret == 0 && !is_return)
 869                         ctx.flags |= TPARG_FL_FENTRY;
 870                 /* Defer the ENOENT case until register kprobe */
 871                 if (ret == -EINVAL && is_return) {
 872                         trace_probe_log_err(0, BAD_RETPROBE);
 873                         goto parse_error;
 874                 }
 875         }
 876
 877         if (symbol && !strchr(symbol, ':')) {
 878                 unsigned int count;
 879
 880                 count = number_of_same_symbols(symbol);
 881                 if (count > 1) {
 882                         /*
 883                          * Users should use ADDR to remove the ambiguity of
 884                          * using KSYM only.
 885                          */
 886                         trace_probe_log_err(0, NON_UNIQ_SYMBOL);
 887                         ret = -EADDRNOTAVAIL;
 888
 889                         goto error;
 890                 } else if (count == 0) {
 891                         /*
 892                          * We can return ENOENT earlier than when register the
 893                          * kprobe.
 894                          */
 895                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 896                         ret = -ENOENT;
 897
 898                         goto error;
 899                 }
 900         }
 901
 902         trace_probe_log_set_index(0);
 903         if (event) {
 904                 ret = traceprobe_parse_event_name(&event, &group, gbuf,
 905                                                   event - argv[0]);
 906                 if (ret)
 907                         goto parse_error;
 908         }
 909
 910         if (!event) {
 911                 /* Make a new event name */
 912                 if (symbol)
 913                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 914                                  is_return ? 'r' : 'p', symbol, offset);
 915                 else
 916                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 917                                  is_return ? 'r' : 'p', addr);
 918                 sanitize_event_name(buf);
 919                 event = buf;
 920         }
 921
 922         argc -= 2; argv += 2;
 923         ctx.funcname = symbol;
 924         new_argv = traceprobe_expand_meta_args(argc, argv, &new_argc,
 925                                                abuf, MAX_BTF_ARGS_LEN, &ctx);
 926         if (IS_ERR(new_argv)) {
 927                 ret = PTR_ERR(new_argv);
 928                 new_argv = NULL;
 929                 goto out;
 930         }
 931         if (new_argv) {
 932                 argc = new_argc;
 933                 argv = new_argv;
 934         }
 935
 936         /* setup a probe */
 937         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 938                                 argc, is_return);
 939         if (IS_ERR(tk)) {
 940                 ret = PTR_ERR(tk);
 941                 /* This must return -ENOMEM, else there is a bug */
 942                 WARN_ON_ONCE(ret != -ENOMEM);
 943                 goto out;       /* We know tk is not allocated */
 944         }
 945
 946         /* parse arguments */
 947         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 948                 trace_probe_log_set_index(i + 2);
 949                 ctx.offset = 0;
 950                 ret = traceprobe_parse_probe_arg(&tk->tp, i, argv[i], &ctx);
 951                 if (ret)
 952                         goto error;     /* This can be -ENOMEM */
 953         }
 954         /* entry handler for kretprobe */
 955         if (is_return && tk->tp.entry_arg) {
 956                 tk->rp.entry_handler = trace_kprobe_entry_handler;
 957                 tk->rp.data_size = traceprobe_get_entry_data_size(&tk->tp);
 958         }
 959
 960         ptype = is_return ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
 961         ret = traceprobe_set_print_fmt(&tk->tp, ptype);
 962         if (ret < 0)
 963                 goto error;
 964
 965         ret = register_trace_kprobe(tk);
 966         if (ret) {
 967                 trace_probe_log_set_index(1);
 968                 if (ret == -EILSEQ)
 969                         trace_probe_log_err(0, BAD_INSN_BNDRY);
 970                 else if (ret == -ENOENT)
 971                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 972                 else if (ret != -ENOMEM && ret != -EEXIST)
 973                         trace_probe_log_err(0, FAIL_REG_PROBE);
 974                 goto error;
 975         }
 976
 977 out:
 978         traceprobe_finish_parse(&ctx);
 979         trace_probe_log_clear();
 980         kfree(new_argv);
 981         kfree(symbol);
 982         return ret;
 983
 984 parse_error:
 985         ret = -EINVAL;
 986 error:
 987         free_trace_kprobe(tk);
 988         goto out;
 989 }
 990
 991 static int trace_kprobe_create(const char *raw_command)
 992 {
 993         return trace_probe_create(raw_command, __trace_kprobe_create);
 994 }
 995
 996 static int create_or_delete_trace_kprobe(const char *raw_command)
 997 {
 998         int ret;
 999
1000         if (raw_command[0] == '-')
1001                 return dyn_event_release(raw_command, &trace_kprobe_ops);
1002
1003         ret = trace_kprobe_create(raw_command);
1004         return ret == -ECANCELED ? -EINVAL : ret;
1005 }
1006
1007 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
1008 {
1009         return create_or_delete_trace_kprobe(cmd->seq.buffer);
1010 }
1011
1012 /**
1013  * kprobe_event_cmd_init - Initialize a kprobe event command object
1014  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1015  * @buf: A pointer to the buffer used to build the command
1016  * @maxlen: The length of the buffer passed in @buf
1017  *
1018  * Initialize a synthetic event command object.  Use this before
1019  * calling any of the other kprobe_event functions.
1020  */
1021 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1022 {
1023         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
1024                           trace_kprobe_run_command);
1025 }
1026 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
1027
1028 /**
1029  * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
1030  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1031  * @kretprobe: Is this a return probe?
1032  * @name: The name of the kprobe event
1033  * @loc: The location of the kprobe event
1034  * @...: Variable number of arg (pairs), one pair for each field
1035  *
1036  * NOTE: Users normally won't want to call this function directly, but
1037  * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
1038  * adds a NULL to the end of the arg list.  If this function is used
1039  * directly, make sure the last arg in the variable arg list is NULL.
1040  *
1041  * Generate a kprobe event command to be executed by
1042  * kprobe_event_gen_cmd_end().  This function can be used to generate the
1043  * complete command or only the first part of it; in the latter case,
1044  * kprobe_event_add_fields() can be used to add more fields following this.
1045  *
1046  * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
1047  * returns -EINVAL if @loc == NULL.
1048  *
1049  * Return: 0 if successful, error otherwise.
1050  */
1051 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
1052                                  const char *name, const char *loc, ...)
1053 {
1054         char buf[MAX_EVENT_NAME_LEN];
1055         struct dynevent_arg arg;
1056         va_list args;
1057         int ret;
1058
1059         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1060                 return -EINVAL;
1061
1062         if (!loc)
1063                 return -EINVAL;
1064
1065         if (kretprobe)
1066                 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
1067         else
1068                 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
1069
1070         ret = dynevent_str_add(cmd, buf);
1071         if (ret)
1072                 return ret;
1073
1074         dynevent_arg_init(&arg, 0);
1075         arg.str = loc;
1076         ret = dynevent_arg_add(cmd, &arg, NULL);
1077         if (ret)
1078                 return ret;
1079
1080         va_start(args, loc);
1081         for (;;) {
1082                 const char *field;
1083
1084                 field = va_arg(args, const char *);
1085                 if (!field)
1086                         break;
1087
1088                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1089                         ret = -EINVAL;
1090                         break;
1091                 }
1092
1093                 arg.str = field;
1094                 ret = dynevent_arg_add(cmd, &arg, NULL);
1095                 if (ret)
1096                         break;
1097         }
1098         va_end(args);
1099
1100         return ret;
1101 }
1102 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1103
1104 /**
1105  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1106  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1107  * @...: Variable number of arg (pairs), one pair for each field
1108  *
1109  * NOTE: Users normally won't want to call this function directly, but
1110  * rather use the kprobe_event_add_fields() wrapper, which
1111  * automatically adds a NULL to the end of the arg list.  If this
1112  * function is used directly, make sure the last arg in the variable
1113  * arg list is NULL.
1114  *
1115  * Add probe fields to an existing kprobe command using a variable
1116  * list of args.  Fields are added in the same order they're listed.
1117  *
1118  * Return: 0 if successful, error otherwise.
1119  */
1120 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1121 {
1122         struct dynevent_arg arg;
1123         va_list args;
1124         int ret = 0;
1125
1126         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1127                 return -EINVAL;
1128
1129         dynevent_arg_init(&arg, 0);
1130
1131         va_start(args, cmd);
1132         for (;;) {
1133                 const char *field;
1134
1135                 field = va_arg(args, const char *);
1136                 if (!field)
1137                         break;
1138
1139                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1140                         ret = -EINVAL;
1141                         break;
1142                 }
1143
1144                 arg.str = field;
1145                 ret = dynevent_arg_add(cmd, &arg, NULL);
1146                 if (ret)
1147                         break;
1148         }
1149         va_end(args);
1150
1151         return ret;
1152 }
1153 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1154
1155 /**
1156  * kprobe_event_delete - Delete a kprobe event
1157  * @name: The name of the kprobe event to delete
1158  *
1159  * Delete a kprobe event with the give @name from kernel code rather
1160  * than directly from the command line.
1161  *
1162  * Return: 0 if successful, error otherwise.
1163  */
1164 int kprobe_event_delete(const char *name)
1165 {
1166         char buf[MAX_EVENT_NAME_LEN];
1167
1168         snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1169
1170         return create_or_delete_trace_kprobe(buf);
1171 }
1172 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1173
1174 static int trace_kprobe_release(struct dyn_event *ev)
1175 {
1176         struct trace_kprobe *tk = to_trace_kprobe(ev);
1177         int ret = unregister_trace_kprobe(tk);
1178
1179         if (!ret)
1180                 free_trace_kprobe(tk);
1181         return ret;
1182 }
1183
1184 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1185 {
1186         struct trace_kprobe *tk = to_trace_kprobe(ev);
1187         int i;
1188
1189         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1190         if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1191                 seq_printf(m, "%d", tk->rp.maxactive);
1192         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1193                                 trace_probe_name(&tk->tp));
1194
1195         if (!tk->symbol)
1196                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1197         else if (tk->rp.kp.offset)
1198                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1199                            tk->rp.kp.offset);
1200         else
1201                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1202
1203         for (i = 0; i < tk->tp.nr_args; i++)
1204                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1205         seq_putc(m, '\n');
1206
1207         return 0;
1208 }
1209
1210 static int probes_seq_show(struct seq_file *m, void *v)
1211 {
1212         struct dyn_event *ev = v;
1213
1214         if (!is_trace_kprobe(ev))
1215                 return 0;
1216
1217         return trace_kprobe_show(m, ev);
1218 }
1219
1220 static const struct seq_operations probes_seq_op = {
1221         .start  = dyn_event_seq_start,
1222         .next   = dyn_event_seq_next,
1223         .stop   = dyn_event_seq_stop,
1224         .show   = probes_seq_show
1225 };
1226
1227 static int probes_open(struct inode *inode, struct file *file)
1228 {
1229         int ret;
1230
1231         ret = security_locked_down(LOCKDOWN_TRACEFS);
1232         if (ret)
1233                 return ret;
1234
1235         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1236                 ret = dyn_events_release_all(&trace_kprobe_ops);
1237                 if (ret < 0)
1238                         return ret;
1239         }
1240
1241         return seq_open(file, &probes_seq_op);
1242 }
1243
1244 static ssize_t probes_write(struct file *file, const char __user *buffer,
1245                             size_t count, loff_t *ppos)
1246 {
1247         return trace_parse_run_command(file, buffer, count, ppos,
1248                                        create_or_delete_trace_kprobe);
1249 }
1250
1251 static const struct file_operations kprobe_events_ops = {
1252         .owner          = THIS_MODULE,
1253         .open           = probes_open,
1254         .read           = seq_read,
1255         .llseek         = seq_lseek,
1256         .release        = seq_release,
1257         .write          = probes_write,
1258 };
1259
1260 static unsigned long trace_kprobe_missed(struct trace_kprobe *tk)
1261 {
1262         return trace_kprobe_is_return(tk) ?
1263                 tk->rp.kp.nmissed + tk->rp.nmissed : tk->rp.kp.nmissed;
1264 }
1265
1266 /* Probes profiling interfaces */
1267 static int probes_profile_seq_show(struct seq_file *m, void *v)
1268 {
1269         struct dyn_event *ev = v;
1270         struct trace_kprobe *tk;
1271         unsigned long nmissed;
1272
1273         if (!is_trace_kprobe(ev))
1274                 return 0;
1275
1276         tk = to_trace_kprobe(ev);
1277         nmissed = trace_kprobe_missed(tk);
1278         seq_printf(m, "  %-44s %15lu %15lu\n",
1279                    trace_probe_name(&tk->tp),
1280                    trace_kprobe_nhit(tk),
1281                    nmissed);
1282
1283         return 0;
1284 }
1285
1286 static const struct seq_operations profile_seq_op = {
1287         .start  = dyn_event_seq_start,
1288         .next   = dyn_event_seq_next,
1289         .stop   = dyn_event_seq_stop,
1290         .show   = probes_profile_seq_show
1291 };
1292
1293 static int profile_open(struct inode *inode, struct file *file)
1294 {
1295         int ret;
1296
1297         ret = security_locked_down(LOCKDOWN_TRACEFS);
1298         if (ret)
1299                 return ret;
1300
1301         return seq_open(file, &profile_seq_op);
1302 }
1303
1304 static const struct file_operations kprobe_profile_ops = {
1305         .owner          = THIS_MODULE,
1306         .open           = profile_open,
1307         .read           = seq_read,
1308         .llseek         = seq_lseek,
1309         .release        = seq_release,
1310 };
1311
1312 /* Note that we don't verify it, since the code does not come from user space */
1313 static int
1314 process_fetch_insn(struct fetch_insn *code, void *rec, void *edata,
1315                    void *dest, void *base)
1316 {
1317         struct pt_regs *regs = rec;
1318         unsigned long val;
1319         int ret;
1320
1321 retry:
1322         /* 1st stage: get value from context */
1323         switch (code->op) {
1324         case FETCH_OP_REG:
1325                 val = regs_get_register(regs, code->param);
1326                 break;
1327         case FETCH_OP_STACK:
1328                 val = regs_get_kernel_stack_nth(regs, code->param);
1329                 break;
1330         case FETCH_OP_STACKP:
1331                 val = kernel_stack_pointer(regs);
1332                 break;
1333         case FETCH_OP_RETVAL:
1334                 val = regs_return_value(regs);
1335                 break;
1336 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1337         case FETCH_OP_ARG:
1338                 val = regs_get_kernel_argument(regs, code->param);
1339                 break;
1340         case FETCH_OP_EDATA:
1341                 val = *(unsigned long *)((unsigned long)edata + code->offset);
1342                 break;
1343 #endif
1344         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1345                 code++;
1346                 goto retry;
1347         default:
1348                 ret = process_common_fetch_insn(code, &val);
1349                 if (ret < 0)
1350                         return ret;
1351         }
1352         code++;
1353
1354         return process_fetch_insn_bottom(code, val, dest, base);
1355 }
1356 NOKPROBE_SYMBOL(process_fetch_insn)
1357
1358 /* Kprobe handler */
1359 static nokprobe_inline void
1360 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1361                     struct trace_event_file *trace_file)
1362 {
1363         struct kprobe_trace_entry_head *entry;
1364         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1365         struct trace_event_buffer fbuffer;
1366         int dsize;
1367
1368         WARN_ON(call != trace_file->event_call);
1369
1370         if (trace_trigger_soft_disabled(trace_file))
1371                 return;
1372
1373         dsize = __get_data_size(&tk->tp, regs, NULL);
1374
1375         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1376                                            sizeof(*entry) + tk->tp.size + dsize);
1377         if (!entry)
1378                 return;
1379
1380         fbuffer.regs = regs;
1381         entry->ip = (unsigned long)tk->rp.kp.addr;
1382         store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1383
1384         trace_event_buffer_commit(&fbuffer);
1385 }
1386
1387 static void
1388 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1389 {
1390         struct event_file_link *link;
1391
1392         trace_probe_for_each_link_rcu(link, &tk->tp)
1393                 __kprobe_trace_func(tk, regs, link->file);
1394 }
1395 NOKPROBE_SYMBOL(kprobe_trace_func);
1396
1397 /* Kretprobe handler */
1398
1399 static int trace_kprobe_entry_handler(struct kretprobe_instance *ri,
1400                                       struct pt_regs *regs)
1401 {
1402         struct kretprobe *rp = get_kretprobe(ri);
1403         struct trace_kprobe *tk;
1404
1405         /*
1406          * There is a small chance that get_kretprobe(ri) returns NULL when
1407          * the kretprobe is unregister on another CPU between kretprobe's
1408          * trampoline_handler and this function.
1409          */
1410         if (unlikely(!rp))
1411                 return -ENOENT;
1412
1413         tk = container_of(rp, struct trace_kprobe, rp);
1414
1415         /* store argument values into ri->data as entry data */
1416         if (tk->tp.entry_arg)
1417                 store_trace_entry_data(ri->data, &tk->tp, regs);
1418
1419         return 0;
1420 }
1421
1422
1423 static nokprobe_inline void
1424 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1425                        struct pt_regs *regs,
1426                        struct trace_event_file *trace_file)
1427 {
1428         struct kretprobe_trace_entry_head *entry;
1429         struct trace_event_buffer fbuffer;
1430         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1431         int dsize;
1432
1433         WARN_ON(call != trace_file->event_call);
1434
1435         if (trace_trigger_soft_disabled(trace_file))
1436                 return;
1437
1438         dsize = __get_data_size(&tk->tp, regs, ri->data);
1439
1440         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
1441                                            sizeof(*entry) + tk->tp.size + dsize);
1442         if (!entry)
1443                 return;
1444
1445         fbuffer.regs = regs;
1446         entry->func = (unsigned long)tk->rp.kp.addr;
1447         entry->ret_ip = get_kretprobe_retaddr(ri);
1448         store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1449
1450         trace_event_buffer_commit(&fbuffer);
1451 }
1452
1453 static void
1454 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1455                      struct pt_regs *regs)
1456 {
1457         struct event_file_link *link;
1458
1459         trace_probe_for_each_link_rcu(link, &tk->tp)
1460                 __kretprobe_trace_func(tk, ri, regs, link->file);
1461 }
1462 NOKPROBE_SYMBOL(kretprobe_trace_func);
1463
1464 /* Event entry printers */
1465 static enum print_line_t
1466 print_kprobe_event(struct trace_iterator *iter, int flags,
1467                    struct trace_event *event)
1468 {
1469         struct kprobe_trace_entry_head *field;
1470         struct trace_seq *s = &iter->seq;
1471         struct trace_probe *tp;
1472
1473         field = (struct kprobe_trace_entry_head *)iter->ent;
1474         tp = trace_probe_primary_from_call(
1475                 container_of(event, struct trace_event_call, event));
1476         if (WARN_ON_ONCE(!tp))
1477                 goto out;
1478
1479         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1480
1481         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1482                 goto out;
1483
1484         trace_seq_putc(s, ')');
1485
1486         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1487                              (u8 *)&field[1], field) < 0)
1488                 goto out;
1489
1490         trace_seq_putc(s, '\n');
1491  out:
1492         return trace_handle_return(s);
1493 }
1494
1495 static enum print_line_t
1496 print_kretprobe_event(struct trace_iterator *iter, int flags,
1497                       struct trace_event *event)
1498 {
1499         struct kretprobe_trace_entry_head *field;
1500         struct trace_seq *s = &iter->seq;
1501         struct trace_probe *tp;
1502
1503         field = (struct kretprobe_trace_entry_head *)iter->ent;
1504         tp = trace_probe_primary_from_call(
1505                 container_of(event, struct trace_event_call, event));
1506         if (WARN_ON_ONCE(!tp))
1507                 goto out;
1508
1509         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1510
1511         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1512                 goto out;
1513
1514         trace_seq_puts(s, " <- ");
1515
1516         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1517                 goto out;
1518
1519         trace_seq_putc(s, ')');
1520
1521         if (trace_probe_print_args(s, tp->args, tp->nr_args,
1522                              (u8 *)&field[1], field) < 0)
1523                 goto out;
1524
1525         trace_seq_putc(s, '\n');
1526
1527  out:
1528         return trace_handle_return(s);
1529 }
1530
1531
1532 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1533 {
1534         int ret;
1535         struct kprobe_trace_entry_head field;
1536         struct trace_probe *tp;
1537
1538         tp = trace_probe_primary_from_call(event_call);
1539         if (WARN_ON_ONCE(!tp))
1540                 return -ENOENT;
1541
1542         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1543
1544         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1545 }
1546
1547 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1548 {
1549         int ret;
1550         struct kretprobe_trace_entry_head field;
1551         struct trace_probe *tp;
1552
1553         tp = trace_probe_primary_from_call(event_call);
1554         if (WARN_ON_ONCE(!tp))
1555                 return -ENOENT;
1556
1557         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1558         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1559
1560         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1561 }
1562
1563 #ifdef CONFIG_PERF_EVENTS
1564
1565 /* Kprobe profile handler */
1566 static int
1567 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1568 {
1569         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1570         struct kprobe_trace_entry_head *entry;
1571         struct hlist_head *head;
1572         int size, __size, dsize;
1573         int rctx;
1574
1575         if (bpf_prog_array_valid(call)) {
1576                 unsigned long orig_ip = instruction_pointer(regs);
1577                 int ret;
1578
1579                 ret = trace_call_bpf(call, regs);
1580
1581                 /*
1582                  * We need to check and see if we modified the pc of the
1583                  * pt_regs, and if so return 1 so that we don't do the
1584                  * single stepping.
1585                  */
1586                 if (orig_ip != instruction_pointer(regs))
1587                         return 1;
1588                 if (!ret)
1589                         return 0;
1590         }
1591
1592         head = this_cpu_ptr(call->perf_events);
1593         if (hlist_empty(head))
1594                 return 0;
1595
1596         dsize = __get_data_size(&tk->tp, regs, NULL);
1597         __size = sizeof(*entry) + tk->tp.size + dsize;
1598         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1599         size -= sizeof(u32);
1600
1601         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1602         if (!entry)
1603                 return 0;
1604
1605         entry->ip = (unsigned long)tk->rp.kp.addr;
1606         memset(&entry[1], 0, dsize);
1607         store_trace_args(&entry[1], &tk->tp, regs, NULL, sizeof(*entry), dsize);
1608         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1609                               head, NULL);
1610         return 0;
1611 }
1612 NOKPROBE_SYMBOL(kprobe_perf_func);
1613
1614 /* Kretprobe profile handler */
1615 static void
1616 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1617                     struct pt_regs *regs)
1618 {
1619         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1620         struct kretprobe_trace_entry_head *entry;
1621         struct hlist_head *head;
1622         int size, __size, dsize;
1623         int rctx;
1624
1625         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1626                 return;
1627
1628         head = this_cpu_ptr(call->perf_events);
1629         if (hlist_empty(head))
1630                 return;
1631
1632         dsize = __get_data_size(&tk->tp, regs, ri->data);
1633         __size = sizeof(*entry) + tk->tp.size + dsize;
1634         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1635         size -= sizeof(u32);
1636
1637         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1638         if (!entry)
1639                 return;
1640
1641         entry->func = (unsigned long)tk->rp.kp.addr;
1642         entry->ret_ip = get_kretprobe_retaddr(ri);
1643         store_trace_args(&entry[1], &tk->tp, regs, ri->data, sizeof(*entry), dsize);
1644         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1645                               head, NULL);
1646 }
1647 NOKPROBE_SYMBOL(kretprobe_perf_func);
1648
1649 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1650                         const char **symbol, u64 *probe_offset,
1651                         u64 *probe_addr, unsigned long *missed,
1652                         bool perf_type_tracepoint)
1653 {
1654         const char *pevent = trace_event_name(event->tp_event);
1655         const char *group = event->tp_event->class->system;
1656         struct trace_kprobe *tk;
1657
1658         if (perf_type_tracepoint)
1659                 tk = find_trace_kprobe(pevent, group);
1660         else
1661                 tk = trace_kprobe_primary_from_call(event->tp_event);
1662         if (!tk)
1663                 return -EINVAL;
1664
1665         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1666                                               : BPF_FD_TYPE_KPROBE;
1667         *probe_offset = tk->rp.kp.offset;
1668         *probe_addr = kallsyms_show_value(current_cred()) ?
1669                       (unsigned long)tk->rp.kp.addr : 0;
1670         *symbol = tk->symbol;
1671         if (missed)
1672                 *missed = trace_kprobe_missed(tk);
1673         return 0;
1674 }
1675 #endif  /* CONFIG_PERF_EVENTS */
1676
1677 /*
1678  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1679  *
1680  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1681  * lockless, but we can't race with this __init function.
1682  */
1683 static int kprobe_register(struct trace_event_call *event,
1684                            enum trace_reg type, void *data)
1685 {
1686         struct trace_event_file *file = data;
1687
1688         switch (type) {
1689         case TRACE_REG_REGISTER:
1690                 return enable_trace_kprobe(event, file);
1691         case TRACE_REG_UNREGISTER:
1692                 return disable_trace_kprobe(event, file);
1693
1694 #ifdef CONFIG_PERF_EVENTS
1695         case TRACE_REG_PERF_REGISTER:
1696                 return enable_trace_kprobe(event, NULL);
1697         case TRACE_REG_PERF_UNREGISTER:
1698                 return disable_trace_kprobe(event, NULL);
1699         case TRACE_REG_PERF_OPEN:
1700         case TRACE_REG_PERF_CLOSE:
1701         case TRACE_REG_PERF_ADD:
1702         case TRACE_REG_PERF_DEL:
1703                 return 0;
1704 #endif
1705         }
1706         return 0;
1707 }
1708
1709 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1710 {
1711         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1712         int ret = 0;
1713
1714         raw_cpu_inc(*tk->nhit);
1715
1716         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1717                 kprobe_trace_func(tk, regs);
1718 #ifdef CONFIG_PERF_EVENTS
1719         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1720                 ret = kprobe_perf_func(tk, regs);
1721 #endif
1722         return ret;
1723 }
1724 NOKPROBE_SYMBOL(kprobe_dispatcher);
1725
1726 static int
1727 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1728 {
1729         struct kretprobe *rp = get_kretprobe(ri);
1730         struct trace_kprobe *tk;
1731
1732         /*
1733          * There is a small chance that get_kretprobe(ri) returns NULL when
1734          * the kretprobe is unregister on another CPU between kretprobe's
1735          * trampoline_handler and this function.
1736          */
1737         if (unlikely(!rp))
1738                 return 0;
1739
1740         tk = container_of(rp, struct trace_kprobe, rp);
1741         raw_cpu_inc(*tk->nhit);
1742
1743         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1744                 kretprobe_trace_func(tk, ri, regs);
1745 #ifdef CONFIG_PERF_EVENTS
1746         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1747                 kretprobe_perf_func(tk, ri, regs);
1748 #endif
1749         return 0;       /* We don't tweak kernel, so just return 0 */
1750 }
1751 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1752
1753 static struct trace_event_functions kretprobe_funcs = {
1754         .trace          = print_kretprobe_event
1755 };
1756
1757 static struct trace_event_functions kprobe_funcs = {
1758         .trace          = print_kprobe_event
1759 };
1760
1761 static struct trace_event_fields kretprobe_fields_array[] = {
1762         { .type = TRACE_FUNCTION_TYPE,
1763           .define_fields = kretprobe_event_define_fields },
1764         {}
1765 };
1766
1767 static struct trace_event_fields kprobe_fields_array[] = {
1768         { .type = TRACE_FUNCTION_TYPE,
1769           .define_fields = kprobe_event_define_fields },
1770         {}
1771 };
1772
1773 static inline void init_trace_event_call(struct trace_kprobe *tk)
1774 {
1775         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1776
1777         if (trace_kprobe_is_return(tk)) {
1778                 call->event.funcs = &kretprobe_funcs;
1779                 call->class->fields_array = kretprobe_fields_array;
1780         } else {
1781                 call->event.funcs = &kprobe_funcs;
1782                 call->class->fields_array = kprobe_fields_array;
1783         }
1784
1785         call->flags = TRACE_EVENT_FL_KPROBE;
1786         call->class->reg = kprobe_register;
1787 }
1788
1789 static int register_kprobe_event(struct trace_kprobe *tk)
1790 {
1791         init_trace_event_call(tk);
1792
1793         return trace_probe_register_event_call(&tk->tp);
1794 }
1795
1796 static int unregister_kprobe_event(struct trace_kprobe *tk)
1797 {
1798         return trace_probe_unregister_event_call(&tk->tp);
1799 }
1800
1801 #ifdef CONFIG_PERF_EVENTS
1802
1803 /* create a trace_kprobe, but don't add it to global lists */
1804 struct trace_event_call *
1805 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1806                           bool is_return)
1807 {
1808         enum probe_print_type ptype;
1809         struct trace_kprobe *tk;
1810         int ret;
1811         char *event;
1812
1813         if (func) {
1814                 unsigned int count;
1815
1816                 count = number_of_same_symbols(func);
1817                 if (count > 1)
1818                         /*
1819                          * Users should use addr to remove the ambiguity of
1820                          * using func only.
1821                          */
1822                         return ERR_PTR(-EADDRNOTAVAIL);
1823                 else if (count == 0)
1824                         /*
1825                          * We can return ENOENT earlier than when register the
1826                          * kprobe.
1827                          */
1828                         return ERR_PTR(-ENOENT);
1829         }
1830
1831         /*
1832          * local trace_kprobes are not added to dyn_event, so they are never
1833          * searched in find_trace_kprobe(). Therefore, there is no concern of
1834          * duplicated name here.
1835          */
1836         event = func ? func : "DUMMY_EVENT";
1837
1838         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1839                                 offs, 0 /* maxactive */, 0 /* nargs */,
1840                                 is_return);
1841
1842         if (IS_ERR(tk)) {
1843                 pr_info("Failed to allocate trace_probe.(%d)\n",
1844                         (int)PTR_ERR(tk));
1845                 return ERR_CAST(tk);
1846         }
1847
1848         init_trace_event_call(tk);
1849
1850         ptype = trace_kprobe_is_return(tk) ?
1851                 PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
1852         if (traceprobe_set_print_fmt(&tk->tp, ptype) < 0) {
1853                 ret = -ENOMEM;
1854                 goto error;
1855         }
1856
1857         ret = __register_trace_kprobe(tk);
1858         if (ret < 0)
1859                 goto error;
1860
1861         return trace_probe_event_call(&tk->tp);
1862 error:
1863         free_trace_kprobe(tk);
1864         return ERR_PTR(ret);
1865 }
1866
1867 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1868 {
1869         struct trace_kprobe *tk;
1870
1871         tk = trace_kprobe_primary_from_call(event_call);
1872         if (unlikely(!tk))
1873                 return;
1874
1875         if (trace_probe_is_enabled(&tk->tp)) {
1876                 WARN_ON(1);
1877                 return;
1878         }
1879
1880         __unregister_trace_kprobe(tk);
1881
1882         free_trace_kprobe(tk);
1883 }
1884 #endif /* CONFIG_PERF_EVENTS */
1885
1886 static __init void enable_boot_kprobe_events(void)
1887 {
1888         struct trace_array *tr = top_trace_array();
1889         struct trace_event_file *file;
1890         struct trace_kprobe *tk;
1891         struct dyn_event *pos;
1892
1893         mutex_lock(&event_mutex);
1894         for_each_trace_kprobe(tk, pos) {
1895                 list_for_each_entry(file, &tr->events, list)
1896                         if (file->event_call == trace_probe_event_call(&tk->tp))
1897                                 trace_event_enable_disable(file, 1, 0);
1898         }
1899         mutex_unlock(&event_mutex);
1900 }
1901
1902 static __init void setup_boot_kprobe_events(void)
1903 {
1904         char *p, *cmd = kprobe_boot_events_buf;
1905         int ret;
1906
1907         strreplace(kprobe_boot_events_buf, ',', ' ');
1908
1909         while (cmd && *cmd != '\0') {
1910                 p = strchr(cmd, ';');
1911                 if (p)
1912                         *p++ = '\0';
1913
1914                 ret = create_or_delete_trace_kprobe(cmd);
1915                 if (ret)
1916                         pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1917
1918                 cmd = p;
1919         }
1920
1921         enable_boot_kprobe_events();
1922 }
1923
1924 /*
1925  * Register dynevent at core_initcall. This allows kernel to setup kprobe
1926  * events in postcore_initcall without tracefs.
1927  */
1928 static __init int init_kprobe_trace_early(void)
1929 {
1930         int ret;
1931
1932         ret = dyn_event_register(&trace_kprobe_ops);
1933         if (ret)
1934                 return ret;
1935
1936         if (register_module_notifier(&trace_kprobe_module_nb))
1937                 return -EINVAL;
1938
1939         return 0;
1940 }
1941 core_initcall(init_kprobe_trace_early);
1942
1943 /* Make a tracefs interface for controlling probe points */
1944 static __init int init_kprobe_trace(void)
1945 {
1946         int ret;
1947
1948         ret = tracing_init_dentry();
1949         if (ret)
1950                 return 0;
1951
1952         /* Event list interface */
1953         trace_create_file("kprobe_events", TRACE_MODE_WRITE,
1954                           NULL, NULL, &kprobe_events_ops);
1955
1956         /* Profile interface */
1957         trace_create_file("kprobe_profile", TRACE_MODE_READ,
1958                           NULL, NULL, &kprobe_profile_ops);
1959
1960         setup_boot_kprobe_events();
1961
1962         return 0;
1963 }
1964 fs_initcall(init_kprobe_trace);
1965
1966
1967 #ifdef CONFIG_FTRACE_STARTUP_TEST
1968 static __init struct trace_event_file *
1969 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1970 {
1971         struct trace_event_file *file;
1972
1973         list_for_each_entry(file, &tr->events, list)
1974                 if (file->event_call == trace_probe_event_call(&tk->tp))
1975                         return file;
1976
1977         return NULL;
1978 }
1979
1980 /*
1981  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1982  * stage, we can do this lockless.
1983  */
1984 static __init int kprobe_trace_self_tests_init(void)
1985 {
1986         int ret, warn = 0;
1987         int (*target)(int, int, int, int, int, int);
1988         struct trace_kprobe *tk;
1989         struct trace_event_file *file;
1990
1991         if (tracing_is_disabled())
1992                 return -ENODEV;
1993
1994         if (tracing_selftest_disabled)
1995                 return 0;
1996
1997         target = kprobe_trace_selftest_target;
1998
1999         pr_info("Testing kprobe tracing: ");
2000
2001         ret = create_or_delete_trace_kprobe("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)");
2002         if (WARN_ON_ONCE(ret)) {
2003                 pr_warn("error on probing function entry.\n");
2004                 warn++;
2005         } else {
2006                 /* Enable trace point */
2007                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2008                 if (WARN_ON_ONCE(tk == NULL)) {
2009                         pr_warn("error on getting new probe.\n");
2010                         warn++;
2011                 } else {
2012                         file = find_trace_probe_file(tk, top_trace_array());
2013                         if (WARN_ON_ONCE(file == NULL)) {
2014                                 pr_warn("error on getting probe file.\n");
2015                                 warn++;
2016                         } else
2017                                 enable_trace_kprobe(
2018                                         trace_probe_event_call(&tk->tp), file);
2019                 }
2020         }
2021
2022         ret = create_or_delete_trace_kprobe("r:testprobe2 kprobe_trace_selftest_target $retval");
2023         if (WARN_ON_ONCE(ret)) {
2024                 pr_warn("error on probing function return.\n");
2025                 warn++;
2026         } else {
2027                 /* Enable trace point */
2028                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2029                 if (WARN_ON_ONCE(tk == NULL)) {
2030                         pr_warn("error on getting 2nd new probe.\n");
2031                         warn++;
2032                 } else {
2033                         file = find_trace_probe_file(tk, top_trace_array());
2034                         if (WARN_ON_ONCE(file == NULL)) {
2035                                 pr_warn("error on getting probe file.\n");
2036                                 warn++;
2037                         } else
2038                                 enable_trace_kprobe(
2039                                         trace_probe_event_call(&tk->tp), file);
2040                 }
2041         }
2042
2043         if (warn)
2044                 goto end;
2045
2046         ret = target(1, 2, 3, 4, 5, 6);
2047
2048         /*
2049          * Not expecting an error here, the check is only to prevent the
2050          * optimizer from removing the call to target() as otherwise there
2051          * are no side-effects and the call is never performed.
2052          */
2053         if (ret != 21)
2054                 warn++;
2055
2056         /* Disable trace points before removing it */
2057         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2058         if (WARN_ON_ONCE(tk == NULL)) {
2059                 pr_warn("error on getting test probe.\n");
2060                 warn++;
2061         } else {
2062                 if (trace_kprobe_nhit(tk) != 1) {
2063                         pr_warn("incorrect number of testprobe hits\n");
2064                         warn++;
2065                 }
2066
2067                 file = find_trace_probe_file(tk, top_trace_array());
2068                 if (WARN_ON_ONCE(file == NULL)) {
2069                         pr_warn("error on getting probe file.\n");
2070                         warn++;
2071                 } else
2072                         disable_trace_kprobe(
2073                                 trace_probe_event_call(&tk->tp), file);
2074         }
2075
2076         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2077         if (WARN_ON_ONCE(tk == NULL)) {
2078                 pr_warn("error on getting 2nd test probe.\n");
2079                 warn++;
2080         } else {
2081                 if (trace_kprobe_nhit(tk) != 1) {
2082                         pr_warn("incorrect number of testprobe2 hits\n");
2083                         warn++;
2084                 }
2085
2086                 file = find_trace_probe_file(tk, top_trace_array());
2087                 if (WARN_ON_ONCE(file == NULL)) {
2088                         pr_warn("error on getting probe file.\n");
2089                         warn++;
2090                 } else
2091                         disable_trace_kprobe(
2092                                 trace_probe_event_call(&tk->tp), file);
2093         }
2094
2095         ret = create_or_delete_trace_kprobe("-:testprobe");
2096         if (WARN_ON_ONCE(ret)) {
2097                 pr_warn("error on deleting a probe.\n");
2098                 warn++;
2099         }
2100
2101         ret = create_or_delete_trace_kprobe("-:testprobe2");
2102         if (WARN_ON_ONCE(ret)) {
2103                 pr_warn("error on deleting a probe.\n");
2104                 warn++;
2105         }
2106
2107 end:
2108         ret = dyn_events_release_all(&trace_kprobe_ops);
2109         if (WARN_ON_ONCE(ret)) {
2110                 pr_warn("error on cleaning up probes.\n");
2111                 warn++;
2112         }
2113         /*
2114          * Wait for the optimizer work to finish. Otherwise it might fiddle
2115          * with probes in already freed __init text.
2116          */
2117         wait_for_kprobe_optimizer();
2118         if (warn)
2119                 pr_cont("NG: Some tests are failed. Please check them.\n");
2120         else
2121                 pr_cont("OK\n");
2122         return 0;
2123 }
2124
2125 late_initcall(kprobe_trace_self_tests_init);
2126
2127 #endif