kernel/trace/trace_kprobe.c

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