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