kernel/trace/trace_kprobe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Kprobes-based tracing events
   4  *
   5  * Created by Masami Hiramatsu <mhiramat@redhat.com>
   6  *
   7  */
   8 #define pr_fmt(fmt)     "trace_kprobe: " fmt
   9
  10 #include <linux/security.h>
  11 #include <linux/module.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/rculist.h>
  14 #include <linux/error-injection.h>
  15
  16 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
  17
  18 #include "trace_dynevent.h"
  19 #include "trace_kprobe_selftest.h"
  20 #include "trace_probe.h"
  21 #include "trace_probe_tmpl.h"
  22
  23 #define KPROBE_EVENT_SYSTEM "kprobes"
  24 #define KRETPROBE_MAXACTIVE_MAX 4096
  25
  26 /* Kprobe early definition from command line */
  27 static char kprobe_boot_events_buf[COMMAND_LINE_SIZE] __initdata;
  28 static bool kprobe_boot_events_enabled __initdata;
  29
  30 static int __init set_kprobe_boot_events(char *str)
  31 {
  32         strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
  33         return 0;
  34 }
  35 __setup("kprobe_event=", set_kprobe_boot_events);
  36
  37 static int trace_kprobe_create(int argc, const char **argv);
  38 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev);
  39 static int trace_kprobe_release(struct dyn_event *ev);
  40 static bool trace_kprobe_is_busy(struct dyn_event *ev);
  41 static bool trace_kprobe_match(const char *system, const char *event,
  42                         int argc, const char **argv, struct dyn_event *ev);
  43
  44 static struct dyn_event_operations trace_kprobe_ops = {
  45         .create = trace_kprobe_create,
  46         .show = trace_kprobe_show,
  47         .is_busy = trace_kprobe_is_busy,
  48         .free = trace_kprobe_release,
  49         .match = trace_kprobe_match,
  50 };
  51
  52 /*
  53  * Kprobe event core functions
  54  */
  55 struct trace_kprobe {
  56         struct dyn_event        devent;
  57         struct kretprobe        rp;     /* Use rp.kp for kprobe use */
  58         unsigned long __percpu *nhit;
  59         const char              *symbol;        /* symbol name */
  60         struct trace_probe      tp;
  61 };
  62
  63 static bool is_trace_kprobe(struct dyn_event *ev)
  64 {
  65         return ev->ops == &trace_kprobe_ops;
  66 }
  67
  68 static struct trace_kprobe *to_trace_kprobe(struct dyn_event *ev)
  69 {
  70         return container_of(ev, struct trace_kprobe, devent);
  71 }
  72
  73 /**
  74  * for_each_trace_kprobe - iterate over the trace_kprobe list
  75  * @pos:        the struct trace_kprobe * for each entry
  76  * @dpos:       the struct dyn_event * to use as a loop cursor
  77  */
  78 #define for_each_trace_kprobe(pos, dpos)        \
  79         for_each_dyn_event(dpos)                \
  80                 if (is_trace_kprobe(dpos) && (pos = to_trace_kprobe(dpos)))
  81
  82 #define SIZEOF_TRACE_KPROBE(n)                          \
  83         (offsetof(struct trace_kprobe, tp.args) +       \
  84         (sizeof(struct probe_arg) * (n)))
  85
  86 static nokprobe_inline bool trace_kprobe_is_return(struct trace_kprobe *tk)
  87 {
  88         return tk->rp.handler != NULL;
  89 }
  90
  91 static nokprobe_inline const char *trace_kprobe_symbol(struct trace_kprobe *tk)
  92 {
  93         return tk->symbol ? tk->symbol : "unknown";
  94 }
  95
  96 static nokprobe_inline unsigned long trace_kprobe_offset(struct trace_kprobe *tk)
  97 {
  98         return tk->rp.kp.offset;
  99 }
 100
 101 static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk)
 102 {
 103         return !!(kprobe_gone(&tk->rp.kp));
 104 }
 105
 106 static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk,
 107                                                  struct module *mod)
 108 {
 109         int len = strlen(mod->name);
 110         const char *name = trace_kprobe_symbol(tk);
 111         return strncmp(mod->name, name, len) == 0 && name[len] == ':';
 112 }
 113
 114 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 115 {
 116         char *p;
 117         bool ret;
 118
 119         if (!tk->symbol)
 120                 return false;
 121         p = strchr(tk->symbol, ':');
 122         if (!p)
 123                 return true;
 124         *p = '\0';
 125         mutex_lock(&module_mutex);
 126         ret = !!find_module(tk->symbol);
 127         mutex_unlock(&module_mutex);
 128         *p = ':';
 129
 130         return ret;
 131 }
 132
 133 static bool trace_kprobe_is_busy(struct dyn_event *ev)
 134 {
 135         struct trace_kprobe *tk = to_trace_kprobe(ev);
 136
 137         return trace_probe_is_enabled(&tk->tp);
 138 }
 139
 140 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
 141                                             int argc, const char **argv)
 142 {
 143         char buf[MAX_ARGSTR_LEN + 1];
 144
 145         if (!argc)
 146                 return true;
 147
 148         if (!tk->symbol)
 149                 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
 150         else if (tk->rp.kp.offset)
 151                 snprintf(buf, sizeof(buf), "%s+%u",
 152                          trace_kprobe_symbol(tk), tk->rp.kp.offset);
 153         else
 154                 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
 155         if (strcmp(buf, argv[0]))
 156                 return false;
 157         argc--; argv++;
 158
 159         return trace_probe_match_command_args(&tk->tp, argc, argv);
 160 }
 161
 162 static bool trace_kprobe_match(const char *system, const char *event,
 163                         int argc, const char **argv, struct dyn_event *ev)
 164 {
 165         struct trace_kprobe *tk = to_trace_kprobe(ev);
 166
 167         return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
 168             (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
 169             trace_kprobe_match_command_head(tk, argc, argv);
 170 }
 171
 172 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 173 {
 174         unsigned long nhit = 0;
 175         int cpu;
 176
 177         for_each_possible_cpu(cpu)
 178                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 179
 180         return nhit;
 181 }
 182
 183 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
 184 {
 185         return !(list_empty(&tk->rp.kp.list) &&
 186                  hlist_unhashed(&tk->rp.kp.hlist));
 187 }
 188
 189 /* Return 0 if it fails to find the symbol address */
 190 static nokprobe_inline
 191 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 192 {
 193         unsigned long addr;
 194
 195         if (tk->symbol) {
 196                 addr = (unsigned long)
 197                         kallsyms_lookup_name(trace_kprobe_symbol(tk));
 198                 if (addr)
 199                         addr += tk->rp.kp.offset;
 200         } else {
 201                 addr = (unsigned long)tk->rp.kp.addr;
 202         }
 203         return addr;
 204 }
 205
 206 static nokprobe_inline struct trace_kprobe *
 207 trace_kprobe_primary_from_call(struct trace_event_call *call)
 208 {
 209         struct trace_probe *tp;
 210
 211         tp = trace_probe_primary_from_call(call);
 212         if (WARN_ON_ONCE(!tp))
 213                 return NULL;
 214
 215         return container_of(tp, struct trace_kprobe, tp);
 216 }
 217
 218 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 219 {
 220         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 221
 222         return tk ? kprobe_on_func_entry(tk->rp.kp.addr,
 223                         tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
 224                         tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false;
 225 }
 226
 227 bool trace_kprobe_error_injectable(struct trace_event_call *call)
 228 {
 229         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 230
 231         return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
 232                false;
 233 }
 234
 235 static int register_kprobe_event(struct trace_kprobe *tk);
 236 static int unregister_kprobe_event(struct trace_kprobe *tk);
 237
 238 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 239 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 240                                 struct pt_regs *regs);
 241
 242 static void free_trace_kprobe(struct trace_kprobe *tk)
 243 {
 244         if (tk) {
 245                 trace_probe_cleanup(&tk->tp);
 246                 kfree(tk->symbol);
 247                 free_percpu(tk->nhit);
 248                 kfree(tk);
 249         }
 250 }
 251
 252 /*
 253  * Allocate new trace_probe and initialize it (including kprobes).
 254  */
 255 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 256                                              const char *event,
 257                                              void *addr,
 258                                              const char *symbol,
 259                                              unsigned long offs,
 260                                              int maxactive,
 261                                              int nargs, bool is_return)
 262 {
 263         struct trace_kprobe *tk;
 264         int ret = -ENOMEM;
 265
 266         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 267         if (!tk)
 268                 return ERR_PTR(ret);
 269
 270         tk->nhit = alloc_percpu(unsigned long);
 271         if (!tk->nhit)
 272                 goto error;
 273
 274         if (symbol) {
 275                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 276                 if (!tk->symbol)
 277                         goto error;
 278                 tk->rp.kp.symbol_name = tk->symbol;
 279                 tk->rp.kp.offset = offs;
 280         } else
 281                 tk->rp.kp.addr = addr;
 282
 283         if (is_return)
 284                 tk->rp.handler = kretprobe_dispatcher;
 285         else
 286                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 287
 288         tk->rp.maxactive = maxactive;
 289         INIT_HLIST_NODE(&tk->rp.kp.hlist);
 290         INIT_LIST_HEAD(&tk->rp.kp.list);
 291
 292         ret = trace_probe_init(&tk->tp, event, group, false);
 293         if (ret < 0)
 294                 goto error;
 295
 296         dyn_event_init(&tk->devent, &trace_kprobe_ops);
 297         return tk;
 298 error:
 299         free_trace_kprobe(tk);
 300         return ERR_PTR(ret);
 301 }
 302
 303 static struct trace_kprobe *find_trace_kprobe(const char *event,
 304                                               const char *group)
 305 {
 306         struct dyn_event *pos;
 307         struct trace_kprobe *tk;
 308
 309         for_each_trace_kprobe(tk, pos)
 310                 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
 311                     strcmp(trace_probe_group_name(&tk->tp), group) == 0)
 312                         return tk;
 313         return NULL;
 314 }
 315
 316 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
 317 {
 318         int ret = 0;
 319
 320         if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
 321                 if (trace_kprobe_is_return(tk))
 322                         ret = enable_kretprobe(&tk->rp);
 323                 else
 324                         ret = enable_kprobe(&tk->rp.kp);
 325         }
 326
 327         return ret;
 328 }
 329
 330 static void __disable_trace_kprobe(struct trace_probe *tp)
 331 {
 332         struct trace_probe *pos;
 333         struct trace_kprobe *tk;
 334
 335         list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
 336                 tk = container_of(pos, struct trace_kprobe, tp);
 337                 if (!trace_kprobe_is_registered(tk))
 338                         continue;
 339                 if (trace_kprobe_is_return(tk))
 340                         disable_kretprobe(&tk->rp);
 341                 else
 342                         disable_kprobe(&tk->rp.kp);
 343         }
 344 }
 345
 346 /*
 347  * Enable trace_probe
 348  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 349  */
 350 static int enable_trace_kprobe(struct trace_event_call *call,
 351                                 struct trace_event_file *file)
 352 {
 353         struct trace_probe *pos, *tp;
 354         struct trace_kprobe *tk;
 355         bool enabled;
 356         int ret = 0;
 357
 358         tp = trace_probe_primary_from_call(call);
 359         if (WARN_ON_ONCE(!tp))
 360                 return -ENODEV;
 361         enabled = trace_probe_is_enabled(tp);
 362
 363         /* This also changes "enabled" state */
 364         if (file) {
 365                 ret = trace_probe_add_file(tp, file);
 366                 if (ret)
 367                         return ret;
 368         } else
 369                 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
 370
 371         if (enabled)
 372                 return 0;
 373
 374         list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
 375                 tk = container_of(pos, struct trace_kprobe, tp);
 376                 if (trace_kprobe_has_gone(tk))
 377                         continue;
 378                 ret = __enable_trace_kprobe(tk);
 379                 if (ret)
 380                         break;
 381                 enabled = true;
 382         }
 383
 384         if (ret) {
 385                 /* Failed to enable one of them. Roll back all */
 386                 if (enabled)
 387                         __disable_trace_kprobe(tp);
 388                 if (file)
 389                         trace_probe_remove_file(tp, file);
 390                 else
 391                         trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 392         }
 393
 394         return ret;
 395 }
 396
 397 /*
 398  * Disable trace_probe
 399  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 400  */
 401 static int disable_trace_kprobe(struct trace_event_call *call,
 402                                 struct trace_event_file *file)
 403 {
 404         struct trace_probe *tp;
 405
 406         tp = trace_probe_primary_from_call(call);
 407         if (WARN_ON_ONCE(!tp))
 408                 return -ENODEV;
 409
 410         if (file) {
 411                 if (!trace_probe_get_file_link(tp, file))
 412                         return -ENOENT;
 413                 if (!trace_probe_has_single_file(tp))
 414                         goto out;
 415                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
 416         } else
 417                 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 418
 419         if (!trace_probe_is_enabled(tp))
 420                 __disable_trace_kprobe(tp);
 421
 422  out:
 423         if (file)
 424                 /*
 425                  * Synchronization is done in below function. For perf event,
 426                  * file == NULL and perf_trace_event_unreg() calls
 427                  * tracepoint_synchronize_unregister() to ensure synchronize
 428                  * event. We don't need to care about it.
 429                  */
 430                 trace_probe_remove_file(tp, file);
 431
 432         return 0;
 433 }
 434
 435 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
 436         !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
 437 static bool __within_notrace_func(unsigned long addr)
 438 {
 439         unsigned long offset, size;
 440
 441         if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
 442                 return false;
 443
 444         /* Get the entry address of the target function */
 445         addr -= offset;
 446
 447         /*
 448          * Since ftrace_location_range() does inclusive range check, we need
 449          * to subtract 1 byte from the end address.
 450          */
 451         return !ftrace_location_range(addr, addr + size - 1);
 452 }
 453
 454 static bool within_notrace_func(struct trace_kprobe *tk)
 455 {
 456         unsigned long addr = trace_kprobe_address(tk);
 457         char symname[KSYM_NAME_LEN], *p;
 458
 459         if (!__within_notrace_func(addr))
 460                 return false;
 461
 462         /* Check if the address is on a suffixed-symbol */
 463         if (!lookup_symbol_name(addr, symname)) {
 464                 p = strchr(symname, '.');
 465                 if (!p)
 466                         return true;
 467                 *p = '\0';
 468                 addr = (unsigned long)kprobe_lookup_name(symname, 0);
 469                 if (addr)
 470                         return __within_notrace_func(addr);
 471         }
 472
 473         return true;
 474 }
 475 #else
 476 #define within_notrace_func(tk) (false)
 477 #endif
 478
 479 /* Internal register function - just handle k*probes and flags */
 480 static int __register_trace_kprobe(struct trace_kprobe *tk)
 481 {
 482         int i, ret;
 483
 484         ret = security_locked_down(LOCKDOWN_KPROBES);
 485         if (ret)
 486                 return ret;
 487
 488         if (trace_kprobe_is_registered(tk))
 489                 return -EINVAL;
 490
 491         if (within_notrace_func(tk)) {
 492                 pr_warn("Could not probe notrace function %s\n",
 493                         trace_kprobe_symbol(tk));
 494                 return -EINVAL;
 495         }
 496
 497         for (i = 0; i < tk->tp.nr_args; i++) {
 498                 ret = traceprobe_update_arg(&tk->tp.args[i]);
 499                 if (ret)
 500                         return ret;
 501         }
 502
 503         /* Set/clear disabled flag according to tp->flag */
 504         if (trace_probe_is_enabled(&tk->tp))
 505                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 506         else
 507                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 508
 509         if (trace_kprobe_is_return(tk))
 510                 ret = register_kretprobe(&tk->rp);
 511         else
 512                 ret = register_kprobe(&tk->rp.kp);
 513
 514         return ret;
 515 }
 516
 517 /* Internal unregister function - just handle k*probes and flags */
 518 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 519 {
 520         if (trace_kprobe_is_registered(tk)) {
 521                 if (trace_kprobe_is_return(tk))
 522                         unregister_kretprobe(&tk->rp);
 523                 else
 524                         unregister_kprobe(&tk->rp.kp);
 525                 /* Cleanup kprobe for reuse and mark it unregistered */
 526                 INIT_HLIST_NODE(&tk->rp.kp.hlist);
 527                 INIT_LIST_HEAD(&tk->rp.kp.list);
 528                 if (tk->rp.kp.symbol_name)
 529                         tk->rp.kp.addr = NULL;
 530         }
 531 }
 532
 533 /* Unregister a trace_probe and probe_event */
 534 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 535 {
 536         /* If other probes are on the event, just unregister kprobe */
 537         if (trace_probe_has_sibling(&tk->tp))
 538                 goto unreg;
 539
 540         /* Enabled event can not be unregistered */
 541         if (trace_probe_is_enabled(&tk->tp))
 542                 return -EBUSY;
 543
 544         /* Will fail if probe is being used by ftrace or perf */
 545         if (unregister_kprobe_event(tk))
 546                 return -EBUSY;
 547
 548 unreg:
 549         __unregister_trace_kprobe(tk);
 550         dyn_event_remove(&tk->devent);
 551         trace_probe_unlink(&tk->tp);
 552
 553         return 0;
 554 }
 555
 556 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
 557                                          struct trace_kprobe *comp)
 558 {
 559         struct trace_probe_event *tpe = orig->tp.event;
 560         struct trace_probe *pos;
 561         int i;
 562
 563         list_for_each_entry(pos, &tpe->probes, list) {
 564                 orig = container_of(pos, struct trace_kprobe, tp);
 565                 if (strcmp(trace_kprobe_symbol(orig),
 566                            trace_kprobe_symbol(comp)) ||
 567                     trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
 568                         continue;
 569
 570                 /*
 571                  * trace_probe_compare_arg_type() ensured that nr_args and
 572                  * each argument name and type are same. Let's compare comm.
 573                  */
 574                 for (i = 0; i < orig->tp.nr_args; i++) {
 575                         if (strcmp(orig->tp.args[i].comm,
 576                                    comp->tp.args[i].comm))
 577                                 break;
 578                 }
 579
 580                 if (i == orig->tp.nr_args)
 581                         return true;
 582         }
 583
 584         return false;
 585 }
 586
 587 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
 588 {
 589         int ret;
 590
 591         ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
 592         if (ret) {
 593                 /* Note that argument starts index = 2 */
 594                 trace_probe_log_set_index(ret + 1);
 595                 trace_probe_log_err(0, DIFF_ARG_TYPE);
 596                 return -EEXIST;
 597         }
 598         if (trace_kprobe_has_same_kprobe(to, tk)) {
 599                 trace_probe_log_set_index(0);
 600                 trace_probe_log_err(0, SAME_PROBE);
 601                 return -EEXIST;
 602         }
 603
 604         /* Append to existing event */
 605         ret = trace_probe_append(&tk->tp, &to->tp);
 606         if (ret)
 607                 return ret;
 608
 609         /* Register k*probe */
 610         ret = __register_trace_kprobe(tk);
 611         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 612                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 613                 ret = 0;
 614         }
 615
 616         if (ret)
 617                 trace_probe_unlink(&tk->tp);
 618         else
 619                 dyn_event_add(&tk->devent);
 620
 621         return ret;
 622 }
 623
 624 /* Register a trace_probe and probe_event */
 625 static int register_trace_kprobe(struct trace_kprobe *tk)
 626 {
 627         struct trace_kprobe *old_tk;
 628         int ret;
 629
 630         mutex_lock(&event_mutex);
 631
 632         old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
 633                                    trace_probe_group_name(&tk->tp));
 634         if (old_tk) {
 635                 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
 636                         trace_probe_log_set_index(0);
 637                         trace_probe_log_err(0, DIFF_PROBE_TYPE);
 638                         ret = -EEXIST;
 639                 } else {
 640                         ret = append_trace_kprobe(tk, old_tk);
 641                 }
 642                 goto end;
 643         }
 644
 645         /* Register new event */
 646         ret = register_kprobe_event(tk);
 647         if (ret) {
 648                 pr_warn("Failed to register probe event(%d)\n", ret);
 649                 goto end;
 650         }
 651
 652         /* Register k*probe */
 653         ret = __register_trace_kprobe(tk);
 654         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 655                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 656                 ret = 0;
 657         }
 658
 659         if (ret < 0)
 660                 unregister_kprobe_event(tk);
 661         else
 662                 dyn_event_add(&tk->devent);
 663
 664 end:
 665         mutex_unlock(&event_mutex);
 666         return ret;
 667 }
 668
 669 /* Module notifier call back, checking event on the module */
 670 static int trace_kprobe_module_callback(struct notifier_block *nb,
 671                                        unsigned long val, void *data)
 672 {
 673         struct module *mod = data;
 674         struct dyn_event *pos;
 675         struct trace_kprobe *tk;
 676         int ret;
 677
 678         if (val != MODULE_STATE_COMING)
 679                 return NOTIFY_DONE;
 680
 681         /* Update probes on coming module */
 682         mutex_lock(&event_mutex);
 683         for_each_trace_kprobe(tk, pos) {
 684                 if (trace_kprobe_within_module(tk, mod)) {
 685                         /* Don't need to check busy - this should have gone. */
 686                         __unregister_trace_kprobe(tk);
 687                         ret = __register_trace_kprobe(tk);
 688                         if (ret)
 689                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 690                                         trace_probe_name(&tk->tp),
 691                                         mod->name, ret);
 692                 }
 693         }
 694         mutex_unlock(&event_mutex);
 695
 696         return NOTIFY_DONE;
 697 }
 698
 699 static struct notifier_block trace_kprobe_module_nb = {
 700         .notifier_call = trace_kprobe_module_callback,
 701         .priority = 1   /* Invoked after kprobe module callback */
 702 };
 703
 704 /* Convert certain expected symbols into '_' when generating event names */
 705 static inline void sanitize_event_name(char *name)
 706 {
 707         while (*name++ != '\0')
 708                 if (*name == ':' || *name == '.')
 709                         *name = '_';
 710 }
 711
 712 static int trace_kprobe_create(int argc, const char *argv[])
 713 {
 714         /*
 715          * Argument syntax:
 716          *  - Add kprobe:
 717          *      p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 718          *  - Add kretprobe:
 719          *      r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 720          * Fetch args:
 721          *  $retval     : fetch return value
 722          *  $stack      : fetch stack address
 723          *  $stackN     : fetch Nth of stack (N:0-)
 724          *  $comm       : fetch current task comm
 725          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 726          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 727          *  %REG        : fetch register REG
 728          * Dereferencing memory fetch:
 729          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 730          * Alias name of args:
 731          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 732          * Type of args:
 733          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 734          */
 735         struct trace_kprobe *tk = NULL;
 736         int i, len, ret = 0;
 737         bool is_return = false;
 738         char *symbol = NULL, *tmp = NULL;
 739         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 740         int maxactive = 0;
 741         long offset = 0;
 742         void *addr = NULL;
 743         char buf[MAX_EVENT_NAME_LEN];
 744         unsigned int flags = TPARG_FL_KERNEL;
 745
 746         switch (argv[0][0]) {
 747         case 'r':
 748                 is_return = true;
 749                 flags |= TPARG_FL_RETURN;
 750                 break;
 751         case 'p':
 752                 break;
 753         default:
 754                 return -ECANCELED;
 755         }
 756         if (argc < 2)
 757                 return -ECANCELED;
 758
 759         trace_probe_log_init("trace_kprobe", argc, argv);
 760
 761         event = strchr(&argv[0][1], ':');
 762         if (event)
 763                 event++;
 764
 765         if (isdigit(argv[0][1])) {
 766                 if (!is_return) {
 767                         trace_probe_log_err(1, MAXACT_NO_KPROBE);
 768                         goto parse_error;
 769                 }
 770                 if (event)
 771                         len = event - &argv[0][1] - 1;
 772                 else
 773                         len = strlen(&argv[0][1]);
 774                 if (len > MAX_EVENT_NAME_LEN - 1) {
 775                         trace_probe_log_err(1, BAD_MAXACT);
 776                         goto parse_error;
 777                 }
 778                 memcpy(buf, &argv[0][1], len);
 779                 buf[len] = '\0';
 780                 ret = kstrtouint(buf, 0, &maxactive);
 781                 if (ret || !maxactive) {
 782                         trace_probe_log_err(1, BAD_MAXACT);
 783                         goto parse_error;
 784                 }
 785                 /* kretprobes instances are iterated over via a list. The
 786                  * maximum should stay reasonable.
 787                  */
 788                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 789                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 790                         goto parse_error;
 791                 }
 792         }
 793
 794         /* try to parse an address. if that fails, try to read the
 795          * input as a symbol. */
 796         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 797                 trace_probe_log_set_index(1);
 798                 /* Check whether uprobe event specified */
 799                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 800                         ret = -ECANCELED;
 801                         goto error;
 802                 }
 803                 /* a symbol specified */
 804                 symbol = kstrdup(argv[1], GFP_KERNEL);
 805                 if (!symbol)
 806                         return -ENOMEM;
 807                 /* TODO: support .init module functions */
 808                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 809                 if (ret || offset < 0 || offset > UINT_MAX) {
 810                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 811                         goto parse_error;
 812                 }
 813                 if (kprobe_on_func_entry(NULL, symbol, offset))
 814                         flags |= TPARG_FL_FENTRY;
 815                 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
 816                         trace_probe_log_err(0, BAD_RETPROBE);
 817                         goto parse_error;
 818                 }
 819         }
 820
 821         trace_probe_log_set_index(0);
 822         if (event) {
 823                 ret = traceprobe_parse_event_name(&event, &group, buf,
 824                                                   event - argv[0]);
 825                 if (ret)
 826                         goto parse_error;
 827         } else {
 828                 /* Make a new event name */
 829                 if (symbol)
 830                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 831                                  is_return ? 'r' : 'p', symbol, offset);
 832                 else
 833                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 834                                  is_return ? 'r' : 'p', addr);
 835                 sanitize_event_name(buf);
 836                 event = buf;
 837         }
 838
 839         /* setup a probe */
 840         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 841                                argc - 2, is_return);
 842         if (IS_ERR(tk)) {
 843                 ret = PTR_ERR(tk);
 844                 /* This must return -ENOMEM, else there is a bug */
 845                 WARN_ON_ONCE(ret != -ENOMEM);
 846                 goto out;       /* We know tk is not allocated */
 847         }
 848         argc -= 2; argv += 2;
 849
 850         /* parse arguments */
 851         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 852                 tmp = kstrdup(argv[i], GFP_KERNEL);
 853                 if (!tmp) {
 854                         ret = -ENOMEM;
 855                         goto error;
 856                 }
 857
 858                 trace_probe_log_set_index(i + 2);
 859                 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
 860                 kfree(tmp);
 861                 if (ret)
 862                         goto error;     /* This can be -ENOMEM */
 863         }
 864
 865         ret = traceprobe_set_print_fmt(&tk->tp, is_return);
 866         if (ret < 0)
 867                 goto error;
 868
 869         ret = register_trace_kprobe(tk);
 870         if (ret) {
 871                 trace_probe_log_set_index(1);
 872                 if (ret == -EILSEQ)
 873                         trace_probe_log_err(0, BAD_INSN_BNDRY);
 874                 else if (ret == -ENOENT)
 875                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 876                 else if (ret != -ENOMEM && ret != -EEXIST)
 877                         trace_probe_log_err(0, FAIL_REG_PROBE);
 878                 goto error;
 879         }
 880
 881 out:
 882         trace_probe_log_clear();
 883         kfree(symbol);
 884         return ret;
 885
 886 parse_error:
 887         ret = -EINVAL;
 888 error:
 889         free_trace_kprobe(tk);
 890         goto out;
 891 }
 892
 893 static int create_or_delete_trace_kprobe(int argc, char **argv)
 894 {
 895         int ret;
 896
 897         if (argv[0][0] == '-')
 898                 return dyn_event_release(argc, argv, &trace_kprobe_ops);
 899
 900         ret = trace_kprobe_create(argc, (const char **)argv);
 901         return ret == -ECANCELED ? -EINVAL : ret;
 902 }
 903
 904 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
 905 {
 906         return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe);
 907 }
 908
 909 /**
 910  * kprobe_event_cmd_init - Initialize a kprobe event command object
 911  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 912  * @buf: A pointer to the buffer used to build the command
 913  * @maxlen: The length of the buffer passed in @buf
 914  *
 915  * Initialize a synthetic event command object.  Use this before
 916  * calling any of the other kprobe_event functions.
 917  */
 918 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
 919 {
 920         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
 921                           trace_kprobe_run_command);
 922 }
 923 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
 924
 925 /**
 926  * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
 927  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 928  * @name: The name of the kprobe event
 929  * @loc: The location of the kprobe event
 930  * @kretprobe: Is this a return probe?
 931  * @args: Variable number of arg (pairs), one pair for each field
 932  *
 933  * NOTE: Users normally won't want to call this function directly, but
 934  * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
 935  * adds a NULL to the end of the arg list.  If this function is used
 936  * directly, make sure the last arg in the variable arg list is NULL.
 937  *
 938  * Generate a kprobe event command to be executed by
 939  * kprobe_event_gen_cmd_end().  This function can be used to generate the
 940  * complete command or only the first part of it; in the latter case,
 941  * kprobe_event_add_fields() can be used to add more fields following this.
 942  *
 943  * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
 944  * returns -EINVAL if @loc == NULL.
 945  *
 946  * Return: 0 if successful, error otherwise.
 947  */
 948 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
 949                                  const char *name, const char *loc, ...)
 950 {
 951         char buf[MAX_EVENT_NAME_LEN];
 952         struct dynevent_arg arg;
 953         va_list args;
 954         int ret;
 955
 956         if (cmd->type != DYNEVENT_TYPE_KPROBE)
 957                 return -EINVAL;
 958
 959         if (!loc)
 960                 return -EINVAL;
 961
 962         if (kretprobe)
 963                 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
 964         else
 965                 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
 966
 967         ret = dynevent_str_add(cmd, buf);
 968         if (ret)
 969                 return ret;
 970
 971         dynevent_arg_init(&arg, 0);
 972         arg.str = loc;
 973         ret = dynevent_arg_add(cmd, &arg, NULL);
 974         if (ret)
 975                 return ret;
 976
 977         va_start(args, loc);
 978         for (;;) {
 979                 const char *field;
 980
 981                 field = va_arg(args, const char *);
 982                 if (!field)
 983                         break;
 984
 985                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
 986                         ret = -EINVAL;
 987                         break;
 988                 }
 989
 990                 arg.str = field;
 991                 ret = dynevent_arg_add(cmd, &arg, NULL);
 992                 if (ret)
 993                         break;
 994         }
 995         va_end(args);
 996
 997         return ret;
 998 }
 999 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1000
1001 /**
1002  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1003  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1004  * @args: Variable number of arg (pairs), one pair for each field
1005  *
1006  * NOTE: Users normally won't want to call this function directly, but
1007  * rather use the kprobe_event_add_fields() wrapper, which
1008  * automatically adds a NULL to the end of the arg list.  If this
1009  * function is used directly, make sure the last arg in the variable
1010  * arg list is NULL.
1011  *
1012  * Add probe fields to an existing kprobe command using a variable
1013  * list of args.  Fields are added in the same order they're listed.
1014  *
1015  * Return: 0 if successful, error otherwise.
1016  */
1017 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1018 {
1019         struct dynevent_arg arg;
1020         va_list args;
1021         int ret = 0;
1022
1023         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1024                 return -EINVAL;
1025
1026         dynevent_arg_init(&arg, 0);
1027
1028         va_start(args, cmd);
1029         for (;;) {
1030                 const char *field;
1031
1032                 field = va_arg(args, const char *);
1033                 if (!field)
1034                         break;
1035
1036                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1037                         ret = -EINVAL;
1038                         break;
1039                 }
1040
1041                 arg.str = field;
1042                 ret = dynevent_arg_add(cmd, &arg, NULL);
1043                 if (ret)
1044                         break;
1045         }
1046         va_end(args);
1047
1048         return ret;
1049 }
1050 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1051
1052 /**
1053  * kprobe_event_delete - Delete a kprobe event
1054  * @name: The name of the kprobe event to delete
1055  *
1056  * Delete a kprobe event with the give @name from kernel code rather
1057  * than directly from the command line.
1058  *
1059  * Return: 0 if successful, error otherwise.
1060  */
1061 int kprobe_event_delete(const char *name)
1062 {
1063         char buf[MAX_EVENT_NAME_LEN];
1064
1065         snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1066
1067         return trace_run_command(buf, create_or_delete_trace_kprobe);
1068 }
1069 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1070
1071 static int trace_kprobe_release(struct dyn_event *ev)
1072 {
1073         struct trace_kprobe *tk = to_trace_kprobe(ev);
1074         int ret = unregister_trace_kprobe(tk);
1075
1076         if (!ret)
1077                 free_trace_kprobe(tk);
1078         return ret;
1079 }
1080
1081 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1082 {
1083         struct trace_kprobe *tk = to_trace_kprobe(ev);
1084         int i;
1085
1086         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1087         if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1088                 seq_printf(m, "%d", tk->rp.maxactive);
1089         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1090                                 trace_probe_name(&tk->tp));
1091
1092         if (!tk->symbol)
1093                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1094         else if (tk->rp.kp.offset)
1095                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1096                            tk->rp.kp.offset);
1097         else
1098                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1099
1100         for (i = 0; i < tk->tp.nr_args; i++)
1101                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1102         seq_putc(m, '\n');
1103
1104         return 0;
1105 }
1106
1107 static int probes_seq_show(struct seq_file *m, void *v)
1108 {
1109         struct dyn_event *ev = v;
1110
1111         if (!is_trace_kprobe(ev))
1112                 return 0;
1113
1114         return trace_kprobe_show(m, ev);
1115 }
1116
1117 static const struct seq_operations probes_seq_op = {
1118         .start  = dyn_event_seq_start,
1119         .next   = dyn_event_seq_next,
1120         .stop   = dyn_event_seq_stop,
1121         .show   = probes_seq_show
1122 };
1123
1124 static int probes_open(struct inode *inode, struct file *file)
1125 {
1126         int ret;
1127
1128         ret = security_locked_down(LOCKDOWN_TRACEFS);
1129         if (ret)
1130                 return ret;
1131
1132         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1133                 ret = dyn_events_release_all(&trace_kprobe_ops);
1134                 if (ret < 0)
1135                         return ret;
1136         }
1137
1138         return seq_open(file, &probes_seq_op);
1139 }
1140
1141 static ssize_t probes_write(struct file *file, const char __user *buffer,
1142                             size_t count, loff_t *ppos)
1143 {
1144         return trace_parse_run_command(file, buffer, count, ppos,
1145                                        create_or_delete_trace_kprobe);
1146 }
1147
1148 static const struct file_operations kprobe_events_ops = {
1149         .owner          = THIS_MODULE,
1150         .open           = probes_open,
1151         .read           = seq_read,
1152         .llseek         = seq_lseek,
1153         .release        = seq_release,
1154         .write          = probes_write,
1155 };
1156
1157 /* Probes profiling interfaces */
1158 static int probes_profile_seq_show(struct seq_file *m, void *v)
1159 {
1160         struct dyn_event *ev = v;
1161         struct trace_kprobe *tk;
1162
1163         if (!is_trace_kprobe(ev))
1164                 return 0;
1165
1166         tk = to_trace_kprobe(ev);
1167         seq_printf(m, "  %-44s %15lu %15lu\n",
1168                    trace_probe_name(&tk->tp),
1169                    trace_kprobe_nhit(tk),
1170                    tk->rp.kp.nmissed);
1171
1172         return 0;
1173 }
1174
1175 static const struct seq_operations profile_seq_op = {
1176         .start  = dyn_event_seq_start,
1177         .next   = dyn_event_seq_next,
1178         .stop   = dyn_event_seq_stop,
1179         .show   = probes_profile_seq_show
1180 };
1181
1182 static int profile_open(struct inode *inode, struct file *file)
1183 {
1184         int ret;
1185
1186         ret = security_locked_down(LOCKDOWN_TRACEFS);
1187         if (ret)
1188                 return ret;
1189
1190         return seq_open(file, &profile_seq_op);
1191 }
1192
1193 static const struct file_operations kprobe_profile_ops = {
1194         .owner          = THIS_MODULE,
1195         .open           = profile_open,
1196         .read           = seq_read,
1197         .llseek         = seq_lseek,
1198         .release        = seq_release,
1199 };
1200
1201 /* Kprobe specific fetch functions */
1202
1203 /* Return the length of string -- including null terminal byte */
1204 static nokprobe_inline int
1205 fetch_store_strlen(unsigned long addr)
1206 {
1207         int ret, len = 0;
1208         u8 c;
1209
1210         do {
1211                 ret = probe_kernel_read(&c, (u8 *)addr + len, 1);
1212                 len++;
1213         } while (c && ret == 0 && len < MAX_STRING_SIZE);
1214
1215         return (ret < 0) ? ret : len;
1216 }
1217
1218 /* Return the length of string -- including null terminal byte */
1219 static nokprobe_inline int
1220 fetch_store_strlen_user(unsigned long addr)
1221 {
1222         const void __user *uaddr =  (__force const void __user *)addr;
1223
1224         return strnlen_unsafe_user(uaddr, MAX_STRING_SIZE);
1225 }
1226
1227 /*
1228  * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1229  * length and relative data location.
1230  */
1231 static nokprobe_inline int
1232 fetch_store_string(unsigned long addr, void *dest, void *base)
1233 {
1234         int maxlen = get_loc_len(*(u32 *)dest);
1235         void *__dest;
1236         long ret;
1237
1238         if (unlikely(!maxlen))
1239                 return -ENOMEM;
1240
1241         __dest = get_loc_data(dest, base);
1242
1243         /*
1244          * Try to get string again, since the string can be changed while
1245          * probing.
1246          */
1247         ret = strncpy_from_unsafe(__dest, (void *)addr, maxlen);
1248         if (ret >= 0)
1249                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1250
1251         return ret;
1252 }
1253
1254 /*
1255  * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1256  * with max length and relative data location.
1257  */
1258 static nokprobe_inline int
1259 fetch_store_string_user(unsigned long addr, void *dest, void *base)
1260 {
1261         const void __user *uaddr =  (__force const void __user *)addr;
1262         int maxlen = get_loc_len(*(u32 *)dest);
1263         void *__dest;
1264         long ret;
1265
1266         if (unlikely(!maxlen))
1267                 return -ENOMEM;
1268
1269         __dest = get_loc_data(dest, base);
1270
1271         ret = strncpy_from_unsafe_user(__dest, uaddr, maxlen);
1272         if (ret >= 0)
1273                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1274
1275         return ret;
1276 }
1277
1278 static nokprobe_inline int
1279 probe_mem_read(void *dest, void *src, size_t size)
1280 {
1281         return probe_kernel_read(dest, src, size);
1282 }
1283
1284 static nokprobe_inline int
1285 probe_mem_read_user(void *dest, void *src, size_t size)
1286 {
1287         const void __user *uaddr =  (__force const void __user *)src;
1288
1289         return probe_user_read(dest, uaddr, size);
1290 }
1291
1292 /* Note that we don't verify it, since the code does not come from user space */
1293 static int
1294 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
1295                    void *base)
1296 {
1297         unsigned long val;
1298
1299 retry:
1300         /* 1st stage: get value from context */
1301         switch (code->op) {
1302         case FETCH_OP_REG:
1303                 val = regs_get_register(regs, code->param);
1304                 break;
1305         case FETCH_OP_STACK:
1306                 val = regs_get_kernel_stack_nth(regs, code->param);
1307                 break;
1308         case FETCH_OP_STACKP:
1309                 val = kernel_stack_pointer(regs);
1310                 break;
1311         case FETCH_OP_RETVAL:
1312                 val = regs_return_value(regs);
1313                 break;
1314         case FETCH_OP_IMM:
1315                 val = code->immediate;
1316                 break;
1317         case FETCH_OP_COMM:
1318                 val = (unsigned long)current->comm;
1319                 break;
1320         case FETCH_OP_DATA:
1321                 val = (unsigned long)code->data;
1322                 break;
1323 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1324         case FETCH_OP_ARG:
1325                 val = regs_get_kernel_argument(regs, code->param);
1326                 break;
1327 #endif
1328         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1329                 code++;
1330                 goto retry;
1331         default:
1332                 return -EILSEQ;
1333         }
1334         code++;
1335
1336         return process_fetch_insn_bottom(code, val, dest, base);
1337 }
1338 NOKPROBE_SYMBOL(process_fetch_insn)
1339
1340 /* Kprobe handler */
1341 static nokprobe_inline void
1342 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1343                     struct trace_event_file *trace_file)
1344 {
1345         struct kprobe_trace_entry_head *entry;
1346         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1347         struct trace_event_buffer fbuffer;
1348         int dsize;
1349
1350         WARN_ON(call != trace_file->event_call);
1351
1352         if (trace_trigger_soft_disabled(trace_file))
1353                 return;
1354
1355         local_save_flags(fbuffer.flags);
1356         fbuffer.pc = preempt_count();
1357         fbuffer.trace_file = trace_file;
1358
1359         dsize = __get_data_size(&tk->tp, regs);
1360
1361         fbuffer.event =
1362                 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1363                                         call->event.type,
1364                                         sizeof(*entry) + tk->tp.size + dsize,
1365                                         fbuffer.flags, fbuffer.pc);
1366         if (!fbuffer.event)
1367                 return;
1368
1369         fbuffer.regs = regs;
1370         entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1371         entry->ip = (unsigned long)tk->rp.kp.addr;
1372         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1373
1374         trace_event_buffer_commit(&fbuffer);
1375 }
1376
1377 static void
1378 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1379 {
1380         struct event_file_link *link;
1381
1382         trace_probe_for_each_link_rcu(link, &tk->tp)
1383                 __kprobe_trace_func(tk, regs, link->file);
1384 }
1385 NOKPROBE_SYMBOL(kprobe_trace_func);
1386
1387 /* Kretprobe handler */
1388 static nokprobe_inline void
1389 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1390                        struct pt_regs *regs,
1391                        struct trace_event_file *trace_file)
1392 {
1393         struct kretprobe_trace_entry_head *entry;
1394         struct trace_event_buffer fbuffer;
1395         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1396         int dsize;
1397
1398         WARN_ON(call != trace_file->event_call);
1399
1400         if (trace_trigger_soft_disabled(trace_file))
1401                 return;
1402
1403         local_save_flags(fbuffer.flags);
1404         fbuffer.pc = preempt_count();
1405         fbuffer.trace_file = trace_file;
1406
1407         dsize = __get_data_size(&tk->tp, regs);
1408         fbuffer.event =
1409                 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1410                                         call->event.type,
1411                                         sizeof(*entry) + tk->tp.size + dsize,
1412                                         fbuffer.flags, fbuffer.pc);
1413         if (!fbuffer.event)
1414                 return;
1415
1416         fbuffer.regs = regs;
1417         entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1418         entry->func = (unsigned long)tk->rp.kp.addr;
1419         entry->ret_ip = (unsigned long)ri->ret_addr;
1420         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1421
1422         trace_event_buffer_commit(&fbuffer);
1423 }
1424
1425 static void
1426 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1427                      struct pt_regs *regs)
1428 {
1429         struct event_file_link *link;
1430
1431         trace_probe_for_each_link_rcu(link, &tk->tp)
1432                 __kretprobe_trace_func(tk, ri, regs, link->file);
1433 }
1434 NOKPROBE_SYMBOL(kretprobe_trace_func);
1435
1436 /* Event entry printers */
1437 static enum print_line_t
1438 print_kprobe_event(struct trace_iterator *iter, int flags,
1439                    struct trace_event *event)
1440 {
1441         struct kprobe_trace_entry_head *field;
1442         struct trace_seq *s = &iter->seq;
1443         struct trace_probe *tp;
1444
1445         field = (struct kprobe_trace_entry_head *)iter->ent;
1446         tp = trace_probe_primary_from_call(
1447                 container_of(event, struct trace_event_call, event));
1448         if (WARN_ON_ONCE(!tp))
1449                 goto out;
1450
1451         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1452
1453         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1454                 goto out;
1455
1456         trace_seq_putc(s, ')');
1457
1458         if (print_probe_args(s, tp->args, tp->nr_args,
1459                              (u8 *)&field[1], field) < 0)
1460                 goto out;
1461
1462         trace_seq_putc(s, '\n');
1463  out:
1464         return trace_handle_return(s);
1465 }
1466
1467 static enum print_line_t
1468 print_kretprobe_event(struct trace_iterator *iter, int flags,
1469                       struct trace_event *event)
1470 {
1471         struct kretprobe_trace_entry_head *field;
1472         struct trace_seq *s = &iter->seq;
1473         struct trace_probe *tp;
1474
1475         field = (struct kretprobe_trace_entry_head *)iter->ent;
1476         tp = trace_probe_primary_from_call(
1477                 container_of(event, struct trace_event_call, event));
1478         if (WARN_ON_ONCE(!tp))
1479                 goto out;
1480
1481         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1482
1483         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1484                 goto out;
1485
1486         trace_seq_puts(s, " <- ");
1487
1488         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1489                 goto out;
1490
1491         trace_seq_putc(s, ')');
1492
1493         if (print_probe_args(s, tp->args, tp->nr_args,
1494                              (u8 *)&field[1], field) < 0)
1495                 goto out;
1496
1497         trace_seq_putc(s, '\n');
1498
1499  out:
1500         return trace_handle_return(s);
1501 }
1502
1503
1504 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1505 {
1506         int ret;
1507         struct kprobe_trace_entry_head field;
1508         struct trace_probe *tp;
1509
1510         tp = trace_probe_primary_from_call(event_call);
1511         if (WARN_ON_ONCE(!tp))
1512                 return -ENOENT;
1513
1514         DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0);
1515
1516         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1517 }
1518
1519 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1520 {
1521         int ret;
1522         struct kretprobe_trace_entry_head field;
1523         struct trace_probe *tp;
1524
1525         tp = trace_probe_primary_from_call(event_call);
1526         if (WARN_ON_ONCE(!tp))
1527                 return -ENOENT;
1528
1529         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1530         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1531
1532         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1533 }
1534
1535 #ifdef CONFIG_PERF_EVENTS
1536
1537 /* Kprobe profile handler */
1538 static int
1539 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1540 {
1541         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1542         struct kprobe_trace_entry_head *entry;
1543         struct hlist_head *head;
1544         int size, __size, dsize;
1545         int rctx;
1546
1547         if (bpf_prog_array_valid(call)) {
1548                 unsigned long orig_ip = instruction_pointer(regs);
1549                 int ret;
1550
1551                 ret = trace_call_bpf(call, regs);
1552
1553                 /*
1554                  * We need to check and see if we modified the pc of the
1555                  * pt_regs, and if so return 1 so that we don't do the
1556                  * single stepping.
1557                  */
1558                 if (orig_ip != instruction_pointer(regs))
1559                         return 1;
1560                 if (!ret)
1561                         return 0;
1562         }
1563
1564         head = this_cpu_ptr(call->perf_events);
1565         if (hlist_empty(head))
1566                 return 0;
1567
1568         dsize = __get_data_size(&tk->tp, regs);
1569         __size = sizeof(*entry) + tk->tp.size + dsize;
1570         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1571         size -= sizeof(u32);
1572
1573         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1574         if (!entry)
1575                 return 0;
1576
1577         entry->ip = (unsigned long)tk->rp.kp.addr;
1578         memset(&entry[1], 0, dsize);
1579         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1580         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1581                               head, NULL);
1582         return 0;
1583 }
1584 NOKPROBE_SYMBOL(kprobe_perf_func);
1585
1586 /* Kretprobe profile handler */
1587 static void
1588 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1589                     struct pt_regs *regs)
1590 {
1591         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1592         struct kretprobe_trace_entry_head *entry;
1593         struct hlist_head *head;
1594         int size, __size, dsize;
1595         int rctx;
1596
1597         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1598                 return;
1599
1600         head = this_cpu_ptr(call->perf_events);
1601         if (hlist_empty(head))
1602                 return;
1603
1604         dsize = __get_data_size(&tk->tp, regs);
1605         __size = sizeof(*entry) + tk->tp.size + dsize;
1606         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1607         size -= sizeof(u32);
1608
1609         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1610         if (!entry)
1611                 return;
1612
1613         entry->func = (unsigned long)tk->rp.kp.addr;
1614         entry->ret_ip = (unsigned long)ri->ret_addr;
1615         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1616         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1617                               head, NULL);
1618 }
1619 NOKPROBE_SYMBOL(kretprobe_perf_func);
1620
1621 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1622                         const char **symbol, u64 *probe_offset,
1623                         u64 *probe_addr, bool perf_type_tracepoint)
1624 {
1625         const char *pevent = trace_event_name(event->tp_event);
1626         const char *group = event->tp_event->class->system;
1627         struct trace_kprobe *tk;
1628
1629         if (perf_type_tracepoint)
1630                 tk = find_trace_kprobe(pevent, group);
1631         else
1632                 tk = event->tp_event->data;
1633         if (!tk)
1634                 return -EINVAL;
1635
1636         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1637                                               : BPF_FD_TYPE_KPROBE;
1638         if (tk->symbol) {
1639                 *symbol = tk->symbol;
1640                 *probe_offset = tk->rp.kp.offset;
1641                 *probe_addr = 0;
1642         } else {
1643                 *symbol = NULL;
1644                 *probe_offset = 0;
1645                 *probe_addr = (unsigned long)tk->rp.kp.addr;
1646         }
1647         return 0;
1648 }
1649 #endif  /* CONFIG_PERF_EVENTS */
1650
1651 /*
1652  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1653  *
1654  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1655  * lockless, but we can't race with this __init function.
1656  */
1657 static int kprobe_register(struct trace_event_call *event,
1658                            enum trace_reg type, void *data)
1659 {
1660         struct trace_event_file *file = data;
1661
1662         switch (type) {
1663         case TRACE_REG_REGISTER:
1664                 return enable_trace_kprobe(event, file);
1665         case TRACE_REG_UNREGISTER:
1666                 return disable_trace_kprobe(event, file);
1667
1668 #ifdef CONFIG_PERF_EVENTS
1669         case TRACE_REG_PERF_REGISTER:
1670                 return enable_trace_kprobe(event, NULL);
1671         case TRACE_REG_PERF_UNREGISTER:
1672                 return disable_trace_kprobe(event, NULL);
1673         case TRACE_REG_PERF_OPEN:
1674         case TRACE_REG_PERF_CLOSE:
1675         case TRACE_REG_PERF_ADD:
1676         case TRACE_REG_PERF_DEL:
1677                 return 0;
1678 #endif
1679         }
1680         return 0;
1681 }
1682
1683 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1684 {
1685         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1686         int ret = 0;
1687
1688         raw_cpu_inc(*tk->nhit);
1689
1690         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1691                 kprobe_trace_func(tk, regs);
1692 #ifdef CONFIG_PERF_EVENTS
1693         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1694                 ret = kprobe_perf_func(tk, regs);
1695 #endif
1696         return ret;
1697 }
1698 NOKPROBE_SYMBOL(kprobe_dispatcher);
1699
1700 static int
1701 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1702 {
1703         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1704
1705         raw_cpu_inc(*tk->nhit);
1706
1707         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1708                 kretprobe_trace_func(tk, ri, regs);
1709 #ifdef CONFIG_PERF_EVENTS
1710         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1711                 kretprobe_perf_func(tk, ri, regs);
1712 #endif
1713         return 0;       /* We don't tweek kernel, so just return 0 */
1714 }
1715 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1716
1717 static struct trace_event_functions kretprobe_funcs = {
1718         .trace          = print_kretprobe_event
1719 };
1720
1721 static struct trace_event_functions kprobe_funcs = {
1722         .trace          = print_kprobe_event
1723 };
1724
1725 static struct trace_event_fields kretprobe_fields_array[] = {
1726         { .type = TRACE_FUNCTION_TYPE,
1727           .define_fields = kretprobe_event_define_fields },
1728         {}
1729 };
1730
1731 static struct trace_event_fields kprobe_fields_array[] = {
1732         { .type = TRACE_FUNCTION_TYPE,
1733           .define_fields = kprobe_event_define_fields },
1734         {}
1735 };
1736
1737 static inline void init_trace_event_call(struct trace_kprobe *tk)
1738 {
1739         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1740
1741         if (trace_kprobe_is_return(tk)) {
1742                 call->event.funcs = &kretprobe_funcs;
1743                 call->class->fields_array = kretprobe_fields_array;
1744         } else {
1745                 call->event.funcs = &kprobe_funcs;
1746                 call->class->fields_array = kprobe_fields_array;
1747         }
1748
1749         call->flags = TRACE_EVENT_FL_KPROBE;
1750         call->class->reg = kprobe_register;
1751 }
1752
1753 static int register_kprobe_event(struct trace_kprobe *tk)
1754 {
1755         init_trace_event_call(tk);
1756
1757         return trace_probe_register_event_call(&tk->tp);
1758 }
1759
1760 static int unregister_kprobe_event(struct trace_kprobe *tk)
1761 {
1762         return trace_probe_unregister_event_call(&tk->tp);
1763 }
1764
1765 #ifdef CONFIG_PERF_EVENTS
1766 /* create a trace_kprobe, but don't add it to global lists */
1767 struct trace_event_call *
1768 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1769                           bool is_return)
1770 {
1771         struct trace_kprobe *tk;
1772         int ret;
1773         char *event;
1774
1775         /*
1776          * local trace_kprobes are not added to dyn_event, so they are never
1777          * searched in find_trace_kprobe(). Therefore, there is no concern of
1778          * duplicated name here.
1779          */
1780         event = func ? func : "DUMMY_EVENT";
1781
1782         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1783                                 offs, 0 /* maxactive */, 0 /* nargs */,
1784                                 is_return);
1785
1786         if (IS_ERR(tk)) {
1787                 pr_info("Failed to allocate trace_probe.(%d)\n",
1788                         (int)PTR_ERR(tk));
1789                 return ERR_CAST(tk);
1790         }
1791
1792         init_trace_event_call(tk);
1793
1794         if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1795                 ret = -ENOMEM;
1796                 goto error;
1797         }
1798
1799         ret = __register_trace_kprobe(tk);
1800         if (ret < 0)
1801                 goto error;
1802
1803         return trace_probe_event_call(&tk->tp);
1804 error:
1805         free_trace_kprobe(tk);
1806         return ERR_PTR(ret);
1807 }
1808
1809 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1810 {
1811         struct trace_kprobe *tk;
1812
1813         tk = trace_kprobe_primary_from_call(event_call);
1814         if (unlikely(!tk))
1815                 return;
1816
1817         if (trace_probe_is_enabled(&tk->tp)) {
1818                 WARN_ON(1);
1819                 return;
1820         }
1821
1822         __unregister_trace_kprobe(tk);
1823
1824         free_trace_kprobe(tk);
1825 }
1826 #endif /* CONFIG_PERF_EVENTS */
1827
1828 static __init void enable_boot_kprobe_events(void)
1829 {
1830         struct trace_array *tr = top_trace_array();
1831         struct trace_event_file *file;
1832         struct trace_kprobe *tk;
1833         struct dyn_event *pos;
1834
1835         mutex_lock(&event_mutex);
1836         for_each_trace_kprobe(tk, pos) {
1837                 list_for_each_entry(file, &tr->events, list)
1838                         if (file->event_call == trace_probe_event_call(&tk->tp))
1839                                 trace_event_enable_disable(file, 1, 0);
1840         }
1841         mutex_unlock(&event_mutex);
1842 }
1843
1844 static __init void setup_boot_kprobe_events(void)
1845 {
1846         char *p, *cmd = kprobe_boot_events_buf;
1847         int ret;
1848
1849         strreplace(kprobe_boot_events_buf, ',', ' ');
1850
1851         while (cmd && *cmd != '\0') {
1852                 p = strchr(cmd, ';');
1853                 if (p)
1854                         *p++ = '\0';
1855
1856                 ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
1857                 if (ret)
1858                         pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1859                 else
1860                         kprobe_boot_events_enabled = true;
1861
1862                 cmd = p;
1863         }
1864
1865         enable_boot_kprobe_events();
1866 }
1867
1868 /*
1869  * Register dynevent at subsys_initcall. This allows kernel to setup kprobe
1870  * events in fs_initcall without tracefs.
1871  */
1872 static __init int init_kprobe_trace_early(void)
1873 {
1874         int ret;
1875
1876         ret = dyn_event_register(&trace_kprobe_ops);
1877         if (ret)
1878                 return ret;
1879
1880         if (register_module_notifier(&trace_kprobe_module_nb))
1881                 return -EINVAL;
1882
1883         return 0;
1884 }
1885 subsys_initcall(init_kprobe_trace_early);
1886
1887 /* Make a tracefs interface for controlling probe points */
1888 static __init int init_kprobe_trace(void)
1889 {
1890         struct dentry *d_tracer;
1891         struct dentry *entry;
1892
1893         d_tracer = tracing_init_dentry();
1894         if (IS_ERR(d_tracer))
1895                 return 0;
1896
1897         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1898                                     NULL, &kprobe_events_ops);
1899
1900         /* Event list interface */
1901         if (!entry)
1902                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1903
1904         /* Profile interface */
1905         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1906                                     NULL, &kprobe_profile_ops);
1907
1908         if (!entry)
1909                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1910
1911         setup_boot_kprobe_events();
1912
1913         return 0;
1914 }
1915 fs_initcall(init_kprobe_trace);
1916
1917
1918 #ifdef CONFIG_FTRACE_STARTUP_TEST
1919 static __init struct trace_event_file *
1920 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1921 {
1922         struct trace_event_file *file;
1923
1924         list_for_each_entry(file, &tr->events, list)
1925                 if (file->event_call == trace_probe_event_call(&tk->tp))
1926                         return file;
1927
1928         return NULL;
1929 }
1930
1931 /*
1932  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1933  * stage, we can do this lockless.
1934  */
1935 static __init int kprobe_trace_self_tests_init(void)
1936 {
1937         int ret, warn = 0;
1938         int (*target)(int, int, int, int, int, int);
1939         struct trace_kprobe *tk;
1940         struct trace_event_file *file;
1941
1942         if (tracing_is_disabled())
1943                 return -ENODEV;
1944
1945         if (kprobe_boot_events_enabled) {
1946                 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n");
1947                 return 0;
1948         }
1949
1950         target = kprobe_trace_selftest_target;
1951
1952         pr_info("Testing kprobe tracing: ");
1953
1954         ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1955                                 create_or_delete_trace_kprobe);
1956         if (WARN_ON_ONCE(ret)) {
1957                 pr_warn("error on probing function entry.\n");
1958                 warn++;
1959         } else {
1960                 /* Enable trace point */
1961                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1962                 if (WARN_ON_ONCE(tk == NULL)) {
1963                         pr_warn("error on getting new probe.\n");
1964                         warn++;
1965                 } else {
1966                         file = find_trace_probe_file(tk, top_trace_array());
1967                         if (WARN_ON_ONCE(file == NULL)) {
1968                                 pr_warn("error on getting probe file.\n");
1969                                 warn++;
1970                         } else
1971                                 enable_trace_kprobe(
1972                                         trace_probe_event_call(&tk->tp), file);
1973                 }
1974         }
1975
1976         ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1977                                 create_or_delete_trace_kprobe);
1978         if (WARN_ON_ONCE(ret)) {
1979                 pr_warn("error on probing function return.\n");
1980                 warn++;
1981         } else {
1982                 /* Enable trace point */
1983                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1984                 if (WARN_ON_ONCE(tk == NULL)) {
1985                         pr_warn("error on getting 2nd new probe.\n");
1986                         warn++;
1987                 } else {
1988                         file = find_trace_probe_file(tk, top_trace_array());
1989                         if (WARN_ON_ONCE(file == NULL)) {
1990                                 pr_warn("error on getting probe file.\n");
1991                                 warn++;
1992                         } else
1993                                 enable_trace_kprobe(
1994                                         trace_probe_event_call(&tk->tp), file);
1995                 }
1996         }
1997
1998         if (warn)
1999                 goto end;
2000
2001         ret = target(1, 2, 3, 4, 5, 6);
2002
2003         /*
2004          * Not expecting an error here, the check is only to prevent the
2005          * optimizer from removing the call to target() as otherwise there
2006          * are no side-effects and the call is never performed.
2007          */
2008         if (ret != 21)
2009                 warn++;
2010
2011         /* Disable trace points before removing it */
2012         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2013         if (WARN_ON_ONCE(tk == NULL)) {
2014                 pr_warn("error on getting test probe.\n");
2015                 warn++;
2016         } else {
2017                 if (trace_kprobe_nhit(tk) != 1) {
2018                         pr_warn("incorrect number of testprobe hits\n");
2019                         warn++;
2020                 }
2021
2022                 file = find_trace_probe_file(tk, top_trace_array());
2023                 if (WARN_ON_ONCE(file == NULL)) {
2024                         pr_warn("error on getting probe file.\n");
2025                         warn++;
2026                 } else
2027                         disable_trace_kprobe(
2028                                 trace_probe_event_call(&tk->tp), file);
2029         }
2030
2031         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2032         if (WARN_ON_ONCE(tk == NULL)) {
2033                 pr_warn("error on getting 2nd test probe.\n");
2034                 warn++;
2035         } else {
2036                 if (trace_kprobe_nhit(tk) != 1) {
2037                         pr_warn("incorrect number of testprobe2 hits\n");
2038                         warn++;
2039                 }
2040
2041                 file = find_trace_probe_file(tk, top_trace_array());
2042                 if (WARN_ON_ONCE(file == NULL)) {
2043                         pr_warn("error on getting probe file.\n");
2044                         warn++;
2045                 } else
2046                         disable_trace_kprobe(
2047                                 trace_probe_event_call(&tk->tp), file);
2048         }
2049
2050         ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
2051         if (WARN_ON_ONCE(ret)) {
2052                 pr_warn("error on deleting a probe.\n");
2053                 warn++;
2054         }
2055
2056         ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
2057         if (WARN_ON_ONCE(ret)) {
2058                 pr_warn("error on deleting a probe.\n");
2059                 warn++;
2060         }
2061
2062 end:
2063         ret = dyn_events_release_all(&trace_kprobe_ops);
2064         if (WARN_ON_ONCE(ret)) {
2065                 pr_warn("error on cleaning up probes.\n");
2066                 warn++;
2067         }
2068         /*
2069          * Wait for the optimizer work to finish. Otherwise it might fiddle
2070          * with probes in already freed __init text.
2071          */
2072         wait_for_kprobe_optimizer();
2073         if (warn)
2074                 pr_cont("NG: Some tests are failed. Please check them.\n");
2075         else
2076                 pr_cont("OK\n");
2077         return 0;
2078 }
2079
2080 late_initcall(kprobe_trace_self_tests_init);
2081
2082 #endif