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(module_name(mod));
 110         const char *name = trace_kprobe_symbol(tk);
 111
 112         return strncmp(module_name(mod), name, len) == 0 && name[len] == ':';
 113 }
 114
 115 static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 116 {
 117         char *p;
 118         bool ret;
 119
 120         if (!tk->symbol)
 121                 return false;
 122         p = strchr(tk->symbol, ':');
 123         if (!p)
 124                 return true;
 125         *p = '\0';
 126         mutex_lock(&module_mutex);
 127         ret = !!find_module(tk->symbol);
 128         mutex_unlock(&module_mutex);
 129         *p = ':';
 130
 131         return ret;
 132 }
 133
 134 static bool trace_kprobe_is_busy(struct dyn_event *ev)
 135 {
 136         struct trace_kprobe *tk = to_trace_kprobe(ev);
 137
 138         return trace_probe_is_enabled(&tk->tp);
 139 }
 140
 141 static bool trace_kprobe_match_command_head(struct trace_kprobe *tk,
 142                                             int argc, const char **argv)
 143 {
 144         char buf[MAX_ARGSTR_LEN + 1];
 145
 146         if (!argc)
 147                 return true;
 148
 149         if (!tk->symbol)
 150                 snprintf(buf, sizeof(buf), "0x%p", tk->rp.kp.addr);
 151         else if (tk->rp.kp.offset)
 152                 snprintf(buf, sizeof(buf), "%s+%u",
 153                          trace_kprobe_symbol(tk), tk->rp.kp.offset);
 154         else
 155                 snprintf(buf, sizeof(buf), "%s", trace_kprobe_symbol(tk));
 156         if (strcmp(buf, argv[0]))
 157                 return false;
 158         argc--; argv++;
 159
 160         return trace_probe_match_command_args(&tk->tp, argc, argv);
 161 }
 162
 163 static bool trace_kprobe_match(const char *system, const char *event,
 164                         int argc, const char **argv, struct dyn_event *ev)
 165 {
 166         struct trace_kprobe *tk = to_trace_kprobe(ev);
 167
 168         return strcmp(trace_probe_name(&tk->tp), event) == 0 &&
 169             (!system || strcmp(trace_probe_group_name(&tk->tp), system) == 0) &&
 170             trace_kprobe_match_command_head(tk, argc, argv);
 171 }
 172
 173 static nokprobe_inline unsigned long trace_kprobe_nhit(struct trace_kprobe *tk)
 174 {
 175         unsigned long nhit = 0;
 176         int cpu;
 177
 178         for_each_possible_cpu(cpu)
 179                 nhit += *per_cpu_ptr(tk->nhit, cpu);
 180
 181         return nhit;
 182 }
 183
 184 static nokprobe_inline bool trace_kprobe_is_registered(struct trace_kprobe *tk)
 185 {
 186         return !(list_empty(&tk->rp.kp.list) &&
 187                  hlist_unhashed(&tk->rp.kp.hlist));
 188 }
 189
 190 /* Return 0 if it fails to find the symbol address */
 191 static nokprobe_inline
 192 unsigned long trace_kprobe_address(struct trace_kprobe *tk)
 193 {
 194         unsigned long addr;
 195
 196         if (tk->symbol) {
 197                 addr = (unsigned long)
 198                         kallsyms_lookup_name(trace_kprobe_symbol(tk));
 199                 if (addr)
 200                         addr += tk->rp.kp.offset;
 201         } else {
 202                 addr = (unsigned long)tk->rp.kp.addr;
 203         }
 204         return addr;
 205 }
 206
 207 static nokprobe_inline struct trace_kprobe *
 208 trace_kprobe_primary_from_call(struct trace_event_call *call)
 209 {
 210         struct trace_probe *tp;
 211
 212         tp = trace_probe_primary_from_call(call);
 213         if (WARN_ON_ONCE(!tp))
 214                 return NULL;
 215
 216         return container_of(tp, struct trace_kprobe, tp);
 217 }
 218
 219 bool trace_kprobe_on_func_entry(struct trace_event_call *call)
 220 {
 221         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 222
 223         return tk ? kprobe_on_func_entry(tk->rp.kp.addr,
 224                         tk->rp.kp.addr ? NULL : tk->rp.kp.symbol_name,
 225                         tk->rp.kp.addr ? 0 : tk->rp.kp.offset) : false;
 226 }
 227
 228 bool trace_kprobe_error_injectable(struct trace_event_call *call)
 229 {
 230         struct trace_kprobe *tk = trace_kprobe_primary_from_call(call);
 231
 232         return tk ? within_error_injection_list(trace_kprobe_address(tk)) :
 233                false;
 234 }
 235
 236 static int register_kprobe_event(struct trace_kprobe *tk);
 237 static int unregister_kprobe_event(struct trace_kprobe *tk);
 238
 239 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 240 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 241                                 struct pt_regs *regs);
 242
 243 static void free_trace_kprobe(struct trace_kprobe *tk)
 244 {
 245         if (tk) {
 246                 trace_probe_cleanup(&tk->tp);
 247                 kfree(tk->symbol);
 248                 free_percpu(tk->nhit);
 249                 kfree(tk);
 250         }
 251 }
 252
 253 /*
 254  * Allocate new trace_probe and initialize it (including kprobes).
 255  */
 256 static struct trace_kprobe *alloc_trace_kprobe(const char *group,
 257                                              const char *event,
 258                                              void *addr,
 259                                              const char *symbol,
 260                                              unsigned long offs,
 261                                              int maxactive,
 262                                              int nargs, bool is_return)
 263 {
 264         struct trace_kprobe *tk;
 265         int ret = -ENOMEM;
 266
 267         tk = kzalloc(SIZEOF_TRACE_KPROBE(nargs), GFP_KERNEL);
 268         if (!tk)
 269                 return ERR_PTR(ret);
 270
 271         tk->nhit = alloc_percpu(unsigned long);
 272         if (!tk->nhit)
 273                 goto error;
 274
 275         if (symbol) {
 276                 tk->symbol = kstrdup(symbol, GFP_KERNEL);
 277                 if (!tk->symbol)
 278                         goto error;
 279                 tk->rp.kp.symbol_name = tk->symbol;
 280                 tk->rp.kp.offset = offs;
 281         } else
 282                 tk->rp.kp.addr = addr;
 283
 284         if (is_return)
 285                 tk->rp.handler = kretprobe_dispatcher;
 286         else
 287                 tk->rp.kp.pre_handler = kprobe_dispatcher;
 288
 289         tk->rp.maxactive = maxactive;
 290         INIT_HLIST_NODE(&tk->rp.kp.hlist);
 291         INIT_LIST_HEAD(&tk->rp.kp.list);
 292
 293         ret = trace_probe_init(&tk->tp, event, group, false);
 294         if (ret < 0)
 295                 goto error;
 296
 297         dyn_event_init(&tk->devent, &trace_kprobe_ops);
 298         return tk;
 299 error:
 300         free_trace_kprobe(tk);
 301         return ERR_PTR(ret);
 302 }
 303
 304 static struct trace_kprobe *find_trace_kprobe(const char *event,
 305                                               const char *group)
 306 {
 307         struct dyn_event *pos;
 308         struct trace_kprobe *tk;
 309
 310         for_each_trace_kprobe(tk, pos)
 311                 if (strcmp(trace_probe_name(&tk->tp), event) == 0 &&
 312                     strcmp(trace_probe_group_name(&tk->tp), group) == 0)
 313                         return tk;
 314         return NULL;
 315 }
 316
 317 static inline int __enable_trace_kprobe(struct trace_kprobe *tk)
 318 {
 319         int ret = 0;
 320
 321         if (trace_kprobe_is_registered(tk) && !trace_kprobe_has_gone(tk)) {
 322                 if (trace_kprobe_is_return(tk))
 323                         ret = enable_kretprobe(&tk->rp);
 324                 else
 325                         ret = enable_kprobe(&tk->rp.kp);
 326         }
 327
 328         return ret;
 329 }
 330
 331 static void __disable_trace_kprobe(struct trace_probe *tp)
 332 {
 333         struct trace_probe *pos;
 334         struct trace_kprobe *tk;
 335
 336         list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
 337                 tk = container_of(pos, struct trace_kprobe, tp);
 338                 if (!trace_kprobe_is_registered(tk))
 339                         continue;
 340                 if (trace_kprobe_is_return(tk))
 341                         disable_kretprobe(&tk->rp);
 342                 else
 343                         disable_kprobe(&tk->rp.kp);
 344         }
 345 }
 346
 347 /*
 348  * Enable trace_probe
 349  * if the file is NULL, enable "perf" handler, or enable "trace" handler.
 350  */
 351 static int enable_trace_kprobe(struct trace_event_call *call,
 352                                 struct trace_event_file *file)
 353 {
 354         struct trace_probe *pos, *tp;
 355         struct trace_kprobe *tk;
 356         bool enabled;
 357         int ret = 0;
 358
 359         tp = trace_probe_primary_from_call(call);
 360         if (WARN_ON_ONCE(!tp))
 361                 return -ENODEV;
 362         enabled = trace_probe_is_enabled(tp);
 363
 364         /* This also changes "enabled" state */
 365         if (file) {
 366                 ret = trace_probe_add_file(tp, file);
 367                 if (ret)
 368                         return ret;
 369         } else
 370                 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
 371
 372         if (enabled)
 373                 return 0;
 374
 375         list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
 376                 tk = container_of(pos, struct trace_kprobe, tp);
 377                 if (trace_kprobe_has_gone(tk))
 378                         continue;
 379                 ret = __enable_trace_kprobe(tk);
 380                 if (ret)
 381                         break;
 382                 enabled = true;
 383         }
 384
 385         if (ret) {
 386                 /* Failed to enable one of them. Roll back all */
 387                 if (enabled)
 388                         __disable_trace_kprobe(tp);
 389                 if (file)
 390                         trace_probe_remove_file(tp, file);
 391                 else
 392                         trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 393         }
 394
 395         return ret;
 396 }
 397
 398 /*
 399  * Disable trace_probe
 400  * if the file is NULL, disable "perf" handler, or disable "trace" handler.
 401  */
 402 static int disable_trace_kprobe(struct trace_event_call *call,
 403                                 struct trace_event_file *file)
 404 {
 405         struct trace_probe *tp;
 406
 407         tp = trace_probe_primary_from_call(call);
 408         if (WARN_ON_ONCE(!tp))
 409                 return -ENODEV;
 410
 411         if (file) {
 412                 if (!trace_probe_get_file_link(tp, file))
 413                         return -ENOENT;
 414                 if (!trace_probe_has_single_file(tp))
 415                         goto out;
 416                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
 417         } else
 418                 trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 419
 420         if (!trace_probe_is_enabled(tp))
 421                 __disable_trace_kprobe(tp);
 422
 423  out:
 424         if (file)
 425                 /*
 426                  * Synchronization is done in below function. For perf event,
 427                  * file == NULL and perf_trace_event_unreg() calls
 428                  * tracepoint_synchronize_unregister() to ensure synchronize
 429                  * event. We don't need to care about it.
 430                  */
 431                 trace_probe_remove_file(tp, file);
 432
 433         return 0;
 434 }
 435
 436 #if defined(CONFIG_KPROBES_ON_FTRACE) && \
 437         !defined(CONFIG_KPROBE_EVENTS_ON_NOTRACE)
 438 static bool __within_notrace_func(unsigned long addr)
 439 {
 440         unsigned long offset, size;
 441
 442         if (!addr || !kallsyms_lookup_size_offset(addr, &size, &offset))
 443                 return false;
 444
 445         /* Get the entry address of the target function */
 446         addr -= offset;
 447
 448         /*
 449          * Since ftrace_location_range() does inclusive range check, we need
 450          * to subtract 1 byte from the end address.
 451          */
 452         return !ftrace_location_range(addr, addr + size - 1);
 453 }
 454
 455 static bool within_notrace_func(struct trace_kprobe *tk)
 456 {
 457         unsigned long addr = trace_kprobe_address(tk);
 458         char symname[KSYM_NAME_LEN], *p;
 459
 460         if (!__within_notrace_func(addr))
 461                 return false;
 462
 463         /* Check if the address is on a suffixed-symbol */
 464         if (!lookup_symbol_name(addr, symname)) {
 465                 p = strchr(symname, '.');
 466                 if (!p)
 467                         return true;
 468                 *p = '\0';
 469                 addr = (unsigned long)kprobe_lookup_name(symname, 0);
 470                 if (addr)
 471                         return __within_notrace_func(addr);
 472         }
 473
 474         return true;
 475 }
 476 #else
 477 #define within_notrace_func(tk) (false)
 478 #endif
 479
 480 /* Internal register function - just handle k*probes and flags */
 481 static int __register_trace_kprobe(struct trace_kprobe *tk)
 482 {
 483         int i, ret;
 484
 485         ret = security_locked_down(LOCKDOWN_KPROBES);
 486         if (ret)
 487                 return ret;
 488
 489         if (trace_kprobe_is_registered(tk))
 490                 return -EINVAL;
 491
 492         if (within_notrace_func(tk)) {
 493                 pr_warn("Could not probe notrace function %s\n",
 494                         trace_kprobe_symbol(tk));
 495                 return -EINVAL;
 496         }
 497
 498         for (i = 0; i < tk->tp.nr_args; i++) {
 499                 ret = traceprobe_update_arg(&tk->tp.args[i]);
 500                 if (ret)
 501                         return ret;
 502         }
 503
 504         /* Set/clear disabled flag according to tp->flag */
 505         if (trace_probe_is_enabled(&tk->tp))
 506                 tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED;
 507         else
 508                 tk->rp.kp.flags |= KPROBE_FLAG_DISABLED;
 509
 510         if (trace_kprobe_is_return(tk))
 511                 ret = register_kretprobe(&tk->rp);
 512         else
 513                 ret = register_kprobe(&tk->rp.kp);
 514
 515         return ret;
 516 }
 517
 518 /* Internal unregister function - just handle k*probes and flags */
 519 static void __unregister_trace_kprobe(struct trace_kprobe *tk)
 520 {
 521         if (trace_kprobe_is_registered(tk)) {
 522                 if (trace_kprobe_is_return(tk))
 523                         unregister_kretprobe(&tk->rp);
 524                 else
 525                         unregister_kprobe(&tk->rp.kp);
 526                 /* Cleanup kprobe for reuse and mark it unregistered */
 527                 INIT_HLIST_NODE(&tk->rp.kp.hlist);
 528                 INIT_LIST_HEAD(&tk->rp.kp.list);
 529                 if (tk->rp.kp.symbol_name)
 530                         tk->rp.kp.addr = NULL;
 531         }
 532 }
 533
 534 /* Unregister a trace_probe and probe_event */
 535 static int unregister_trace_kprobe(struct trace_kprobe *tk)
 536 {
 537         /* If other probes are on the event, just unregister kprobe */
 538         if (trace_probe_has_sibling(&tk->tp))
 539                 goto unreg;
 540
 541         /* Enabled event can not be unregistered */
 542         if (trace_probe_is_enabled(&tk->tp))
 543                 return -EBUSY;
 544
 545         /* Will fail if probe is being used by ftrace or perf */
 546         if (unregister_kprobe_event(tk))
 547                 return -EBUSY;
 548
 549 unreg:
 550         __unregister_trace_kprobe(tk);
 551         dyn_event_remove(&tk->devent);
 552         trace_probe_unlink(&tk->tp);
 553
 554         return 0;
 555 }
 556
 557 static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
 558                                          struct trace_kprobe *comp)
 559 {
 560         struct trace_probe_event *tpe = orig->tp.event;
 561         struct trace_probe *pos;
 562         int i;
 563
 564         list_for_each_entry(pos, &tpe->probes, list) {
 565                 orig = container_of(pos, struct trace_kprobe, tp);
 566                 if (strcmp(trace_kprobe_symbol(orig),
 567                            trace_kprobe_symbol(comp)) ||
 568                     trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
 569                         continue;
 570
 571                 /*
 572                  * trace_probe_compare_arg_type() ensured that nr_args and
 573                  * each argument name and type are same. Let's compare comm.
 574                  */
 575                 for (i = 0; i < orig->tp.nr_args; i++) {
 576                         if (strcmp(orig->tp.args[i].comm,
 577                                    comp->tp.args[i].comm))
 578                                 break;
 579                 }
 580
 581                 if (i == orig->tp.nr_args)
 582                         return true;
 583         }
 584
 585         return false;
 586 }
 587
 588 static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
 589 {
 590         int ret;
 591
 592         ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
 593         if (ret) {
 594                 /* Note that argument starts index = 2 */
 595                 trace_probe_log_set_index(ret + 1);
 596                 trace_probe_log_err(0, DIFF_ARG_TYPE);
 597                 return -EEXIST;
 598         }
 599         if (trace_kprobe_has_same_kprobe(to, tk)) {
 600                 trace_probe_log_set_index(0);
 601                 trace_probe_log_err(0, SAME_PROBE);
 602                 return -EEXIST;
 603         }
 604
 605         /* Append to existing event */
 606         ret = trace_probe_append(&tk->tp, &to->tp);
 607         if (ret)
 608                 return ret;
 609
 610         /* Register k*probe */
 611         ret = __register_trace_kprobe(tk);
 612         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 613                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 614                 ret = 0;
 615         }
 616
 617         if (ret)
 618                 trace_probe_unlink(&tk->tp);
 619         else
 620                 dyn_event_add(&tk->devent);
 621
 622         return ret;
 623 }
 624
 625 /* Register a trace_probe and probe_event */
 626 static int register_trace_kprobe(struct trace_kprobe *tk)
 627 {
 628         struct trace_kprobe *old_tk;
 629         int ret;
 630
 631         mutex_lock(&event_mutex);
 632
 633         old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
 634                                    trace_probe_group_name(&tk->tp));
 635         if (old_tk) {
 636                 if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
 637                         trace_probe_log_set_index(0);
 638                         trace_probe_log_err(0, DIFF_PROBE_TYPE);
 639                         ret = -EEXIST;
 640                 } else {
 641                         ret = append_trace_kprobe(tk, old_tk);
 642                 }
 643                 goto end;
 644         }
 645
 646         /* Register new event */
 647         ret = register_kprobe_event(tk);
 648         if (ret) {
 649                 pr_warn("Failed to register probe event(%d)\n", ret);
 650                 goto end;
 651         }
 652
 653         /* Register k*probe */
 654         ret = __register_trace_kprobe(tk);
 655         if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
 656                 pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
 657                 ret = 0;
 658         }
 659
 660         if (ret < 0)
 661                 unregister_kprobe_event(tk);
 662         else
 663                 dyn_event_add(&tk->devent);
 664
 665 end:
 666         mutex_unlock(&event_mutex);
 667         return ret;
 668 }
 669
 670 /* Module notifier call back, checking event on the module */
 671 static int trace_kprobe_module_callback(struct notifier_block *nb,
 672                                        unsigned long val, void *data)
 673 {
 674         struct module *mod = data;
 675         struct dyn_event *pos;
 676         struct trace_kprobe *tk;
 677         int ret;
 678
 679         if (val != MODULE_STATE_COMING)
 680                 return NOTIFY_DONE;
 681
 682         /* Update probes on coming module */
 683         mutex_lock(&event_mutex);
 684         for_each_trace_kprobe(tk, pos) {
 685                 if (trace_kprobe_within_module(tk, mod)) {
 686                         /* Don't need to check busy - this should have gone. */
 687                         __unregister_trace_kprobe(tk);
 688                         ret = __register_trace_kprobe(tk);
 689                         if (ret)
 690                                 pr_warn("Failed to re-register probe %s on %s: %d\n",
 691                                         trace_probe_name(&tk->tp),
 692                                         module_name(mod), ret);
 693                 }
 694         }
 695         mutex_unlock(&event_mutex);
 696
 697         return NOTIFY_DONE;
 698 }
 699
 700 static struct notifier_block trace_kprobe_module_nb = {
 701         .notifier_call = trace_kprobe_module_callback,
 702         .priority = 1   /* Invoked after kprobe module callback */
 703 };
 704
 705 /* Convert certain expected symbols into '_' when generating event names */
 706 static inline void sanitize_event_name(char *name)
 707 {
 708         while (*name++ != '\0')
 709                 if (*name == ':' || *name == '.')
 710                         *name = '_';
 711 }
 712
 713 static int trace_kprobe_create(int argc, const char *argv[])
 714 {
 715         /*
 716          * Argument syntax:
 717          *  - Add kprobe:
 718          *      p[:[GRP/]EVENT] [MOD:]KSYM[+OFFS]|KADDR [FETCHARGS]
 719          *  - Add kretprobe:
 720          *      r[MAXACTIVE][:[GRP/]EVENT] [MOD:]KSYM[+0] [FETCHARGS]
 721          * Fetch args:
 722          *  $retval     : fetch return value
 723          *  $stack      : fetch stack address
 724          *  $stackN     : fetch Nth of stack (N:0-)
 725          *  $comm       : fetch current task comm
 726          *  @ADDR       : fetch memory at ADDR (ADDR should be in kernel)
 727          *  @SYM[+|-offs] : fetch memory at SYM +|- offs (SYM is a data symbol)
 728          *  %REG        : fetch register REG
 729          * Dereferencing memory fetch:
 730          *  +|-offs(ARG) : fetch memory at ARG +|- offs address.
 731          * Alias name of args:
 732          *  NAME=FETCHARG : set NAME as alias of FETCHARG.
 733          * Type of args:
 734          *  FETCHARG:TYPE : use TYPE instead of unsigned long.
 735          */
 736         struct trace_kprobe *tk = NULL;
 737         int i, len, ret = 0;
 738         bool is_return = false;
 739         char *symbol = NULL, *tmp = NULL;
 740         const char *event = NULL, *group = KPROBE_EVENT_SYSTEM;
 741         int maxactive = 0;
 742         long offset = 0;
 743         void *addr = NULL;
 744         char buf[MAX_EVENT_NAME_LEN];
 745         unsigned int flags = TPARG_FL_KERNEL;
 746
 747         switch (argv[0][0]) {
 748         case 'r':
 749                 is_return = true;
 750                 flags |= TPARG_FL_RETURN;
 751                 break;
 752         case 'p':
 753                 break;
 754         default:
 755                 return -ECANCELED;
 756         }
 757         if (argc < 2)
 758                 return -ECANCELED;
 759
 760         trace_probe_log_init("trace_kprobe", argc, argv);
 761
 762         event = strchr(&argv[0][1], ':');
 763         if (event)
 764                 event++;
 765
 766         if (isdigit(argv[0][1])) {
 767                 if (!is_return) {
 768                         trace_probe_log_err(1, MAXACT_NO_KPROBE);
 769                         goto parse_error;
 770                 }
 771                 if (event)
 772                         len = event - &argv[0][1] - 1;
 773                 else
 774                         len = strlen(&argv[0][1]);
 775                 if (len > MAX_EVENT_NAME_LEN - 1) {
 776                         trace_probe_log_err(1, BAD_MAXACT);
 777                         goto parse_error;
 778                 }
 779                 memcpy(buf, &argv[0][1], len);
 780                 buf[len] = '\0';
 781                 ret = kstrtouint(buf, 0, &maxactive);
 782                 if (ret || !maxactive) {
 783                         trace_probe_log_err(1, BAD_MAXACT);
 784                         goto parse_error;
 785                 }
 786                 /* kretprobes instances are iterated over via a list. The
 787                  * maximum should stay reasonable.
 788                  */
 789                 if (maxactive > KRETPROBE_MAXACTIVE_MAX) {
 790                         trace_probe_log_err(1, MAXACT_TOO_BIG);
 791                         goto parse_error;
 792                 }
 793         }
 794
 795         /* try to parse an address. if that fails, try to read the
 796          * input as a symbol. */
 797         if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
 798                 trace_probe_log_set_index(1);
 799                 /* Check whether uprobe event specified */
 800                 if (strchr(argv[1], '/') && strchr(argv[1], ':')) {
 801                         ret = -ECANCELED;
 802                         goto error;
 803                 }
 804                 /* a symbol specified */
 805                 symbol = kstrdup(argv[1], GFP_KERNEL);
 806                 if (!symbol)
 807                         return -ENOMEM;
 808                 /* TODO: support .init module functions */
 809                 ret = traceprobe_split_symbol_offset(symbol, &offset);
 810                 if (ret || offset < 0 || offset > UINT_MAX) {
 811                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 812                         goto parse_error;
 813                 }
 814                 if (kprobe_on_func_entry(NULL, symbol, offset))
 815                         flags |= TPARG_FL_FENTRY;
 816                 if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
 817                         trace_probe_log_err(0, BAD_RETPROBE);
 818                         goto parse_error;
 819                 }
 820         }
 821
 822         trace_probe_log_set_index(0);
 823         if (event) {
 824                 ret = traceprobe_parse_event_name(&event, &group, buf,
 825                                                   event - argv[0]);
 826                 if (ret)
 827                         goto parse_error;
 828         } else {
 829                 /* Make a new event name */
 830                 if (symbol)
 831                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_%ld",
 832                                  is_return ? 'r' : 'p', symbol, offset);
 833                 else
 834                         snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 835                                  is_return ? 'r' : 'p', addr);
 836                 sanitize_event_name(buf);
 837                 event = buf;
 838         }
 839
 840         /* setup a probe */
 841         tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
 842                                argc - 2, is_return);
 843         if (IS_ERR(tk)) {
 844                 ret = PTR_ERR(tk);
 845                 /* This must return -ENOMEM, else there is a bug */
 846                 WARN_ON_ONCE(ret != -ENOMEM);
 847                 goto out;       /* We know tk is not allocated */
 848         }
 849         argc -= 2; argv += 2;
 850
 851         /* parse arguments */
 852         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 853                 tmp = kstrdup(argv[i], GFP_KERNEL);
 854                 if (!tmp) {
 855                         ret = -ENOMEM;
 856                         goto error;
 857                 }
 858
 859                 trace_probe_log_set_index(i + 2);
 860                 ret = traceprobe_parse_probe_arg(&tk->tp, i, tmp, flags);
 861                 kfree(tmp);
 862                 if (ret)
 863                         goto error;     /* This can be -ENOMEM */
 864         }
 865
 866         ret = traceprobe_set_print_fmt(&tk->tp, is_return);
 867         if (ret < 0)
 868                 goto error;
 869
 870         ret = register_trace_kprobe(tk);
 871         if (ret) {
 872                 trace_probe_log_set_index(1);
 873                 if (ret == -EILSEQ)
 874                         trace_probe_log_err(0, BAD_INSN_BNDRY);
 875                 else if (ret == -ENOENT)
 876                         trace_probe_log_err(0, BAD_PROBE_ADDR);
 877                 else if (ret != -ENOMEM && ret != -EEXIST)
 878                         trace_probe_log_err(0, FAIL_REG_PROBE);
 879                 goto error;
 880         }
 881
 882 out:
 883         trace_probe_log_clear();
 884         kfree(symbol);
 885         return ret;
 886
 887 parse_error:
 888         ret = -EINVAL;
 889 error:
 890         free_trace_kprobe(tk);
 891         goto out;
 892 }
 893
 894 static int create_or_delete_trace_kprobe(int argc, char **argv)
 895 {
 896         int ret;
 897
 898         if (argv[0][0] == '-')
 899                 return dyn_event_release(argc, argv, &trace_kprobe_ops);
 900
 901         ret = trace_kprobe_create(argc, (const char **)argv);
 902         return ret == -ECANCELED ? -EINVAL : ret;
 903 }
 904
 905 static int trace_kprobe_run_command(struct dynevent_cmd *cmd)
 906 {
 907         return trace_run_command(cmd->seq.buffer, create_or_delete_trace_kprobe);
 908 }
 909
 910 /**
 911  * kprobe_event_cmd_init - Initialize a kprobe event command object
 912  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 913  * @buf: A pointer to the buffer used to build the command
 914  * @maxlen: The length of the buffer passed in @buf
 915  *
 916  * Initialize a synthetic event command object.  Use this before
 917  * calling any of the other kprobe_event functions.
 918  */
 919 void kprobe_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
 920 {
 921         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_KPROBE,
 922                           trace_kprobe_run_command);
 923 }
 924 EXPORT_SYMBOL_GPL(kprobe_event_cmd_init);
 925
 926 /**
 927  * __kprobe_event_gen_cmd_start - Generate a kprobe event command from arg list
 928  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 929  * @name: The name of the kprobe event
 930  * @loc: The location of the kprobe event
 931  * @kretprobe: Is this a return probe?
 932  * @args: Variable number of arg (pairs), one pair for each field
 933  *
 934  * NOTE: Users normally won't want to call this function directly, but
 935  * rather use the kprobe_event_gen_cmd_start() wrapper, which automatically
 936  * adds a NULL to the end of the arg list.  If this function is used
 937  * directly, make sure the last arg in the variable arg list is NULL.
 938  *
 939  * Generate a kprobe event command to be executed by
 940  * kprobe_event_gen_cmd_end().  This function can be used to generate the
 941  * complete command or only the first part of it; in the latter case,
 942  * kprobe_event_add_fields() can be used to add more fields following this.
 943  *
 944  * Unlikely the synth_event_gen_cmd_start(), @loc must be specified. This
 945  * returns -EINVAL if @loc == NULL.
 946  *
 947  * Return: 0 if successful, error otherwise.
 948  */
 949 int __kprobe_event_gen_cmd_start(struct dynevent_cmd *cmd, bool kretprobe,
 950                                  const char *name, const char *loc, ...)
 951 {
 952         char buf[MAX_EVENT_NAME_LEN];
 953         struct dynevent_arg arg;
 954         va_list args;
 955         int ret;
 956
 957         if (cmd->type != DYNEVENT_TYPE_KPROBE)
 958                 return -EINVAL;
 959
 960         if (!loc)
 961                 return -EINVAL;
 962
 963         if (kretprobe)
 964                 snprintf(buf, MAX_EVENT_NAME_LEN, "r:kprobes/%s", name);
 965         else
 966                 snprintf(buf, MAX_EVENT_NAME_LEN, "p:kprobes/%s", name);
 967
 968         ret = dynevent_str_add(cmd, buf);
 969         if (ret)
 970                 return ret;
 971
 972         dynevent_arg_init(&arg, 0);
 973         arg.str = loc;
 974         ret = dynevent_arg_add(cmd, &arg, NULL);
 975         if (ret)
 976                 return ret;
 977
 978         va_start(args, loc);
 979         for (;;) {
 980                 const char *field;
 981
 982                 field = va_arg(args, const char *);
 983                 if (!field)
 984                         break;
 985
 986                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
 987                         ret = -EINVAL;
 988                         break;
 989                 }
 990
 991                 arg.str = field;
 992                 ret = dynevent_arg_add(cmd, &arg, NULL);
 993                 if (ret)
 994                         break;
 995         }
 996         va_end(args);
 997
 998         return ret;
 999 }
1000 EXPORT_SYMBOL_GPL(__kprobe_event_gen_cmd_start);
1001
1002 /**
1003  * __kprobe_event_add_fields - Add probe fields to a kprobe command from arg list
1004  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1005  * @args: Variable number of arg (pairs), one pair for each field
1006  *
1007  * NOTE: Users normally won't want to call this function directly, but
1008  * rather use the kprobe_event_add_fields() wrapper, which
1009  * automatically adds a NULL to the end of the arg list.  If this
1010  * function is used directly, make sure the last arg in the variable
1011  * arg list is NULL.
1012  *
1013  * Add probe fields to an existing kprobe command using a variable
1014  * list of args.  Fields are added in the same order they're listed.
1015  *
1016  * Return: 0 if successful, error otherwise.
1017  */
1018 int __kprobe_event_add_fields(struct dynevent_cmd *cmd, ...)
1019 {
1020         struct dynevent_arg arg;
1021         va_list args;
1022         int ret = 0;
1023
1024         if (cmd->type != DYNEVENT_TYPE_KPROBE)
1025                 return -EINVAL;
1026
1027         dynevent_arg_init(&arg, 0);
1028
1029         va_start(args, cmd);
1030         for (;;) {
1031                 const char *field;
1032
1033                 field = va_arg(args, const char *);
1034                 if (!field)
1035                         break;
1036
1037                 if (++cmd->n_fields > MAX_TRACE_ARGS) {
1038                         ret = -EINVAL;
1039                         break;
1040                 }
1041
1042                 arg.str = field;
1043                 ret = dynevent_arg_add(cmd, &arg, NULL);
1044                 if (ret)
1045                         break;
1046         }
1047         va_end(args);
1048
1049         return ret;
1050 }
1051 EXPORT_SYMBOL_GPL(__kprobe_event_add_fields);
1052
1053 /**
1054  * kprobe_event_delete - Delete a kprobe event
1055  * @name: The name of the kprobe event to delete
1056  *
1057  * Delete a kprobe event with the give @name from kernel code rather
1058  * than directly from the command line.
1059  *
1060  * Return: 0 if successful, error otherwise.
1061  */
1062 int kprobe_event_delete(const char *name)
1063 {
1064         char buf[MAX_EVENT_NAME_LEN];
1065
1066         snprintf(buf, MAX_EVENT_NAME_LEN, "-:%s", name);
1067
1068         return trace_run_command(buf, create_or_delete_trace_kprobe);
1069 }
1070 EXPORT_SYMBOL_GPL(kprobe_event_delete);
1071
1072 static int trace_kprobe_release(struct dyn_event *ev)
1073 {
1074         struct trace_kprobe *tk = to_trace_kprobe(ev);
1075         int ret = unregister_trace_kprobe(tk);
1076
1077         if (!ret)
1078                 free_trace_kprobe(tk);
1079         return ret;
1080 }
1081
1082 static int trace_kprobe_show(struct seq_file *m, struct dyn_event *ev)
1083 {
1084         struct trace_kprobe *tk = to_trace_kprobe(ev);
1085         int i;
1086
1087         seq_putc(m, trace_kprobe_is_return(tk) ? 'r' : 'p');
1088         if (trace_kprobe_is_return(tk) && tk->rp.maxactive)
1089                 seq_printf(m, "%d", tk->rp.maxactive);
1090         seq_printf(m, ":%s/%s", trace_probe_group_name(&tk->tp),
1091                                 trace_probe_name(&tk->tp));
1092
1093         if (!tk->symbol)
1094                 seq_printf(m, " 0x%p", tk->rp.kp.addr);
1095         else if (tk->rp.kp.offset)
1096                 seq_printf(m, " %s+%u", trace_kprobe_symbol(tk),
1097                            tk->rp.kp.offset);
1098         else
1099                 seq_printf(m, " %s", trace_kprobe_symbol(tk));
1100
1101         for (i = 0; i < tk->tp.nr_args; i++)
1102                 seq_printf(m, " %s=%s", tk->tp.args[i].name, tk->tp.args[i].comm);
1103         seq_putc(m, '\n');
1104
1105         return 0;
1106 }
1107
1108 static int probes_seq_show(struct seq_file *m, void *v)
1109 {
1110         struct dyn_event *ev = v;
1111
1112         if (!is_trace_kprobe(ev))
1113                 return 0;
1114
1115         return trace_kprobe_show(m, ev);
1116 }
1117
1118 static const struct seq_operations probes_seq_op = {
1119         .start  = dyn_event_seq_start,
1120         .next   = dyn_event_seq_next,
1121         .stop   = dyn_event_seq_stop,
1122         .show   = probes_seq_show
1123 };
1124
1125 static int probes_open(struct inode *inode, struct file *file)
1126 {
1127         int ret;
1128
1129         ret = security_locked_down(LOCKDOWN_TRACEFS);
1130         if (ret)
1131                 return ret;
1132
1133         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
1134                 ret = dyn_events_release_all(&trace_kprobe_ops);
1135                 if (ret < 0)
1136                         return ret;
1137         }
1138
1139         return seq_open(file, &probes_seq_op);
1140 }
1141
1142 static ssize_t probes_write(struct file *file, const char __user *buffer,
1143                             size_t count, loff_t *ppos)
1144 {
1145         return trace_parse_run_command(file, buffer, count, ppos,
1146                                        create_or_delete_trace_kprobe);
1147 }
1148
1149 static const struct file_operations kprobe_events_ops = {
1150         .owner          = THIS_MODULE,
1151         .open           = probes_open,
1152         .read           = seq_read,
1153         .llseek         = seq_lseek,
1154         .release        = seq_release,
1155         .write          = probes_write,
1156 };
1157
1158 /* Probes profiling interfaces */
1159 static int probes_profile_seq_show(struct seq_file *m, void *v)
1160 {
1161         struct dyn_event *ev = v;
1162         struct trace_kprobe *tk;
1163
1164         if (!is_trace_kprobe(ev))
1165                 return 0;
1166
1167         tk = to_trace_kprobe(ev);
1168         seq_printf(m, "  %-44s %15lu %15lu\n",
1169                    trace_probe_name(&tk->tp),
1170                    trace_kprobe_nhit(tk),
1171                    tk->rp.kp.nmissed);
1172
1173         return 0;
1174 }
1175
1176 static const struct seq_operations profile_seq_op = {
1177         .start  = dyn_event_seq_start,
1178         .next   = dyn_event_seq_next,
1179         .stop   = dyn_event_seq_stop,
1180         .show   = probes_profile_seq_show
1181 };
1182
1183 static int profile_open(struct inode *inode, struct file *file)
1184 {
1185         int ret;
1186
1187         ret = security_locked_down(LOCKDOWN_TRACEFS);
1188         if (ret)
1189                 return ret;
1190
1191         return seq_open(file, &profile_seq_op);
1192 }
1193
1194 static const struct file_operations kprobe_profile_ops = {
1195         .owner          = THIS_MODULE,
1196         .open           = profile_open,
1197         .read           = seq_read,
1198         .llseek         = seq_lseek,
1199         .release        = seq_release,
1200 };
1201
1202 /* Kprobe specific fetch functions */
1203
1204 /* Return the length of string -- including null terminal byte */
1205 static nokprobe_inline int
1206 fetch_store_strlen_user(unsigned long addr)
1207 {
1208         const void __user *uaddr =  (__force const void __user *)addr;
1209
1210         return strnlen_user_nofault(uaddr, MAX_STRING_SIZE);
1211 }
1212
1213 /* Return the length of string -- including null terminal byte */
1214 static nokprobe_inline int
1215 fetch_store_strlen(unsigned long addr)
1216 {
1217         int ret, len = 0;
1218         u8 c;
1219
1220 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1221         if (addr < TASK_SIZE)
1222                 return fetch_store_strlen_user(addr);
1223 #endif
1224
1225         do {
1226                 ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1);
1227                 len++;
1228         } while (c && ret == 0 && len < MAX_STRING_SIZE);
1229
1230         return (ret < 0) ? ret : len;
1231 }
1232
1233 /*
1234  * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf
1235  * with max length and relative data location.
1236  */
1237 static nokprobe_inline int
1238 fetch_store_string_user(unsigned long addr, void *dest, void *base)
1239 {
1240         const void __user *uaddr =  (__force const void __user *)addr;
1241         int maxlen = get_loc_len(*(u32 *)dest);
1242         void *__dest;
1243         long ret;
1244
1245         if (unlikely(!maxlen))
1246                 return -ENOMEM;
1247
1248         __dest = get_loc_data(dest, base);
1249
1250         ret = strncpy_from_user_nofault(__dest, uaddr, maxlen);
1251         if (ret >= 0)
1252                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1253
1254         return ret;
1255 }
1256
1257 /*
1258  * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max
1259  * length and relative data location.
1260  */
1261 static nokprobe_inline int
1262 fetch_store_string(unsigned long addr, void *dest, void *base)
1263 {
1264         int maxlen = get_loc_len(*(u32 *)dest);
1265         void *__dest;
1266         long ret;
1267
1268 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1269         if ((unsigned long)addr < TASK_SIZE)
1270                 return fetch_store_string_user(addr, dest, base);
1271 #endif
1272
1273         if (unlikely(!maxlen))
1274                 return -ENOMEM;
1275
1276         __dest = get_loc_data(dest, base);
1277
1278         /*
1279          * Try to get string again, since the string can be changed while
1280          * probing.
1281          */
1282         ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen);
1283         if (ret >= 0)
1284                 *(u32 *)dest = make_data_loc(ret, __dest - base);
1285
1286         return ret;
1287 }
1288
1289 static nokprobe_inline int
1290 probe_mem_read_user(void *dest, void *src, size_t size)
1291 {
1292         const void __user *uaddr =  (__force const void __user *)src;
1293
1294         return copy_from_user_nofault(dest, uaddr, size);
1295 }
1296
1297 static nokprobe_inline int
1298 probe_mem_read(void *dest, void *src, size_t size)
1299 {
1300 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
1301         if ((unsigned long)src < TASK_SIZE)
1302                 return probe_mem_read_user(dest, src, size);
1303 #endif
1304         return copy_from_kernel_nofault(dest, src, size);
1305 }
1306
1307 /* Note that we don't verify it, since the code does not come from user space */
1308 static int
1309 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
1310                    void *base)
1311 {
1312         unsigned long val;
1313
1314 retry:
1315         /* 1st stage: get value from context */
1316         switch (code->op) {
1317         case FETCH_OP_REG:
1318                 val = regs_get_register(regs, code->param);
1319                 break;
1320         case FETCH_OP_STACK:
1321                 val = regs_get_kernel_stack_nth(regs, code->param);
1322                 break;
1323         case FETCH_OP_STACKP:
1324                 val = kernel_stack_pointer(regs);
1325                 break;
1326         case FETCH_OP_RETVAL:
1327                 val = regs_return_value(regs);
1328                 break;
1329         case FETCH_OP_IMM:
1330                 val = code->immediate;
1331                 break;
1332         case FETCH_OP_COMM:
1333                 val = (unsigned long)current->comm;
1334                 break;
1335         case FETCH_OP_DATA:
1336                 val = (unsigned long)code->data;
1337                 break;
1338 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
1339         case FETCH_OP_ARG:
1340                 val = regs_get_kernel_argument(regs, code->param);
1341                 break;
1342 #endif
1343         case FETCH_NOP_SYMBOL:  /* Ignore a place holder */
1344                 code++;
1345                 goto retry;
1346         default:
1347                 return -EILSEQ;
1348         }
1349         code++;
1350
1351         return process_fetch_insn_bottom(code, val, dest, base);
1352 }
1353 NOKPROBE_SYMBOL(process_fetch_insn)
1354
1355 /* Kprobe handler */
1356 static nokprobe_inline void
1357 __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
1358                     struct trace_event_file *trace_file)
1359 {
1360         struct kprobe_trace_entry_head *entry;
1361         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1362         struct trace_event_buffer fbuffer;
1363         int dsize;
1364
1365         WARN_ON(call != trace_file->event_call);
1366
1367         if (trace_trigger_soft_disabled(trace_file))
1368                 return;
1369
1370         local_save_flags(fbuffer.flags);
1371         fbuffer.pc = preempt_count();
1372         fbuffer.trace_file = trace_file;
1373
1374         dsize = __get_data_size(&tk->tp, regs);
1375
1376         fbuffer.event =
1377                 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1378                                         call->event.type,
1379                                         sizeof(*entry) + tk->tp.size + dsize,
1380                                         fbuffer.flags, fbuffer.pc);
1381         if (!fbuffer.event)
1382                 return;
1383
1384         fbuffer.regs = regs;
1385         entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1386         entry->ip = (unsigned long)tk->rp.kp.addr;
1387         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1388
1389         trace_event_buffer_commit(&fbuffer);
1390 }
1391
1392 static void
1393 kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs)
1394 {
1395         struct event_file_link *link;
1396
1397         trace_probe_for_each_link_rcu(link, &tk->tp)
1398                 __kprobe_trace_func(tk, regs, link->file);
1399 }
1400 NOKPROBE_SYMBOL(kprobe_trace_func);
1401
1402 /* Kretprobe handler */
1403 static nokprobe_inline void
1404 __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1405                        struct pt_regs *regs,
1406                        struct trace_event_file *trace_file)
1407 {
1408         struct kretprobe_trace_entry_head *entry;
1409         struct trace_event_buffer fbuffer;
1410         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1411         int dsize;
1412
1413         WARN_ON(call != trace_file->event_call);
1414
1415         if (trace_trigger_soft_disabled(trace_file))
1416                 return;
1417
1418         local_save_flags(fbuffer.flags);
1419         fbuffer.pc = preempt_count();
1420         fbuffer.trace_file = trace_file;
1421
1422         dsize = __get_data_size(&tk->tp, regs);
1423         fbuffer.event =
1424                 trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
1425                                         call->event.type,
1426                                         sizeof(*entry) + tk->tp.size + dsize,
1427                                         fbuffer.flags, fbuffer.pc);
1428         if (!fbuffer.event)
1429                 return;
1430
1431         fbuffer.regs = regs;
1432         entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
1433         entry->func = (unsigned long)tk->rp.kp.addr;
1434         entry->ret_ip = (unsigned long)ri->ret_addr;
1435         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1436
1437         trace_event_buffer_commit(&fbuffer);
1438 }
1439
1440 static void
1441 kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1442                      struct pt_regs *regs)
1443 {
1444         struct event_file_link *link;
1445
1446         trace_probe_for_each_link_rcu(link, &tk->tp)
1447                 __kretprobe_trace_func(tk, ri, regs, link->file);
1448 }
1449 NOKPROBE_SYMBOL(kretprobe_trace_func);
1450
1451 /* Event entry printers */
1452 static enum print_line_t
1453 print_kprobe_event(struct trace_iterator *iter, int flags,
1454                    struct trace_event *event)
1455 {
1456         struct kprobe_trace_entry_head *field;
1457         struct trace_seq *s = &iter->seq;
1458         struct trace_probe *tp;
1459
1460         field = (struct kprobe_trace_entry_head *)iter->ent;
1461         tp = trace_probe_primary_from_call(
1462                 container_of(event, struct trace_event_call, event));
1463         if (WARN_ON_ONCE(!tp))
1464                 goto out;
1465
1466         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1467
1468         if (!seq_print_ip_sym(s, field->ip, flags | TRACE_ITER_SYM_OFFSET))
1469                 goto out;
1470
1471         trace_seq_putc(s, ')');
1472
1473         if (print_probe_args(s, tp->args, tp->nr_args,
1474                              (u8 *)&field[1], field) < 0)
1475                 goto out;
1476
1477         trace_seq_putc(s, '\n');
1478  out:
1479         return trace_handle_return(s);
1480 }
1481
1482 static enum print_line_t
1483 print_kretprobe_event(struct trace_iterator *iter, int flags,
1484                       struct trace_event *event)
1485 {
1486         struct kretprobe_trace_entry_head *field;
1487         struct trace_seq *s = &iter->seq;
1488         struct trace_probe *tp;
1489
1490         field = (struct kretprobe_trace_entry_head *)iter->ent;
1491         tp = trace_probe_primary_from_call(
1492                 container_of(event, struct trace_event_call, event));
1493         if (WARN_ON_ONCE(!tp))
1494                 goto out;
1495
1496         trace_seq_printf(s, "%s: (", trace_probe_name(tp));
1497
1498         if (!seq_print_ip_sym(s, field->ret_ip, flags | TRACE_ITER_SYM_OFFSET))
1499                 goto out;
1500
1501         trace_seq_puts(s, " <- ");
1502
1503         if (!seq_print_ip_sym(s, field->func, flags & ~TRACE_ITER_SYM_OFFSET))
1504                 goto out;
1505
1506         trace_seq_putc(s, ')');
1507
1508         if (print_probe_args(s, tp->args, tp->nr_args,
1509                              (u8 *)&field[1], field) < 0)
1510                 goto out;
1511
1512         trace_seq_putc(s, '\n');
1513
1514  out:
1515         return trace_handle_return(s);
1516 }
1517
1518
1519 static int kprobe_event_define_fields(struct trace_event_call *event_call)
1520 {
1521         int ret;
1522         struct kprobe_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, ip, FIELD_STRING_IP, 0);
1530
1531         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1532 }
1533
1534 static int kretprobe_event_define_fields(struct trace_event_call *event_call)
1535 {
1536         int ret;
1537         struct kretprobe_trace_entry_head field;
1538         struct trace_probe *tp;
1539
1540         tp = trace_probe_primary_from_call(event_call);
1541         if (WARN_ON_ONCE(!tp))
1542                 return -ENOENT;
1543
1544         DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0);
1545         DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0);
1546
1547         return traceprobe_define_arg_fields(event_call, sizeof(field), tp);
1548 }
1549
1550 #ifdef CONFIG_PERF_EVENTS
1551
1552 /* Kprobe profile handler */
1553 static int
1554 kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)
1555 {
1556         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1557         struct kprobe_trace_entry_head *entry;
1558         struct hlist_head *head;
1559         int size, __size, dsize;
1560         int rctx;
1561
1562         if (bpf_prog_array_valid(call)) {
1563                 unsigned long orig_ip = instruction_pointer(regs);
1564                 int ret;
1565
1566                 ret = trace_call_bpf(call, regs);
1567
1568                 /*
1569                  * We need to check and see if we modified the pc of the
1570                  * pt_regs, and if so return 1 so that we don't do the
1571                  * single stepping.
1572                  */
1573                 if (orig_ip != instruction_pointer(regs))
1574                         return 1;
1575                 if (!ret)
1576                         return 0;
1577         }
1578
1579         head = this_cpu_ptr(call->perf_events);
1580         if (hlist_empty(head))
1581                 return 0;
1582
1583         dsize = __get_data_size(&tk->tp, regs);
1584         __size = sizeof(*entry) + tk->tp.size + dsize;
1585         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1586         size -= sizeof(u32);
1587
1588         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1589         if (!entry)
1590                 return 0;
1591
1592         entry->ip = (unsigned long)tk->rp.kp.addr;
1593         memset(&entry[1], 0, dsize);
1594         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1595         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1596                               head, NULL);
1597         return 0;
1598 }
1599 NOKPROBE_SYMBOL(kprobe_perf_func);
1600
1601 /* Kretprobe profile handler */
1602 static void
1603 kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
1604                     struct pt_regs *regs)
1605 {
1606         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1607         struct kretprobe_trace_entry_head *entry;
1608         struct hlist_head *head;
1609         int size, __size, dsize;
1610         int rctx;
1611
1612         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1613                 return;
1614
1615         head = this_cpu_ptr(call->perf_events);
1616         if (hlist_empty(head))
1617                 return;
1618
1619         dsize = __get_data_size(&tk->tp, regs);
1620         __size = sizeof(*entry) + tk->tp.size + dsize;
1621         size = ALIGN(__size + sizeof(u32), sizeof(u64));
1622         size -= sizeof(u32);
1623
1624         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1625         if (!entry)
1626                 return;
1627
1628         entry->func = (unsigned long)tk->rp.kp.addr;
1629         entry->ret_ip = (unsigned long)ri->ret_addr;
1630         store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);
1631         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1632                               head, NULL);
1633 }
1634 NOKPROBE_SYMBOL(kretprobe_perf_func);
1635
1636 int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type,
1637                         const char **symbol, u64 *probe_offset,
1638                         u64 *probe_addr, bool perf_type_tracepoint)
1639 {
1640         const char *pevent = trace_event_name(event->tp_event);
1641         const char *group = event->tp_event->class->system;
1642         struct trace_kprobe *tk;
1643
1644         if (perf_type_tracepoint)
1645                 tk = find_trace_kprobe(pevent, group);
1646         else
1647                 tk = trace_kprobe_primary_from_call(event->tp_event);
1648         if (!tk)
1649                 return -EINVAL;
1650
1651         *fd_type = trace_kprobe_is_return(tk) ? BPF_FD_TYPE_KRETPROBE
1652                                               : BPF_FD_TYPE_KPROBE;
1653         if (tk->symbol) {
1654                 *symbol = tk->symbol;
1655                 *probe_offset = tk->rp.kp.offset;
1656                 *probe_addr = 0;
1657         } else {
1658                 *symbol = NULL;
1659                 *probe_offset = 0;
1660                 *probe_addr = (unsigned long)tk->rp.kp.addr;
1661         }
1662         return 0;
1663 }
1664 #endif  /* CONFIG_PERF_EVENTS */
1665
1666 /*
1667  * called by perf_trace_init() or __ftrace_set_clr_event() under event_mutex.
1668  *
1669  * kprobe_trace_self_tests_init() does enable_trace_probe/disable_trace_probe
1670  * lockless, but we can't race with this __init function.
1671  */
1672 static int kprobe_register(struct trace_event_call *event,
1673                            enum trace_reg type, void *data)
1674 {
1675         struct trace_event_file *file = data;
1676
1677         switch (type) {
1678         case TRACE_REG_REGISTER:
1679                 return enable_trace_kprobe(event, file);
1680         case TRACE_REG_UNREGISTER:
1681                 return disable_trace_kprobe(event, file);
1682
1683 #ifdef CONFIG_PERF_EVENTS
1684         case TRACE_REG_PERF_REGISTER:
1685                 return enable_trace_kprobe(event, NULL);
1686         case TRACE_REG_PERF_UNREGISTER:
1687                 return disable_trace_kprobe(event, NULL);
1688         case TRACE_REG_PERF_OPEN:
1689         case TRACE_REG_PERF_CLOSE:
1690         case TRACE_REG_PERF_ADD:
1691         case TRACE_REG_PERF_DEL:
1692                 return 0;
1693 #endif
1694         }
1695         return 0;
1696 }
1697
1698 static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
1699 {
1700         struct trace_kprobe *tk = container_of(kp, struct trace_kprobe, rp.kp);
1701         int ret = 0;
1702
1703         raw_cpu_inc(*tk->nhit);
1704
1705         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1706                 kprobe_trace_func(tk, regs);
1707 #ifdef CONFIG_PERF_EVENTS
1708         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1709                 ret = kprobe_perf_func(tk, regs);
1710 #endif
1711         return ret;
1712 }
1713 NOKPROBE_SYMBOL(kprobe_dispatcher);
1714
1715 static int
1716 kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
1717 {
1718         struct trace_kprobe *tk = container_of(ri->rp, struct trace_kprobe, rp);
1719
1720         raw_cpu_inc(*tk->nhit);
1721
1722         if (trace_probe_test_flag(&tk->tp, TP_FLAG_TRACE))
1723                 kretprobe_trace_func(tk, ri, regs);
1724 #ifdef CONFIG_PERF_EVENTS
1725         if (trace_probe_test_flag(&tk->tp, TP_FLAG_PROFILE))
1726                 kretprobe_perf_func(tk, ri, regs);
1727 #endif
1728         return 0;       /* We don't tweek kernel, so just return 0 */
1729 }
1730 NOKPROBE_SYMBOL(kretprobe_dispatcher);
1731
1732 static struct trace_event_functions kretprobe_funcs = {
1733         .trace          = print_kretprobe_event
1734 };
1735
1736 static struct trace_event_functions kprobe_funcs = {
1737         .trace          = print_kprobe_event
1738 };
1739
1740 static struct trace_event_fields kretprobe_fields_array[] = {
1741         { .type = TRACE_FUNCTION_TYPE,
1742           .define_fields = kretprobe_event_define_fields },
1743         {}
1744 };
1745
1746 static struct trace_event_fields kprobe_fields_array[] = {
1747         { .type = TRACE_FUNCTION_TYPE,
1748           .define_fields = kprobe_event_define_fields },
1749         {}
1750 };
1751
1752 static inline void init_trace_event_call(struct trace_kprobe *tk)
1753 {
1754         struct trace_event_call *call = trace_probe_event_call(&tk->tp);
1755
1756         if (trace_kprobe_is_return(tk)) {
1757                 call->event.funcs = &kretprobe_funcs;
1758                 call->class->fields_array = kretprobe_fields_array;
1759         } else {
1760                 call->event.funcs = &kprobe_funcs;
1761                 call->class->fields_array = kprobe_fields_array;
1762         }
1763
1764         call->flags = TRACE_EVENT_FL_KPROBE;
1765         call->class->reg = kprobe_register;
1766 }
1767
1768 static int register_kprobe_event(struct trace_kprobe *tk)
1769 {
1770         init_trace_event_call(tk);
1771
1772         return trace_probe_register_event_call(&tk->tp);
1773 }
1774
1775 static int unregister_kprobe_event(struct trace_kprobe *tk)
1776 {
1777         return trace_probe_unregister_event_call(&tk->tp);
1778 }
1779
1780 #ifdef CONFIG_PERF_EVENTS
1781 /* create a trace_kprobe, but don't add it to global lists */
1782 struct trace_event_call *
1783 create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
1784                           bool is_return)
1785 {
1786         struct trace_kprobe *tk;
1787         int ret;
1788         char *event;
1789
1790         /*
1791          * local trace_kprobes are not added to dyn_event, so they are never
1792          * searched in find_trace_kprobe(). Therefore, there is no concern of
1793          * duplicated name here.
1794          */
1795         event = func ? func : "DUMMY_EVENT";
1796
1797         tk = alloc_trace_kprobe(KPROBE_EVENT_SYSTEM, event, (void *)addr, func,
1798                                 offs, 0 /* maxactive */, 0 /* nargs */,
1799                                 is_return);
1800
1801         if (IS_ERR(tk)) {
1802                 pr_info("Failed to allocate trace_probe.(%d)\n",
1803                         (int)PTR_ERR(tk));
1804                 return ERR_CAST(tk);
1805         }
1806
1807         init_trace_event_call(tk);
1808
1809         if (traceprobe_set_print_fmt(&tk->tp, trace_kprobe_is_return(tk)) < 0) {
1810                 ret = -ENOMEM;
1811                 goto error;
1812         }
1813
1814         ret = __register_trace_kprobe(tk);
1815         if (ret < 0)
1816                 goto error;
1817
1818         return trace_probe_event_call(&tk->tp);
1819 error:
1820         free_trace_kprobe(tk);
1821         return ERR_PTR(ret);
1822 }
1823
1824 void destroy_local_trace_kprobe(struct trace_event_call *event_call)
1825 {
1826         struct trace_kprobe *tk;
1827
1828         tk = trace_kprobe_primary_from_call(event_call);
1829         if (unlikely(!tk))
1830                 return;
1831
1832         if (trace_probe_is_enabled(&tk->tp)) {
1833                 WARN_ON(1);
1834                 return;
1835         }
1836
1837         __unregister_trace_kprobe(tk);
1838
1839         free_trace_kprobe(tk);
1840 }
1841 #endif /* CONFIG_PERF_EVENTS */
1842
1843 static __init void enable_boot_kprobe_events(void)
1844 {
1845         struct trace_array *tr = top_trace_array();
1846         struct trace_event_file *file;
1847         struct trace_kprobe *tk;
1848         struct dyn_event *pos;
1849
1850         mutex_lock(&event_mutex);
1851         for_each_trace_kprobe(tk, pos) {
1852                 list_for_each_entry(file, &tr->events, list)
1853                         if (file->event_call == trace_probe_event_call(&tk->tp))
1854                                 trace_event_enable_disable(file, 1, 0);
1855         }
1856         mutex_unlock(&event_mutex);
1857 }
1858
1859 static __init void setup_boot_kprobe_events(void)
1860 {
1861         char *p, *cmd = kprobe_boot_events_buf;
1862         int ret;
1863
1864         strreplace(kprobe_boot_events_buf, ',', ' ');
1865
1866         while (cmd && *cmd != '\0') {
1867                 p = strchr(cmd, ';');
1868                 if (p)
1869                         *p++ = '\0';
1870
1871                 ret = trace_run_command(cmd, create_or_delete_trace_kprobe);
1872                 if (ret)
1873                         pr_warn("Failed to add event(%d): %s\n", ret, cmd);
1874                 else
1875                         kprobe_boot_events_enabled = true;
1876
1877                 cmd = p;
1878         }
1879
1880         enable_boot_kprobe_events();
1881 }
1882
1883 /*
1884  * Register dynevent at subsys_initcall. This allows kernel to setup kprobe
1885  * events in fs_initcall without tracefs.
1886  */
1887 static __init int init_kprobe_trace_early(void)
1888 {
1889         int ret;
1890
1891         ret = dyn_event_register(&trace_kprobe_ops);
1892         if (ret)
1893                 return ret;
1894
1895         if (register_module_notifier(&trace_kprobe_module_nb))
1896                 return -EINVAL;
1897
1898         return 0;
1899 }
1900 subsys_initcall(init_kprobe_trace_early);
1901
1902 /* Make a tracefs interface for controlling probe points */
1903 static __init int init_kprobe_trace(void)
1904 {
1905         struct dentry *d_tracer;
1906         struct dentry *entry;
1907
1908         d_tracer = tracing_init_dentry();
1909         if (IS_ERR(d_tracer))
1910                 return 0;
1911
1912         entry = tracefs_create_file("kprobe_events", 0644, d_tracer,
1913                                     NULL, &kprobe_events_ops);
1914
1915         /* Event list interface */
1916         if (!entry)
1917                 pr_warn("Could not create tracefs 'kprobe_events' entry\n");
1918
1919         /* Profile interface */
1920         entry = tracefs_create_file("kprobe_profile", 0444, d_tracer,
1921                                     NULL, &kprobe_profile_ops);
1922
1923         if (!entry)
1924                 pr_warn("Could not create tracefs 'kprobe_profile' entry\n");
1925
1926         setup_boot_kprobe_events();
1927
1928         return 0;
1929 }
1930 fs_initcall(init_kprobe_trace);
1931
1932
1933 #ifdef CONFIG_FTRACE_STARTUP_TEST
1934 static __init struct trace_event_file *
1935 find_trace_probe_file(struct trace_kprobe *tk, struct trace_array *tr)
1936 {
1937         struct trace_event_file *file;
1938
1939         list_for_each_entry(file, &tr->events, list)
1940                 if (file->event_call == trace_probe_event_call(&tk->tp))
1941                         return file;
1942
1943         return NULL;
1944 }
1945
1946 /*
1947  * Nobody but us can call enable_trace_kprobe/disable_trace_kprobe at this
1948  * stage, we can do this lockless.
1949  */
1950 static __init int kprobe_trace_self_tests_init(void)
1951 {
1952         int ret, warn = 0;
1953         int (*target)(int, int, int, int, int, int);
1954         struct trace_kprobe *tk;
1955         struct trace_event_file *file;
1956
1957         if (tracing_is_disabled())
1958                 return -ENODEV;
1959
1960         if (kprobe_boot_events_enabled) {
1961                 pr_info("Skipping kprobe tests due to kprobe_event on cmdline\n");
1962                 return 0;
1963         }
1964
1965         target = kprobe_trace_selftest_target;
1966
1967         pr_info("Testing kprobe tracing: ");
1968
1969         ret = trace_run_command("p:testprobe kprobe_trace_selftest_target $stack $stack0 +0($stack)",
1970                                 create_or_delete_trace_kprobe);
1971         if (WARN_ON_ONCE(ret)) {
1972                 pr_warn("error on probing function entry.\n");
1973                 warn++;
1974         } else {
1975                 /* Enable trace point */
1976                 tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
1977                 if (WARN_ON_ONCE(tk == NULL)) {
1978                         pr_warn("error on getting new probe.\n");
1979                         warn++;
1980                 } else {
1981                         file = find_trace_probe_file(tk, top_trace_array());
1982                         if (WARN_ON_ONCE(file == NULL)) {
1983                                 pr_warn("error on getting probe file.\n");
1984                                 warn++;
1985                         } else
1986                                 enable_trace_kprobe(
1987                                         trace_probe_event_call(&tk->tp), file);
1988                 }
1989         }
1990
1991         ret = trace_run_command("r:testprobe2 kprobe_trace_selftest_target $retval",
1992                                 create_or_delete_trace_kprobe);
1993         if (WARN_ON_ONCE(ret)) {
1994                 pr_warn("error on probing function return.\n");
1995                 warn++;
1996         } else {
1997                 /* Enable trace point */
1998                 tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
1999                 if (WARN_ON_ONCE(tk == NULL)) {
2000                         pr_warn("error on getting 2nd new probe.\n");
2001                         warn++;
2002                 } else {
2003                         file = find_trace_probe_file(tk, top_trace_array());
2004                         if (WARN_ON_ONCE(file == NULL)) {
2005                                 pr_warn("error on getting probe file.\n");
2006                                 warn++;
2007                         } else
2008                                 enable_trace_kprobe(
2009                                         trace_probe_event_call(&tk->tp), file);
2010                 }
2011         }
2012
2013         if (warn)
2014                 goto end;
2015
2016         ret = target(1, 2, 3, 4, 5, 6);
2017
2018         /*
2019          * Not expecting an error here, the check is only to prevent the
2020          * optimizer from removing the call to target() as otherwise there
2021          * are no side-effects and the call is never performed.
2022          */
2023         if (ret != 21)
2024                 warn++;
2025
2026         /* Disable trace points before removing it */
2027         tk = find_trace_kprobe("testprobe", KPROBE_EVENT_SYSTEM);
2028         if (WARN_ON_ONCE(tk == NULL)) {
2029                 pr_warn("error on getting test probe.\n");
2030                 warn++;
2031         } else {
2032                 if (trace_kprobe_nhit(tk) != 1) {
2033                         pr_warn("incorrect number of testprobe hits\n");
2034                         warn++;
2035                 }
2036
2037                 file = find_trace_probe_file(tk, top_trace_array());
2038                 if (WARN_ON_ONCE(file == NULL)) {
2039                         pr_warn("error on getting probe file.\n");
2040                         warn++;
2041                 } else
2042                         disable_trace_kprobe(
2043                                 trace_probe_event_call(&tk->tp), file);
2044         }
2045
2046         tk = find_trace_kprobe("testprobe2", KPROBE_EVENT_SYSTEM);
2047         if (WARN_ON_ONCE(tk == NULL)) {
2048                 pr_warn("error on getting 2nd test probe.\n");
2049                 warn++;
2050         } else {
2051                 if (trace_kprobe_nhit(tk) != 1) {
2052                         pr_warn("incorrect number of testprobe2 hits\n");
2053                         warn++;
2054                 }
2055
2056                 file = find_trace_probe_file(tk, top_trace_array());
2057                 if (WARN_ON_ONCE(file == NULL)) {
2058                         pr_warn("error on getting probe file.\n");
2059                         warn++;
2060                 } else
2061                         disable_trace_kprobe(
2062                                 trace_probe_event_call(&tk->tp), file);
2063         }
2064
2065         ret = trace_run_command("-:testprobe", create_or_delete_trace_kprobe);
2066         if (WARN_ON_ONCE(ret)) {
2067                 pr_warn("error on deleting a probe.\n");
2068                 warn++;
2069         }
2070
2071         ret = trace_run_command("-:testprobe2", create_or_delete_trace_kprobe);
2072         if (WARN_ON_ONCE(ret)) {
2073                 pr_warn("error on deleting a probe.\n");
2074                 warn++;
2075         }
2076
2077 end:
2078         ret = dyn_events_release_all(&trace_kprobe_ops);
2079         if (WARN_ON_ONCE(ret)) {
2080                 pr_warn("error on cleaning up probes.\n");
2081                 warn++;
2082         }
2083         /*
2084          * Wait for the optimizer work to finish. Otherwise it might fiddle
2085          * with probes in already freed __init text.
2086          */
2087         wait_for_kprobe_optimizer();
2088         if (warn)
2089                 pr_cont("NG: Some tests are failed. Please check them.\n");
2090         else
2091                 pr_cont("OK\n");
2092         return 0;
2093 }
2094
2095 late_initcall(kprobe_trace_self_tests_init);
2096
2097 #endif