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