kernel/trace/trace_uprobe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * uprobes-based tracing events
   4  *
   5  * Copyright (C) IBM Corporation, 2010-2012
   6  * Author:      Srikar Dronamraju <srikar@linux.vnet.ibm.com>
   7  */
   8 #define pr_fmt(fmt)     "trace_uprobe: " fmt
   9
  10 #include <linux/ctype.h>
  11 #include <linux/module.h>
  12 #include <linux/uaccess.h>
  13 #include <linux/uprobes.h>
  14 #include <linux/namei.h>
  15 #include <linux/string.h>
  16 #include <linux/rculist.h>
  17
  18 #include "trace_dynevent.h"
  19 #include "trace_probe.h"
  20 #include "trace_probe_tmpl.h"
  21
  22 #define UPROBE_EVENT_SYSTEM     "uprobes"
  23
  24 struct uprobe_trace_entry_head {
  25         struct trace_entry      ent;
  26         unsigned long           vaddr[];
  27 };
  28
  29 #define SIZEOF_TRACE_ENTRY(is_return)                   \
  30         (sizeof(struct uprobe_trace_entry_head) +       \
  31          sizeof(unsigned long) * (is_return ? 2 : 1))
  32
  33 #define DATAOF_TRACE_ENTRY(entry, is_return)            \
  34         ((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
  35
  36 struct trace_uprobe_filter {
  37         rwlock_t                rwlock;
  38         int                     nr_systemwide;
  39         struct list_head        perf_events;
  40 };
  41
  42 static int trace_uprobe_create(int argc, const char **argv);
  43 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
  44 static int trace_uprobe_release(struct dyn_event *ev);
  45 static bool trace_uprobe_is_busy(struct dyn_event *ev);
  46 static bool trace_uprobe_match(const char *system, const char *event,
  47                                struct dyn_event *ev);
  48
  49 static struct dyn_event_operations trace_uprobe_ops = {
  50         .create = trace_uprobe_create,
  51         .show = trace_uprobe_show,
  52         .is_busy = trace_uprobe_is_busy,
  53         .free = trace_uprobe_release,
  54         .match = trace_uprobe_match,
  55 };
  56
  57 /*
  58  * uprobe event core functions
  59  */
  60 struct trace_uprobe {
  61         struct dyn_event                devent;
  62         struct trace_uprobe_filter      filter;
  63         struct uprobe_consumer          consumer;
  64         struct path                     path;
  65         struct inode                    *inode;
  66         char                            *filename;
  67         unsigned long                   offset;
  68         unsigned long                   ref_ctr_offset;
  69         unsigned long                   nhit;
  70         struct trace_probe              tp;
  71 };
  72
  73 static bool is_trace_uprobe(struct dyn_event *ev)
  74 {
  75         return ev->ops == &trace_uprobe_ops;
  76 }
  77
  78 static struct trace_uprobe *to_trace_uprobe(struct dyn_event *ev)
  79 {
  80         return container_of(ev, struct trace_uprobe, devent);
  81 }
  82
  83 /**
  84  * for_each_trace_uprobe - iterate over the trace_uprobe list
  85  * @pos:        the struct trace_uprobe * for each entry
  86  * @dpos:       the struct dyn_event * to use as a loop cursor
  87  */
  88 #define for_each_trace_uprobe(pos, dpos)        \
  89         for_each_dyn_event(dpos)                \
  90                 if (is_trace_uprobe(dpos) && (pos = to_trace_uprobe(dpos)))
  91
  92 #define SIZEOF_TRACE_UPROBE(n)                          \
  93         (offsetof(struct trace_uprobe, tp.args) +       \
  94         (sizeof(struct probe_arg) * (n)))
  95
  96 static int register_uprobe_event(struct trace_uprobe *tu);
  97 static int unregister_uprobe_event(struct trace_uprobe *tu);
  98
  99 struct uprobe_dispatch_data {
 100         struct trace_uprobe     *tu;
 101         unsigned long           bp_addr;
 102 };
 103
 104 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
 105 static int uretprobe_dispatcher(struct uprobe_consumer *con,
 106                                 unsigned long func, struct pt_regs *regs);
 107
 108 #ifdef CONFIG_STACK_GROWSUP
 109 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 110 {
 111         return addr - (n * sizeof(long));
 112 }
 113 #else
 114 static unsigned long adjust_stack_addr(unsigned long addr, unsigned int n)
 115 {
 116         return addr + (n * sizeof(long));
 117 }
 118 #endif
 119
 120 static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n)
 121 {
 122         unsigned long ret;
 123         unsigned long addr = user_stack_pointer(regs);
 124
 125         addr = adjust_stack_addr(addr, n);
 126
 127         if (copy_from_user(&ret, (void __force __user *) addr, sizeof(ret)))
 128                 return 0;
 129
 130         return ret;
 131 }
 132
 133 /*
 134  * Uprobes-specific fetch functions
 135  */
 136 static nokprobe_inline int
 137 probe_mem_read(void *dest, void *src, size_t size)
 138 {
 139         void __user *vaddr = (void __force __user *)src;
 140
 141         return copy_from_user(dest, vaddr, size) ? -EFAULT : 0;
 142 }
 143 /*
 144  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 145  * length and relative data location.
 146  */
 147 static nokprobe_inline int
 148 fetch_store_string(unsigned long addr, void *dest, void *base)
 149 {
 150         long ret;
 151         u32 loc = *(u32 *)dest;
 152         int maxlen  = get_loc_len(loc);
 153         u8 *dst = get_loc_data(dest, base);
 154         void __user *src = (void __force __user *) addr;
 155
 156         if (unlikely(!maxlen))
 157                 return -ENOMEM;
 158
 159         ret = strncpy_from_user(dst, src, maxlen);
 160         if (ret >= 0) {
 161                 if (ret == maxlen)
 162                         dst[ret - 1] = '\0';
 163                 else
 164                         /*
 165                          * Include the terminating null byte. In this case it
 166                          * was copied by strncpy_from_user but not accounted
 167                          * for in ret.
 168                          */
 169                         ret++;
 170                 *(u32 *)dest = make_data_loc(ret, (void *)dst - base);
 171         }
 172
 173         return ret;
 174 }
 175
 176 /* Return the length of string -- including null terminal byte */
 177 static nokprobe_inline int
 178 fetch_store_strlen(unsigned long addr)
 179 {
 180         int len;
 181         void __user *vaddr = (void __force __user *) addr;
 182
 183         len = strnlen_user(vaddr, MAX_STRING_SIZE);
 184
 185         return (len > MAX_STRING_SIZE) ? 0 : len;
 186 }
 187
 188 static unsigned long translate_user_vaddr(unsigned long file_offset)
 189 {
 190         unsigned long base_addr;
 191         struct uprobe_dispatch_data *udd;
 192
 193         udd = (void *) current->utask->vaddr;
 194
 195         base_addr = udd->bp_addr - udd->tu->offset;
 196         return base_addr + file_offset;
 197 }
 198
 199 /* Note that we don't verify it, since the code does not come from user space */
 200 static int
 201 process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
 202                    void *base)
 203 {
 204         unsigned long val;
 205
 206         /* 1st stage: get value from context */
 207         switch (code->op) {
 208         case FETCH_OP_REG:
 209                 val = regs_get_register(regs, code->param);
 210                 break;
 211         case FETCH_OP_STACK:
 212                 val = get_user_stack_nth(regs, code->param);
 213                 break;
 214         case FETCH_OP_STACKP:
 215                 val = user_stack_pointer(regs);
 216                 break;
 217         case FETCH_OP_RETVAL:
 218                 val = regs_return_value(regs);
 219                 break;
 220         case FETCH_OP_IMM:
 221                 val = code->immediate;
 222                 break;
 223         case FETCH_OP_FOFFS:
 224                 val = translate_user_vaddr(code->immediate);
 225                 break;
 226         default:
 227                 return -EILSEQ;
 228         }
 229         code++;
 230
 231         return process_fetch_insn_bottom(code, val, dest, base);
 232 }
 233 NOKPROBE_SYMBOL(process_fetch_insn)
 234
 235 static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
 236 {
 237         rwlock_init(&filter->rwlock);
 238         filter->nr_systemwide = 0;
 239         INIT_LIST_HEAD(&filter->perf_events);
 240 }
 241
 242 static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
 243 {
 244         return !filter->nr_systemwide && list_empty(&filter->perf_events);
 245 }
 246
 247 static inline bool is_ret_probe(struct trace_uprobe *tu)
 248 {
 249         return tu->consumer.ret_handler != NULL;
 250 }
 251
 252 static bool trace_uprobe_is_busy(struct dyn_event *ev)
 253 {
 254         struct trace_uprobe *tu = to_trace_uprobe(ev);
 255
 256         return trace_probe_is_enabled(&tu->tp);
 257 }
 258
 259 static bool trace_uprobe_match(const char *system, const char *event,
 260                                struct dyn_event *ev)
 261 {
 262         struct trace_uprobe *tu = to_trace_uprobe(ev);
 263
 264         return strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
 265                 (!system || strcmp(tu->tp.call.class->system, system) == 0);
 266 }
 267
 268 /*
 269  * Allocate new trace_uprobe and initialize it (including uprobes).
 270  */
 271 static struct trace_uprobe *
 272 alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
 273 {
 274         struct trace_uprobe *tu;
 275
 276         if (!event || !group)
 277                 return ERR_PTR(-EINVAL);
 278
 279         tu = kzalloc(SIZEOF_TRACE_UPROBE(nargs), GFP_KERNEL);
 280         if (!tu)
 281                 return ERR_PTR(-ENOMEM);
 282
 283         tu->tp.call.class = &tu->tp.class;
 284         tu->tp.call.name = kstrdup(event, GFP_KERNEL);
 285         if (!tu->tp.call.name)
 286                 goto error;
 287
 288         tu->tp.class.system = kstrdup(group, GFP_KERNEL);
 289         if (!tu->tp.class.system)
 290                 goto error;
 291
 292         dyn_event_init(&tu->devent, &trace_uprobe_ops);
 293         INIT_LIST_HEAD(&tu->tp.files);
 294         tu->consumer.handler = uprobe_dispatcher;
 295         if (is_ret)
 296                 tu->consumer.ret_handler = uretprobe_dispatcher;
 297         init_trace_uprobe_filter(&tu->filter);
 298         return tu;
 299
 300 error:
 301         kfree(tu->tp.call.name);
 302         kfree(tu);
 303
 304         return ERR_PTR(-ENOMEM);
 305 }
 306
 307 static void free_trace_uprobe(struct trace_uprobe *tu)
 308 {
 309         int i;
 310
 311         if (!tu)
 312                 return;
 313
 314         for (i = 0; i < tu->tp.nr_args; i++)
 315                 traceprobe_free_probe_arg(&tu->tp.args[i]);
 316
 317         path_put(&tu->path);
 318         kfree(tu->tp.call.class->system);
 319         kfree(tu->tp.call.name);
 320         kfree(tu->filename);
 321         kfree(tu);
 322 }
 323
 324 static struct trace_uprobe *find_probe_event(const char *event, const char *group)
 325 {
 326         struct dyn_event *pos;
 327         struct trace_uprobe *tu;
 328
 329         for_each_trace_uprobe(tu, pos)
 330                 if (strcmp(trace_event_name(&tu->tp.call), event) == 0 &&
 331                     strcmp(tu->tp.call.class->system, group) == 0)
 332                         return tu;
 333
 334         return NULL;
 335 }
 336
 337 /* Unregister a trace_uprobe and probe_event */
 338 static int unregister_trace_uprobe(struct trace_uprobe *tu)
 339 {
 340         int ret;
 341
 342         ret = unregister_uprobe_event(tu);
 343         if (ret)
 344                 return ret;
 345
 346         dyn_event_remove(&tu->devent);
 347         free_trace_uprobe(tu);
 348         return 0;
 349 }
 350
 351 /*
 352  * Uprobe with multiple reference counter is not allowed. i.e.
 353  * If inode and offset matches, reference counter offset *must*
 354  * match as well. Though, there is one exception: If user is
 355  * replacing old trace_uprobe with new one(same group/event),
 356  * then we allow same uprobe with new reference counter as far
 357  * as the new one does not conflict with any other existing
 358  * ones.
 359  */
 360 static struct trace_uprobe *find_old_trace_uprobe(struct trace_uprobe *new)
 361 {
 362         struct dyn_event *pos;
 363         struct trace_uprobe *tmp, *old = NULL;
 364         struct inode *new_inode = d_real_inode(new->path.dentry);
 365
 366         old = find_probe_event(trace_event_name(&new->tp.call),
 367                                 new->tp.call.class->system);
 368
 369         for_each_trace_uprobe(tmp, pos) {
 370                 if ((old ? old != tmp : true) &&
 371                     new_inode == d_real_inode(tmp->path.dentry) &&
 372                     new->offset == tmp->offset &&
 373                     new->ref_ctr_offset != tmp->ref_ctr_offset) {
 374                         pr_warn("Reference counter offset mismatch.");
 375                         return ERR_PTR(-EINVAL);
 376                 }
 377         }
 378         return old;
 379 }
 380
 381 /* Register a trace_uprobe and probe_event */
 382 static int register_trace_uprobe(struct trace_uprobe *tu)
 383 {
 384         struct trace_uprobe *old_tu;
 385         int ret;
 386
 387         mutex_lock(&event_mutex);
 388
 389         /* register as an event */
 390         old_tu = find_old_trace_uprobe(tu);
 391         if (IS_ERR(old_tu)) {
 392                 ret = PTR_ERR(old_tu);
 393                 goto end;
 394         }
 395
 396         if (old_tu) {
 397                 /* delete old event */
 398                 ret = unregister_trace_uprobe(old_tu);
 399                 if (ret)
 400                         goto end;
 401         }
 402
 403         ret = register_uprobe_event(tu);
 404         if (ret) {
 405                 pr_warn("Failed to register probe event(%d)\n", ret);
 406                 goto end;
 407         }
 408
 409         dyn_event_add(&tu->devent);
 410
 411 end:
 412         mutex_unlock(&event_mutex);
 413
 414         return ret;
 415 }
 416
 417 /*
 418  * Argument syntax:
 419  *  - Add uprobe: p|r[:[GRP/]EVENT] PATH:OFFSET [FETCHARGS]
 420  *
 421  *  - Remove uprobe: -:[GRP/]EVENT
 422  */
 423 static int trace_uprobe_create(int argc, const char **argv)
 424 {
 425         struct trace_uprobe *tu;
 426         const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
 427         char *arg, *filename, *rctr, *rctr_end, *tmp;
 428         char buf[MAX_EVENT_NAME_LEN];
 429         struct path path;
 430         unsigned long offset, ref_ctr_offset;
 431         bool is_return = false;
 432         int i, ret;
 433
 434         ret = 0;
 435         ref_ctr_offset = 0;
 436
 437         /* argc must be >= 1 */
 438         if (argv[0][0] == 'r')
 439                 is_return = true;
 440         else if (argv[0][0] != 'p' || argc < 2)
 441                 return -ECANCELED;
 442
 443         if (argv[0][1] == ':')
 444                 event = &argv[0][2];
 445
 446         if (!strchr(argv[1], '/'))
 447                 return -ECANCELED;
 448
 449         filename = kstrdup(argv[1], GFP_KERNEL);
 450         if (!filename)
 451                 return -ENOMEM;
 452
 453         /* Find the last occurrence, in case the path contains ':' too. */
 454         arg = strrchr(filename, ':');
 455         if (!arg || !isdigit(arg[1])) {
 456                 kfree(filename);
 457                 return -ECANCELED;
 458         }
 459
 460         *arg++ = '\0';
 461         ret = kern_path(filename, LOOKUP_FOLLOW, &path);
 462         if (ret) {
 463                 kfree(filename);
 464                 return ret;
 465         }
 466         if (!d_is_reg(path.dentry)) {
 467                 ret = -EINVAL;
 468                 goto fail_address_parse;
 469         }
 470
 471         /* Parse reference counter offset if specified. */
 472         rctr = strchr(arg, '(');
 473         if (rctr) {
 474                 rctr_end = strchr(rctr, ')');
 475                 if (rctr > rctr_end || *(rctr_end + 1) != 0) {
 476                         ret = -EINVAL;
 477                         pr_info("Invalid reference counter offset.\n");
 478                         goto fail_address_parse;
 479                 }
 480
 481                 *rctr++ = '\0';
 482                 *rctr_end = '\0';
 483                 ret = kstrtoul(rctr, 0, &ref_ctr_offset);
 484                 if (ret) {
 485                         pr_info("Invalid reference counter offset.\n");
 486                         goto fail_address_parse;
 487                 }
 488         }
 489
 490         /* Parse uprobe offset. */
 491         ret = kstrtoul(arg, 0, &offset);
 492         if (ret)
 493                 goto fail_address_parse;
 494
 495         argc -= 2;
 496         argv += 2;
 497
 498         /* setup a probe */
 499         if (event) {
 500                 ret = traceprobe_parse_event_name(&event, &group, buf);
 501                 if (ret)
 502                         goto fail_address_parse;
 503         } else {
 504                 char *tail;
 505                 char *ptr;
 506
 507                 tail = kstrdup(kbasename(filename), GFP_KERNEL);
 508                 if (!tail) {
 509                         ret = -ENOMEM;
 510                         goto fail_address_parse;
 511                 }
 512
 513                 ptr = strpbrk(tail, ".-_");
 514                 if (ptr)
 515                         *ptr = '\0';
 516
 517                 snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, offset);
 518                 event = buf;
 519                 kfree(tail);
 520         }
 521
 522         tu = alloc_trace_uprobe(group, event, argc, is_return);
 523         if (IS_ERR(tu)) {
 524                 ret = PTR_ERR(tu);
 525                 /* This must return -ENOMEM otherwise there is a bug */
 526                 WARN_ON_ONCE(ret != -ENOMEM);
 527                 goto fail_address_parse;
 528         }
 529         tu->offset = offset;
 530         tu->ref_ctr_offset = ref_ctr_offset;
 531         tu->path = path;
 532         tu->filename = filename;
 533
 534         /* parse arguments */
 535         for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 536                 tmp = kstrdup(argv[i], GFP_KERNEL);
 537                 if (!tmp) {
 538                         ret = -ENOMEM;
 539                         goto error;
 540                 }
 541
 542                 ret = traceprobe_parse_probe_arg(&tu->tp, i, tmp,
 543                                         is_return ? TPARG_FL_RETURN : 0);
 544                 kfree(tmp);
 545                 if (ret)
 546                         goto error;
 547         }
 548
 549         ret = register_trace_uprobe(tu);
 550         if (ret)
 551                 goto error;
 552         return 0;
 553
 554 error:
 555         free_trace_uprobe(tu);
 556         return ret;
 557
 558 fail_address_parse:
 559         path_put(&path);
 560         kfree(filename);
 561
 562         pr_info("Failed to parse address or file.\n");
 563
 564         return ret;
 565 }
 566
 567 static int create_or_delete_trace_uprobe(int argc, char **argv)
 568 {
 569         int ret;
 570
 571         if (argv[0][0] == '-')
 572                 return dyn_event_release(argc, argv, &trace_uprobe_ops);
 573
 574         ret = trace_uprobe_create(argc, (const char **)argv);
 575         return ret == -ECANCELED ? -EINVAL : ret;
 576 }
 577
 578 static int trace_uprobe_release(struct dyn_event *ev)
 579 {
 580         struct trace_uprobe *tu = to_trace_uprobe(ev);
 581
 582         return unregister_trace_uprobe(tu);
 583 }
 584
 585 /* Probes listing interfaces */
 586 static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev)
 587 {
 588         struct trace_uprobe *tu = to_trace_uprobe(ev);
 589         char c = is_ret_probe(tu) ? 'r' : 'p';
 590         int i;
 591
 592         seq_printf(m, "%c:%s/%s %s:0x%0*lx", c, tu->tp.call.class->system,
 593                         trace_event_name(&tu->tp.call), tu->filename,
 594                         (int)(sizeof(void *) * 2), tu->offset);
 595
 596         if (tu->ref_ctr_offset)
 597                 seq_printf(m, "(0x%lx)", tu->ref_ctr_offset);
 598
 599         for (i = 0; i < tu->tp.nr_args; i++)
 600                 seq_printf(m, " %s=%s", tu->tp.args[i].name, tu->tp.args[i].comm);
 601
 602         seq_putc(m, '\n');
 603         return 0;
 604 }
 605
 606 static int probes_seq_show(struct seq_file *m, void *v)
 607 {
 608         struct dyn_event *ev = v;
 609
 610         if (!is_trace_uprobe(ev))
 611                 return 0;
 612
 613         return trace_uprobe_show(m, ev);
 614 }
 615
 616 static const struct seq_operations probes_seq_op = {
 617         .start  = dyn_event_seq_start,
 618         .next   = dyn_event_seq_next,
 619         .stop   = dyn_event_seq_stop,
 620         .show   = probes_seq_show
 621 };
 622
 623 static int probes_open(struct inode *inode, struct file *file)
 624 {
 625         int ret;
 626
 627         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
 628                 ret = dyn_events_release_all(&trace_uprobe_ops);
 629                 if (ret)
 630                         return ret;
 631         }
 632
 633         return seq_open(file, &probes_seq_op);
 634 }
 635
 636 static ssize_t probes_write(struct file *file, const char __user *buffer,
 637                             size_t count, loff_t *ppos)
 638 {
 639         return trace_parse_run_command(file, buffer, count, ppos,
 640                                         create_or_delete_trace_uprobe);
 641 }
 642
 643 static const struct file_operations uprobe_events_ops = {
 644         .owner          = THIS_MODULE,
 645         .open           = probes_open,
 646         .read           = seq_read,
 647         .llseek         = seq_lseek,
 648         .release        = seq_release,
 649         .write          = probes_write,
 650 };
 651
 652 /* Probes profiling interfaces */
 653 static int probes_profile_seq_show(struct seq_file *m, void *v)
 654 {
 655         struct dyn_event *ev = v;
 656         struct trace_uprobe *tu;
 657
 658         if (!is_trace_uprobe(ev))
 659                 return 0;
 660
 661         tu = to_trace_uprobe(ev);
 662         seq_printf(m, "  %s %-44s %15lu\n", tu->filename,
 663                         trace_event_name(&tu->tp.call), tu->nhit);
 664         return 0;
 665 }
 666
 667 static const struct seq_operations profile_seq_op = {
 668         .start  = dyn_event_seq_start,
 669         .next   = dyn_event_seq_next,
 670         .stop   = dyn_event_seq_stop,
 671         .show   = probes_profile_seq_show
 672 };
 673
 674 static int profile_open(struct inode *inode, struct file *file)
 675 {
 676         return seq_open(file, &profile_seq_op);
 677 }
 678
 679 static const struct file_operations uprobe_profile_ops = {
 680         .owner          = THIS_MODULE,
 681         .open           = profile_open,
 682         .read           = seq_read,
 683         .llseek         = seq_lseek,
 684         .release        = seq_release,
 685 };
 686
 687 struct uprobe_cpu_buffer {
 688         struct mutex mutex;
 689         void *buf;
 690 };
 691 static struct uprobe_cpu_buffer __percpu *uprobe_cpu_buffer;
 692 static int uprobe_buffer_refcnt;
 693
 694 static int uprobe_buffer_init(void)
 695 {
 696         int cpu, err_cpu;
 697
 698         uprobe_cpu_buffer = alloc_percpu(struct uprobe_cpu_buffer);
 699         if (uprobe_cpu_buffer == NULL)
 700                 return -ENOMEM;
 701
 702         for_each_possible_cpu(cpu) {
 703                 struct page *p = alloc_pages_node(cpu_to_node(cpu),
 704                                                   GFP_KERNEL, 0);
 705                 if (p == NULL) {
 706                         err_cpu = cpu;
 707                         goto err;
 708                 }
 709                 per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf = page_address(p);
 710                 mutex_init(&per_cpu_ptr(uprobe_cpu_buffer, cpu)->mutex);
 711         }
 712
 713         return 0;
 714
 715 err:
 716         for_each_possible_cpu(cpu) {
 717                 if (cpu == err_cpu)
 718                         break;
 719                 free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer, cpu)->buf);
 720         }
 721
 722         free_percpu(uprobe_cpu_buffer);
 723         return -ENOMEM;
 724 }
 725
 726 static int uprobe_buffer_enable(void)
 727 {
 728         int ret = 0;
 729
 730         BUG_ON(!mutex_is_locked(&event_mutex));
 731
 732         if (uprobe_buffer_refcnt++ == 0) {
 733                 ret = uprobe_buffer_init();
 734                 if (ret < 0)
 735                         uprobe_buffer_refcnt--;
 736         }
 737
 738         return ret;
 739 }
 740
 741 static void uprobe_buffer_disable(void)
 742 {
 743         int cpu;
 744
 745         BUG_ON(!mutex_is_locked(&event_mutex));
 746
 747         if (--uprobe_buffer_refcnt == 0) {
 748                 for_each_possible_cpu(cpu)
 749                         free_page((unsigned long)per_cpu_ptr(uprobe_cpu_buffer,
 750                                                              cpu)->buf);
 751
 752                 free_percpu(uprobe_cpu_buffer);
 753                 uprobe_cpu_buffer = NULL;
 754         }
 755 }
 756
 757 static struct uprobe_cpu_buffer *uprobe_buffer_get(void)
 758 {
 759         struct uprobe_cpu_buffer *ucb;
 760         int cpu;
 761
 762         cpu = raw_smp_processor_id();
 763         ucb = per_cpu_ptr(uprobe_cpu_buffer, cpu);
 764
 765         /*
 766          * Use per-cpu buffers for fastest access, but we might migrate
 767          * so the mutex makes sure we have sole access to it.
 768          */
 769         mutex_lock(&ucb->mutex);
 770
 771         return ucb;
 772 }
 773
 774 static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
 775 {
 776         mutex_unlock(&ucb->mutex);
 777 }
 778
 779 static void __uprobe_trace_func(struct trace_uprobe *tu,
 780                                 unsigned long func, struct pt_regs *regs,
 781                                 struct uprobe_cpu_buffer *ucb, int dsize,
 782                                 struct trace_event_file *trace_file)
 783 {
 784         struct uprobe_trace_entry_head *entry;
 785         struct ring_buffer_event *event;
 786         struct ring_buffer *buffer;
 787         void *data;
 788         int size, esize;
 789         struct trace_event_call *call = &tu->tp.call;
 790
 791         WARN_ON(call != trace_file->event_call);
 792
 793         if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
 794                 return;
 795
 796         if (trace_trigger_soft_disabled(trace_file))
 797                 return;
 798
 799         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
 800         size = esize + tu->tp.size + dsize;
 801         event = trace_event_buffer_lock_reserve(&buffer, trace_file,
 802                                                 call->event.type, size, 0, 0);
 803         if (!event)
 804                 return;
 805
 806         entry = ring_buffer_event_data(event);
 807         if (is_ret_probe(tu)) {
 808                 entry->vaddr[0] = func;
 809                 entry->vaddr[1] = instruction_pointer(regs);
 810                 data = DATAOF_TRACE_ENTRY(entry, true);
 811         } else {
 812                 entry->vaddr[0] = instruction_pointer(regs);
 813                 data = DATAOF_TRACE_ENTRY(entry, false);
 814         }
 815
 816         memcpy(data, ucb->buf, tu->tp.size + dsize);
 817
 818         event_trigger_unlock_commit(trace_file, buffer, event, entry, 0, 0);
 819 }
 820
 821 /* uprobe handler */
 822 static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
 823                              struct uprobe_cpu_buffer *ucb, int dsize)
 824 {
 825         struct event_file_link *link;
 826
 827         if (is_ret_probe(tu))
 828                 return 0;
 829
 830         rcu_read_lock();
 831         list_for_each_entry_rcu(link, &tu->tp.files, list)
 832                 __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
 833         rcu_read_unlock();
 834
 835         return 0;
 836 }
 837
 838 static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
 839                                  struct pt_regs *regs,
 840                                  struct uprobe_cpu_buffer *ucb, int dsize)
 841 {
 842         struct event_file_link *link;
 843
 844         rcu_read_lock();
 845         list_for_each_entry_rcu(link, &tu->tp.files, list)
 846                 __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
 847         rcu_read_unlock();
 848 }
 849
 850 /* Event entry printers */
 851 static enum print_line_t
 852 print_uprobe_event(struct trace_iterator *iter, int flags, struct trace_event *event)
 853 {
 854         struct uprobe_trace_entry_head *entry;
 855         struct trace_seq *s = &iter->seq;
 856         struct trace_uprobe *tu;
 857         u8 *data;
 858
 859         entry = (struct uprobe_trace_entry_head *)iter->ent;
 860         tu = container_of(event, struct trace_uprobe, tp.call.event);
 861
 862         if (is_ret_probe(tu)) {
 863                 trace_seq_printf(s, "%s: (0x%lx <- 0x%lx)",
 864                                  trace_event_name(&tu->tp.call),
 865                                  entry->vaddr[1], entry->vaddr[0]);
 866                 data = DATAOF_TRACE_ENTRY(entry, true);
 867         } else {
 868                 trace_seq_printf(s, "%s: (0x%lx)",
 869                                  trace_event_name(&tu->tp.call),
 870                                  entry->vaddr[0]);
 871                 data = DATAOF_TRACE_ENTRY(entry, false);
 872         }
 873
 874         if (print_probe_args(s, tu->tp.args, tu->tp.nr_args, data, entry) < 0)
 875                 goto out;
 876
 877         trace_seq_putc(s, '\n');
 878
 879  out:
 880         return trace_handle_return(s);
 881 }
 882
 883 typedef bool (*filter_func_t)(struct uprobe_consumer *self,
 884                                 enum uprobe_filter_ctx ctx,
 885                                 struct mm_struct *mm);
 886
 887 static int
 888 probe_event_enable(struct trace_uprobe *tu, struct trace_event_file *file,
 889                    filter_func_t filter)
 890 {
 891         bool enabled = trace_probe_is_enabled(&tu->tp);
 892         struct event_file_link *link = NULL;
 893         int ret;
 894
 895         if (file) {
 896                 if (tu->tp.flags & TP_FLAG_PROFILE)
 897                         return -EINTR;
 898
 899                 link = kmalloc(sizeof(*link), GFP_KERNEL);
 900                 if (!link)
 901                         return -ENOMEM;
 902
 903                 link->file = file;
 904                 list_add_tail_rcu(&link->list, &tu->tp.files);
 905
 906                 tu->tp.flags |= TP_FLAG_TRACE;
 907         } else {
 908                 if (tu->tp.flags & TP_FLAG_TRACE)
 909                         return -EINTR;
 910
 911                 tu->tp.flags |= TP_FLAG_PROFILE;
 912         }
 913
 914         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 915
 916         if (enabled)
 917                 return 0;
 918
 919         ret = uprobe_buffer_enable();
 920         if (ret)
 921                 goto err_flags;
 922
 923         tu->consumer.filter = filter;
 924         tu->inode = d_real_inode(tu->path.dentry);
 925         if (tu->ref_ctr_offset) {
 926                 ret = uprobe_register_refctr(tu->inode, tu->offset,
 927                                 tu->ref_ctr_offset, &tu->consumer);
 928         } else {
 929                 ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
 930         }
 931
 932         if (ret)
 933                 goto err_buffer;
 934
 935         return 0;
 936
 937  err_buffer:
 938         uprobe_buffer_disable();
 939
 940  err_flags:
 941         if (file) {
 942                 list_del(&link->list);
 943                 kfree(link);
 944                 tu->tp.flags &= ~TP_FLAG_TRACE;
 945         } else {
 946                 tu->tp.flags &= ~TP_FLAG_PROFILE;
 947         }
 948         return ret;
 949 }
 950
 951 static void
 952 probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)
 953 {
 954         if (!trace_probe_is_enabled(&tu->tp))
 955                 return;
 956
 957         if (file) {
 958                 struct event_file_link *link;
 959
 960                 link = find_event_file_link(&tu->tp, file);
 961                 if (!link)
 962                         return;
 963
 964                 list_del_rcu(&link->list);
 965                 /* synchronize with u{,ret}probe_trace_func */
 966                 synchronize_rcu();
 967                 kfree(link);
 968
 969                 if (!list_empty(&tu->tp.files))
 970                         return;
 971         }
 972
 973         WARN_ON(!uprobe_filter_is_empty(&tu->filter));
 974
 975         uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
 976         tu->inode = NULL;
 977         tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
 978
 979         uprobe_buffer_disable();
 980 }
 981
 982 static int uprobe_event_define_fields(struct trace_event_call *event_call)
 983 {
 984         int ret, size;
 985         struct uprobe_trace_entry_head field;
 986         struct trace_uprobe *tu = event_call->data;
 987
 988         if (is_ret_probe(tu)) {
 989                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_FUNC, 0);
 990                 DEFINE_FIELD(unsigned long, vaddr[1], FIELD_STRING_RETIP, 0);
 991                 size = SIZEOF_TRACE_ENTRY(true);
 992         } else {
 993                 DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0);
 994                 size = SIZEOF_TRACE_ENTRY(false);
 995         }
 996
 997         return traceprobe_define_arg_fields(event_call, size, &tu->tp);
 998 }
 999
1000 #ifdef CONFIG_PERF_EVENTS
1001 static bool
1002 __uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
1003 {
1004         struct perf_event *event;
1005
1006         if (filter->nr_systemwide)
1007                 return true;
1008
1009         list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
1010                 if (event->hw.target->mm == mm)
1011                         return true;
1012         }
1013
1014         return false;
1015 }
1016
1017 static inline bool
1018 uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
1019 {
1020         return __uprobe_perf_filter(&tu->filter, event->hw.target->mm);
1021 }
1022
1023 static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
1024 {
1025         bool done;
1026
1027         write_lock(&tu->filter.rwlock);
1028         if (event->hw.target) {
1029                 list_del(&event->hw.tp_list);
1030                 done = tu->filter.nr_systemwide ||
1031                         (event->hw.target->flags & PF_EXITING) ||
1032                         uprobe_filter_event(tu, event);
1033         } else {
1034                 tu->filter.nr_systemwide--;
1035                 done = tu->filter.nr_systemwide;
1036         }
1037         write_unlock(&tu->filter.rwlock);
1038
1039         if (!done)
1040                 return uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
1041
1042         return 0;
1043 }
1044
1045 static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
1046 {
1047         bool done;
1048         int err;
1049
1050         write_lock(&tu->filter.rwlock);
1051         if (event->hw.target) {
1052                 /*
1053                  * event->parent != NULL means copy_process(), we can avoid
1054                  * uprobe_apply(). current->mm must be probed and we can rely
1055                  * on dup_mmap() which preserves the already installed bp's.
1056                  *
1057                  * attr.enable_on_exec means that exec/mmap will install the
1058                  * breakpoints we need.
1059                  */
1060                 done = tu->filter.nr_systemwide ||
1061                         event->parent || event->attr.enable_on_exec ||
1062                         uprobe_filter_event(tu, event);
1063                 list_add(&event->hw.tp_list, &tu->filter.perf_events);
1064         } else {
1065                 done = tu->filter.nr_systemwide;
1066                 tu->filter.nr_systemwide++;
1067         }
1068         write_unlock(&tu->filter.rwlock);
1069
1070         err = 0;
1071         if (!done) {
1072                 err = uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
1073                 if (err)
1074                         uprobe_perf_close(tu, event);
1075         }
1076         return err;
1077 }
1078
1079 static bool uprobe_perf_filter(struct uprobe_consumer *uc,
1080                                 enum uprobe_filter_ctx ctx, struct mm_struct *mm)
1081 {
1082         struct trace_uprobe *tu;
1083         int ret;
1084
1085         tu = container_of(uc, struct trace_uprobe, consumer);
1086         read_lock(&tu->filter.rwlock);
1087         ret = __uprobe_perf_filter(&tu->filter, mm);
1088         read_unlock(&tu->filter.rwlock);
1089
1090         return ret;
1091 }
1092
1093 static void __uprobe_perf_func(struct trace_uprobe *tu,
1094                                unsigned long func, struct pt_regs *regs,
1095                                struct uprobe_cpu_buffer *ucb, int dsize)
1096 {
1097         struct trace_event_call *call = &tu->tp.call;
1098         struct uprobe_trace_entry_head *entry;
1099         struct hlist_head *head;
1100         void *data;
1101         int size, esize;
1102         int rctx;
1103
1104         if (bpf_prog_array_valid(call) && !trace_call_bpf(call, regs))
1105                 return;
1106
1107         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1108
1109         size = esize + tu->tp.size + dsize;
1110         size = ALIGN(size + sizeof(u32), sizeof(u64)) - sizeof(u32);
1111         if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
1112                 return;
1113
1114         preempt_disable();
1115         head = this_cpu_ptr(call->perf_events);
1116         if (hlist_empty(head))
1117                 goto out;
1118
1119         entry = perf_trace_buf_alloc(size, NULL, &rctx);
1120         if (!entry)
1121                 goto out;
1122
1123         if (is_ret_probe(tu)) {
1124                 entry->vaddr[0] = func;
1125                 entry->vaddr[1] = instruction_pointer(regs);
1126                 data = DATAOF_TRACE_ENTRY(entry, true);
1127         } else {
1128                 entry->vaddr[0] = instruction_pointer(regs);
1129                 data = DATAOF_TRACE_ENTRY(entry, false);
1130         }
1131
1132         memcpy(data, ucb->buf, tu->tp.size + dsize);
1133
1134         if (size - esize > tu->tp.size + dsize) {
1135                 int len = tu->tp.size + dsize;
1136
1137                 memset(data + len, 0, size - esize - len);
1138         }
1139
1140         perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs,
1141                               head, NULL);
1142  out:
1143         preempt_enable();
1144 }
1145
1146 /* uprobe profile handler */
1147 static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs,
1148                             struct uprobe_cpu_buffer *ucb, int dsize)
1149 {
1150         if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
1151                 return UPROBE_HANDLER_REMOVE;
1152
1153         if (!is_ret_probe(tu))
1154                 __uprobe_perf_func(tu, 0, regs, ucb, dsize);
1155         return 0;
1156 }
1157
1158 static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
1159                                 struct pt_regs *regs,
1160                                 struct uprobe_cpu_buffer *ucb, int dsize)
1161 {
1162         __uprobe_perf_func(tu, func, regs, ucb, dsize);
1163 }
1164
1165 int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
1166                         const char **filename, u64 *probe_offset,
1167                         bool perf_type_tracepoint)
1168 {
1169         const char *pevent = trace_event_name(event->tp_event);
1170         const char *group = event->tp_event->class->system;
1171         struct trace_uprobe *tu;
1172
1173         if (perf_type_tracepoint)
1174                 tu = find_probe_event(pevent, group);
1175         else
1176                 tu = event->tp_event->data;
1177         if (!tu)
1178                 return -EINVAL;
1179
1180         *fd_type = is_ret_probe(tu) ? BPF_FD_TYPE_URETPROBE
1181                                     : BPF_FD_TYPE_UPROBE;
1182         *filename = tu->filename;
1183         *probe_offset = tu->offset;
1184         return 0;
1185 }
1186 #endif  /* CONFIG_PERF_EVENTS */
1187
1188 static int
1189 trace_uprobe_register(struct trace_event_call *event, enum trace_reg type,
1190                       void *data)
1191 {
1192         struct trace_uprobe *tu = event->data;
1193         struct trace_event_file *file = data;
1194
1195         switch (type) {
1196         case TRACE_REG_REGISTER:
1197                 return probe_event_enable(tu, file, NULL);
1198
1199         case TRACE_REG_UNREGISTER:
1200                 probe_event_disable(tu, file);
1201                 return 0;
1202
1203 #ifdef CONFIG_PERF_EVENTS
1204         case TRACE_REG_PERF_REGISTER:
1205                 return probe_event_enable(tu, NULL, uprobe_perf_filter);
1206
1207         case TRACE_REG_PERF_UNREGISTER:
1208                 probe_event_disable(tu, NULL);
1209                 return 0;
1210
1211         case TRACE_REG_PERF_OPEN:
1212                 return uprobe_perf_open(tu, data);
1213
1214         case TRACE_REG_PERF_CLOSE:
1215                 return uprobe_perf_close(tu, data);
1216
1217 #endif
1218         default:
1219                 return 0;
1220         }
1221         return 0;
1222 }
1223
1224 static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
1225 {
1226         struct trace_uprobe *tu;
1227         struct uprobe_dispatch_data udd;
1228         struct uprobe_cpu_buffer *ucb;
1229         int dsize, esize;
1230         int ret = 0;
1231
1232
1233         tu = container_of(con, struct trace_uprobe, consumer);
1234         tu->nhit++;
1235
1236         udd.tu = tu;
1237         udd.bp_addr = instruction_pointer(regs);
1238
1239         current->utask->vaddr = (unsigned long) &udd;
1240
1241         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1242                 return 0;
1243
1244         dsize = __get_data_size(&tu->tp, regs);
1245         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1246
1247         ucb = uprobe_buffer_get();
1248         store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
1249
1250         if (tu->tp.flags & TP_FLAG_TRACE)
1251                 ret |= uprobe_trace_func(tu, regs, ucb, dsize);
1252
1253 #ifdef CONFIG_PERF_EVENTS
1254         if (tu->tp.flags & TP_FLAG_PROFILE)
1255                 ret |= uprobe_perf_func(tu, regs, ucb, dsize);
1256 #endif
1257         uprobe_buffer_put(ucb);
1258         return ret;
1259 }
1260
1261 static int uretprobe_dispatcher(struct uprobe_consumer *con,
1262                                 unsigned long func, struct pt_regs *regs)
1263 {
1264         struct trace_uprobe *tu;
1265         struct uprobe_dispatch_data udd;
1266         struct uprobe_cpu_buffer *ucb;
1267         int dsize, esize;
1268
1269         tu = container_of(con, struct trace_uprobe, consumer);
1270
1271         udd.tu = tu;
1272         udd.bp_addr = func;
1273
1274         current->utask->vaddr = (unsigned long) &udd;
1275
1276         if (WARN_ON_ONCE(!uprobe_cpu_buffer))
1277                 return 0;
1278
1279         dsize = __get_data_size(&tu->tp, regs);
1280         esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
1281
1282         ucb = uprobe_buffer_get();
1283         store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);
1284
1285         if (tu->tp.flags & TP_FLAG_TRACE)
1286                 uretprobe_trace_func(tu, func, regs, ucb, dsize);
1287
1288 #ifdef CONFIG_PERF_EVENTS
1289         if (tu->tp.flags & TP_FLAG_PROFILE)
1290                 uretprobe_perf_func(tu, func, regs, ucb, dsize);
1291 #endif
1292         uprobe_buffer_put(ucb);
1293         return 0;
1294 }
1295
1296 static struct trace_event_functions uprobe_funcs = {
1297         .trace          = print_uprobe_event
1298 };
1299
1300 static inline void init_trace_event_call(struct trace_uprobe *tu,
1301                                          struct trace_event_call *call)
1302 {
1303         INIT_LIST_HEAD(&call->class->fields);
1304         call->event.funcs = &uprobe_funcs;
1305         call->class->define_fields = uprobe_event_define_fields;
1306
1307         call->flags = TRACE_EVENT_FL_UPROBE;
1308         call->class->reg = trace_uprobe_register;
1309         call->data = tu;
1310 }
1311
1312 static int register_uprobe_event(struct trace_uprobe *tu)
1313 {
1314         struct trace_event_call *call = &tu->tp.call;
1315         int ret = 0;
1316
1317         init_trace_event_call(tu, call);
1318
1319         if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0)
1320                 return -ENOMEM;
1321
1322         ret = register_trace_event(&call->event);
1323         if (!ret) {
1324                 kfree(call->print_fmt);
1325                 return -ENODEV;
1326         }
1327
1328         ret = trace_add_event_call(call);
1329
1330         if (ret) {
1331                 pr_info("Failed to register uprobe event: %s\n",
1332                         trace_event_name(call));
1333                 kfree(call->print_fmt);
1334                 unregister_trace_event(&call->event);
1335         }
1336
1337         return ret;
1338 }
1339
1340 static int unregister_uprobe_event(struct trace_uprobe *tu)
1341 {
1342         int ret;
1343
1344         /* tu->event is unregistered in trace_remove_event_call() */
1345         ret = trace_remove_event_call(&tu->tp.call);
1346         if (ret)
1347                 return ret;
1348         kfree(tu->tp.call.print_fmt);
1349         tu->tp.call.print_fmt = NULL;
1350         return 0;
1351 }
1352
1353 #ifdef CONFIG_PERF_EVENTS
1354 struct trace_event_call *
1355 create_local_trace_uprobe(char *name, unsigned long offs,
1356                           unsigned long ref_ctr_offset, bool is_return)
1357 {
1358         struct trace_uprobe *tu;
1359         struct path path;
1360         int ret;
1361
1362         ret = kern_path(name, LOOKUP_FOLLOW, &path);
1363         if (ret)
1364                 return ERR_PTR(ret);
1365
1366         if (!d_is_reg(path.dentry)) {
1367                 path_put(&path);
1368                 return ERR_PTR(-EINVAL);
1369         }
1370
1371         /*
1372          * local trace_kprobes are not added to dyn_event, so they are never
1373          * searched in find_trace_kprobe(). Therefore, there is no concern of
1374          * duplicated name "DUMMY_EVENT" here.
1375          */
1376         tu = alloc_trace_uprobe(UPROBE_EVENT_SYSTEM, "DUMMY_EVENT", 0,
1377                                 is_return);
1378
1379         if (IS_ERR(tu)) {
1380                 pr_info("Failed to allocate trace_uprobe.(%d)\n",
1381                         (int)PTR_ERR(tu));
1382                 path_put(&path);
1383                 return ERR_CAST(tu);
1384         }
1385
1386         tu->offset = offs;
1387         tu->path = path;
1388         tu->ref_ctr_offset = ref_ctr_offset;
1389         tu->filename = kstrdup(name, GFP_KERNEL);
1390         init_trace_event_call(tu, &tu->tp.call);
1391
1392         if (traceprobe_set_print_fmt(&tu->tp, is_ret_probe(tu)) < 0) {
1393                 ret = -ENOMEM;
1394                 goto error;
1395         }
1396
1397         return &tu->tp.call;
1398 error:
1399         free_trace_uprobe(tu);
1400         return ERR_PTR(ret);
1401 }
1402
1403 void destroy_local_trace_uprobe(struct trace_event_call *event_call)
1404 {
1405         struct trace_uprobe *tu;
1406
1407         tu = container_of(event_call, struct trace_uprobe, tp.call);
1408
1409         kfree(tu->tp.call.print_fmt);
1410         tu->tp.call.print_fmt = NULL;
1411
1412         free_trace_uprobe(tu);
1413 }
1414 #endif /* CONFIG_PERF_EVENTS */
1415
1416 /* Make a trace interface for controling probe points */
1417 static __init int init_uprobe_trace(void)
1418 {
1419         struct dentry *d_tracer;
1420         int ret;
1421
1422         ret = dyn_event_register(&trace_uprobe_ops);
1423         if (ret)
1424                 return ret;
1425
1426         d_tracer = tracing_init_dentry();
1427         if (IS_ERR(d_tracer))
1428                 return 0;
1429
1430         trace_create_file("uprobe_events", 0644, d_tracer,
1431                                     NULL, &uprobe_events_ops);
1432         /* Profile interface */
1433         trace_create_file("uprobe_profile", 0444, d_tracer,
1434                                     NULL, &uprobe_profile_ops);
1435         return 0;
1436 }
1437
1438 fs_initcall(init_uprobe_trace);