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