kernel/trace/trace

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

DEFINITIONS
