lib/asan/asan_rtl.cc

   1 //===-- asan_rtl.cc -------------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file is a part of AddressSanitizer, an address sanity checker.
  11 //
  12 // Main file of the ASan run-time library.
  13 //===----------------------------------------------------------------------===//
  14 #include "asan_allocator.h"
  15 #include "asan_interceptors.h"
  16 #include "asan_internal.h"
  17 #include "asan_mapping.h"
  18 #include "asan_poisoning.h"
  19 #include "asan_report.h"
  20 #include "asan_stack.h"
  21 #include "asan_stats.h"
  22 #include "asan_thread.h"
  23 #include "sanitizer_common/sanitizer_atomic.h"
  24 #include "sanitizer_common/sanitizer_flags.h"
  25 #include "sanitizer_common/sanitizer_libc.h"
  26 #include "sanitizer_common/sanitizer_symbolizer.h"
  27 #include "lsan/lsan_common.h"
  28
  29 namespace __asan {
  30
  31 uptr AsanMappingProfile[kAsanMappingProfileSize];
  32
  33 static void AsanDie() {
  34   static atomic_uint32_t num_calls;
  35   if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
  36     // Don't die twice - run a busy loop.
  37     while (1) { }
  38   }
  39   if (flags()->sleep_before_dying) {
  40     Report("Sleeping for %d second(s)\n", flags()->sleep_before_dying);
  41     SleepForSeconds(flags()->sleep_before_dying);
  42   }
  43   if (flags()->unmap_shadow_on_exit) {
  44     if (kMidMemBeg) {
  45       UnmapOrDie((void*)kLowShadowBeg, kMidMemBeg - kLowShadowBeg);
  46       UnmapOrDie((void*)kMidMemEnd, kHighShadowEnd - kMidMemEnd);
  47     } else {
  48       UnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
  49     }
  50   }
  51   if (death_callback)
  52     death_callback();
  53   if (flags()->abort_on_error)
  54     Abort();
  55   internal__exit(flags()->exitcode);
  56 }
  57
  58 static void AsanCheckFailed(const char *file, int line, const char *cond,
  59                             u64 v1, u64 v2) {
  60   Report("AddressSanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n",
  61              file, line, cond, (uptr)v1, (uptr)v2);
  62   // FIXME: check for infinite recursion without a thread-local counter here.
  63   PRINT_CURRENT_STACK();
  64   Die();
  65 }
  66
  67 // -------------------------- Flags ------------------------- {{{1
  68 static const int kDefaultMallocContextSize = 30;
  69
  70 Flags asan_flags_dont_use_directly;  // use via flags().
  71
  72 static const char *MaybeCallAsanDefaultOptions() {
  73   return (&__asan_default_options) ? __asan_default_options() : "";
  74 }
  75
  76 static const char *MaybeUseAsanDefaultOptionsCompileDefiniton() {
  77 #ifdef ASAN_DEFAULT_OPTIONS
  78 // Stringize the macro value.
  79 # define ASAN_STRINGIZE(x) #x
  80 # define ASAN_STRINGIZE_OPTIONS(options) ASAN_STRINGIZE(options)
  81   return ASAN_STRINGIZE_OPTIONS(ASAN_DEFAULT_OPTIONS);
  82 #else
  83   return "";
  84 #endif
  85 }
  86
  87 static void ParseFlagsFromString(Flags *f, const char *str) {
  88   ParseCommonFlagsFromString(str);
  89   CHECK((uptr)common_flags()->malloc_context_size <= kStackTraceMax);
  90
  91   ParseFlag(str, &f->quarantine_size, "quarantine_size");
  92   ParseFlag(str, &f->verbosity, "verbosity");
  93   ParseFlag(str, &f->redzone, "redzone");
  94   CHECK_GE(f->redzone, 16);
  95   CHECK(IsPowerOfTwo(f->redzone));
  96
  97   ParseFlag(str, &f->debug, "debug");
  98   ParseFlag(str, &f->report_globals, "report_globals");
  99   ParseFlag(str, &f->check_initialization_order, "check_initialization_order");
 100
 101   ParseFlag(str, &f->replace_str, "replace_str");
 102   ParseFlag(str, &f->replace_intrin, "replace_intrin");
 103   ParseFlag(str, &f->mac_ignore_invalid_free, "mac_ignore_invalid_free");
 104   ParseFlag(str, &f->use_fake_stack, "use_fake_stack");
 105   ParseFlag(str, &f->max_malloc_fill_size, "max_malloc_fill_size");
 106   ParseFlag(str, &f->malloc_fill_byte, "malloc_fill_byte");
 107   ParseFlag(str, &f->exitcode, "exitcode");
 108   ParseFlag(str, &f->allow_user_poisoning, "allow_user_poisoning");
 109   ParseFlag(str, &f->sleep_before_dying, "sleep_before_dying");
 110   ParseFlag(str, &f->handle_segv, "handle_segv");
 111   ParseFlag(str, &f->allow_user_segv_handler, "allow_user_segv_handler");
 112   ParseFlag(str, &f->use_sigaltstack, "use_sigaltstack");
 113   ParseFlag(str, &f->check_malloc_usable_size, "check_malloc_usable_size");
 114   ParseFlag(str, &f->unmap_shadow_on_exit, "unmap_shadow_on_exit");
 115   ParseFlag(str, &f->abort_on_error, "abort_on_error");
 116   ParseFlag(str, &f->print_stats, "print_stats");
 117   ParseFlag(str, &f->print_legend, "print_legend");
 118   ParseFlag(str, &f->atexit, "atexit");
 119   ParseFlag(str, &f->disable_core, "disable_core");
 120   ParseFlag(str, &f->allow_reexec, "allow_reexec");
 121   ParseFlag(str, &f->print_full_thread_history, "print_full_thread_history");
 122   ParseFlag(str, &f->poison_heap, "poison_heap");
 123   ParseFlag(str, &f->alloc_dealloc_mismatch, "alloc_dealloc_mismatch");
 124   ParseFlag(str, &f->use_stack_depot, "use_stack_depot");
 125   ParseFlag(str, &f->strict_memcmp, "strict_memcmp");
 126   ParseFlag(str, &f->strict_init_order, "strict_init_order");
 127 }
 128
 129 void InitializeFlags(Flags *f, const char *env) {
 130   CommonFlags *cf = common_flags();
 131   cf->external_symbolizer_path = GetEnv("ASAN_SYMBOLIZER_PATH");
 132   cf->symbolize = true;
 133   cf->malloc_context_size = kDefaultMallocContextSize;
 134   cf->fast_unwind_on_fatal = false;
 135   cf->fast_unwind_on_malloc = true;
 136   cf->strip_path_prefix = "";
 137   cf->handle_ioctl = false;
 138   cf->log_path = 0;
 139   cf->detect_leaks = false;
 140   cf->leak_check_at_exit = true;
 141
 142   internal_memset(f, 0, sizeof(*f));
 143   f->quarantine_size = (ASAN_LOW_MEMORY) ? 1UL << 26 : 1UL << 28;
 144   f->verbosity = 0;
 145   f->redzone = 16;
 146   f->debug = false;
 147   f->report_globals = 1;
 148   f->check_initialization_order = false;
 149   f->replace_str = true;
 150   f->replace_intrin = true;
 151   f->mac_ignore_invalid_free = false;
 152   f->use_fake_stack = true;
 153   f->max_malloc_fill_size = 0x1000;  // By default, fill only the first 4K.
 154   f->malloc_fill_byte = 0xbe;
 155   f->exitcode = ASAN_DEFAULT_FAILURE_EXITCODE;
 156   f->allow_user_poisoning = true;
 157   f->sleep_before_dying = 0;
 158   f->handle_segv = ASAN_NEEDS_SEGV;
 159   f->allow_user_segv_handler = false;
 160   f->use_sigaltstack = false;
 161   f->check_malloc_usable_size = true;
 162   f->unmap_shadow_on_exit = false;
 163   f->abort_on_error = false;
 164   f->print_stats = false;
 165   f->print_legend = true;
 166   f->atexit = false;
 167   f->disable_core = (SANITIZER_WORDSIZE == 64);
 168   f->allow_reexec = true;
 169   f->print_full_thread_history = true;
 170   f->poison_heap = true;
 171   // Turn off alloc/dealloc mismatch checker on Mac for now.
 172   // TODO(glider): Fix known issues and enable this back.
 173   f->alloc_dealloc_mismatch = (SANITIZER_MAC == 0);;
 174   f->use_stack_depot = true;
 175   f->strict_memcmp = true;
 176   f->strict_init_order = false;
 177
 178   // Override from compile definition.
 179   ParseFlagsFromString(f, MaybeUseAsanDefaultOptionsCompileDefiniton());
 180
 181   // Override from user-specified string.
 182   ParseFlagsFromString(f, MaybeCallAsanDefaultOptions());
 183   if (flags()->verbosity) {
 184     Report("Using the defaults from __asan_default_options: %s\n",
 185            MaybeCallAsanDefaultOptions());
 186   }
 187
 188   // Override from command line.
 189   ParseFlagsFromString(f, env);
 190
 191 #if !CAN_SANITIZE_LEAKS
 192   if (cf->detect_leaks) {
 193     Report("%s: detect_leaks is not supported on this platform.\n",
 194            SanitizerToolName);
 195     cf->detect_leaks = false;
 196   }
 197 #endif
 198
 199   if (cf->detect_leaks && !f->use_stack_depot) {
 200     Report("%s: detect_leaks is ignored (requires use_stack_depot).\n",
 201            SanitizerToolName);
 202     cf->detect_leaks = false;
 203   }
 204 }
 205
 206 // -------------------------- Globals --------------------- {{{1
 207 int asan_inited;
 208 bool asan_init_is_running;
 209 void (*death_callback)(void);
 210
 211 #if !ASAN_FIXED_MAPPING
 212 uptr kHighMemEnd, kMidMemBeg, kMidMemEnd;
 213 #endif
 214
 215 // -------------------------- Misc ---------------- {{{1
 216 void ShowStatsAndAbort() {
 217   __asan_print_accumulated_stats();
 218   Die();
 219 }
 220
 221 // ---------------------- mmap -------------------- {{{1
 222 // Reserve memory range [beg, end].
 223 static void ReserveShadowMemoryRange(uptr beg, uptr end) {
 224   CHECK_EQ((beg % GetPageSizeCached()), 0);
 225   CHECK_EQ(((end + 1) % GetPageSizeCached()), 0);
 226   uptr size = end - beg + 1;
 227   void *res = MmapFixedNoReserve(beg, size);
 228   if (res != (void*)beg) {
 229     Report("ReserveShadowMemoryRange failed while trying to map 0x%zx bytes. "
 230            "Perhaps you're using ulimit -v\n", size);
 231     Abort();
 232   }
 233 }
 234
 235 // --------------- LowLevelAllocateCallbac ---------- {{{1
 236 static void OnLowLevelAllocate(uptr ptr, uptr size) {
 237   PoisonShadow(ptr, size, kAsanInternalHeapMagic);
 238 }
 239
 240 // -------------------------- Run-time entry ------------------- {{{1
 241 // exported functions
 242 #define ASAN_REPORT_ERROR(type, is_write, size)                     \
 243 extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
 244 void __asan_report_ ## type ## size(uptr addr);                \
 245 void __asan_report_ ## type ## size(uptr addr) {               \
 246   GET_CALLER_PC_BP_SP;                                              \
 247   __asan_report_error(pc, bp, sp, addr, is_write, size);            \
 248 }
 249
 250 ASAN_REPORT_ERROR(load, false, 1)
 251 ASAN_REPORT_ERROR(load, false, 2)
 252 ASAN_REPORT_ERROR(load, false, 4)
 253 ASAN_REPORT_ERROR(load, false, 8)
 254 ASAN_REPORT_ERROR(load, false, 16)
 255 ASAN_REPORT_ERROR(store, true, 1)
 256 ASAN_REPORT_ERROR(store, true, 2)
 257 ASAN_REPORT_ERROR(store, true, 4)
 258 ASAN_REPORT_ERROR(store, true, 8)
 259 ASAN_REPORT_ERROR(store, true, 16)
 260
 261 #define ASAN_REPORT_ERROR_N(type, is_write)                    \
 262 extern "C" NOINLINE INTERFACE_ATTRIBUTE                        \
 263 void __asan_report_ ## type ## _n(uptr addr, uptr size);       \
 264 void __asan_report_ ## type ## _n(uptr addr, uptr size) {      \
 265   GET_CALLER_PC_BP_SP;                                         \
 266   __asan_report_error(pc, bp, sp, addr, is_write, size);       \
 267 }
 268
 269 ASAN_REPORT_ERROR_N(load, false)
 270 ASAN_REPORT_ERROR_N(store, true)
 271
 272 // Force the linker to keep the symbols for various ASan interface functions.
 273 // We want to keep those in the executable in order to let the instrumented
 274 // dynamic libraries access the symbol even if it is not used by the executable
 275 // itself. This should help if the build system is removing dead code at link
 276 // time.
 277 static NOINLINE void force_interface_symbols() {
 278   volatile int fake_condition = 0;  // prevent dead condition elimination.
 279   // __asan_report_* functions are noreturn, so we need a switch to prevent
 280   // the compiler from removing any of them.
 281   switch (fake_condition) {
 282     case 1: __asan_report_load1(0); break;
 283     case 2: __asan_report_load2(0); break;
 284     case 3: __asan_report_load4(0); break;
 285     case 4: __asan_report_load8(0); break;
 286     case 5: __asan_report_load16(0); break;
 287     case 6: __asan_report_store1(0); break;
 288     case 7: __asan_report_store2(0); break;
 289     case 8: __asan_report_store4(0); break;
 290     case 9: __asan_report_store8(0); break;
 291     case 10: __asan_report_store16(0); break;
 292     case 12: __asan_register_globals(0, 0); break;
 293     case 13: __asan_unregister_globals(0, 0); break;
 294     case 14: __asan_set_death_callback(0); break;
 295     case 15: __asan_set_error_report_callback(0); break;
 296     case 16: __asan_handle_no_return(); break;
 297     case 17: __asan_address_is_poisoned(0); break;
 298     case 18: __asan_get_allocated_size(0); break;
 299     case 19: __asan_get_current_allocated_bytes(); break;
 300     case 20: __asan_get_estimated_allocated_size(0); break;
 301     case 21: __asan_get_free_bytes(); break;
 302     case 22: __asan_get_heap_size(); break;
 303     case 23: __asan_get_ownership(0); break;
 304     case 24: __asan_get_unmapped_bytes(); break;
 305     case 25: __asan_poison_memory_region(0, 0); break;
 306     case 26: __asan_unpoison_memory_region(0, 0); break;
 307     case 27: __asan_set_error_exit_code(0); break;
 308     case 28: __asan_stack_free(0, 0, 0); break;
 309     case 29: __asan_stack_malloc(0, 0); break;
 310     case 30: __asan_before_dynamic_init(0); break;
 311     case 31: __asan_after_dynamic_init(); break;
 312     case 32: __asan_poison_stack_memory(0, 0); break;
 313     case 33: __asan_unpoison_stack_memory(0, 0); break;
 314     case 34: __asan_region_is_poisoned(0, 0); break;
 315     case 35: __asan_describe_address(0); break;
 316   }
 317 }
 318
 319 static void asan_atexit() {
 320   Printf("AddressSanitizer exit stats:\n");
 321   __asan_print_accumulated_stats();
 322   // Print AsanMappingProfile.
 323   for (uptr i = 0; i < kAsanMappingProfileSize; i++) {
 324     if (AsanMappingProfile[i] == 0) continue;
 325     Printf("asan_mapping.h:%zd -- %zd\n", i, AsanMappingProfile[i]);
 326   }
 327 }
 328
 329 static void InitializeHighMemEnd() {
 330 #if !ASAN_FIXED_MAPPING
 331   kHighMemEnd = GetMaxVirtualAddress();
 332   // Increase kHighMemEnd to make sure it's properly
 333   // aligned together with kHighMemBeg:
 334   kHighMemEnd |= SHADOW_GRANULARITY * GetPageSizeCached() - 1;
 335 #endif  // !ASAN_FIXED_MAPPING
 336   CHECK_EQ((kHighMemBeg % GetPageSizeCached()), 0);
 337 }
 338
 339 static void ProtectGap(uptr a, uptr size) {
 340   CHECK_EQ(a, (uptr)Mprotect(a, size));
 341 }
 342
 343 static void PrintAddressSpaceLayout() {
 344   Printf("|| `[%p, %p]` || HighMem    ||\n",
 345          (void*)kHighMemBeg, (void*)kHighMemEnd);
 346   Printf("|| `[%p, %p]` || HighShadow ||\n",
 347          (void*)kHighShadowBeg, (void*)kHighShadowEnd);
 348   if (kMidMemBeg) {
 349     Printf("|| `[%p, %p]` || ShadowGap3 ||\n",
 350            (void*)kShadowGap3Beg, (void*)kShadowGap3End);
 351     Printf("|| `[%p, %p]` || MidMem     ||\n",
 352            (void*)kMidMemBeg, (void*)kMidMemEnd);
 353     Printf("|| `[%p, %p]` || ShadowGap2 ||\n",
 354            (void*)kShadowGap2Beg, (void*)kShadowGap2End);
 355     Printf("|| `[%p, %p]` || MidShadow  ||\n",
 356            (void*)kMidShadowBeg, (void*)kMidShadowEnd);
 357   }
 358   Printf("|| `[%p, %p]` || ShadowGap  ||\n",
 359          (void*)kShadowGapBeg, (void*)kShadowGapEnd);
 360   if (kLowShadowBeg) {
 361     Printf("|| `[%p, %p]` || LowShadow  ||\n",
 362            (void*)kLowShadowBeg, (void*)kLowShadowEnd);
 363     Printf("|| `[%p, %p]` || LowMem     ||\n",
 364            (void*)kLowMemBeg, (void*)kLowMemEnd);
 365   }
 366   Printf("MemToShadow(shadow): %p %p %p %p",
 367          (void*)MEM_TO_SHADOW(kLowShadowBeg),
 368          (void*)MEM_TO_SHADOW(kLowShadowEnd),
 369          (void*)MEM_TO_SHADOW(kHighShadowBeg),
 370          (void*)MEM_TO_SHADOW(kHighShadowEnd));
 371   if (kMidMemBeg) {
 372     Printf(" %p %p",
 373            (void*)MEM_TO_SHADOW(kMidShadowBeg),
 374            (void*)MEM_TO_SHADOW(kMidShadowEnd));
 375   }
 376   Printf("\n");
 377   Printf("red_zone=%zu\n", (uptr)flags()->redzone);
 378   Printf("malloc_context_size=%zu\n",
 379          (uptr)common_flags()->malloc_context_size);
 380
 381   Printf("SHADOW_SCALE: %zx\n", (uptr)SHADOW_SCALE);
 382   Printf("SHADOW_GRANULARITY: %zx\n", (uptr)SHADOW_GRANULARITY);
 383   Printf("SHADOW_OFFSET: %zx\n", (uptr)SHADOW_OFFSET);
 384   CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
 385   if (kMidMemBeg)
 386     CHECK(kMidShadowBeg > kLowShadowEnd &&
 387           kMidMemBeg > kMidShadowEnd &&
 388           kHighShadowBeg > kMidMemEnd);
 389 }
 390
 391 }  // namespace __asan
 392
 393 // ---------------------- Interface ---------------- {{{1
 394 using namespace __asan;  // NOLINT
 395
 396 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
 397 extern "C" {
 398 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 399 const char* __asan_default_options() { return ""; }
 400 }  // extern "C"
 401 #endif
 402
 403 int NOINLINE __asan_set_error_exit_code(int exit_code) {
 404   int old = flags()->exitcode;
 405   flags()->exitcode = exit_code;
 406   return old;
 407 }
 408
 409 void NOINLINE __asan_handle_no_return() {
 410   int local_stack;
 411   AsanThread *curr_thread = GetCurrentThread();
 412   CHECK(curr_thread);
 413   uptr PageSize = GetPageSizeCached();
 414   uptr top = curr_thread->stack_top();
 415   uptr bottom = ((uptr)&local_stack - PageSize) & ~(PageSize-1);
 416   static const uptr kMaxExpectedCleanupSize = 64 << 20;  // 64M
 417   if (top - bottom > kMaxExpectedCleanupSize) {
 418     static bool reported_warning = false;
 419     if (reported_warning)
 420       return;
 421     reported_warning = true;
 422     Report("WARNING: ASan is ignoring requested __asan_handle_no_return: "
 423            "stack top: %p; bottom %p; size: %p (%zd)\n"
 424            "False positive error reports may follow\n"
 425            "For details see "
 426            "http://code.google.com/p/address-sanitizer/issues/detail?id=189\n",
 427            top, bottom, top - bottom, top - bottom);
 428     return;
 429   }
 430   PoisonShadow(bottom, top - bottom, 0);
 431 }
 432
 433 void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
 434   death_callback = callback;
 435 }
 436
 437 void __asan_init() {
 438   if (asan_inited) return;
 439   SanitizerToolName = "AddressSanitizer";
 440   CHECK(!asan_init_is_running && "ASan init calls itself!");
 441   asan_init_is_running = true;
 442   InitializeHighMemEnd();
 443
 444   // Make sure we are not statically linked.
 445   AsanDoesNotSupportStaticLinkage();
 446
 447   // Install tool-specific callbacks in sanitizer_common.
 448   SetDieCallback(AsanDie);
 449   SetCheckFailedCallback(AsanCheckFailed);
 450   SetPrintfAndReportCallback(AppendToErrorMessageBuffer);
 451
 452   // Initialize flags. This must be done early, because most of the
 453   // initialization steps look at flags().
 454   const char *options = GetEnv("ASAN_OPTIONS");
 455   InitializeFlags(flags(), options);
 456   __sanitizer_set_report_path(common_flags()->log_path);
 457
 458   if (flags()->verbosity && options) {
 459     Report("Parsed ASAN_OPTIONS: %s\n", options);
 460   }
 461
 462   // Re-exec ourselves if we need to set additional env or command line args.
 463   MaybeReexec();
 464
 465   // Setup internal allocator callback.
 466   SetLowLevelAllocateCallback(OnLowLevelAllocate);
 467
 468   if (flags()->atexit) {
 469     Atexit(asan_atexit);
 470   }
 471
 472   // interceptors
 473   InitializeAsanInterceptors();
 474
 475   ReplaceSystemMalloc();
 476   ReplaceOperatorsNewAndDelete();
 477
 478   uptr shadow_start = kLowShadowBeg;
 479   if (kLowShadowBeg)
 480     shadow_start -= GetMmapGranularity();
 481   bool full_shadow_is_available =
 482       MemoryRangeIsAvailable(shadow_start, kHighShadowEnd);
 483
 484 #if SANITIZER_LINUX && defined(__x86_64__) && !ASAN_FIXED_MAPPING
 485   if (!full_shadow_is_available) {
 486     kMidMemBeg = kLowMemEnd < 0x3000000000ULL ? 0x3000000000ULL : 0;
 487     kMidMemEnd = kLowMemEnd < 0x3000000000ULL ? 0x4fffffffffULL : 0;
 488   }
 489 #endif
 490
 491   if (flags()->verbosity)
 492     PrintAddressSpaceLayout();
 493
 494   if (flags()->disable_core) {
 495     DisableCoreDumper();
 496   }
 497
 498   if (full_shadow_is_available) {
 499     // mmap the low shadow plus at least one page at the left.
 500     if (kLowShadowBeg)
 501       ReserveShadowMemoryRange(shadow_start, kLowShadowEnd);
 502     // mmap the high shadow.
 503     ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
 504     // protect the gap.
 505     ProtectGap(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
 506   } else if (kMidMemBeg &&
 507       MemoryRangeIsAvailable(shadow_start, kMidMemBeg - 1) &&
 508       MemoryRangeIsAvailable(kMidMemEnd + 1, kHighShadowEnd)) {
 509     CHECK(kLowShadowBeg != kLowShadowEnd);
 510     // mmap the low shadow plus at least one page at the left.
 511     ReserveShadowMemoryRange(shadow_start, kLowShadowEnd);
 512     // mmap the mid shadow.
 513     ReserveShadowMemoryRange(kMidShadowBeg, kMidShadowEnd);
 514     // mmap the high shadow.
 515     ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd);
 516     // protect the gaps.
 517     ProtectGap(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
 518     ProtectGap(kShadowGap2Beg, kShadowGap2End - kShadowGap2Beg + 1);
 519     ProtectGap(kShadowGap3Beg, kShadowGap3End - kShadowGap3Beg + 1);
 520   } else {
 521     Report("Shadow memory range interleaves with an existing memory mapping. "
 522            "ASan cannot proceed correctly. ABORTING.\n");
 523     DumpProcessMap();
 524     Die();
 525   }
 526
 527   InstallSignalHandlers();
 528
 529   AsanTSDInit(AsanThread::TSDDtor);
 530   // Allocator should be initialized before starting external symbolizer, as
 531   // fork() on Mac locks the allocator.
 532   InitializeAllocator();
 533
 534   // Start symbolizer process if necessary.
 535   const char* external_symbolizer = common_flags()->external_symbolizer_path;
 536   if (common_flags()->symbolize && external_symbolizer &&
 537       external_symbolizer[0]) {
 538     InitializeExternalSymbolizer(external_symbolizer);
 539   }
 540
 541   // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
 542   // should be set to 1 prior to initializing the threads.
 543   asan_inited = 1;
 544   asan_init_is_running = false;
 545
 546   InitTlsSize();
 547
 548   // Create main thread.
 549   AsanThread *main_thread = AsanThread::Create(0, 0);
 550   CreateThreadContextArgs create_main_args = { main_thread, 0 };
 551   u32 main_tid = asanThreadRegistry().CreateThread(
 552       0, true, 0, &create_main_args);
 553   CHECK_EQ(0, main_tid);
 554   SetCurrentThread(main_thread);
 555   main_thread->ThreadStart(internal_getpid());
 556   force_interface_symbols();  // no-op.
 557
 558 #if CAN_SANITIZE_LEAKS
 559   __lsan::InitCommonLsan();
 560   if (common_flags()->detect_leaks && common_flags()->leak_check_at_exit) {
 561     Atexit(__lsan::DoLeakCheck);
 562   }
 563 #endif  // CAN_SANITIZE_LEAKS
 564
 565   if (flags()->verbosity) {
 566     Report("AddressSanitizer Init done\n");
 567   }
 568 }