Home | History | Annotate | Download | only in asan 
      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 
     15 #include "asan_activation.h"
     16 #include "asan_allocator.h"
     17 #include "asan_interceptors.h"
     18 #include "asan_interface_internal.h"
     19 #include "asan_internal.h"
     20 #include "asan_mapping.h"
     21 #include "asan_poisoning.h"
     22 #include "asan_report.h"
     23 #include "asan_stack.h"
     24 #include "asan_stats.h"
     25 #include "asan_suppressions.h"
     26 #include "asan_thread.h"
     27 #include "sanitizer_common/sanitizer_atomic.h"
     28 #include "sanitizer_common/sanitizer_flags.h"
     29 #include "sanitizer_common/sanitizer_libc.h"
     30 #include "sanitizer_common/sanitizer_symbolizer.h"
     31 #include "lsan/lsan_common.h"
     32 #include "ubsan/ubsan_init.h"
     33 #include "ubsan/ubsan_platform.h"
     34 
     35 int __asan_option_detect_stack_use_after_return;  // Global interface symbol.
     36 uptr *__asan_test_only_reported_buggy_pointer;  // Used only for testing asan.
     37 
     38 namespace __asan {
     39 
     40 uptr AsanMappingProfile[kAsanMappingProfileSize];
     41 
     42 static void AsanDie() {
     43   static atomic_uint32_t num_calls;
     44   if (atomic_fetch_add(&num_calls, 1, memory_order_relaxed) != 0) {
     45     // Don't die twice - run a busy loop.
     46     while (1) { }
     47   }
     48   if (flags()->sleep_before_dying) {
     49     Report("Sleeping for %d second(s)\n", flags()->sleep_before_dying);
     50     SleepForSeconds(flags()->sleep_before_dying);
     51   }
     52   if (flags()->unmap_shadow_on_exit) {
     53     if (kMidMemBeg) {
     54       UnmapOrDie((void*)kLowShadowBeg, kMidMemBeg - kLowShadowBeg);
     55       UnmapOrDie((void*)kMidMemEnd, kHighShadowEnd - kMidMemEnd);
     56     } else {
     57       UnmapOrDie((void*)kLowShadowBeg, kHighShadowEnd - kLowShadowBeg);
     58     }
     59   }
     60 }
     61 
     62 static void AsanCheckFailed(const char *file, int line, const char *cond,
     63                             u64 v1, u64 v2) {
     64   Report("AddressSanitizer CHECK failed: %s:%d \"%s\" (0x%zx, 0x%zx)\n", file,
     65          line, cond, (uptr)v1, (uptr)v2);
     66   // FIXME: check for infinite recursion without a thread-local counter here.
     67   PRINT_CURRENT_STACK_CHECK();
     68   Die();
     69 }
     70 
     71 // -------------------------- Globals --------------------- {{{1
     72 int asan_inited;
     73 bool asan_init_is_running;
     74 
     75 #if !ASAN_FIXED_MAPPING
     76 uptr kHighMemEnd, kMidMemBeg, kMidMemEnd;
     77 #endif
     78 
     79 // -------------------------- Misc ---------------- {{{1
     80 void ShowStatsAndAbort() {
     81   __asan_print_accumulated_stats();
     82   Die();
     83 }
     84 
     85 // ---------------------- mmap -------------------- {{{1
     86 // Reserve memory range [beg, end].
     87 // We need to use inclusive range because end+1 may not be representable.
     88 void ReserveShadowMemoryRange(uptr beg, uptr end, const char *name) {
     89   CHECK_EQ((beg % GetMmapGranularity()), 0);
     90   CHECK_EQ(((end + 1) % GetMmapGranularity()), 0);
     91   uptr size = end - beg + 1;
     92   DecreaseTotalMmap(size);  // Don't count the shadow against mmap_limit_mb.
     93   void *res = MmapFixedNoReserve(beg, size, name);
     94   if (res != (void*)beg) {
     95     Report("ReserveShadowMemoryRange failed while trying to map 0x%zx bytes. "
     96            "Perhaps you're using ulimit -v\n", size);
     97     Abort();
     98   }
     99   if (common_flags()->no_huge_pages_for_shadow)
    100     NoHugePagesInRegion(beg, size);
    101   if (common_flags()->use_madv_dontdump)
    102     DontDumpShadowMemory(beg, size);
    103 }
    104 
    105 // --------------- LowLevelAllocateCallbac ---------- {{{1
    106 static void OnLowLevelAllocate(uptr ptr, uptr size) {
    107   PoisonShadow(ptr, size, kAsanInternalHeapMagic);
    108 }
    109 
    110 // -------------------------- Run-time entry ------------------- {{{1
    111 // exported functions
    112 #define ASAN_REPORT_ERROR(type, is_write, size)                     \
    113 extern "C" NOINLINE INTERFACE_ATTRIBUTE                             \
    114 void __asan_report_ ## type ## size(uptr addr) {                    \
    115   GET_CALLER_PC_BP_SP;                                              \
    116   ReportGenericError(pc, bp, sp, addr, is_write, size, 0, true);    \
    117 }                                                                   \
    118 extern "C" NOINLINE INTERFACE_ATTRIBUTE                             \
    119 void __asan_report_exp_ ## type ## size(uptr addr, u32 exp) {       \
    120   GET_CALLER_PC_BP_SP;                                              \
    121   ReportGenericError(pc, bp, sp, addr, is_write, size, exp, true);  \
    122 }                                                                   \
    123 extern "C" NOINLINE INTERFACE_ATTRIBUTE                             \
    124 void __asan_report_ ## type ## size ## _noabort(uptr addr) {        \
    125   GET_CALLER_PC_BP_SP;                                              \
    126   ReportGenericError(pc, bp, sp, addr, is_write, size, 0, false);   \
    127 }                                                                   \
    128 
    129 ASAN_REPORT_ERROR(load, false, 1)
    130 ASAN_REPORT_ERROR(load, false, 2)
    131 ASAN_REPORT_ERROR(load, false, 4)
    132 ASAN_REPORT_ERROR(load, false, 8)
    133 ASAN_REPORT_ERROR(load, false, 16)
    134 ASAN_REPORT_ERROR(store, true, 1)
    135 ASAN_REPORT_ERROR(store, true, 2)
    136 ASAN_REPORT_ERROR(store, true, 4)
    137 ASAN_REPORT_ERROR(store, true, 8)
    138 ASAN_REPORT_ERROR(store, true, 16)
    139 
    140 #define ASAN_REPORT_ERROR_N(type, is_write)                                 \
    141 extern "C" NOINLINE INTERFACE_ATTRIBUTE                                     \
    142 void __asan_report_ ## type ## _n(uptr addr, uptr size) {                   \
    143   GET_CALLER_PC_BP_SP;                                                      \
    144   ReportGenericError(pc, bp, sp, addr, is_write, size, 0, true);            \
    145 }                                                                           \
    146 extern "C" NOINLINE INTERFACE_ATTRIBUTE                                     \
    147 void __asan_report_exp_ ## type ## _n(uptr addr, uptr size, u32 exp) {      \
    148   GET_CALLER_PC_BP_SP;                                                      \
    149   ReportGenericError(pc, bp, sp, addr, is_write, size, exp, true);          \
    150 }                                                                           \
    151 extern "C" NOINLINE INTERFACE_ATTRIBUTE                                     \
    152 void __asan_report_ ## type ## _n_noabort(uptr addr, uptr size) {           \
    153   GET_CALLER_PC_BP_SP;                                                      \
    154   ReportGenericError(pc, bp, sp, addr, is_write, size, 0, false);           \
    155 }                                                                           \
    156 
    157 ASAN_REPORT_ERROR_N(load, false)
    158 ASAN_REPORT_ERROR_N(store, true)
    159 
    160 #define ASAN_MEMORY_ACCESS_CALLBACK_BODY(type, is_write, size, exp_arg, fatal) \
    161     uptr sp = MEM_TO_SHADOW(addr);                                             \
    162     uptr s = size <= SHADOW_GRANULARITY ? *reinterpret_cast<u8 *>(sp)          \
    163                                         : *reinterpret_cast<u16 *>(sp);        \
    164     if (UNLIKELY(s)) {                                                         \
    165       if (UNLIKELY(size >= SHADOW_GRANULARITY ||                               \
    166                    ((s8)((addr & (SHADOW_GRANULARITY - 1)) + size - 1)) >=     \
    167                        (s8)s)) {                                               \
    168         if (__asan_test_only_reported_buggy_pointer) {                         \
    169           *__asan_test_only_reported_buggy_pointer = addr;                     \
    170         } else {                                                               \
    171           GET_CALLER_PC_BP_SP;                                                 \
    172           ReportGenericError(pc, bp, sp, addr, is_write, size, exp_arg,        \
    173                               fatal);                                          \
    174         }                                                                      \
    175       }                                                                        \
    176     }
    177 
    178 #define ASAN_MEMORY_ACCESS_CALLBACK(type, is_write, size)                      \
    179   extern "C" NOINLINE INTERFACE_ATTRIBUTE                                      \
    180   void __asan_##type##size(uptr addr) {                                        \
    181     ASAN_MEMORY_ACCESS_CALLBACK_BODY(type, is_write, size, 0, true)            \
    182   }                                                                            \
    183   extern "C" NOINLINE INTERFACE_ATTRIBUTE                                      \
    184   void __asan_exp_##type##size(uptr addr, u32 exp) {                           \
    185     ASAN_MEMORY_ACCESS_CALLBACK_BODY(type, is_write, size, exp, true)          \
    186   }                                                                            \
    187   extern "C" NOINLINE INTERFACE_ATTRIBUTE                                      \
    188   void __asan_##type##size ## _noabort(uptr addr) {                            \
    189     ASAN_MEMORY_ACCESS_CALLBACK_BODY(type, is_write, size, 0, false)           \
    190   }                                                                            \
    191 
    192 ASAN_MEMORY_ACCESS_CALLBACK(load, false, 1)
    193 ASAN_MEMORY_ACCESS_CALLBACK(load, false, 2)
    194 ASAN_MEMORY_ACCESS_CALLBACK(load, false, 4)
    195 ASAN_MEMORY_ACCESS_CALLBACK(load, false, 8)
    196 ASAN_MEMORY_ACCESS_CALLBACK(load, false, 16)
    197 ASAN_MEMORY_ACCESS_CALLBACK(store, true, 1)
    198 ASAN_MEMORY_ACCESS_CALLBACK(store, true, 2)
    199 ASAN_MEMORY_ACCESS_CALLBACK(store, true, 4)
    200 ASAN_MEMORY_ACCESS_CALLBACK(store, true, 8)
    201 ASAN_MEMORY_ACCESS_CALLBACK(store, true, 16)
    202 
    203 extern "C"
    204 NOINLINE INTERFACE_ATTRIBUTE
    205 void __asan_loadN(uptr addr, uptr size) {
    206   if (__asan_region_is_poisoned(addr, size)) {
    207     GET_CALLER_PC_BP_SP;
    208     ReportGenericError(pc, bp, sp, addr, false, size, 0, true);
    209   }
    210 }
    211 
    212 extern "C"
    213 NOINLINE INTERFACE_ATTRIBUTE
    214 void __asan_exp_loadN(uptr addr, uptr size, u32 exp) {
    215   if (__asan_region_is_poisoned(addr, size)) {
    216     GET_CALLER_PC_BP_SP;
    217     ReportGenericError(pc, bp, sp, addr, false, size, exp, true);
    218   }
    219 }
    220 
    221 extern "C"
    222 NOINLINE INTERFACE_ATTRIBUTE
    223 void __asan_loadN_noabort(uptr addr, uptr size) {
    224   if (__asan_region_is_poisoned(addr, size)) {
    225     GET_CALLER_PC_BP_SP;
    226     ReportGenericError(pc, bp, sp, addr, false, size, 0, false);
    227   }
    228 }
    229 
    230 extern "C"
    231 NOINLINE INTERFACE_ATTRIBUTE
    232 void __asan_storeN(uptr addr, uptr size) {
    233   if (__asan_region_is_poisoned(addr, size)) {
    234     GET_CALLER_PC_BP_SP;
    235     ReportGenericError(pc, bp, sp, addr, true, size, 0, true);
    236   }
    237 }
    238 
    239 extern "C"
    240 NOINLINE INTERFACE_ATTRIBUTE
    241 void __asan_exp_storeN(uptr addr, uptr size, u32 exp) {
    242   if (__asan_region_is_poisoned(addr, size)) {
    243     GET_CALLER_PC_BP_SP;
    244     ReportGenericError(pc, bp, sp, addr, true, size, exp, true);
    245   }
    246 }
    247 
    248 extern "C"
    249 NOINLINE INTERFACE_ATTRIBUTE
    250 void __asan_storeN_noabort(uptr addr, uptr size) {
    251   if (__asan_region_is_poisoned(addr, size)) {
    252     GET_CALLER_PC_BP_SP;
    253     ReportGenericError(pc, bp, sp, addr, true, size, 0, false);
    254   }
    255 }
    256 
    257 // Force the linker to keep the symbols for various ASan interface functions.
    258 // We want to keep those in the executable in order to let the instrumented
    259 // dynamic libraries access the symbol even if it is not used by the executable
    260 // itself. This should help if the build system is removing dead code at link
    261 // time.
    262 static NOINLINE void force_interface_symbols() {
    263   volatile int fake_condition = 0;  // prevent dead condition elimination.
    264   // __asan_report_* functions are noreturn, so we need a switch to prevent
    265   // the compiler from removing any of them.
    266   switch (fake_condition) {
    267     case 1: __asan_report_load1(0); break;
    268     case 2: __asan_report_load2(0); break;
    269     case 3: __asan_report_load4(0); break;
    270     case 4: __asan_report_load8(0); break;
    271     case 5: __asan_report_load16(0); break;
    272     case 6: __asan_report_load_n(0, 0); break;
    273     case 7: __asan_report_store1(0); break;
    274     case 8: __asan_report_store2(0); break;
    275     case 9: __asan_report_store4(0); break;
    276     case 10: __asan_report_store8(0); break;
    277     case 11: __asan_report_store16(0); break;
    278     case 12: __asan_report_store_n(0, 0); break;
    279     case 13: __asan_report_exp_load1(0, 0); break;
    280     case 14: __asan_report_exp_load2(0, 0); break;
    281     case 15: __asan_report_exp_load4(0, 0); break;
    282     case 16: __asan_report_exp_load8(0, 0); break;
    283     case 17: __asan_report_exp_load16(0, 0); break;
    284     case 18: __asan_report_exp_load_n(0, 0, 0); break;
    285     case 19: __asan_report_exp_store1(0, 0); break;
    286     case 20: __asan_report_exp_store2(0, 0); break;
    287     case 21: __asan_report_exp_store4(0, 0); break;
    288     case 22: __asan_report_exp_store8(0, 0); break;
    289     case 23: __asan_report_exp_store16(0, 0); break;
    290     case 24: __asan_report_exp_store_n(0, 0, 0); break;
    291     case 25: __asan_register_globals(nullptr, 0); break;
    292     case 26: __asan_unregister_globals(nullptr, 0); break;
    293     case 27: __asan_set_death_callback(nullptr); break;
    294     case 28: __asan_set_error_report_callback(nullptr); break;
    295     case 29: __asan_handle_no_return(); break;
    296     case 30: __asan_address_is_poisoned(nullptr); break;
    297     case 31: __asan_poison_memory_region(nullptr, 0); break;
    298     case 32: __asan_unpoison_memory_region(nullptr, 0); break;
    299     case 34: __asan_before_dynamic_init(nullptr); break;
    300     case 35: __asan_after_dynamic_init(); break;
    301     case 36: __asan_poison_stack_memory(0, 0); break;
    302     case 37: __asan_unpoison_stack_memory(0, 0); break;
    303     case 38: __asan_region_is_poisoned(0, 0); break;
    304     case 39: __asan_describe_address(0); break;
    305   }
    306 }
    307 
    308 static void asan_atexit() {
    309   Printf("AddressSanitizer exit stats:\n");
    310   __asan_print_accumulated_stats();
    311   // Print AsanMappingProfile.
    312   for (uptr i = 0; i < kAsanMappingProfileSize; i++) {
    313     if (AsanMappingProfile[i] == 0) continue;
    314     Printf("asan_mapping.h:%zd -- %zd\n", i, AsanMappingProfile[i]);
    315   }
    316 }
    317 
    318 static void InitializeHighMemEnd() {
    319 #if !ASAN_FIXED_MAPPING
    320   kHighMemEnd = GetMaxVirtualAddress();
    321   // Increase kHighMemEnd to make sure it's properly
    322   // aligned together with kHighMemBeg:
    323   kHighMemEnd |= SHADOW_GRANULARITY * GetMmapGranularity() - 1;
    324 #endif  // !ASAN_FIXED_MAPPING
    325   CHECK_EQ((kHighMemBeg % GetMmapGranularity()), 0);
    326 }
    327 
    328 static void ProtectGap(uptr addr, uptr size) {
    329   if (!flags()->protect_shadow_gap)
    330     return;
    331   void *res = MmapFixedNoAccess(addr, size, "shadow gap");
    332   if (addr == (uptr)res)
    333     return;
    334   // A few pages at the start of the address space can not be protected.
    335   // But we really want to protect as much as possible, to prevent this memory
    336   // being returned as a result of a non-FIXED mmap().
    337   if (addr == kZeroBaseShadowStart) {
    338     uptr step = GetMmapGranularity();
    339     while (size > step && addr < kZeroBaseMaxShadowStart) {
    340       addr += step;
    341       size -= step;
    342       void *res = MmapFixedNoAccess(addr, size, "shadow gap");
    343       if (addr == (uptr)res)
    344         return;
    345     }
    346   }
    347 
    348   Report("ERROR: Failed to protect the shadow gap. "
    349          "ASan cannot proceed correctly. ABORTING.\n");
    350   DumpProcessMap();
    351   Die();
    352 }
    353 
    354 static void PrintAddressSpaceLayout() {
    355   Printf("|| `[%p, %p]` || HighMem    ||\n",
    356          (void*)kHighMemBeg, (void*)kHighMemEnd);
    357   Printf("|| `[%p, %p]` || HighShadow ||\n",
    358          (void*)kHighShadowBeg, (void*)kHighShadowEnd);
    359   if (kMidMemBeg) {
    360     Printf("|| `[%p, %p]` || ShadowGap3 ||\n",
    361            (void*)kShadowGap3Beg, (void*)kShadowGap3End);
    362     Printf("|| `[%p, %p]` || MidMem     ||\n",
    363            (void*)kMidMemBeg, (void*)kMidMemEnd);
    364     Printf("|| `[%p, %p]` || ShadowGap2 ||\n",
    365            (void*)kShadowGap2Beg, (void*)kShadowGap2End);
    366     Printf("|| `[%p, %p]` || MidShadow  ||\n",
    367            (void*)kMidShadowBeg, (void*)kMidShadowEnd);
    368   }
    369   Printf("|| `[%p, %p]` || ShadowGap  ||\n",
    370          (void*)kShadowGapBeg, (void*)kShadowGapEnd);
    371   if (kLowShadowBeg) {
    372     Printf("|| `[%p, %p]` || LowShadow  ||\n",
    373            (void*)kLowShadowBeg, (void*)kLowShadowEnd);
    374     Printf("|| `[%p, %p]` || LowMem     ||\n",
    375            (void*)kLowMemBeg, (void*)kLowMemEnd);
    376   }
    377   Printf("MemToShadow(shadow): %p %p %p %p",
    378          (void*)MEM_TO_SHADOW(kLowShadowBeg),
    379          (void*)MEM_TO_SHADOW(kLowShadowEnd),
    380          (void*)MEM_TO_SHADOW(kHighShadowBeg),
    381          (void*)MEM_TO_SHADOW(kHighShadowEnd));
    382   if (kMidMemBeg) {
    383     Printf(" %p %p",
    384            (void*)MEM_TO_SHADOW(kMidShadowBeg),
    385            (void*)MEM_TO_SHADOW(kMidShadowEnd));
    386   }
    387   Printf("\n");
    388   Printf("redzone=%zu\n", (uptr)flags()->redzone);
    389   Printf("max_redzone=%zu\n", (uptr)flags()->max_redzone);
    390   Printf("quarantine_size_mb=%zuM\n", (uptr)flags()->quarantine_size_mb);
    391   Printf("malloc_context_size=%zu\n",
    392          (uptr)common_flags()->malloc_context_size);
    393 
    394   Printf("SHADOW_SCALE: %d\n", (int)SHADOW_SCALE);
    395   Printf("SHADOW_GRANULARITY: %d\n", (int)SHADOW_GRANULARITY);
    396   Printf("SHADOW_OFFSET: 0x%zx\n", (uptr)SHADOW_OFFSET);
    397   CHECK(SHADOW_SCALE >= 3 && SHADOW_SCALE <= 7);
    398   if (kMidMemBeg)
    399     CHECK(kMidShadowBeg > kLowShadowEnd &&
    400           kMidMemBeg > kMidShadowEnd &&
    401           kHighShadowBeg > kMidMemEnd);
    402 }
    403 
    404 static void AsanInitInternal() {
    405   if (LIKELY(asan_inited)) return;
    406   SanitizerToolName = "AddressSanitizer";
    407   CHECK(!asan_init_is_running && "ASan init calls itself!");
    408   asan_init_is_running = true;
    409 
    410   CacheBinaryName();
    411 
    412   // Initialize flags. This must be done early, because most of the
    413   // initialization steps look at flags().
    414   InitializeFlags();
    415 
    416   AsanCheckIncompatibleRT();
    417   AsanCheckDynamicRTPrereqs();
    418   AvoidCVE_2016_2143();
    419 
    420   SetCanPoisonMemory(flags()->poison_heap);
    421   SetMallocContextSize(common_flags()->malloc_context_size);
    422 
    423   InitializePlatformExceptionHandlers();
    424 
    425   InitializeHighMemEnd();
    426 
    427   // Make sure we are not statically linked.
    428   AsanDoesNotSupportStaticLinkage();
    429 
    430   // Install tool-specific callbacks in sanitizer_common.
    431   AddDieCallback(AsanDie);
    432   SetCheckFailedCallback(AsanCheckFailed);
    433   SetPrintfAndReportCallback(AppendToErrorMessageBuffer);
    434 
    435   __sanitizer_set_report_path(common_flags()->log_path);
    436 
    437   // Enable UAR detection, if required.
    438   __asan_option_detect_stack_use_after_return =
    439       flags()->detect_stack_use_after_return;
    440 
    441   // Re-exec ourselves if we need to set additional env or command line args.
    442   MaybeReexec();
    443 
    444   // Setup internal allocator callback.
    445   SetLowLevelAllocateCallback(OnLowLevelAllocate);
    446 
    447   InitializeAsanInterceptors();
    448 
    449   // Enable system log ("adb logcat") on Android.
    450   // Doing this before interceptors are initialized crashes in:
    451   // AsanInitInternal -> android_log_write -> __interceptor_strcmp
    452   AndroidLogInit();
    453 
    454   ReplaceSystemMalloc();
    455 
    456   uptr shadow_start = kLowShadowBeg;
    457   if (kLowShadowBeg)
    458     shadow_start -= GetMmapGranularity();
    459   bool full_shadow_is_available =
    460       MemoryRangeIsAvailable(shadow_start, kHighShadowEnd);
    461 
    462 #if SANITIZER_LINUX && defined(__x86_64__) && defined(_LP64) &&                \
    463     !ASAN_FIXED_MAPPING
    464   if (!full_shadow_is_available) {
    465     kMidMemBeg = kLowMemEnd < 0x3000000000ULL ? 0x3000000000ULL : 0;
    466     kMidMemEnd = kLowMemEnd < 0x3000000000ULL ? 0x4fffffffffULL : 0;
    467   }
    468 #elif SANITIZER_WINDOWS64
    469   // Disable the "mid mem" shadow layout.
    470   if (!full_shadow_is_available) {
    471     kMidMemBeg = 0;
    472     kMidMemEnd = 0;
    473   }
    474 #endif
    475 
    476   if (Verbosity()) PrintAddressSpaceLayout();
    477 
    478   DisableCoreDumperIfNecessary();
    479 
    480   if (full_shadow_is_available) {
    481     // mmap the low shadow plus at least one page at the left.
    482     if (kLowShadowBeg)
    483       ReserveShadowMemoryRange(shadow_start, kLowShadowEnd, "low shadow");
    484     // mmap the high shadow.
    485     ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd, "high shadow");
    486     // protect the gap.
    487     ProtectGap(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
    488     CHECK_EQ(kShadowGapEnd, kHighShadowBeg - 1);
    489   } else if (kMidMemBeg &&
    490       MemoryRangeIsAvailable(shadow_start, kMidMemBeg - 1) &&
    491       MemoryRangeIsAvailable(kMidMemEnd + 1, kHighShadowEnd)) {
    492     CHECK(kLowShadowBeg != kLowShadowEnd);
    493     // mmap the low shadow plus at least one page at the left.
    494     ReserveShadowMemoryRange(shadow_start, kLowShadowEnd, "low shadow");
    495     // mmap the mid shadow.
    496     ReserveShadowMemoryRange(kMidShadowBeg, kMidShadowEnd, "mid shadow");
    497     // mmap the high shadow.
    498     ReserveShadowMemoryRange(kHighShadowBeg, kHighShadowEnd, "high shadow");
    499     // protect the gaps.
    500     ProtectGap(kShadowGapBeg, kShadowGapEnd - kShadowGapBeg + 1);
    501     ProtectGap(kShadowGap2Beg, kShadowGap2End - kShadowGap2Beg + 1);
    502     ProtectGap(kShadowGap3Beg, kShadowGap3End - kShadowGap3Beg + 1);
    503   } else {
    504     Report("Shadow memory range interleaves with an existing memory mapping. "
    505            "ASan cannot proceed correctly. ABORTING.\n");
    506     Report("ASan shadow was supposed to be located in the [%p-%p] range.\n",
    507            shadow_start, kHighShadowEnd);
    508     DumpProcessMap();
    509     Die();
    510   }
    511 
    512   AsanTSDInit(PlatformTSDDtor);
    513   InstallDeadlySignalHandlers(AsanOnDeadlySignal);
    514 
    515   AllocatorOptions allocator_options;
    516   allocator_options.SetFrom(flags(), common_flags());
    517   InitializeAllocator(allocator_options);
    518 
    519   MaybeStartBackgroudThread();
    520   SetSoftRssLimitExceededCallback(AsanSoftRssLimitExceededCallback);
    521 
    522   // On Linux AsanThread::ThreadStart() calls malloc() that's why asan_inited
    523   // should be set to 1 prior to initializing the threads.
    524   asan_inited = 1;
    525   asan_init_is_running = false;
    526 
    527   if (flags()->atexit)
    528     Atexit(asan_atexit);
    529 
    530   InitializeCoverage(common_flags()->coverage, common_flags()->coverage_dir);
    531 
    532   // Now that ASan runtime is (mostly) initialized, deactivate it if
    533   // necessary, so that it can be re-activated when requested.
    534   if (flags()->start_deactivated)
    535     AsanDeactivate();
    536 
    537   // interceptors
    538   InitTlsSize();
    539 
    540   // Create main thread.
    541   AsanThread *main_thread = AsanThread::Create(
    542       /* start_routine */ nullptr, /* arg */ nullptr, /* parent_tid */ 0,
    543       /* stack */ nullptr, /* detached */ true);
    544   CHECK_EQ(0, main_thread->tid());
    545   SetCurrentThread(main_thread);
    546   main_thread->ThreadStart(internal_getpid(),
    547                            /* signal_thread_is_registered */ nullptr);
    548   force_interface_symbols();  // no-op.
    549   SanitizerInitializeUnwinder();
    550 
    551   if (CAN_SANITIZE_LEAKS) {
    552     __lsan::InitCommonLsan();
    553     if (common_flags()->detect_leaks && common_flags()->leak_check_at_exit) {
    554       Atexit(__lsan::DoLeakCheck);
    555     }
    556   }
    557 
    558 #if CAN_SANITIZE_UB
    559   __ubsan::InitAsPlugin();
    560 #endif
    561 
    562   InitializeSuppressions();
    563 
    564   if (CAN_SANITIZE_LEAKS) {
    565     // LateInitialize() calls dlsym, which can allocate an error string buffer
    566     // in the TLS.  Let's ignore the allocation to avoid reporting a leak.
    567     __lsan::ScopedInterceptorDisabler disabler;
    568     Symbolizer::LateInitialize();
    569   } else {
    570     Symbolizer::LateInitialize();
    571   }
    572 
    573   VReport(1, "AddressSanitizer Init done\n");
    574 }
    575 
    576 // Initialize as requested from some part of ASan runtime library (interceptors,
    577 // allocator, etc).
    578 void AsanInitFromRtl() {
    579   AsanInitInternal();
    580 }
    581 
    582 #if ASAN_DYNAMIC
    583 // Initialize runtime in case it's LD_PRELOAD-ed into unsanitized executable
    584 // (and thus normal initializers from .preinit_array or modules haven't run).
    585 
    586 class AsanInitializer {
    587 public:  // NOLINT
    588   AsanInitializer() {
    589     AsanInitFromRtl();
    590   }
    591 };
    592 
    593 static AsanInitializer asan_initializer;
    594 #endif  // ASAN_DYNAMIC
    595 
    596 } // namespace __asan
    597 
    598 // ---------------------- Interface ---------------- {{{1
    599 using namespace __asan;  // NOLINT
    600 
    601 void NOINLINE __asan_handle_no_return() {
    602   int local_stack;
    603   AsanThread *curr_thread = GetCurrentThread();
    604   uptr PageSize = GetPageSizeCached();
    605   uptr top, bottom;
    606   if (curr_thread) {
    607     top = curr_thread->stack_top();
    608     bottom = ((uptr)&local_stack - PageSize) & ~(PageSize - 1);
    609   } else {
    610     // If we haven't seen this thread, try asking the OS for stack bounds.
    611     uptr tls_addr, tls_size, stack_size;
    612     GetThreadStackAndTls(/*main=*/false, &bottom, &stack_size, &tls_addr,
    613                          &tls_size);
    614     top = bottom + stack_size;
    615   }
    616   static const uptr kMaxExpectedCleanupSize = 64 << 20;  // 64M
    617   if (top - bottom > kMaxExpectedCleanupSize) {
    618     static bool reported_warning = false;
    619     if (reported_warning)
    620       return;
    621     reported_warning = true;
    622     Report("WARNING: ASan is ignoring requested __asan_handle_no_return: "
    623            "stack top: %p; bottom %p; size: %p (%zd)\n"
    624            "False positive error reports may follow\n"
    625            "For details see "
    626            "https://github.com/google/sanitizers/issues/189\n",
    627            top, bottom, top - bottom, top - bottom);
    628     return;
    629   }
    630   PoisonShadow(bottom, top - bottom, 0);
    631   if (curr_thread && curr_thread->has_fake_stack())
    632     curr_thread->fake_stack()->HandleNoReturn();
    633 }
    634 
    635 void NOINLINE __asan_set_death_callback(void (*callback)(void)) {
    636   SetUserDieCallback(callback);
    637 }
    638 
    639 // Initialize as requested from instrumented application code.
    640 // We use this call as a trigger to wake up ASan from deactivated state.
    641 void __asan_init() {
    642   AsanActivate();
    643   AsanInitInternal();
    644 }
    645 
    646 void __asan_version_mismatch_check() {
    647   // Do nothing.
    648 }
    649