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      1 //=-- lsan_common.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 LeakSanitizer.
     11 // Implementation of common leak checking functionality.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "lsan_common.h"
     16 
     17 #include "sanitizer_common/sanitizer_common.h"
     18 #include "sanitizer_common/sanitizer_flags.h"
     19 #include "sanitizer_common/sanitizer_placement_new.h"
     20 #include "sanitizer_common/sanitizer_stackdepot.h"
     21 #include "sanitizer_common/sanitizer_stacktrace.h"
     22 #include "sanitizer_common/sanitizer_stoptheworld.h"
     23 #include "sanitizer_common/sanitizer_suppressions.h"
     24 
     25 #if CAN_SANITIZE_LEAKS
     26 namespace __lsan {
     27 
     28 // This mutex is used to prevent races between DoLeakCheck and IgnoreObject.
     29 BlockingMutex global_mutex(LINKER_INITIALIZED);
     30 
     31 THREADLOCAL int disable_counter;
     32 bool DisabledInThisThread() { return disable_counter > 0; }
     33 
     34 Flags lsan_flags;
     35 
     36 static void InitializeFlags() {
     37   Flags *f = flags();
     38   // Default values.
     39   f->report_objects = false;
     40   f->resolution = 0;
     41   f->max_leaks = 0;
     42   f->exitcode = 23;
     43   f->suppressions="";
     44   f->use_registers = true;
     45   f->use_globals = true;
     46   f->use_stacks = true;
     47   f->use_tls = true;
     48   f->use_unaligned = false;
     49   f->verbosity = 0;
     50   f->log_pointers = false;
     51   f->log_threads = false;
     52 
     53   const char *options = GetEnv("LSAN_OPTIONS");
     54   if (options) {
     55     ParseFlag(options, &f->use_registers, "use_registers");
     56     ParseFlag(options, &f->use_globals, "use_globals");
     57     ParseFlag(options, &f->use_stacks, "use_stacks");
     58     ParseFlag(options, &f->use_tls, "use_tls");
     59     ParseFlag(options, &f->use_unaligned, "use_unaligned");
     60     ParseFlag(options, &f->report_objects, "report_objects");
     61     ParseFlag(options, &f->resolution, "resolution");
     62     CHECK_GE(&f->resolution, 0);
     63     ParseFlag(options, &f->max_leaks, "max_leaks");
     64     CHECK_GE(&f->max_leaks, 0);
     65     ParseFlag(options, &f->verbosity, "verbosity");
     66     ParseFlag(options, &f->log_pointers, "log_pointers");
     67     ParseFlag(options, &f->log_threads, "log_threads");
     68     ParseFlag(options, &f->exitcode, "exitcode");
     69     ParseFlag(options, &f->suppressions, "suppressions");
     70   }
     71 }
     72 
     73 SuppressionContext *suppression_ctx;
     74 
     75 void InitializeSuppressions() {
     76   CHECK(!suppression_ctx);
     77   ALIGNED(64) static char placeholder_[sizeof(SuppressionContext)];
     78   suppression_ctx = new(placeholder_) SuppressionContext;
     79   char *suppressions_from_file;
     80   uptr buffer_size;
     81   if (ReadFileToBuffer(flags()->suppressions, &suppressions_from_file,
     82                        &buffer_size, 1 << 26 /* max_len */))
     83     suppression_ctx->Parse(suppressions_from_file);
     84   if (flags()->suppressions[0] && !buffer_size) {
     85     Printf("LeakSanitizer: failed to read suppressions file '%s'\n",
     86            flags()->suppressions);
     87     Die();
     88   }
     89   if (&__lsan_default_suppressions)
     90     suppression_ctx->Parse(__lsan_default_suppressions());
     91 }
     92 
     93 void InitCommonLsan() {
     94   InitializeFlags();
     95   InitializeSuppressions();
     96   InitializePlatformSpecificModules();
     97 }
     98 
     99 static inline bool CanBeAHeapPointer(uptr p) {
    100   // Since our heap is located in mmap-ed memory, we can assume a sensible lower
    101   // bound on heap addresses.
    102   const uptr kMinAddress = 4 * 4096;
    103   if (p < kMinAddress) return false;
    104 #ifdef __x86_64__
    105   // Accept only canonical form user-space addresses.
    106   return ((p >> 47) == 0);
    107 #else
    108   return true;
    109 #endif
    110 }
    111 
    112 // Scans the memory range, looking for byte patterns that point into allocator
    113 // chunks. Marks those chunks with |tag| and adds them to |frontier|.
    114 // There are two usage modes for this function: finding reachable or ignored
    115 // chunks (|tag| = kReachable or kIgnored) and finding indirectly leaked chunks
    116 // (|tag| = kIndirectlyLeaked). In the second case, there's no flood fill,
    117 // so |frontier| = 0.
    118 void ScanRangeForPointers(uptr begin, uptr end,
    119                           Frontier *frontier,
    120                           const char *region_type, ChunkTag tag) {
    121   const uptr alignment = flags()->pointer_alignment();
    122   if (flags()->log_pointers)
    123     Report("Scanning %s range %p-%p.\n", region_type, begin, end);
    124   uptr pp = begin;
    125   if (pp % alignment)
    126     pp = pp + alignment - pp % alignment;
    127   for (; pp + sizeof(void *) <= end; pp += alignment) {  // NOLINT
    128     void *p = *reinterpret_cast<void **>(pp);
    129     if (!CanBeAHeapPointer(reinterpret_cast<uptr>(p))) continue;
    130     uptr chunk = PointsIntoChunk(p);
    131     if (!chunk) continue;
    132     LsanMetadata m(chunk);
    133     // Reachable beats ignored beats leaked.
    134     if (m.tag() == kReachable) continue;
    135     if (m.tag() == kIgnored && tag != kReachable) continue;
    136     m.set_tag(tag);
    137     if (flags()->log_pointers)
    138       Report("%p: found %p pointing into chunk %p-%p of size %zu.\n", pp, p,
    139              chunk, chunk + m.requested_size(), m.requested_size());
    140     if (frontier)
    141       frontier->push_back(chunk);
    142   }
    143 }
    144 
    145 // Scans thread data (stacks and TLS) for heap pointers.
    146 static void ProcessThreads(SuspendedThreadsList const &suspended_threads,
    147                            Frontier *frontier) {
    148   InternalScopedBuffer<uptr> registers(SuspendedThreadsList::RegisterCount());
    149   uptr registers_begin = reinterpret_cast<uptr>(registers.data());
    150   uptr registers_end = registers_begin + registers.size();
    151   for (uptr i = 0; i < suspended_threads.thread_count(); i++) {
    152     uptr os_id = static_cast<uptr>(suspended_threads.GetThreadID(i));
    153     if (flags()->log_threads) Report("Processing thread %d.\n", os_id);
    154     uptr stack_begin, stack_end, tls_begin, tls_end, cache_begin, cache_end;
    155     bool thread_found = GetThreadRangesLocked(os_id, &stack_begin, &stack_end,
    156                                               &tls_begin, &tls_end,
    157                                               &cache_begin, &cache_end);
    158     if (!thread_found) {
    159       // If a thread can't be found in the thread registry, it's probably in the
    160       // process of destruction. Log this event and move on.
    161       if (flags()->log_threads)
    162         Report("Thread %d not found in registry.\n", os_id);
    163       continue;
    164     }
    165     uptr sp;
    166     bool have_registers =
    167         (suspended_threads.GetRegistersAndSP(i, registers.data(), &sp) == 0);
    168     if (!have_registers) {
    169       Report("Unable to get registers from thread %d.\n");
    170       // If unable to get SP, consider the entire stack to be reachable.
    171       sp = stack_begin;
    172     }
    173 
    174     if (flags()->use_registers && have_registers)
    175       ScanRangeForPointers(registers_begin, registers_end, frontier,
    176                            "REGISTERS", kReachable);
    177 
    178     if (flags()->use_stacks) {
    179       if (flags()->log_threads)
    180         Report("Stack at %p-%p, SP = %p.\n", stack_begin, stack_end, sp);
    181       if (sp < stack_begin || sp >= stack_end) {
    182         // SP is outside the recorded stack range (e.g. the thread is running a
    183         // signal handler on alternate stack). Again, consider the entire stack
    184         // range to be reachable.
    185         if (flags()->log_threads)
    186           Report("WARNING: stack pointer not in stack range.\n");
    187       } else {
    188         // Shrink the stack range to ignore out-of-scope values.
    189         stack_begin = sp;
    190       }
    191       ScanRangeForPointers(stack_begin, stack_end, frontier, "STACK",
    192                            kReachable);
    193     }
    194 
    195     if (flags()->use_tls) {
    196       if (flags()->log_threads) Report("TLS at %p-%p.\n", tls_begin, tls_end);
    197       if (cache_begin == cache_end) {
    198         ScanRangeForPointers(tls_begin, tls_end, frontier, "TLS", kReachable);
    199       } else {
    200         // Because LSan should not be loaded with dlopen(), we can assume
    201         // that allocator cache will be part of static TLS image.
    202         CHECK_LE(tls_begin, cache_begin);
    203         CHECK_GE(tls_end, cache_end);
    204         if (tls_begin < cache_begin)
    205           ScanRangeForPointers(tls_begin, cache_begin, frontier, "TLS",
    206                                kReachable);
    207         if (tls_end > cache_end)
    208           ScanRangeForPointers(cache_end, tls_end, frontier, "TLS", kReachable);
    209       }
    210     }
    211   }
    212 }
    213 
    214 static void FloodFillTag(Frontier *frontier, ChunkTag tag) {
    215   while (frontier->size()) {
    216     uptr next_chunk = frontier->back();
    217     frontier->pop_back();
    218     LsanMetadata m(next_chunk);
    219     ScanRangeForPointers(next_chunk, next_chunk + m.requested_size(), frontier,
    220                          "HEAP", tag);
    221   }
    222 }
    223 
    224 // ForEachChunk callback. If the chunk is marked as leaked, marks all chunks
    225 // which are reachable from it as indirectly leaked.
    226 static void MarkIndirectlyLeakedCb(uptr chunk, void *arg) {
    227   chunk = GetUserBegin(chunk);
    228   LsanMetadata m(chunk);
    229   if (m.allocated() && m.tag() != kReachable) {
    230     ScanRangeForPointers(chunk, chunk + m.requested_size(),
    231                          /* frontier */ 0, "HEAP", kIndirectlyLeaked);
    232   }
    233 }
    234 
    235 // ForEachChunk callback. If chunk is marked as ignored, adds its address to
    236 // frontier.
    237 static void CollectIgnoredCb(uptr chunk, void *arg) {
    238   CHECK(arg);
    239   chunk = GetUserBegin(chunk);
    240   LsanMetadata m(chunk);
    241   if (m.allocated() && m.tag() == kIgnored)
    242     reinterpret_cast<Frontier *>(arg)->push_back(chunk);
    243 }
    244 
    245 // Sets the appropriate tag on each chunk.
    246 static void ClassifyAllChunks(SuspendedThreadsList const &suspended_threads) {
    247   // Holds the flood fill frontier.
    248   Frontier frontier(GetPageSizeCached());
    249 
    250   if (flags()->use_globals)
    251     ProcessGlobalRegions(&frontier);
    252   ProcessThreads(suspended_threads, &frontier);
    253   FloodFillTag(&frontier, kReachable);
    254   // The check here is relatively expensive, so we do this in a separate flood
    255   // fill. That way we can skip the check for chunks that are reachable
    256   // otherwise.
    257   ProcessPlatformSpecificAllocations(&frontier);
    258   FloodFillTag(&frontier, kReachable);
    259 
    260   if (flags()->log_pointers)
    261     Report("Scanning ignored chunks.\n");
    262   CHECK_EQ(0, frontier.size());
    263   ForEachChunk(CollectIgnoredCb, &frontier);
    264   FloodFillTag(&frontier, kIgnored);
    265 
    266   // Iterate over leaked chunks and mark those that are reachable from other
    267   // leaked chunks.
    268   if (flags()->log_pointers)
    269     Report("Scanning leaked chunks.\n");
    270   ForEachChunk(MarkIndirectlyLeakedCb, 0 /* arg */);
    271 }
    272 
    273 static void PrintStackTraceById(u32 stack_trace_id) {
    274   CHECK(stack_trace_id);
    275   uptr size = 0;
    276   const uptr *trace = StackDepotGet(stack_trace_id, &size);
    277   StackTrace::PrintStack(trace, size, common_flags()->symbolize,
    278                          common_flags()->strip_path_prefix, 0);
    279 }
    280 
    281 // ForEachChunk callback. Aggregates unreachable chunks into a LeakReport.
    282 static void CollectLeaksCb(uptr chunk, void *arg) {
    283   CHECK(arg);
    284   LeakReport *leak_report = reinterpret_cast<LeakReport *>(arg);
    285   chunk = GetUserBegin(chunk);
    286   LsanMetadata m(chunk);
    287   if (!m.allocated()) return;
    288   if (m.tag() == kDirectlyLeaked || m.tag() == kIndirectlyLeaked) {
    289     uptr resolution = flags()->resolution;
    290     if (resolution > 0) {
    291       uptr size = 0;
    292       const uptr *trace = StackDepotGet(m.stack_trace_id(), &size);
    293       size = Min(size, resolution);
    294       leak_report->Add(StackDepotPut(trace, size), m.requested_size(), m.tag());
    295     } else {
    296       leak_report->Add(m.stack_trace_id(), m.requested_size(), m.tag());
    297     }
    298   }
    299 }
    300 
    301 // ForEachChunkCallback. Prints addresses of unreachable chunks.
    302 static void PrintLeakedCb(uptr chunk, void *arg) {
    303   chunk = GetUserBegin(chunk);
    304   LsanMetadata m(chunk);
    305   if (!m.allocated()) return;
    306   if (m.tag() == kDirectlyLeaked || m.tag() == kIndirectlyLeaked) {
    307     Printf("%s leaked %zu byte object at %p.\n",
    308            m.tag() == kDirectlyLeaked ? "Directly" : "Indirectly",
    309            m.requested_size(), chunk);
    310   }
    311 }
    312 
    313 static void PrintMatchedSuppressions() {
    314   InternalMmapVector<Suppression *> matched(1);
    315   suppression_ctx->GetMatched(&matched);
    316   if (!matched.size())
    317     return;
    318   const char *line = "-----------------------------------------------------";
    319   Printf("%s\n", line);
    320   Printf("Suppressions used:\n");
    321   Printf("  count      bytes template\n");
    322   for (uptr i = 0; i < matched.size(); i++)
    323     Printf("%7zu %10zu %s\n", static_cast<uptr>(matched[i]->hit_count),
    324            matched[i]->weight, matched[i]->templ);
    325   Printf("%s\n\n", line);
    326 }
    327 
    328 static void PrintLeaked() {
    329   Printf("\n");
    330   Printf("Reporting individual objects:\n");
    331   ForEachChunk(PrintLeakedCb, 0 /* arg */);
    332 }
    333 
    334 struct DoLeakCheckParam {
    335   bool success;
    336   LeakReport leak_report;
    337 };
    338 
    339 static void DoLeakCheckCallback(const SuspendedThreadsList &suspended_threads,
    340                                 void *arg) {
    341   DoLeakCheckParam *param = reinterpret_cast<DoLeakCheckParam *>(arg);
    342   CHECK(param);
    343   CHECK(!param->success);
    344   CHECK(param->leak_report.IsEmpty());
    345   ClassifyAllChunks(suspended_threads);
    346   ForEachChunk(CollectLeaksCb, &param->leak_report);
    347   if (!param->leak_report.IsEmpty() && flags()->report_objects)
    348     PrintLeaked();
    349   param->success = true;
    350 }
    351 
    352 void DoLeakCheck() {
    353   EnsureMainThreadIDIsCorrect();
    354   BlockingMutexLock l(&global_mutex);
    355   static bool already_done;
    356   if (already_done) return;
    357   already_done = true;
    358   if (&__lsan_is_turned_off && __lsan_is_turned_off())
    359     return;
    360 
    361   DoLeakCheckParam param;
    362   param.success = false;
    363   LockThreadRegistry();
    364   LockAllocator();
    365   StopTheWorld(DoLeakCheckCallback, &param);
    366   UnlockAllocator();
    367   UnlockThreadRegistry();
    368 
    369   if (!param.success) {
    370     Report("LeakSanitizer has encountered a fatal error.\n");
    371     Die();
    372   }
    373   uptr have_unsuppressed = param.leak_report.ApplySuppressions();
    374   if (have_unsuppressed) {
    375     Printf("\n"
    376            "================================================================="
    377            "\n");
    378     Report("ERROR: LeakSanitizer: detected memory leaks\n");
    379     param.leak_report.PrintLargest(flags()->max_leaks);
    380   }
    381   if (have_unsuppressed || (flags()->verbosity >= 1)) {
    382     PrintMatchedSuppressions();
    383     param.leak_report.PrintSummary();
    384   }
    385   if (have_unsuppressed && flags()->exitcode)
    386     internal__exit(flags()->exitcode);
    387 }
    388 
    389 static Suppression *GetSuppressionForAddr(uptr addr) {
    390   static const uptr kMaxAddrFrames = 16;
    391   InternalScopedBuffer<AddressInfo> addr_frames(kMaxAddrFrames);
    392   for (uptr i = 0; i < kMaxAddrFrames; i++) new (&addr_frames[i]) AddressInfo();
    393   uptr addr_frames_num = __sanitizer::SymbolizeCode(addr, addr_frames.data(),
    394                                                     kMaxAddrFrames);
    395   for (uptr i = 0; i < addr_frames_num; i++) {
    396     Suppression* s;
    397     if (suppression_ctx->Match(addr_frames[i].function, SuppressionLeak, &s) ||
    398         suppression_ctx->Match(addr_frames[i].file, SuppressionLeak, &s) ||
    399         suppression_ctx->Match(addr_frames[i].module, SuppressionLeak, &s))
    400       return s;
    401   }
    402   return 0;
    403 }
    404 
    405 static Suppression *GetSuppressionForStack(u32 stack_trace_id) {
    406   uptr size = 0;
    407   const uptr *trace = StackDepotGet(stack_trace_id, &size);
    408   for (uptr i = 0; i < size; i++) {
    409     Suppression *s =
    410         GetSuppressionForAddr(StackTrace::GetPreviousInstructionPc(trace[i]));
    411     if (s) return s;
    412   }
    413   return 0;
    414 }
    415 
    416 ///// LeakReport implementation. /////
    417 
    418 // A hard limit on the number of distinct leaks, to avoid quadratic complexity
    419 // in LeakReport::Add(). We don't expect to ever see this many leaks in
    420 // real-world applications.
    421 // FIXME: Get rid of this limit by changing the implementation of LeakReport to
    422 // use a hash table.
    423 const uptr kMaxLeaksConsidered = 5000;
    424 
    425 void LeakReport::Add(u32 stack_trace_id, uptr leaked_size, ChunkTag tag) {
    426   CHECK(tag == kDirectlyLeaked || tag == kIndirectlyLeaked);
    427   bool is_directly_leaked = (tag == kDirectlyLeaked);
    428   for (uptr i = 0; i < leaks_.size(); i++)
    429     if (leaks_[i].stack_trace_id == stack_trace_id &&
    430         leaks_[i].is_directly_leaked == is_directly_leaked) {
    431       leaks_[i].hit_count++;
    432       leaks_[i].total_size += leaked_size;
    433       return;
    434     }
    435   if (leaks_.size() == kMaxLeaksConsidered) return;
    436   Leak leak = { /* hit_count */ 1, leaked_size, stack_trace_id,
    437                 is_directly_leaked, /* is_suppressed */ false };
    438   leaks_.push_back(leak);
    439 }
    440 
    441 static bool LeakComparator(const Leak &leak1, const Leak &leak2) {
    442   if (leak1.is_directly_leaked == leak2.is_directly_leaked)
    443     return leak1.total_size > leak2.total_size;
    444   else
    445     return leak1.is_directly_leaked;
    446 }
    447 
    448 void LeakReport::PrintLargest(uptr num_leaks_to_print) {
    449   CHECK(leaks_.size() <= kMaxLeaksConsidered);
    450   Printf("\n");
    451   if (leaks_.size() == kMaxLeaksConsidered)
    452     Printf("Too many leaks! Only the first %zu leaks encountered will be "
    453            "reported.\n",
    454            kMaxLeaksConsidered);
    455 
    456   uptr unsuppressed_count = 0;
    457   for (uptr i = 0; i < leaks_.size(); i++)
    458     if (!leaks_[i].is_suppressed) unsuppressed_count++;
    459   if (num_leaks_to_print > 0 && num_leaks_to_print < unsuppressed_count)
    460     Printf("The %zu largest leak(s):\n", num_leaks_to_print);
    461   InternalSort(&leaks_, leaks_.size(), LeakComparator);
    462   uptr leaks_printed = 0;
    463   for (uptr i = 0; i < leaks_.size(); i++) {
    464     if (leaks_[i].is_suppressed) continue;
    465     Printf("%s leak of %zu byte(s) in %zu object(s) allocated from:\n",
    466            leaks_[i].is_directly_leaked ? "Direct" : "Indirect",
    467            leaks_[i].total_size, leaks_[i].hit_count);
    468     PrintStackTraceById(leaks_[i].stack_trace_id);
    469     Printf("\n");
    470     leaks_printed++;
    471     if (leaks_printed == num_leaks_to_print) break;
    472   }
    473   if (leaks_printed < unsuppressed_count) {
    474     uptr remaining = unsuppressed_count - leaks_printed;
    475     Printf("Omitting %zu more leak(s).\n", remaining);
    476   }
    477 }
    478 
    479 void LeakReport::PrintSummary() {
    480   CHECK(leaks_.size() <= kMaxLeaksConsidered);
    481   uptr bytes = 0, allocations = 0;
    482   for (uptr i = 0; i < leaks_.size(); i++) {
    483       if (leaks_[i].is_suppressed) continue;
    484       bytes += leaks_[i].total_size;
    485       allocations += leaks_[i].hit_count;
    486   }
    487   const int kMaxSummaryLength = 128;
    488   InternalScopedBuffer<char> summary(kMaxSummaryLength);
    489   internal_snprintf(summary.data(), kMaxSummaryLength,
    490                     "LeakSanitizer: %zu byte(s) leaked in %zu allocation(s).",
    491                     bytes, allocations);
    492   __sanitizer_report_error_summary(summary.data());
    493 }
    494 
    495 uptr LeakReport::ApplySuppressions() {
    496   uptr unsuppressed_count = 0;
    497   for (uptr i = 0; i < leaks_.size(); i++) {
    498     Suppression *s = GetSuppressionForStack(leaks_[i].stack_trace_id);
    499     if (s) {
    500       s->weight += leaks_[i].total_size;
    501       s->hit_count += leaks_[i].hit_count;
    502       leaks_[i].is_suppressed = true;
    503     } else {
    504     unsuppressed_count++;
    505     }
    506   }
    507   return unsuppressed_count;
    508 }
    509 }  // namespace __lsan
    510 #endif  // CAN_SANITIZE_LEAKS
    511 
    512 using namespace __lsan;  // NOLINT
    513 
    514 extern "C" {
    515 SANITIZER_INTERFACE_ATTRIBUTE
    516 void __lsan_ignore_object(const void *p) {
    517 #if CAN_SANITIZE_LEAKS
    518   // Cannot use PointsIntoChunk or LsanMetadata here, since the allocator is not
    519   // locked.
    520   BlockingMutexLock l(&global_mutex);
    521   IgnoreObjectResult res = IgnoreObjectLocked(p);
    522   if (res == kIgnoreObjectInvalid && flags()->verbosity >= 2)
    523     Report("__lsan_ignore_object(): no heap object found at %p", p);
    524   if (res == kIgnoreObjectAlreadyIgnored && flags()->verbosity >= 2)
    525     Report("__lsan_ignore_object(): "
    526            "heap object at %p is already being ignored\n", p);
    527   if (res == kIgnoreObjectSuccess && flags()->verbosity >= 3)
    528     Report("__lsan_ignore_object(): ignoring heap object at %p\n", p);
    529 #endif  // CAN_SANITIZE_LEAKS
    530 }
    531 
    532 SANITIZER_INTERFACE_ATTRIBUTE
    533 void __lsan_disable() {
    534 #if CAN_SANITIZE_LEAKS
    535   __lsan::disable_counter++;
    536 #endif
    537 }
    538 
    539 SANITIZER_INTERFACE_ATTRIBUTE
    540 void __lsan_enable() {
    541 #if CAN_SANITIZE_LEAKS
    542   if (!__lsan::disable_counter) {
    543     Report("Unmatched call to __lsan_enable().\n");
    544     Die();
    545   }
    546   __lsan::disable_counter--;
    547 #endif
    548 }
    549 
    550 SANITIZER_INTERFACE_ATTRIBUTE
    551 void __lsan_do_leak_check() {
    552 #if CAN_SANITIZE_LEAKS
    553   if (common_flags()->detect_leaks)
    554     __lsan::DoLeakCheck();
    555 #endif  // CAN_SANITIZE_LEAKS
    556 }
    557 
    558 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
    559 SANITIZER_WEAK_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE
    560 int __lsan_is_turned_off() {
    561   return 0;
    562 }
    563 #endif
    564 }  // extern "C"
    565