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      1 //===-- tsan_mman.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 ThreadSanitizer (TSan), a race detector.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 #include "sanitizer_common/sanitizer_allocator_interface.h"
     14 #include "sanitizer_common/sanitizer_common.h"
     15 #include "sanitizer_common/sanitizer_placement_new.h"
     16 #include "tsan_mman.h"
     17 #include "tsan_rtl.h"
     18 #include "tsan_report.h"
     19 #include "tsan_flags.h"
     20 
     21 // May be overriden by front-end.
     22 SANITIZER_WEAK_DEFAULT_IMPL
     23 void __sanitizer_malloc_hook(void *ptr, uptr size) {
     24   (void)ptr;
     25   (void)size;
     26 }
     27 
     28 SANITIZER_WEAK_DEFAULT_IMPL
     29 void __sanitizer_free_hook(void *ptr) {
     30   (void)ptr;
     31 }
     32 
     33 namespace __tsan {
     34 
     35 struct MapUnmapCallback {
     36   void OnMap(uptr p, uptr size) const { }
     37   void OnUnmap(uptr p, uptr size) const {
     38     // We are about to unmap a chunk of user memory.
     39     // Mark the corresponding shadow memory as not needed.
     40     DontNeedShadowFor(p, size);
     41     // Mark the corresponding meta shadow memory as not needed.
     42     // Note the block does not contain any meta info at this point
     43     // (this happens after free).
     44     const uptr kMetaRatio = kMetaShadowCell / kMetaShadowSize;
     45     const uptr kPageSize = GetPageSizeCached() * kMetaRatio;
     46     // Block came from LargeMmapAllocator, so must be large.
     47     // We rely on this in the calculations below.
     48     CHECK_GE(size, 2 * kPageSize);
     49     uptr diff = RoundUp(p, kPageSize) - p;
     50     if (diff != 0) {
     51       p += diff;
     52       size -= diff;
     53     }
     54     diff = p + size - RoundDown(p + size, kPageSize);
     55     if (diff != 0)
     56       size -= diff;
     57     FlushUnneededShadowMemory((uptr)MemToMeta(p), size / kMetaRatio);
     58   }
     59 };
     60 
     61 static char allocator_placeholder[sizeof(Allocator)] ALIGNED(64);
     62 Allocator *allocator() {
     63   return reinterpret_cast<Allocator*>(&allocator_placeholder);
     64 }
     65 
     66 struct GlobalProc {
     67   Mutex mtx;
     68   Processor *proc;
     69 
     70   GlobalProc()
     71       : mtx(MutexTypeGlobalProc, StatMtxGlobalProc)
     72       , proc(ProcCreate()) {
     73   }
     74 };
     75 
     76 static char global_proc_placeholder[sizeof(GlobalProc)] ALIGNED(64);
     77 GlobalProc *global_proc() {
     78   return reinterpret_cast<GlobalProc*>(&global_proc_placeholder);
     79 }
     80 
     81 ScopedGlobalProcessor::ScopedGlobalProcessor() {
     82   GlobalProc *gp = global_proc();
     83   ThreadState *thr = cur_thread();
     84   if (thr->proc())
     85     return;
     86   // If we don't have a proc, use the global one.
     87   // There are currently only two known case where this path is triggered:
     88   //   __interceptor_free
     89   //   __nptl_deallocate_tsd
     90   //   start_thread
     91   //   clone
     92   // and:
     93   //   ResetRange
     94   //   __interceptor_munmap
     95   //   __deallocate_stack
     96   //   start_thread
     97   //   clone
     98   // Ideally, we destroy thread state (and unwire proc) when a thread actually
     99   // exits (i.e. when we join/wait it). Then we would not need the global proc
    100   gp->mtx.Lock();
    101   ProcWire(gp->proc, thr);
    102 }
    103 
    104 ScopedGlobalProcessor::~ScopedGlobalProcessor() {
    105   GlobalProc *gp = global_proc();
    106   ThreadState *thr = cur_thread();
    107   if (thr->proc() != gp->proc)
    108     return;
    109   ProcUnwire(gp->proc, thr);
    110   gp->mtx.Unlock();
    111 }
    112 
    113 void InitializeAllocator() {
    114   allocator()->Init(common_flags()->allocator_may_return_null);
    115 }
    116 
    117 void InitializeAllocatorLate() {
    118   new(global_proc()) GlobalProc();
    119 }
    120 
    121 void AllocatorProcStart(Processor *proc) {
    122   allocator()->InitCache(&proc->alloc_cache);
    123   internal_allocator()->InitCache(&proc->internal_alloc_cache);
    124 }
    125 
    126 void AllocatorProcFinish(Processor *proc) {
    127   allocator()->DestroyCache(&proc->alloc_cache);
    128   internal_allocator()->DestroyCache(&proc->internal_alloc_cache);
    129 }
    130 
    131 void AllocatorPrintStats() {
    132   allocator()->PrintStats();
    133 }
    134 
    135 static void SignalUnsafeCall(ThreadState *thr, uptr pc) {
    136   if (atomic_load_relaxed(&thr->in_signal_handler) == 0 ||
    137       !flags()->report_signal_unsafe)
    138     return;
    139   VarSizeStackTrace stack;
    140   ObtainCurrentStack(thr, pc, &stack);
    141   if (IsFiredSuppression(ctx, ReportTypeSignalUnsafe, stack))
    142     return;
    143   ThreadRegistryLock l(ctx->thread_registry);
    144   ScopedReport rep(ReportTypeSignalUnsafe);
    145   rep.AddStack(stack, true);
    146   OutputReport(thr, rep);
    147 }
    148 
    149 void *user_alloc(ThreadState *thr, uptr pc, uptr sz, uptr align, bool signal) {
    150   if ((sz >= (1ull << 40)) || (align >= (1ull << 40)))
    151     return allocator()->ReturnNullOrDie();
    152   void *p = allocator()->Allocate(&thr->proc()->alloc_cache, sz, align);
    153   if (p == 0)
    154     return 0;
    155   if (ctx && ctx->initialized)
    156     OnUserAlloc(thr, pc, (uptr)p, sz, true);
    157   if (signal)
    158     SignalUnsafeCall(thr, pc);
    159   return p;
    160 }
    161 
    162 void *user_calloc(ThreadState *thr, uptr pc, uptr size, uptr n) {
    163   if (CallocShouldReturnNullDueToOverflow(size, n))
    164     return allocator()->ReturnNullOrDie();
    165   void *p = user_alloc(thr, pc, n * size);
    166   if (p)
    167     internal_memset(p, 0, n * size);
    168   return p;
    169 }
    170 
    171 void user_free(ThreadState *thr, uptr pc, void *p, bool signal) {
    172   ScopedGlobalProcessor sgp;
    173   if (ctx && ctx->initialized)
    174     OnUserFree(thr, pc, (uptr)p, true);
    175   allocator()->Deallocate(&thr->proc()->alloc_cache, p);
    176   if (signal)
    177     SignalUnsafeCall(thr, pc);
    178 }
    179 
    180 void OnUserAlloc(ThreadState *thr, uptr pc, uptr p, uptr sz, bool write) {
    181   DPrintf("#%d: alloc(%zu) = %p\n", thr->tid, sz, p);
    182   ctx->metamap.AllocBlock(thr, pc, p, sz);
    183   if (write && thr->ignore_reads_and_writes == 0)
    184     MemoryRangeImitateWrite(thr, pc, (uptr)p, sz);
    185   else
    186     MemoryResetRange(thr, pc, (uptr)p, sz);
    187 }
    188 
    189 void OnUserFree(ThreadState *thr, uptr pc, uptr p, bool write) {
    190   CHECK_NE(p, (void*)0);
    191   uptr sz = ctx->metamap.FreeBlock(thr->proc(), p);
    192   DPrintf("#%d: free(%p, %zu)\n", thr->tid, p, sz);
    193   if (write && thr->ignore_reads_and_writes == 0)
    194     MemoryRangeFreed(thr, pc, (uptr)p, sz);
    195 }
    196 
    197 void *user_realloc(ThreadState *thr, uptr pc, void *p, uptr sz) {
    198   void *p2 = 0;
    199   // FIXME: Handle "shrinking" more efficiently,
    200   // it seems that some software actually does this.
    201   if (sz) {
    202     p2 = user_alloc(thr, pc, sz);
    203     if (p2 == 0)
    204       return 0;
    205     if (p) {
    206       uptr oldsz = user_alloc_usable_size(p);
    207       internal_memcpy(p2, p, min(oldsz, sz));
    208     }
    209   }
    210   if (p)
    211     user_free(thr, pc, p);
    212   return p2;
    213 }
    214 
    215 uptr user_alloc_usable_size(const void *p) {
    216   if (p == 0)
    217     return 0;
    218   MBlock *b = ctx->metamap.GetBlock((uptr)p);
    219   if (!b)
    220     return 0;  // Not a valid pointer.
    221   if (b->siz == 0)
    222     return 1;  // Zero-sized allocations are actually 1 byte.
    223   return b->siz;
    224 }
    225 
    226 void invoke_malloc_hook(void *ptr, uptr size) {
    227   ThreadState *thr = cur_thread();
    228   if (ctx == 0 || !ctx->initialized || thr->ignore_interceptors)
    229     return;
    230   __sanitizer_malloc_hook(ptr, size);
    231   RunMallocHooks(ptr, size);
    232 }
    233 
    234 void invoke_free_hook(void *ptr) {
    235   ThreadState *thr = cur_thread();
    236   if (ctx == 0 || !ctx->initialized || thr->ignore_interceptors)
    237     return;
    238   __sanitizer_free_hook(ptr);
    239   RunFreeHooks(ptr);
    240 }
    241 
    242 void *internal_alloc(MBlockType typ, uptr sz) {
    243   ThreadState *thr = cur_thread();
    244   if (thr->nomalloc) {
    245     thr->nomalloc = 0;  // CHECK calls internal_malloc().
    246     CHECK(0);
    247   }
    248   return InternalAlloc(sz, &thr->proc()->internal_alloc_cache);
    249 }
    250 
    251 void internal_free(void *p) {
    252   ThreadState *thr = cur_thread();
    253   if (thr->nomalloc) {
    254     thr->nomalloc = 0;  // CHECK calls internal_malloc().
    255     CHECK(0);
    256   }
    257   InternalFree(p, &thr->proc()->internal_alloc_cache);
    258 }
    259 
    260 }  // namespace __tsan
    261 
    262 using namespace __tsan;
    263 
    264 extern "C" {
    265 uptr __sanitizer_get_current_allocated_bytes() {
    266   uptr stats[AllocatorStatCount];
    267   allocator()->GetStats(stats);
    268   return stats[AllocatorStatAllocated];
    269 }
    270 
    271 uptr __sanitizer_get_heap_size() {
    272   uptr stats[AllocatorStatCount];
    273   allocator()->GetStats(stats);
    274   return stats[AllocatorStatMapped];
    275 }
    276 
    277 uptr __sanitizer_get_free_bytes() {
    278   return 1;
    279 }
    280 
    281 uptr __sanitizer_get_unmapped_bytes() {
    282   return 1;
    283 }
    284 
    285 uptr __sanitizer_get_estimated_allocated_size(uptr size) {
    286   return size;
    287 }
    288 
    289 int __sanitizer_get_ownership(const void *p) {
    290   return allocator()->GetBlockBegin(p) != 0;
    291 }
    292 
    293 uptr __sanitizer_get_allocated_size(const void *p) {
    294   return user_alloc_usable_size(p);
    295 }
    296 
    297 void __tsan_on_thread_idle() {
    298   ThreadState *thr = cur_thread();
    299   allocator()->SwallowCache(&thr->proc()->alloc_cache);
    300   internal_allocator()->SwallowCache(&thr->proc()->internal_alloc_cache);
    301   ctx->metamap.OnProcIdle(thr->proc());
    302 }
    303 }  // extern "C"
    304