libsanitizer/tsan/tsan_platform_posix.cpp

   1 //===-- tsan_platform_posix.cpp -------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of ThreadSanitizer (TSan), a race detector.
  10 //
  11 // POSIX-specific code.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_common/sanitizer_platform.h"
  15 #if SANITIZER_POSIX
  16
  17 #  include <dlfcn.h>
  18
  19 #  include "sanitizer_common/sanitizer_common.h"
  20 #  include "sanitizer_common/sanitizer_errno.h"
  21 #  include "sanitizer_common/sanitizer_libc.h"
  22 #  include "sanitizer_common/sanitizer_procmaps.h"
  23 #  include "tsan_platform.h"
  24 #  include "tsan_rtl.h"
  25
  26 namespace __tsan {
  27
  28 static const char kShadowMemoryMappingWarning[] =
  29     "FATAL: %s can not madvise shadow region [%zx, %zx] with %s (errno: %d)\n";
  30 static const char kShadowMemoryMappingHint[] =
  31     "HINT: if %s is not supported in your environment, you may set "
  32     "TSAN_OPTIONS=%s=0\n";
  33
  34 #  if !SANITIZER_GO
  35 void DontDumpShadow(uptr addr, uptr size) {
  36   if (common_flags()->use_madv_dontdump)
  37     if (!DontDumpShadowMemory(addr, size)) {
  38       Printf(kShadowMemoryMappingWarning, SanitizerToolName, addr, addr + size,
  39              "MADV_DONTDUMP", errno);
  40       Printf(kShadowMemoryMappingHint, "MADV_DONTDUMP", "use_madv_dontdump");
  41       Die();
  42     }
  43 }
  44
  45 void InitializeShadowMemory() {
  46   // Map memory shadow.
  47   if (!MmapFixedSuperNoReserve(ShadowBeg(), ShadowEnd() - ShadowBeg(),
  48                                "shadow")) {
  49     Printf("FATAL: ThreadSanitizer can not mmap the shadow memory\n");
  50     Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n");
  51     Die();
  52   }
  53   // This memory range is used for thread stacks and large user mmaps.
  54   // Frequently a thread uses only a small part of stack and similarly
  55   // a program uses a small part of large mmap. On some programs
  56   // we see 20% memory usage reduction without huge pages for this range.
  57   DontDumpShadow(ShadowBeg(), ShadowEnd() - ShadowBeg());
  58   DPrintf("memory shadow: %zx-%zx (%zuGB)\n",
  59       ShadowBeg(), ShadowEnd(),
  60       (ShadowEnd() - ShadowBeg()) >> 30);
  61
  62   // Map meta shadow.
  63   const uptr meta = MetaShadowBeg();
  64   const uptr meta_size = MetaShadowEnd() - meta;
  65   if (!MmapFixedSuperNoReserve(meta, meta_size, "meta shadow")) {
  66     Printf("FATAL: ThreadSanitizer can not mmap the shadow memory\n");
  67     Printf("FATAL: Make sure to compile with -fPIE and to link with -pie.\n");
  68     Die();
  69   }
  70   DontDumpShadow(meta, meta_size);
  71   DPrintf("meta shadow: %zx-%zx (%zuGB)\n",
  72       meta, meta + meta_size, meta_size >> 30);
  73
  74   InitializeShadowMemoryPlatform();
  75
  76   on_initialize = reinterpret_cast<void (*)(void)>(
  77       dlsym(RTLD_DEFAULT, "__tsan_on_initialize"));
  78   on_finalize =
  79       reinterpret_cast<int (*)(int)>(dlsym(RTLD_DEFAULT, "__tsan_on_finalize"));
  80 }
  81
  82 static bool TryProtectRange(uptr beg, uptr end) {
  83   CHECK_LE(beg, end);
  84   if (beg == end)
  85     return true;
  86   return beg == (uptr)MmapFixedNoAccess(beg, end - beg);
  87 }
  88
  89 static void ProtectRange(uptr beg, uptr end) {
  90   if (!TryProtectRange(beg, end)) {
  91     Printf("FATAL: ThreadSanitizer can not protect [%zx,%zx]\n", beg, end);
  92     Printf("FATAL: Make sure you are not using unlimited stack\n");
  93     Die();
  94   }
  95 }
  96
  97 void CheckAndProtect() {
  98   // Ensure that the binary is indeed compiled with -pie.
  99   MemoryMappingLayout proc_maps(true);
 100   MemoryMappedSegment segment;
 101   while (proc_maps.Next(&segment)) {
 102     if (IsAppMem(segment.start)) continue;
 103     if (segment.start >= HeapMemEnd() && segment.start < HeapEnd()) continue;
 104     if (segment.protection == 0)  // Zero page or mprotected.
 105       continue;
 106     if (segment.start >= VdsoBeg())  // vdso
 107       break;
 108     Printf("FATAL: ThreadSanitizer: unexpected memory mapping 0x%zx-0x%zx\n",
 109            segment.start, segment.end);
 110     Die();
 111   }
 112
 113 #    if SANITIZER_IOS && !SANITIZER_IOSSIM
 114   ProtectRange(HeapMemEnd(), ShadowBeg());
 115   ProtectRange(ShadowEnd(), MetaShadowBeg());
 116   ProtectRange(MetaShadowEnd(), HiAppMemBeg());
 117 #    else
 118   ProtectRange(LoAppMemEnd(), ShadowBeg());
 119   ProtectRange(ShadowEnd(), MetaShadowBeg());
 120   if (MidAppMemBeg()) {
 121     ProtectRange(MetaShadowEnd(), MidAppMemBeg());
 122     ProtectRange(MidAppMemEnd(), HeapMemBeg());
 123   } else {
 124     ProtectRange(MetaShadowEnd(), HeapMemBeg());
 125   }
 126   ProtectRange(HeapEnd(), HiAppMemBeg());
 127 #    endif
 128
 129 #    if defined(__s390x__)
 130   // Protect the rest of the address space.
 131   const uptr user_addr_max_l4 = 0x0020000000000000ull;
 132   const uptr user_addr_max_l5 = 0xfffffffffffff000ull;
 133   // All the maintained s390x kernels support at least 4-level page tables.
 134   ProtectRange(HiAppMemEnd(), user_addr_max_l4);
 135   // Older s390x kernels may not support 5-level page tables.
 136   TryProtectRange(user_addr_max_l4, user_addr_max_l5);
 137 #endif
 138 }
 139 #endif
 140
 141 }  // namespace __tsan
 142
 143 #endif  // SANITIZER_POSIX