175 lines · 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-exception6//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_POSIX16 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 26namespace __tsan {27 28static const char kShadowMemoryMappingWarning[] =29 "FATAL: %s can not madvise shadow region [%zx, %zx] with %s (errno: %d)\n";30static 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_GO35void 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 45void 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 similarly55 // a program uses a small part of large mmap. On some programs56 // 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 82static 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 89static 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// CheckAndProtect will check if the memory layout is compatible with TSan.98// Optionally (if 'protect' is true), it will set the memory regions between99// app memory to be inaccessible.100// 'ignore_heap' means it will not consider heap memory allocations to be a101// conflict. Set this based on whether we are calling CheckAndProtect before102// or after the allocator has initialized the heap.103bool CheckAndProtect(bool protect, bool ignore_heap, bool print_warnings) {104 // Ensure that the binary is indeed compiled with -pie.105 MemoryMappingLayout proc_maps(true);106 MemoryMappedSegment segment;107 while (proc_maps.Next(&segment)) {108 if (segment.start >= HeapMemBeg() && segment.end <= HeapEnd()) {109 if (ignore_heap) {110 continue;111 } else {112 return false;113 }114 }115 116 // Note: IsAppMem includes if it is heap memory, hence we must117 // put this check after the heap bounds check.118 if (IsAppMem(segment.start) && IsAppMem(segment.end - 1))119 continue;120 121 // Guard page after the heap end122 if (segment.start >= HeapMemEnd() && segment.start < HeapEnd()) continue;123 124 if (segment.protection == 0) // Zero page or mprotected.125 continue;126 127 if (segment.start >= VdsoBeg()) // vdso128 break;129 130 // Debug output can break tests. Suppress this message in most cases.131 if (print_warnings)132 Printf(133 "WARNING: ThreadSanitizer: unexpected memory mapping 0x%zx-0x%zx\n",134 segment.start, segment.end);135 136 return false;137 }138 139 if (!protect)140 return true;141 142# if SANITIZER_IOS && !SANITIZER_IOSSIM143 ProtectRange(HeapMemEnd(), ShadowBeg());144 ProtectRange(ShadowEnd(), MetaShadowBeg());145 ProtectRange(MetaShadowEnd(), HiAppMemBeg());146# else147 ProtectRange(LoAppMemEnd(), ShadowBeg());148 ProtectRange(ShadowEnd(), MetaShadowBeg());149 if (MidAppMemBeg()) {150 ProtectRange(MetaShadowEnd(), MidAppMemBeg());151 ProtectRange(MidAppMemEnd(), HeapMemBeg());152 } else {153 ProtectRange(MetaShadowEnd(), HeapMemBeg());154 }155 ProtectRange(HeapEnd(), HiAppMemBeg());156# endif157 158# if defined(__s390x__)159 // Protect the rest of the address space.160 const uptr user_addr_max_l4 = 0x0020000000000000ull;161 const uptr user_addr_max_l5 = 0xfffffffffffff000ull;162 // All the maintained s390x kernels support at least 4-level page tables.163 ProtectRange(HiAppMemEnd(), user_addr_max_l4);164 // Older s390x kernels may not support 5-level page tables.165 TryProtectRange(user_addr_max_l4, user_addr_max_l5);166#endif167 168 return true;169}170# endif171 172} // namespace __tsan173 174#endif // SANITIZER_POSIX175