1 //===-- asan_thread.h -------------------------------------------*- C++ -*-===// 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 AddressSanitizer, an address sanity checker. 10 // 11 // ASan-private header for asan_thread.cpp. 12 //===----------------------------------------------------------------------===// 13 14 #ifndef ASAN_THREAD_H 15 #define ASAN_THREAD_H 16 17 #include "asan_allocator.h" 18 #include "asan_fake_stack.h" 19 #include "asan_internal.h" 20 #include "asan_stats.h" 21 #include "sanitizer_common/sanitizer_common.h" 22 #include "sanitizer_common/sanitizer_libc.h" 23 #include "sanitizer_common/sanitizer_thread_arg_retval.h" 24 #include "sanitizer_common/sanitizer_thread_registry.h" 25 26 namespace __sanitizer { 27 struct DTLS; 28 } // namespace __sanitizer 29 30 namespace __asan { 31 32 class AsanThread; 33 34 // These objects are created for every thread and are never deleted, 35 // so we can find them by tid even if the thread is long dead. 36 class AsanThreadContext final : public ThreadContextBase { 37 public: 38 explicit AsanThreadContext(int tid) 39 : ThreadContextBase(tid), announced(false), 40 destructor_iterations(GetPthreadDestructorIterations()), stack_id(0), 41 thread(nullptr) {} 42 bool announced; 43 u8 destructor_iterations; 44 u32 stack_id; 45 AsanThread *thread; 46 47 void OnCreated(void *arg) override; 48 void OnFinished() override; 49 50 struct CreateThreadContextArgs { 51 AsanThread *thread; 52 StackTrace *stack; 53 }; 54 }; 55 56 // AsanThreadContext objects are never freed, so we need many of them. 57 COMPILER_CHECK(sizeof(AsanThreadContext) <= 256); 58 59 // AsanThread are stored in TSD and destroyed when the thread dies. 60 class AsanThread { 61 public: 62 static AsanThread *Create(thread_callback_t start_routine, void *arg, 63 u32 parent_tid, StackTrace *stack, bool detached); 64 static void TSDDtor(void *tsd); 65 void Destroy(); 66 67 struct InitOptions; 68 void Init(const InitOptions *options = nullptr); 69 70 thread_return_t ThreadStart(tid_t os_id); 71 72 uptr stack_top(); 73 uptr stack_bottom(); 74 uptr stack_size(); 75 uptr tls_begin() { return tls_begin_; } 76 uptr tls_end() { return tls_end_; } 77 DTLS *dtls() { return dtls_; } 78 u32 tid() { return context_->tid; } 79 AsanThreadContext *context() { return context_; } 80 void set_context(AsanThreadContext *context) { context_ = context; } 81 82 struct StackFrameAccess { 83 uptr offset; 84 uptr frame_pc; 85 const char *frame_descr; 86 }; 87 bool GetStackFrameAccessByAddr(uptr addr, StackFrameAccess *access); 88 89 // Returns a pointer to the start of the stack variable's shadow memory. 90 uptr GetStackVariableShadowStart(uptr addr); 91 92 bool AddrIsInStack(uptr addr); 93 94 void DeleteFakeStack(int tid) { 95 if (!fake_stack_) return; 96 FakeStack *t = fake_stack_; 97 fake_stack_ = nullptr; 98 SetTLSFakeStack(nullptr); 99 t->Destroy(tid); 100 } 101 102 void StartSwitchFiber(FakeStack **fake_stack_save, uptr bottom, uptr size); 103 void FinishSwitchFiber(FakeStack *fake_stack_save, uptr *bottom_old, 104 uptr *size_old); 105 106 FakeStack *get_fake_stack() { 107 if (atomic_load(&stack_switching_, memory_order_relaxed)) 108 return nullptr; 109 if (reinterpret_cast<uptr>(fake_stack_) <= 1) 110 return nullptr; 111 return fake_stack_; 112 } 113 114 FakeStack *get_or_create_fake_stack() { 115 if (atomic_load(&stack_switching_, memory_order_relaxed)) 116 return nullptr; 117 if (reinterpret_cast<uptr>(fake_stack_) <= 1) 118 return AsyncSignalSafeLazyInitFakeStack(); 119 return fake_stack_; 120 } 121 122 // True is this thread is currently unwinding stack (i.e. collecting a stack 123 // trace). Used to prevent deadlocks on platforms where libc unwinder calls 124 // malloc internally. See PR17116 for more details. 125 bool isUnwinding() const { return unwinding_; } 126 void setUnwinding(bool b) { unwinding_ = b; } 127 128 AsanThreadLocalMallocStorage &malloc_storage() { return malloc_storage_; } 129 AsanStats &stats() { return stats_; } 130 131 void *extra_spill_area() { return &extra_spill_area_; } 132 133 void *get_arg() const { return arg_; } 134 135 private: 136 // NOTE: There is no AsanThread constructor. It is allocated 137 // via mmap() and *must* be valid in zero-initialized state. 138 139 void SetThreadStackAndTls(const InitOptions *options); 140 141 void ClearShadowForThreadStackAndTLS(); 142 FakeStack *AsyncSignalSafeLazyInitFakeStack(); 143 144 struct StackBounds { 145 uptr bottom; 146 uptr top; 147 }; 148 StackBounds GetStackBounds() const; 149 150 AsanThreadContext *context_; 151 thread_callback_t start_routine_; 152 void *arg_; 153 154 uptr stack_top_; 155 uptr stack_bottom_; 156 // these variables are used when the thread is about to switch stack 157 uptr next_stack_top_; 158 uptr next_stack_bottom_; 159 // true if switching is in progress 160 atomic_uint8_t stack_switching_; 161 162 uptr tls_begin_; 163 uptr tls_end_; 164 DTLS *dtls_; 165 166 FakeStack *fake_stack_; 167 AsanThreadLocalMallocStorage malloc_storage_; 168 AsanStats stats_; 169 bool unwinding_; 170 uptr extra_spill_area_; 171 }; 172 173 // Returns a single instance of registry. 174 ThreadRegistry &asanThreadRegistry(); 175 ThreadArgRetval &asanThreadArgRetval(); 176 177 // Must be called under ThreadRegistryLock. 178 AsanThreadContext *GetThreadContextByTidLocked(u32 tid); 179 180 // Get the current thread. May return 0. 181 AsanThread *GetCurrentThread(); 182 void SetCurrentThread(AsanThread *t); 183 u32 GetCurrentTidOrInvalid(); 184 AsanThread *FindThreadByStackAddress(uptr addr); 185 186 // Used to handle fork(). 187 void EnsureMainThreadIDIsCorrect(); 188 } // namespace __asan 189 190 #endif // ASAN_THREAD_H 191