asan_thread.cc revision dcf98bf49d68533c7aebadbf6c4467afdd486c99
1//===-- asan_thread.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 AddressSanitizer, an address sanity checker. 11// 12// Thread-related code. 13//===----------------------------------------------------------------------===// 14#include "asan_allocator.h" 15#include "asan_interceptors.h" 16#include "asan_poisoning.h" 17#include "asan_stack.h" 18#include "asan_thread.h" 19#include "asan_mapping.h" 20#include "sanitizer_common/sanitizer_common.h" 21#include "sanitizer_common/sanitizer_placement_new.h" 22#include "lsan/lsan_common.h" 23 24namespace __asan { 25 26// AsanThreadContext implementation. 27 28void AsanThreadContext::OnCreated(void *arg) { 29 CreateThreadContextArgs *args = static_cast<CreateThreadContextArgs*>(arg); 30 if (args->stack) { 31 internal_memcpy(&stack, args->stack, sizeof(stack)); 32 } 33 thread = args->thread; 34 thread->set_context(this); 35} 36 37void AsanThreadContext::OnFinished() { 38 // Drop the link to the AsanThread object. 39 thread = 0; 40} 41 42// MIPS requires aligned address 43static ALIGNED(16) char thread_registry_placeholder[sizeof(ThreadRegistry)]; 44static ThreadRegistry *asan_thread_registry; 45 46static ThreadContextBase *GetAsanThreadContext(u32 tid) { 47 void *mem = MmapOrDie(sizeof(AsanThreadContext), "AsanThreadContext"); 48 return new(mem) AsanThreadContext(tid); 49} 50 51ThreadRegistry &asanThreadRegistry() { 52 static bool initialized; 53 // Don't worry about thread_safety - this should be called when there is 54 // a single thread. 55 if (!initialized) { 56 // Never reuse ASan threads: we store pointer to AsanThreadContext 57 // in TSD and can't reliably tell when no more TSD destructors will 58 // be called. It would be wrong to reuse AsanThreadContext for another 59 // thread before all TSD destructors will be called for it. 60 asan_thread_registry = new(thread_registry_placeholder) ThreadRegistry( 61 GetAsanThreadContext, kMaxNumberOfThreads, kMaxNumberOfThreads); 62 initialized = true; 63 } 64 return *asan_thread_registry; 65} 66 67AsanThreadContext *GetThreadContextByTidLocked(u32 tid) { 68 return static_cast<AsanThreadContext *>( 69 asanThreadRegistry().GetThreadLocked(tid)); 70} 71 72// AsanThread implementation. 73 74AsanThread *AsanThread::Create(thread_callback_t start_routine, 75 void *arg) { 76 uptr PageSize = GetPageSizeCached(); 77 uptr size = RoundUpTo(sizeof(AsanThread), PageSize); 78 AsanThread *thread = (AsanThread*)MmapOrDie(size, __FUNCTION__); 79 thread->start_routine_ = start_routine; 80 thread->arg_ = arg; 81 thread->context_ = 0; 82 83 return thread; 84} 85 86void AsanThread::TSDDtor(void *tsd) { 87 AsanThreadContext *context = (AsanThreadContext*)tsd; 88 if (flags()->verbosity >= 1) 89 Report("T%d TSDDtor\n", context->tid); 90 if (context->thread) 91 context->thread->Destroy(); 92} 93 94void AsanThread::Destroy() { 95 if (flags()->verbosity >= 1) { 96 Report("T%d exited\n", tid()); 97 } 98 99 asanThreadRegistry().FinishThread(tid()); 100 FlushToDeadThreadStats(&stats_); 101 // We also clear the shadow on thread destruction because 102 // some code may still be executing in later TSD destructors 103 // and we don't want it to have any poisoned stack. 104 ClearShadowForThreadStackAndTLS(); 105 DeleteFakeStack(); 106 uptr size = RoundUpTo(sizeof(AsanThread), GetPageSizeCached()); 107 UnmapOrDie(this, size); 108} 109 110// We want to create the FakeStack lazyly on the first use, but not eralier 111// than the stack size is known and the procedure has to be async-signal safe. 112FakeStack *AsanThread::AsyncSignalSafeLazyInitFakeStack() { 113 uptr stack_size = this->stack_size(); 114 if (stack_size == 0) // stack_size is not yet available, don't use FakeStack. 115 return 0; 116 uptr old_val = 0; 117 // fake_stack_ has 3 states: 118 // 0 -- not initialized 119 // 1 -- being initialized 120 // ptr -- initialized 121 // This CAS checks if the state was 0 and if so changes it to state 1, 122 // if that was successfull, it initilizes the pointer. 123 if (atomic_compare_exchange_strong( 124 reinterpret_cast<atomic_uintptr_t *>(&fake_stack_), &old_val, 1UL, 125 memory_order_relaxed)) 126 return fake_stack_ = 127 FakeStack::Create(Log2(RoundUpToPowerOfTwo(stack_size))); 128 return 0; 129} 130 131void AsanThread::Init() { 132 SetThreadStackAndTls(); 133 CHECK(AddrIsInMem(stack_bottom_)); 134 CHECK(AddrIsInMem(stack_top_ - 1)); 135 ClearShadowForThreadStackAndTLS(); 136 if (flags()->verbosity >= 1) { 137 int local = 0; 138 Report("T%d: stack [%p,%p) size 0x%zx; local=%p\n", 139 tid(), (void*)stack_bottom_, (void*)stack_top_, 140 stack_top_ - stack_bottom_, &local); 141 } 142 fake_stack_ = 0; // Will be initialized lazily if needed. 143 AsanPlatformThreadInit(); 144} 145 146thread_return_t AsanThread::ThreadStart(uptr os_id) { 147 Init(); 148 asanThreadRegistry().StartThread(tid(), os_id, 0); 149 if (flags()->use_sigaltstack) SetAlternateSignalStack(); 150 151 if (!start_routine_) { 152 // start_routine_ == 0 if we're on the main thread or on one of the 153 // OS X libdispatch worker threads. But nobody is supposed to call 154 // ThreadStart() for the worker threads. 155 CHECK_EQ(tid(), 0); 156 return 0; 157 } 158 159 thread_return_t res = start_routine_(arg_); 160 malloc_storage().CommitBack(); 161 if (flags()->use_sigaltstack) UnsetAlternateSignalStack(); 162 163 this->Destroy(); 164 165 return res; 166} 167 168void AsanThread::SetThreadStackAndTls() { 169 uptr stack_size = 0, tls_size = 0; 170 GetThreadStackAndTls(tid() == 0, &stack_bottom_, &stack_size, &tls_begin_, 171 &tls_size); 172 stack_top_ = stack_bottom_ + stack_size; 173 tls_end_ = tls_begin_ + tls_size; 174 175 int local; 176 CHECK(AddrIsInStack((uptr)&local)); 177} 178 179void AsanThread::ClearShadowForThreadStackAndTLS() { 180 PoisonShadow(stack_bottom_, stack_top_ - stack_bottom_, 0); 181 if (tls_begin_ != tls_end_) 182 PoisonShadow(tls_begin_, tls_end_ - tls_begin_, 0); 183} 184 185const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset, 186 uptr *frame_pc) { 187 uptr bottom = 0; 188 if (AddrIsInStack(addr)) { 189 bottom = stack_bottom(); 190 } else if (has_fake_stack()) { 191 bottom = fake_stack()->AddrIsInFakeStack(addr); 192 CHECK(bottom); 193 *offset = addr - bottom; 194 *frame_pc = ((uptr*)bottom)[2]; 195 return (const char *)((uptr*)bottom)[1]; 196 } 197 uptr aligned_addr = addr & ~(SANITIZER_WORDSIZE/8 - 1); // align addr. 198 u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr); 199 u8 *shadow_bottom = (u8*)MemToShadow(bottom); 200 201 while (shadow_ptr >= shadow_bottom && 202 *shadow_ptr != kAsanStackLeftRedzoneMagic) { 203 shadow_ptr--; 204 } 205 206 while (shadow_ptr >= shadow_bottom && 207 *shadow_ptr == kAsanStackLeftRedzoneMagic) { 208 shadow_ptr--; 209 } 210 211 if (shadow_ptr < shadow_bottom) { 212 *offset = 0; 213 return "UNKNOWN"; 214 } 215 216 uptr* ptr = (uptr*)SHADOW_TO_MEM((uptr)(shadow_ptr + 1)); 217 CHECK(ptr[0] == kCurrentStackFrameMagic); 218 *offset = addr - (uptr)ptr; 219 *frame_pc = ptr[2]; 220 return (const char*)ptr[1]; 221} 222 223static bool ThreadStackContainsAddress(ThreadContextBase *tctx_base, 224 void *addr) { 225 AsanThreadContext *tctx = static_cast<AsanThreadContext*>(tctx_base); 226 AsanThread *t = tctx->thread; 227 if (!t) return false; 228 if (t->AddrIsInStack((uptr)addr)) return true; 229 if (t->fake_stack() && t->fake_stack()->AddrIsInFakeStack((uptr)addr)) 230 return true; 231 return false; 232} 233 234AsanThread *GetCurrentThread() { 235 AsanThreadContext *context = 236 reinterpret_cast<AsanThreadContext *>(AsanTSDGet()); 237 if (!context) { 238 if (SANITIZER_ANDROID) { 239 // On Android, libc constructor is called _after_ asan_init, and cleans up 240 // TSD. Try to figure out if this is still the main thread by the stack 241 // address. We are not entirely sure that we have correct main thread 242 // limits, so only do this magic on Android, and only if the found thread 243 // is the main thread. 244 AsanThreadContext *tctx = GetThreadContextByTidLocked(0); 245 if (ThreadStackContainsAddress(tctx, &context)) { 246 SetCurrentThread(tctx->thread); 247 return tctx->thread; 248 } 249 } 250 return 0; 251 } 252 return context->thread; 253} 254 255void SetCurrentThread(AsanThread *t) { 256 CHECK(t->context()); 257 if (flags()->verbosity >= 2) { 258 Report("SetCurrentThread: %p for thread %p\n", 259 t->context(), (void*)GetThreadSelf()); 260 } 261 // Make sure we do not reset the current AsanThread. 262 CHECK_EQ(0, AsanTSDGet()); 263 AsanTSDSet(t->context()); 264 CHECK_EQ(t->context(), AsanTSDGet()); 265} 266 267u32 GetCurrentTidOrInvalid() { 268 AsanThread *t = GetCurrentThread(); 269 return t ? t->tid() : kInvalidTid; 270} 271 272AsanThread *FindThreadByStackAddress(uptr addr) { 273 asanThreadRegistry().CheckLocked(); 274 AsanThreadContext *tctx = static_cast<AsanThreadContext *>( 275 asanThreadRegistry().FindThreadContextLocked(ThreadStackContainsAddress, 276 (void *)addr)); 277 return tctx ? tctx->thread : 0; 278} 279 280void EnsureMainThreadIDIsCorrect() { 281 AsanThreadContext *context = 282 reinterpret_cast<AsanThreadContext *>(AsanTSDGet()); 283 if (context && (context->tid == 0)) 284 context->os_id = GetTid(); 285} 286} // namespace __asan 287 288// --- Implementation of LSan-specific functions --- {{{1 289namespace __lsan { 290bool GetThreadRangesLocked(uptr os_id, uptr *stack_begin, uptr *stack_end, 291 uptr *tls_begin, uptr *tls_end, 292 uptr *cache_begin, uptr *cache_end) { 293 __asan::AsanThreadContext *context = static_cast<__asan::AsanThreadContext *>( 294 __asan::asanThreadRegistry().FindThreadContextByOsIDLocked(os_id)); 295 if (!context) return false; 296 __asan::AsanThread *t = context->thread; 297 if (!t) return false; 298 *stack_begin = t->stack_bottom(); 299 *stack_end = t->stack_top(); 300 *tls_begin = t->tls_begin(); 301 *tls_end = t->tls_end(); 302 // ASan doesn't keep allocator caches in TLS, so these are unused. 303 *cache_begin = 0; 304 *cache_end = 0; 305 return true; 306} 307 308void LockThreadRegistry() { 309 __asan::asanThreadRegistry().Lock(); 310} 311 312void UnlockThreadRegistry() { 313 __asan::asanThreadRegistry().Unlock(); 314} 315 316void EnsureMainThreadIDIsCorrect() { 317 __asan::EnsureMainThreadIDIsCorrect(); 318} 319} // namespace __lsan 320