asan_thread.cc revision 230e52f4e91b53f05ce19dbbf11047f4a0113483
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 uptr stack_size_log = Log2(RoundUpToPowerOfTwo(stack_size)); 127 fake_stack_ = FakeStack::Create(stack_size_log); 128 SetTLSFakeStack(fake_stack_); 129 if (flags()->verbosity) { 130 u8 *p = reinterpret_cast<u8 *>(fake_stack_); 131 Report("T%d: FakeStack created: %p -- %p\n", tid(), p, 132 p + FakeStack::RequiredSize(stack_size_log)); 133 } 134 return fake_stack_; 135 } 136 return 0; 137} 138 139void AsanThread::Init() { 140 SetThreadStackAndTls(); 141 CHECK(AddrIsInMem(stack_bottom_)); 142 CHECK(AddrIsInMem(stack_top_ - 1)); 143 ClearShadowForThreadStackAndTLS(); 144 if (flags()->verbosity >= 1) { 145 int local = 0; 146 Report("T%d: stack [%p,%p) size 0x%zx; local=%p\n", 147 tid(), (void*)stack_bottom_, (void*)stack_top_, 148 stack_top_ - stack_bottom_, &local); 149 } 150 fake_stack_ = 0; // Will be initialized lazily if needed. 151 AsanPlatformThreadInit(); 152} 153 154thread_return_t AsanThread::ThreadStart(uptr os_id) { 155 Init(); 156 asanThreadRegistry().StartThread(tid(), os_id, 0); 157 if (flags()->use_sigaltstack) SetAlternateSignalStack(); 158 159 if (!start_routine_) { 160 // start_routine_ == 0 if we're on the main thread or on one of the 161 // OS X libdispatch worker threads. But nobody is supposed to call 162 // ThreadStart() for the worker threads. 163 CHECK_EQ(tid(), 0); 164 return 0; 165 } 166 167 thread_return_t res = start_routine_(arg_); 168 malloc_storage().CommitBack(); 169 if (flags()->use_sigaltstack) UnsetAlternateSignalStack(); 170 171 this->Destroy(); 172 173 return res; 174} 175 176void AsanThread::SetThreadStackAndTls() { 177 uptr stack_size = 0, tls_size = 0; 178 GetThreadStackAndTls(tid() == 0, &stack_bottom_, &stack_size, &tls_begin_, 179 &tls_size); 180 stack_top_ = stack_bottom_ + stack_size; 181 tls_end_ = tls_begin_ + tls_size; 182 183 int local; 184 CHECK(AddrIsInStack((uptr)&local)); 185} 186 187void AsanThread::ClearShadowForThreadStackAndTLS() { 188 PoisonShadow(stack_bottom_, stack_top_ - stack_bottom_, 0); 189 if (tls_begin_ != tls_end_) 190 PoisonShadow(tls_begin_, tls_end_ - tls_begin_, 0); 191} 192 193const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset, 194 uptr *frame_pc) { 195 uptr bottom = 0; 196 if (AddrIsInStack(addr)) { 197 bottom = stack_bottom(); 198 } else if (has_fake_stack()) { 199 bottom = fake_stack()->AddrIsInFakeStack(addr); 200 CHECK(bottom); 201 *offset = addr - bottom; 202 *frame_pc = ((uptr*)bottom)[2]; 203 return (const char *)((uptr*)bottom)[1]; 204 } 205 uptr aligned_addr = addr & ~(SANITIZER_WORDSIZE/8 - 1); // align addr. 206 u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr); 207 u8 *shadow_bottom = (u8*)MemToShadow(bottom); 208 209 while (shadow_ptr >= shadow_bottom && 210 *shadow_ptr != kAsanStackLeftRedzoneMagic) { 211 shadow_ptr--; 212 } 213 214 while (shadow_ptr >= shadow_bottom && 215 *shadow_ptr == kAsanStackLeftRedzoneMagic) { 216 shadow_ptr--; 217 } 218 219 if (shadow_ptr < shadow_bottom) { 220 *offset = 0; 221 return "UNKNOWN"; 222 } 223 224 uptr* ptr = (uptr*)SHADOW_TO_MEM((uptr)(shadow_ptr + 1)); 225 CHECK(ptr[0] == kCurrentStackFrameMagic); 226 *offset = addr - (uptr)ptr; 227 *frame_pc = ptr[2]; 228 return (const char*)ptr[1]; 229} 230 231static bool ThreadStackContainsAddress(ThreadContextBase *tctx_base, 232 void *addr) { 233 AsanThreadContext *tctx = static_cast<AsanThreadContext*>(tctx_base); 234 AsanThread *t = tctx->thread; 235 if (!t) return false; 236 if (t->AddrIsInStack((uptr)addr)) return true; 237 if (t->has_fake_stack() && t->fake_stack()->AddrIsInFakeStack((uptr)addr)) 238 return true; 239 return false; 240} 241 242AsanThread *GetCurrentThread() { 243 AsanThreadContext *context = 244 reinterpret_cast<AsanThreadContext *>(AsanTSDGet()); 245 if (!context) { 246 if (SANITIZER_ANDROID) { 247 // On Android, libc constructor is called _after_ asan_init, and cleans up 248 // TSD. Try to figure out if this is still the main thread by the stack 249 // address. We are not entirely sure that we have correct main thread 250 // limits, so only do this magic on Android, and only if the found thread 251 // is the main thread. 252 AsanThreadContext *tctx = GetThreadContextByTidLocked(0); 253 if (ThreadStackContainsAddress(tctx, &context)) { 254 SetCurrentThread(tctx->thread); 255 return tctx->thread; 256 } 257 } 258 return 0; 259 } 260 return context->thread; 261} 262 263void SetCurrentThread(AsanThread *t) { 264 CHECK(t->context()); 265 if (flags()->verbosity >= 2) { 266 Report("SetCurrentThread: %p for thread %p\n", 267 t->context(), (void*)GetThreadSelf()); 268 } 269 // Make sure we do not reset the current AsanThread. 270 CHECK_EQ(0, AsanTSDGet()); 271 AsanTSDSet(t->context()); 272 CHECK_EQ(t->context(), AsanTSDGet()); 273} 274 275u32 GetCurrentTidOrInvalid() { 276 AsanThread *t = GetCurrentThread(); 277 return t ? t->tid() : kInvalidTid; 278} 279 280AsanThread *FindThreadByStackAddress(uptr addr) { 281 asanThreadRegistry().CheckLocked(); 282 AsanThreadContext *tctx = static_cast<AsanThreadContext *>( 283 asanThreadRegistry().FindThreadContextLocked(ThreadStackContainsAddress, 284 (void *)addr)); 285 return tctx ? tctx->thread : 0; 286} 287 288void EnsureMainThreadIDIsCorrect() { 289 AsanThreadContext *context = 290 reinterpret_cast<AsanThreadContext *>(AsanTSDGet()); 291 if (context && (context->tid == 0)) 292 context->os_id = GetTid(); 293} 294} // namespace __asan 295 296// --- Implementation of LSan-specific functions --- {{{1 297namespace __lsan { 298bool GetThreadRangesLocked(uptr os_id, uptr *stack_begin, uptr *stack_end, 299 uptr *tls_begin, uptr *tls_end, 300 uptr *cache_begin, uptr *cache_end) { 301 __asan::AsanThreadContext *context = static_cast<__asan::AsanThreadContext *>( 302 __asan::asanThreadRegistry().FindThreadContextByOsIDLocked(os_id)); 303 if (!context) return false; 304 __asan::AsanThread *t = context->thread; 305 if (!t) return false; 306 *stack_begin = t->stack_bottom(); 307 *stack_end = t->stack_top(); 308 *tls_begin = t->tls_begin(); 309 *tls_end = t->tls_end(); 310 // ASan doesn't keep allocator caches in TLS, so these are unused. 311 *cache_begin = 0; 312 *cache_end = 0; 313 return true; 314} 315 316void LockThreadRegistry() { 317 __asan::asanThreadRegistry().Lock(); 318} 319 320void UnlockThreadRegistry() { 321 __asan::asanThreadRegistry().Unlock(); 322} 323 324void EnsureMainThreadIDIsCorrect() { 325 __asan::EnsureMainThreadIDIsCorrect(); 326} 327} // namespace __lsan 328