| //===-- asan_thread.cc ----------------------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file is a part of AddressSanitizer, an address sanity checker. |
| // |
| // Thread-related code. |
| //===----------------------------------------------------------------------===// |
| #include "asan_allocator.h" |
| #include "asan_interceptors.h" |
| #include "asan_poisoning.h" |
| #include "asan_stack.h" |
| #include "asan_thread.h" |
| #include "asan_mapping.h" |
| #include "sanitizer_common/sanitizer_common.h" |
| #include "sanitizer_common/sanitizer_placement_new.h" |
| #include "lsan/lsan_common.h" |
| |
| namespace __asan { |
| |
| // AsanThreadContext implementation. |
| |
| void AsanThreadContext::OnCreated(void *arg) { |
| CreateThreadContextArgs *args = static_cast<CreateThreadContextArgs*>(arg); |
| if (args->stack) { |
| internal_memcpy(&stack, args->stack, sizeof(stack)); |
| } |
| thread = args->thread; |
| thread->set_context(this); |
| } |
| |
| void AsanThreadContext::OnFinished() { |
| // Drop the link to the AsanThread object. |
| thread = 0; |
| } |
| |
| // MIPS requires aligned address |
| static ALIGNED(16) char thread_registry_placeholder[sizeof(ThreadRegistry)]; |
| static ThreadRegistry *asan_thread_registry; |
| |
| static ThreadContextBase *GetAsanThreadContext(u32 tid) { |
| void *mem = MmapOrDie(sizeof(AsanThreadContext), "AsanThreadContext"); |
| return new(mem) AsanThreadContext(tid); |
| } |
| |
| ThreadRegistry &asanThreadRegistry() { |
| static bool initialized; |
| // Don't worry about thread_safety - this should be called when there is |
| // a single thread. |
| if (!initialized) { |
| // Never reuse ASan threads: we store pointer to AsanThreadContext |
| // in TSD and can't reliably tell when no more TSD destructors will |
| // be called. It would be wrong to reuse AsanThreadContext for another |
| // thread before all TSD destructors will be called for it. |
| asan_thread_registry = new(thread_registry_placeholder) ThreadRegistry( |
| GetAsanThreadContext, kMaxNumberOfThreads, kMaxNumberOfThreads); |
| initialized = true; |
| } |
| return *asan_thread_registry; |
| } |
| |
| AsanThreadContext *GetThreadContextByTidLocked(u32 tid) { |
| return static_cast<AsanThreadContext *>( |
| asanThreadRegistry().GetThreadLocked(tid)); |
| } |
| |
| // AsanThread implementation. |
| |
| AsanThread *AsanThread::Create(thread_callback_t start_routine, |
| void *arg) { |
| uptr PageSize = GetPageSizeCached(); |
| uptr size = RoundUpTo(sizeof(AsanThread), PageSize); |
| AsanThread *thread = (AsanThread*)MmapOrDie(size, __FUNCTION__); |
| thread->start_routine_ = start_routine; |
| thread->arg_ = arg; |
| thread->context_ = 0; |
| |
| return thread; |
| } |
| |
| void AsanThread::TSDDtor(void *tsd) { |
| AsanThreadContext *context = (AsanThreadContext*)tsd; |
| if (flags()->verbosity >= 1) |
| Report("T%d TSDDtor\n", context->tid); |
| if (context->thread) |
| context->thread->Destroy(); |
| } |
| |
| void AsanThread::Destroy() { |
| if (flags()->verbosity >= 1) { |
| Report("T%d exited\n", tid()); |
| } |
| |
| asanThreadRegistry().FinishThread(tid()); |
| FlushToDeadThreadStats(&stats_); |
| // We also clear the shadow on thread destruction because |
| // some code may still be executing in later TSD destructors |
| // and we don't want it to have any poisoned stack. |
| ClearShadowForThreadStackAndTLS(); |
| DeleteFakeStack(); |
| uptr size = RoundUpTo(sizeof(AsanThread), GetPageSizeCached()); |
| UnmapOrDie(this, size); |
| } |
| |
| // We want to create the FakeStack lazyly on the first use, but not eralier |
| // than the stack size is known and the procedure has to be async-signal safe. |
| FakeStack *AsanThread::AsyncSignalSafeLazyInitFakeStack() { |
| uptr stack_size = this->stack_size(); |
| if (stack_size == 0) // stack_size is not yet available, don't use FakeStack. |
| return 0; |
| uptr old_val = 0; |
| // fake_stack_ has 3 states: |
| // 0 -- not initialized |
| // 1 -- being initialized |
| // ptr -- initialized |
| // This CAS checks if the state was 0 and if so changes it to state 1, |
| // if that was successfull, it initilizes the pointer. |
| if (atomic_compare_exchange_strong( |
| reinterpret_cast<atomic_uintptr_t *>(&fake_stack_), &old_val, 1UL, |
| memory_order_relaxed)) { |
| uptr stack_size_log = Log2(RoundUpToPowerOfTwo(stack_size)); |
| if (flags()->uar_stack_size_log) |
| stack_size_log = static_cast<uptr>(flags()->uar_stack_size_log); |
| fake_stack_ = FakeStack::Create(stack_size_log); |
| SetTLSFakeStack(fake_stack_); |
| return fake_stack_; |
| } |
| return 0; |
| } |
| |
| void AsanThread::Init() { |
| SetThreadStackAndTls(); |
| CHECK(AddrIsInMem(stack_bottom_)); |
| CHECK(AddrIsInMem(stack_top_ - 1)); |
| ClearShadowForThreadStackAndTLS(); |
| if (flags()->verbosity >= 1) { |
| int local = 0; |
| Report("T%d: stack [%p,%p) size 0x%zx; local=%p\n", |
| tid(), (void*)stack_bottom_, (void*)stack_top_, |
| stack_top_ - stack_bottom_, &local); |
| } |
| fake_stack_ = 0; // Will be initialized lazily if needed. |
| AsanPlatformThreadInit(); |
| } |
| |
| thread_return_t AsanThread::ThreadStart(uptr os_id) { |
| Init(); |
| asanThreadRegistry().StartThread(tid(), os_id, 0); |
| if (flags()->use_sigaltstack) SetAlternateSignalStack(); |
| |
| if (!start_routine_) { |
| // start_routine_ == 0 if we're on the main thread or on one of the |
| // OS X libdispatch worker threads. But nobody is supposed to call |
| // ThreadStart() for the worker threads. |
| CHECK_EQ(tid(), 0); |
| return 0; |
| } |
| |
| thread_return_t res = start_routine_(arg_); |
| malloc_storage().CommitBack(); |
| if (flags()->use_sigaltstack) UnsetAlternateSignalStack(); |
| |
| // On POSIX systems we defer this to the TSD destructor. LSan will consider |
| // the thread's memory as non-live from the moment we call Destroy(), even |
| // though that memory might contain pointers to heap objects which will be |
| // cleaned up by a user-defined TSD destructor. Thus, calling Destroy() before |
| // the TSD destructors have run might cause false positives in LSan. |
| if (!SANITIZER_POSIX) |
| this->Destroy(); |
| |
| return res; |
| } |
| |
| void AsanThread::SetThreadStackAndTls() { |
| uptr tls_size = 0; |
| GetThreadStackAndTls(tid() == 0, &stack_bottom_, &stack_size_, &tls_begin_, |
| &tls_size); |
| stack_top_ = stack_bottom_ + stack_size_; |
| tls_end_ = tls_begin_ + tls_size; |
| |
| int local; |
| CHECK(AddrIsInStack((uptr)&local)); |
| } |
| |
| void AsanThread::ClearShadowForThreadStackAndTLS() { |
| PoisonShadow(stack_bottom_, stack_top_ - stack_bottom_, 0); |
| if (tls_begin_ != tls_end_) |
| PoisonShadow(tls_begin_, tls_end_ - tls_begin_, 0); |
| } |
| |
| const char *AsanThread::GetFrameNameByAddr(uptr addr, uptr *offset, |
| uptr *frame_pc) { |
| uptr bottom = 0; |
| if (AddrIsInStack(addr)) { |
| bottom = stack_bottom(); |
| } else if (has_fake_stack()) { |
| bottom = fake_stack()->AddrIsInFakeStack(addr); |
| CHECK(bottom); |
| *offset = addr - bottom; |
| *frame_pc = ((uptr*)bottom)[2]; |
| return (const char *)((uptr*)bottom)[1]; |
| } |
| uptr aligned_addr = addr & ~(SANITIZER_WORDSIZE/8 - 1); // align addr. |
| u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr); |
| u8 *shadow_bottom = (u8*)MemToShadow(bottom); |
| |
| while (shadow_ptr >= shadow_bottom && |
| *shadow_ptr != kAsanStackLeftRedzoneMagic) { |
| shadow_ptr--; |
| } |
| |
| while (shadow_ptr >= shadow_bottom && |
| *shadow_ptr == kAsanStackLeftRedzoneMagic) { |
| shadow_ptr--; |
| } |
| |
| if (shadow_ptr < shadow_bottom) { |
| *offset = 0; |
| return "UNKNOWN"; |
| } |
| |
| uptr* ptr = (uptr*)SHADOW_TO_MEM((uptr)(shadow_ptr + 1)); |
| CHECK(ptr[0] == kCurrentStackFrameMagic); |
| *offset = addr - (uptr)ptr; |
| *frame_pc = ptr[2]; |
| return (const char*)ptr[1]; |
| } |
| |
| static bool ThreadStackContainsAddress(ThreadContextBase *tctx_base, |
| void *addr) { |
| AsanThreadContext *tctx = static_cast<AsanThreadContext*>(tctx_base); |
| AsanThread *t = tctx->thread; |
| if (!t) return false; |
| if (t->AddrIsInStack((uptr)addr)) return true; |
| if (t->has_fake_stack() && t->fake_stack()->AddrIsInFakeStack((uptr)addr)) |
| return true; |
| return false; |
| } |
| |
| AsanThread *GetCurrentThread() { |
| AsanThreadContext *context = |
| reinterpret_cast<AsanThreadContext *>(AsanTSDGet()); |
| if (!context) { |
| if (SANITIZER_ANDROID) { |
| // On Android, libc constructor is called _after_ asan_init, and cleans up |
| // TSD. Try to figure out if this is still the main thread by the stack |
| // address. We are not entirely sure that we have correct main thread |
| // limits, so only do this magic on Android, and only if the found thread |
| // is the main thread. |
| AsanThreadContext *tctx = GetThreadContextByTidLocked(0); |
| if (ThreadStackContainsAddress(tctx, &context)) { |
| SetCurrentThread(tctx->thread); |
| return tctx->thread; |
| } |
| } |
| return 0; |
| } |
| return context->thread; |
| } |
| |
| void SetCurrentThread(AsanThread *t) { |
| CHECK(t->context()); |
| if (flags()->verbosity >= 2) { |
| Report("SetCurrentThread: %p for thread %p\n", |
| t->context(), (void*)GetThreadSelf()); |
| } |
| // Make sure we do not reset the current AsanThread. |
| CHECK_EQ(0, AsanTSDGet()); |
| AsanTSDSet(t->context()); |
| CHECK_EQ(t->context(), AsanTSDGet()); |
| } |
| |
| u32 GetCurrentTidOrInvalid() { |
| AsanThread *t = GetCurrentThread(); |
| return t ? t->tid() : kInvalidTid; |
| } |
| |
| AsanThread *FindThreadByStackAddress(uptr addr) { |
| asanThreadRegistry().CheckLocked(); |
| AsanThreadContext *tctx = static_cast<AsanThreadContext *>( |
| asanThreadRegistry().FindThreadContextLocked(ThreadStackContainsAddress, |
| (void *)addr)); |
| return tctx ? tctx->thread : 0; |
| } |
| |
| void EnsureMainThreadIDIsCorrect() { |
| AsanThreadContext *context = |
| reinterpret_cast<AsanThreadContext *>(AsanTSDGet()); |
| if (context && (context->tid == 0)) |
| context->os_id = GetTid(); |
| } |
| } // namespace __asan |
| |
| // --- Implementation of LSan-specific functions --- {{{1 |
| namespace __lsan { |
| bool GetThreadRangesLocked(uptr os_id, uptr *stack_begin, uptr *stack_end, |
| uptr *tls_begin, uptr *tls_end, |
| uptr *cache_begin, uptr *cache_end) { |
| __asan::AsanThreadContext *context = static_cast<__asan::AsanThreadContext *>( |
| __asan::asanThreadRegistry().FindThreadContextByOsIDLocked(os_id)); |
| if (!context) return false; |
| __asan::AsanThread *t = context->thread; |
| if (!t) return false; |
| *stack_begin = t->stack_bottom(); |
| *stack_end = t->stack_top(); |
| *tls_begin = t->tls_begin(); |
| *tls_end = t->tls_end(); |
| // ASan doesn't keep allocator caches in TLS, so these are unused. |
| *cache_begin = 0; |
| *cache_end = 0; |
| return true; |
| } |
| |
| void LockThreadRegistry() { |
| __asan::asanThreadRegistry().Lock(); |
| } |
| |
| void UnlockThreadRegistry() { |
| __asan::asanThreadRegistry().Unlock(); |
| } |
| |
| void EnsureMainThreadIDIsCorrect() { |
| __asan::EnsureMainThreadIDIsCorrect(); |
| } |
| } // namespace __lsan |