Synchronize thread creation on posix platforms.

src/platform-posix.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 565 matching lines @@
   }
   set_name(options.name());
 }
 
 
 Thread::~Thread() {
   delete data_;
 }
 
 
+// Synchronizes thread creation
+static Mutex thread_creation_mutex_;
+
+
 static void SetThreadName(const char* name) {
 #if V8_OS_DRAGONFLYBSD || V8_OS_FREEBSD || V8_OS_OPENBSD
   pthread_set_name_np(pthread_self(), name);
 #elif V8_OS_NETBSD
   STATIC_ASSERT(Thread::kMaxThreadNameLength <= PTHREAD_MAX_NAMELEN_NP);
   pthread_setname_np(pthread_self(), "%s", name);
 #elif V8_OS_MACOSX
   // pthread_setname_np is only available in 10.6 or later, so test
   // for it at runtime.
   int (*dynamic_pthread_setname_np)(const char*);
   *reinterpret_cast<void**>(&dynamic_pthread_setname_np) =
     dlsym(RTLD_DEFAULT, "pthread_setname_np");
   if (dynamic_pthread_setname_np == NULL)
     return;
 
   // Mac OS X does not expose the length limit of the name, so hardcode it.
   static const int kMaxNameLength = 63;
   STATIC_ASSERT(Thread::kMaxThreadNameLength <= kMaxNameLength);
   dynamic_pthread_setname_np(name);
 #elif defined(PR_SET_NAME)
   prctl(PR_SET_NAME,
         reinterpret_cast<unsigned long>(name),  // NOLINT
         0, 0, 0);
 #endif
 }
 
 
 static void* ThreadEntry(void* arg) {
   Thread* thread = reinterpret_cast<Thread*>(arg);
-  // This is also initialized by the first argument to pthread_create() but we
-  // don't know which thread will run first (the original thread or the new
-  // one) so we initialize it here too.
-  thread->data()->thread_ = pthread_self();
+  // We take the lock here to make sure that pthread_create finished first since
+  // we don't know which thread will run first (the original thread or the new
+  // one).
+  { LockGuard<Mutex> lock_guard(&thread_creation_mutex_); }
   SetThreadName(thread->name());
   ASSERT(thread->data()->thread_ != kNoThread);
   thread->NotifyStartedAndRun();
   return NULL;
 }
 
 
 void Thread::set_name(const char* name) {
   strncpy(name_, name, sizeof(name_));
   name_[sizeof(name_) - 1] = '\0';
 }
 
 
 void Thread::Start() {
   int result;
   pthread_attr_t attr;
   memset(&attr, 0, sizeof(attr));
   result = pthread_attr_init(&attr);
   ASSERT_EQ(0, result);
   // Native client uses default stack size.
 #if !V8_OS_NACL
   if (stack_size_ > 0) {
     result = pthread_attr_setstacksize(&attr, static_cast<size_t>(stack_size_));
     ASSERT_EQ(0, result);
   }
 #endif
-  result = pthread_create(&data_->thread_, &attr, ThreadEntry, this);
+  {
+    LockGuard<Mutex> lock_guard(&thread_creation_mutex_);
+    result = pthread_create(&data_->thread_, &attr, ThreadEntry, this);
+  }
   ASSERT_EQ(0, result);
   result = pthread_attr_destroy(&attr);
   ASSERT_EQ(0, result);
   ASSERT(data_->thread_ != kNoThread);
   USE(result);
 }
 
 
 void Thread::Join() {
   pthread_join(data_->thread_, NULL);
@@ skipping 125 matching lines @@
 
 void Thread::SetThreadLocal(LocalStorageKey key, void* value) {
   pthread_key_t pthread_key = LocalKeyToPthreadKey(key);
   int result = pthread_setspecific(pthread_key, value);
   ASSERT_EQ(0, result);
   USE(result);
 }
 
 
 } }  // namespace v8::internal