[Tsan] Make calloc() to not track allocated space unless thread is completely initialized

[kutuzov.viktor.84]

Summary

The critical section in __tsan_thread_start_func() where the associated ThreadState object is not completely initialized contains a pthread_setspecific() call which in turn use calloc() on FreeBSD. The calloc() call thus relies on under-initialized thread state data and leads to generating the "data race" kind of error.

extern "C" void *__tsan_thread_start_func(void *arg) {
...
  {
    ThreadState *thr = cur_thread();
    // Thread-local state is not initialized yet.
    ScopedIgnoreInterceptors ignore;
    if (pthread_setspecific(g_thread_finalize_key,
                            (void *)kPthreadDestructorIterations)) {
      Printf("ThreadSanitizer: failed to set thread key\n");
      Die();
    }
    ...
  }
...
}

[dvyukov]

Will the following do?

• lib/tsan/rtl/tsan_interceptors.cc (revision 220555)

+++ lib/tsan/rtl/tsan_interceptors.cc (working copy)
@@ -872,11 +872,13 @@

ThreadState *thr = cur_thread();
// Thread-local state is not initialized yet.
ScopedIgnoreInterceptors ignore;

+ ThreadIgnoreBegin(thr, 0);

if (pthread_setspecific(g_thread_finalize_key,
                        (void *)kPthreadDestructorIterations)) {
  Printf("ThreadSanitizer: failed to set thread key\n");
  Die();
}

+ ThreadIgnoreEnd(thr, 0);

while ((tid = atomic_load(&p->tid, memory_order_acquire)) == 0)
  pthread_yield();
atomic_store(&p->tid, 0, memory_order_release);

I've tested that 'make presubmit' passes with this change.
If it works for freebsd, then I pre-approve such change.

I strongly don't want to touch malloc interceptors without a significant reason. The set of things that we ignore and don't ignore in malloc interceptors is crafted over several years. There is long tail of implications on Java integration, Chromium with non-instrumented libraries and other weird contexts. We don't have any known issues with the current version.

[kutuzov.viktor.84]

Yes, it worked. Updated.

[dvyukov]

LGTM

Closed by commit rL220673 (authored by vkutuzov).

lib/tsan/rtl/tsan_interceptors.cc

extern "C" void *__tsan_thread_start_func(void *arg) {
   ThreadParam *p = (ThreadParam*)arg;
   void* (*callback)(void *arg) = p->callback;
   void *param = p->param;
   int tid = 0;
   {
     ThreadState *thr = cur_thread();
     // Thread-local state is not initialized yet.
     ScopedIgnoreInterceptors ignore;
+    ThreadIgnoreBegin(thr, 0);
     if (pthread_setspecific(g_thread_finalize_key,
                             (void *)kPthreadDestructorIterations)) {
       Printf("ThreadSanitizer: failed to set thread key\n");
       Die();
     }
+    ThreadIgnoreEnd(thr, 0);
     while ((tid = atomic_load(&p->tid, memory_order_acquire)) == 0)
       pthread_yield();
     atomic_store(&p->tid, 0, memory_order_release);
     ThreadStart(thr, tid, GetTid());
   }
   void *res = callback(param);
   // Prevent the callback from being tail called,
   // it mixes up stack traces.