diff --git a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
--- a/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
+++ b/compiler-rt/lib/tsan/rtl/tsan_interceptors_posix.cpp
@@ -933,14 +933,15 @@
 struct ThreadParam {
   void* (*callback)(void *arg);
   void *param;
-  atomic_uintptr_t tid;
+  Tid tid;
+  Semaphore created;
+  Semaphore started;
 };
 
 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;
   {
     cur_thread_init();
     ThreadState *thr = cur_thread();
@@ -955,12 +956,11 @@
     }
     ThreadIgnoreEnd(thr);
 #endif
-    while ((tid = atomic_load(&p->tid, memory_order_acquire)) == 0)
-      internal_sched_yield();
+    p->created.Wait();
     Processor *proc = ProcCreate();
     ProcWire(proc, thr);
-    ThreadStart(thr, tid, GetTid(), ThreadType::Regular);
-    atomic_store(&p->tid, 0, memory_order_release);
+    ThreadStart(thr, p->tid, GetTid(), ThreadType::Regular);
+    p->started.Post();
   }
   void *res = callback(param);
   // Prevent the callback from being tail called,
@@ -999,7 +999,6 @@
   ThreadParam p;
   p.callback = callback;
   p.param = param;
-  atomic_store(&p.tid, 0, memory_order_relaxed);
   int res = -1;
   {
     // Otherwise we see false positives in pthread stack manipulation.
@@ -1009,8 +1008,8 @@
     ThreadIgnoreEnd(thr);
   }
   if (res == 0) {
-    Tid tid = ThreadCreate(thr, pc, *(uptr *)th, IsStateDetached(detached));
-    CHECK_NE(tid, kMainTid);
+    p.tid = ThreadCreate(thr, pc, *(uptr *)th, IsStateDetached(detached));
+    CHECK_NE(p.tid, kMainTid);
     // Synchronization on p.tid serves two purposes:
     // 1. ThreadCreate must finish before the new thread starts.
     //    Otherwise the new thread can call pthread_detach, but the pthread_t
@@ -1018,9 +1017,8 @@
     // 2. ThreadStart must finish before this thread continues.
     //    Otherwise, this thread can call pthread_detach and reset thr->sync
     //    before the new thread got a chance to acquire from it in ThreadStart.
-    atomic_store(&p.tid, tid, memory_order_release);
-    while (atomic_load(&p.tid, memory_order_acquire) != 0)
-      internal_sched_yield();
+    p.created.Post();
+    p.started.Wait();
   }
   if (attr == &myattr)
     pthread_attr_destroy(&myattr);