Index: compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
===================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
@@ -413,7 +413,7 @@
 }
 
 static void SetJmp(ThreadState *thr, uptr sp, uptr mangled_sp) {
-  if (thr->shadow_stack_pos == 0)  // called from libc guts during bootstrap
+  if (!thr->is_inited)  // called from libc guts during bootstrap
     return;
   // Cleanup old bufs.
   JmpBufGarbageCollect(thr, sp);
@@ -669,9 +669,12 @@
 }
 
 TSAN_INTERCEPTOR(void*, memcpy, void *dst, const void *src, uptr size) {
-  SCOPED_TSAN_INTERCEPTOR(memcpy, dst, src, size);
-  MemoryAccessRange(thr, pc, (uptr)dst, size, true);
-  MemoryAccessRange(thr, pc, (uptr)src, size, false);
+  // On FreeBSD we get here from libthr internals on thread initialization.
+  if (cur_thread()->is_inited) {
+    SCOPED_TSAN_INTERCEPTOR(memcpy, dst, src, size);
+    MemoryAccessRange(thr, pc, (uptr)dst, size, true);
+    MemoryAccessRange(thr, pc, (uptr)src, size, false);
+  }
   return internal_memcpy(dst, src, size);
 }
 
Index: compiler-rt/trunk/lib/tsan/rtl/tsan_rtl.h
===================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_rtl.h
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_rtl.h
@@ -371,6 +371,7 @@
   const int unique_id;
   bool in_symbolizer;
   bool in_ignored_lib;
+  bool is_inited;
   bool is_dead;
   bool is_freeing;
   bool is_vptr_access;
Index: compiler-rt/trunk/lib/tsan/rtl/tsan_rtl.cc
===================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_rtl.cc
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_rtl.cc
@@ -461,7 +461,7 @@
 #endif
 
 u32 CurrentStackId(ThreadState *thr, uptr pc) {
-  if (thr->shadow_stack_pos == 0)  // May happen during bootstrap.
+  if (!thr->is_inited)  // May happen during bootstrap.
     return 0;
   if (pc != 0) {
 #ifndef SANITIZER_GO
Index: compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_thread.cc
===================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_thread.cc
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_rtl_thread.cc
@@ -120,6 +120,7 @@
   AcquireImpl(thr, 0, &sync);
   StatInc(thr, StatSyncAcquire);
   sync.Reset(&thr->clock_cache);
+  thr->is_inited = true;
   DPrintf("#%d: ThreadStart epoch=%zu stk_addr=%zx stk_size=%zx "
           "tls_addr=%zx tls_size=%zx\n",
           tid, (uptr)epoch0, args->stk_addr, args->stk_size,