diff --git a/compiler-rt/include/sanitizer/dfsan_interface.h b/compiler-rt/include/sanitizer/dfsan_interface.h
--- a/compiler-rt/include/sanitizer/dfsan_interface.h
+++ b/compiler-rt/include/sanitizer/dfsan_interface.h
@@ -80,8 +80,7 @@
 size_t dfsan_get_label_count(void);
 
 /// Flushes the DFSan shadow, i.e. forgets about all labels currently associated
-/// with the application memory. Will work only if there are no other
-/// threads executing DFSan-instrumented code concurrently.
+/// with the application memory.
 /// Use this call to start over the taint tracking within the same procces.
 void dfsan_flush(void);
 
diff --git a/compiler-rt/lib/dfsan/dfsan.cpp b/compiler-rt/lib/dfsan/dfsan.cpp
--- a/compiler-rt/lib/dfsan/dfsan.cpp
+++ b/compiler-rt/lib/dfsan/dfsan.cpp
@@ -428,7 +428,6 @@
 }
 
 extern "C" void dfsan_flush() {
-  UnmapOrDie((void*)ShadowAddr(), UnusedAddr() - ShadowAddr());
   if (!MmapFixedNoReserve(ShadowAddr(), UnusedAddr() - ShadowAddr()))
     Die();
 }