Index: compiler-rt/lib/scudo/standalone/fuchsia.cpp
===================================================================
--- compiler-rt/lib/scudo/standalone/fuchsia.cpp
+++ compiler-rt/lib/scudo/standalone/fuchsia.cpp
@@ -57,8 +57,9 @@
   if (Flags & MAP_NOACCESS)
     return allocateVmar(Size, Data, AllowNoMem);
 
-  const zx_handle_t Vmar = Data ? Data->Vmar : _zx_vmar_root_self();
-  CHECK_NE(Vmar, ZX_HANDLE_INVALID);
+  zx_handle_t Vmar = _zx_vmar_root_self();
+  if (Data && Data->Vmar != ZX_HANDLE_INVALID)
+    Vmar = Data->Vmar;
 
   zx_status_t Status;
   zx_handle_t Vmo;
@@ -126,7 +127,9 @@
     CHECK_EQ(_zx_vmar_destroy(Vmar), ZX_OK);
     CHECK_EQ(_zx_handle_close(Vmar), ZX_OK);
   } else {
-    const zx_handle_t Vmar = Data ? Data->Vmar : _zx_vmar_root_self();
+    zx_handle_t Vmar = _zx_vmar_root_self();
+    if (Data && Data->Vmar != ZX_HANDLE_INVALID)
+      Vmar = Data->Vmar;
     const zx_status_t Status =
         _zx_vmar_unmap(Vmar, reinterpret_cast<uintptr_t>(Addr), Size);
     if (UNLIKELY(Status != ZX_OK))