diff --git a/compiler-rt/lib/scudo/standalone/mem_map_base.h b/compiler-rt/lib/scudo/standalone/mem_map_base.h
--- a/compiler-rt/lib/scudo/standalone/mem_map_base.h
+++ b/compiler-rt/lib/scudo/standalone/mem_map_base.h
@@ -50,6 +50,7 @@
   void setMemoryPermission(uptr Addr, uptr Size, uptr Flags) {
     DCHECK(isAllocated());
     DCHECK((Addr >= getBase()) && (Addr + Size <= getBase() + getCapacity()));
+    DCHECK_EQ(Flags & ~MAP_NOACCESS, 0);
     return static_cast<Derived *>(this)->setMemoryPermissionImpl(Addr, Size,
                                                                  Flags);
   }
@@ -96,6 +97,7 @@
   // Reserve a chunk of memory at a suggested address.
   bool create(uptr Addr, uptr Size, const char *Name, uptr Flags = 0) {
     DCHECK(!isCreated());
+    DCHECK_EQ(Flags & ~MAP_ALLOWNOMEM, 0);
     return invokeImpl(&Derived::createImpl, Addr, Size, Name, Flags);
   }