diff --git a/compiler-rt/lib/hwasan/hwasan_thread.cpp b/compiler-rt/lib/hwasan/hwasan_thread.cpp
--- a/compiler-rt/lib/hwasan/hwasan_thread.cpp
+++ b/compiler-rt/lib/hwasan/hwasan_thread.cpp
@@ -108,7 +108,15 @@
 
 // Generate a (pseudo-)random non-zero tag.
 tag_t Thread::GenerateRandomTag() {
-  if (tagging_disabled_) return 0;
+  // Return non-zero when tagging is not disabled so that the allocator
+  // fallback knows whatever pointer is being created has not come from the
+  // system allocator.
+  if (tagging_disabled_)
+#if HWASAN_WITH_INTERCEPTORS
+    return flags()->disable_allocator_tagging ? 0 : 0x10;
+#else
+    return 0;
+#endif
   tag_t tag;
   do {
     if (flags()->random_tags) {