diff --git a/libc/bionic/malloc_common.cpp b/libc/bionic/malloc_common.cpp
index 9744968..e159fdc 100644
--- a/libc/bionic/malloc_common.cpp
+++ b/libc/bionic/malloc_common.cpp
@@ -333,6 +333,14 @@
 
     return EnableGwpAsan(*reinterpret_cast<android_mallopt_gwp_asan_options_t*>(arg));
   }
+  if (opcode == M_MEMTAG_STACK_IS_ON) {
+    if (arg == nullptr || arg_size != sizeof(bool)) {
+      errno = EINVAL;
+      return false;
+    }
+    *reinterpret_cast<bool*>(arg) = atomic_load(&__libc_globals->memtag_stack);
+    return true;
+  }
   errno = ENOTSUP;
   return false;
 }