diff --git a/compiler-rt/lib/scudo/standalone/allocator_config.h b/compiler-rt/lib/scudo/standalone/allocator_config.h
--- a/compiler-rt/lib/scudo/standalone/allocator_config.h
+++ b/compiler-rt/lib/scudo/standalone/allocator_config.h
@@ -170,7 +170,7 @@
 
   typedef SizeClassAllocator64<FuchsiaConfig> Primary;
   static const uptr PrimaryRegionSizeLog = 30U;
-  static const uptr PrimaryGroupSizeLog = 30U;
+  static const uptr PrimaryGroupSizeLog = 27U;
   typedef u32 PrimaryCompactPtrT;
   static const bool PrimaryEnableRandomOffset = true;
   static const uptr PrimaryMapSizeIncrement = 1UL << 18;