diff --git a/test/hotspot/gtest/gc/g1/test_freeRegionList.cpp b/test/hotspot/gtest/gc/g1/test_freeRegionList.cpp
index ea8027df2a715..e61ce43fdb618 100644
--- a/test/hotspot/gtest/gc/g1/test_freeRegionList.cpp
+++ b/test/hotspot/gtest/gc/g1/test_freeRegionList.cpp
@@ -44,7 +44,10 @@ TEST_OTHER_VM(G1FreeRegionList, length) {
 
   // Create a fake heap. It does not need to be valid, as the G1HeapRegion constructor
   // does not access it.
-  MemRegion heap(nullptr, num_regions_in_test * G1HeapRegion::GrainWords);
+  const size_t szw = num_regions_in_test * G1HeapRegion::GrainWords;
+  const size_t sz = szw * BytesPerWord;
+  char* addr = os::reserve_memory_aligned(sz, G1HeapRegion::GrainBytes, mtTest);
+  MemRegion heap((HeapWord*)addr, szw);
 
   // Allocate a fake BOT because the G1HeapRegion constructor initializes
   // the BOT.
@@ -87,5 +90,6 @@ TEST_OTHER_VM(G1FreeRegionList, length) {
 
   bot_storage->uncommit_regions(0, num_regions_in_test);
   delete bot_storage;
+  os::release_memory(addr, sz);
   FREE_C_HEAP_ARRAY(HeapWord, bot_data);
 }