diff --git a/compiler-rt/lib/hwasan/hwasan_allocator.h b/compiler-rt/lib/hwasan/hwasan_allocator.h
--- a/compiler-rt/lib/hwasan/hwasan_allocator.h
+++ b/compiler-rt/lib/hwasan/hwasan_allocator.h
@@ -28,9 +28,17 @@
 namespace __hwasan {
 
 struct Metadata {
-  u32 requested_size : 31;  // sizes are < 2G.
-  u32 right_aligned  : 1;
+  u32 requested_size_low;
+  u32 requested_size_high : 31;
+  u32 right_aligned : 1;
   u32 alloc_context_id;
+  u64 get_requested_size() {
+    return (static_cast<u64>(requested_size_high) << 32) + requested_size_low;
+  }
+  void set_requested_size(u64 size) {
+    requested_size_low = size & ((1ul << 32) - 1);
+    requested_size_high = size >> 32;
+  }
 };
 
 struct HwasanMapUnmapCallback {
@@ -43,7 +51,7 @@
   }
 };
 
-static const uptr kMaxAllowedMallocSize = 2UL << 30;  // 2G
+static const uptr kMaxAllowedMallocSize = 1UL << 40;  // 1T
 
 struct AP64 {
   static const uptr kSpaceBeg = ~0ULL;
diff --git a/compiler-rt/lib/hwasan/hwasan_allocator.cpp b/compiler-rt/lib/hwasan/hwasan_allocator.cpp
--- a/compiler-rt/lib/hwasan/hwasan_allocator.cpp
+++ b/compiler-rt/lib/hwasan/hwasan_allocator.cpp
@@ -42,7 +42,8 @@
 static ALIGNED(16) u8 tail_magic[kShadowAlignment - 1];
 
 bool HwasanChunkView::IsAllocated() const {
-  return metadata_ && metadata_->alloc_context_id && metadata_->requested_size;
+  return metadata_ && metadata_->alloc_context_id &&
+         metadata_->get_requested_size();
 }
 
 // Aligns the 'addr' right to the granule boundary.
@@ -54,14 +55,14 @@
 
 uptr HwasanChunkView::Beg() const {
   if (metadata_ && metadata_->right_aligned)
-    return AlignRight(block_, metadata_->requested_size);
+    return AlignRight(block_, metadata_->get_requested_size());
   return block_;
 }
 uptr HwasanChunkView::End() const {
   return Beg() + UsedSize();
 }
 uptr HwasanChunkView::UsedSize() const {
-  return metadata_->requested_size;
+  return metadata_->get_requested_size();
 }
 u32 HwasanChunkView::GetAllocStackId() const {
   return metadata_->alloc_context_id;
@@ -129,7 +130,7 @@
   }
   Metadata *meta =
       reinterpret_cast<Metadata *>(allocator.GetMetaData(allocated));
-  meta->requested_size = static_cast<u32>(orig_size);
+  meta->set_requested_size(orig_size);
   meta->alloc_context_id = StackDepotPut(*stack);
   meta->right_aligned = false;
   if (zeroise) {
@@ -191,7 +192,7 @@
       RoundDownTo(reinterpret_cast<uptr>(untagged_ptr), kShadowAlignment));
   Metadata *meta =
       reinterpret_cast<Metadata *>(allocator.GetMetaData(aligned_ptr));
-  uptr orig_size = meta->requested_size;
+  uptr orig_size = meta->get_requested_size();
   u32 free_context_id = StackDepotPut(*stack);
   u32 alloc_context_id = meta->alloc_context_id;
 
@@ -208,7 +209,7 @@
                             orig_size, tail_magic);
   }
 
-  meta->requested_size = 0;
+  meta->set_requested_size(0);
   meta->alloc_context_id = 0;
   // This memory will not be reused by anyone else, so we are free to keep it
   // poisoned.
@@ -245,8 +246,9 @@
     void *untagged_ptr_old =  UntagPtr(tagged_ptr_old);
     Metadata *meta =
         reinterpret_cast<Metadata *>(allocator.GetMetaData(untagged_ptr_old));
-    internal_memcpy(UntagPtr(tagged_ptr_new), untagged_ptr_old,
-                    Min(new_size, static_cast<uptr>(meta->requested_size)));
+    internal_memcpy(
+        UntagPtr(tagged_ptr_new), untagged_ptr_old,
+        Min(new_size, static_cast<uptr>(meta->get_requested_size())));
     HwasanDeallocate(stack, tagged_ptr_old);
   }
   return tagged_ptr_new;
@@ -282,7 +284,7 @@
   } else {
     if (beg != untagged_ptr) return 0;
   }
-  return b->requested_size;
+  return b->get_requested_size();
 }
 
 void *hwasan_malloc(uptr size, StackTrace *stack) {
diff --git a/compiler-rt/test/hwasan/TestCases/allocator_returns_null.cpp b/compiler-rt/test/hwasan/TestCases/allocator_returns_null.cpp
--- a/compiler-rt/test/hwasan/TestCases/allocator_returns_null.cpp
+++ b/compiler-rt/test/hwasan/TestCases/allocator_returns_null.cpp
@@ -55,7 +55,7 @@
   const char *action = argv[1];
   untag_fprintf(stderr, "%s:\n", action);
 
-  static const size_t kMaxAllowedMallocSizePlusOne = (2UL << 30) + 1;
+  static const size_t kMaxAllowedMallocSizePlusOne = (1UL << 40) + 1;
 
   void *x = nullptr;
   if (!untag_strcmp(action, "malloc")) {
diff --git a/compiler-rt/test/hwasan/TestCases/sizes.cpp b/compiler-rt/test/hwasan/TestCases/sizes.cpp
--- a/compiler-rt/test/hwasan/TestCases/sizes.cpp
+++ b/compiler-rt/test/hwasan/TestCases/sizes.cpp
@@ -44,7 +44,7 @@
   static const size_t kChunkHeaderSize = 16;
 
   size_t MallocSize = test_size_max ? std::numeric_limits<size_t>::max()
-                                    : kMaxAllowedMallocSize;
+                                    : (kMaxAllowedMallocSize + 1);
 
   if (!untag_strcmp(argv[1], "malloc")) {
     void *p = malloc(MallocSize);