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
@@ -17,6 +17,7 @@
 #include "hwasan_interface_internal.h"
 #include "hwasan_mapping.h"
 #include "hwasan_poisoning.h"
+#include "lsan/lsan_common.h"
 #include "sanitizer_common/sanitizer_allocator.h"
 #include "sanitizer_common/sanitizer_allocator_checks.h"
 #include "sanitizer_common/sanitizer_allocator_interface.h"
@@ -31,14 +32,26 @@
 namespace __hwasan {
 
 struct Metadata {
+ private:
+  atomic_uint64_t alloc_context_id;
   u32 requested_size_low;
-  u32 requested_size_high : 31;
-  u32 right_aligned : 1;
-  u32 alloc_context_id;
-  u64 get_requested_size() {
+  u16 requested_size_high;
+
+ public:
+  u8 right_aligned;
+  u8 lsan_tag;
+
+  void SetAllocContext(u32 stack);
+  void GetAllocContext(u32 &tid, u32 &stack) const;
+
+  bool IsAllocated() const;
+  u32 GetAllocStackId() const;
+
+  u64 get_requested_size() const {
     return (static_cast<u64>(requested_size_high) << 32) + requested_size_low;
   }
   void set_requested_size(u64 size) {
+    static_assert(sizeof(Metadata) == 16);
     requested_size_low = size & ((1ul << 32) - 1);
     requested_size_high = size >> 32;
   }
@@ -89,6 +102,7 @@
   u32 GetAllocStackId() const;
   bool FromSmallHeap() const;
  private:
+  friend class __lsan::LsanMetadata;
   uptr block_;
   Metadata *const metadata_;
 };
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
@@ -21,6 +21,7 @@
 #include "hwasan_malloc_bisect.h"
 #include "hwasan_thread.h"
 #include "hwasan_report.h"
+#include "lsan/lsan_common.h"
 
 namespace __hwasan {
 
@@ -42,8 +43,7 @@
 static ALIGNED(16) u8 tail_magic[kShadowAlignment - 1];
 
 bool HwasanChunkView::IsAllocated() const {
-  return metadata_ && metadata_->alloc_context_id &&
-         metadata_->get_requested_size();
+  return metadata_ && metadata_->IsAllocated();
 }
 
 // Aligns the 'addr' right to the granule boundary.
@@ -65,7 +65,7 @@
   return metadata_->get_requested_size();
 }
 u32 HwasanChunkView::GetAllocStackId() const {
-  return metadata_->alloc_context_id;
+  return metadata_->GetAllocStackId();
 }
 
 uptr HwasanChunkView::ActualSize() const {
@@ -76,6 +76,33 @@
   return allocator.FromPrimary(reinterpret_cast<void *>(block_));
 }
 
+void Metadata::SetAllocContext(u32 stack) {
+  Thread *t = GetCurrentThread();
+  u64 context = t ? t->unique_id() : kMainTid;
+  context <<= 32;
+  context += stack;
+  __sanitizer::atomic_store(&alloc_context_id, context, memory_order_relaxed);
+}
+
+void Metadata::GetAllocContext(u32 &tid, u32 &stack) const {
+  u64 context =
+      __sanitizer::atomic_load(&alloc_context_id, memory_order_relaxed);
+  stack = context;
+  context >>= 32;
+  tid = context;
+}
+
+bool Metadata::IsAllocated() const {
+  return __sanitizer::atomic_load(&alloc_context_id, memory_order_relaxed) &&
+         get_requested_size();
+}
+
+u32 Metadata::GetAllocStackId() const {
+  return __sanitizer::atomic_load(&alloc_context_id, memory_order_relaxed);
+}
+
+static const uptr kChunkHeaderSize = sizeof(HwasanChunkView);
+
 void GetAllocatorStats(AllocatorStatCounters s) {
   allocator.GetStats(s);
 }
@@ -158,7 +185,7 @@
   Metadata *meta =
       reinterpret_cast<Metadata *>(allocator.GetMetaData(allocated));
   meta->set_requested_size(orig_size);
-  meta->alloc_context_id = StackDepotPut(*stack);
+  meta->SetAllocContext(StackDepotPut(*stack));
   meta->right_aligned = false;
   if (zeroise) {
     internal_memset(allocated, 0, size);
@@ -246,7 +273,9 @@
   }
   uptr orig_size = meta->get_requested_size();
   u32 free_context_id = StackDepotPut(*stack);
-  u32 alloc_context_id = meta->alloc_context_id;
+  u32 tid;
+  u32 stack_id;
+  meta->GetAllocContext(tid, stack_id);
 
   // Check tail magic.
   uptr tagged_size = TaggedSize(orig_size);
@@ -266,7 +295,7 @@
   }
 
   meta->set_requested_size(0);
-  meta->alloc_context_id = 0;
+  meta->SetAllocContext(0);
   // This memory will not be reused by anyone else, so we are free to keep it
   // poisoned.
   Thread *t = GetCurrentThread();
@@ -298,7 +327,7 @@
   if (t) {
     allocator.Deallocate(t->allocator_cache(), aligned_ptr);
     if (auto *ha = t->heap_allocations())
-      ha->push({reinterpret_cast<uptr>(tagged_ptr), alloc_context_id,
+      ha->push({reinterpret_cast<uptr>(tagged_ptr), stack_id,
                 free_context_id, static_cast<u32>(orig_size)});
   } else {
     SpinMutexLock l(&fallback_mutex);
@@ -451,6 +480,52 @@
 
 }  // namespace __hwasan
 
+// --- Implementation of LSan-specific functions --- {{{1
+namespace __lsan {
+
+LsanMetadata::LsanMetadata(uptr chunk) {
+  metadata_ = chunk ? reinterpret_cast<void *>(chunk - __hwasan::kChunkHeaderSize)
+                    : nullptr;
+  metadata_ = nullptr;
+}
+
+bool LsanMetadata::allocated() const {
+  if (!metadata_)
+    return false;
+  __hwasan::HwasanChunkView *m = reinterpret_cast<__hwasan::HwasanChunkView *>(metadata_);
+  // TODO(kstoimenov): is this thread safe?
+  return m->IsAllocated();
+}
+
+ChunkTag LsanMetadata::tag() const {
+  __hwasan::HwasanChunkView *m = reinterpret_cast<__hwasan::HwasanChunkView *>(metadata_);;
+  return static_cast<ChunkTag>(m->metadata_->lsan_tag);
+}
+
+void LsanMetadata::set_tag(ChunkTag value) {
+  __hwasan::HwasanChunkView *m = reinterpret_cast<__hwasan::HwasanChunkView *>(metadata_);;
+  m->metadata_->lsan_tag = value;
+}
+
+uptr LsanMetadata::requested_size() const {
+  __hwasan::HwasanChunkView *m = reinterpret_cast<__hwasan::HwasanChunkView *>(metadata_);;
+  return m->UsedSize();
+}
+
+u32 LsanMetadata::stack_trace_id() const {
+  __hwasan::HwasanChunkView *m = reinterpret_cast<__hwasan::HwasanChunkView *>(metadata_);;
+  u32 tid = 0;
+  u32 stack = 0;
+  m->metadata_->GetAllocContext(tid, stack);
+  return stack;
+}
+
+void ForEachChunk(ForEachChunkCallback callback, void *arg) {
+  __hwasan::allocator.ForEachChunk(callback, arg);
+}
+
+}  // namespace __lsan
+
 using namespace __hwasan;
 
 void __hwasan_enable_allocator_tagging() {