diff --git a/compiler-rt/lib/asan/asan_allocator.cpp b/compiler-rt/lib/asan/asan_allocator.cpp
--- a/compiler-rt/lib/asan/asan_allocator.cpp
+++ b/compiler-rt/lib/asan/asan_allocator.cpp
@@ -62,11 +62,12 @@
 // If the left redzone is greater than the ChunkHeader size we store a magic
 // value in the first uptr word of the memory block and store the address of
 // ChunkBase in the next uptr.
-// M B L L L L L L L L L  H H U U U U U U
+// M B L L L L L L L L S  H H U U U U U U
 //   |                    ^
 //   ---------------------|
 //   M -- magic value kAllocBegMagic
 //   B -- address of ChunkHeader pointing to the first 'H'
+//   S -- Maybe user_requested_size
 static const uptr kAllocBegMagic = 0xCC6E96B9;
 
 struct ChunkHeader {
@@ -81,8 +82,7 @@
   u32 lsan_tag          : 2;
   // 2-nd 8 bytes
   // This field is used for small sizes. For large sizes it is equal to
-  // SizeClassMap::kMaxSize and the actual size is stored in the
-  // SecondaryAllocator's metadata.
+  // SizeClassMap::kMaxSize and the actual size is stored left to the header.
   u32 user_requested_size : 29;
   // align < 8 -> 0
   // else      -> log2(min(align, 512)) - 2
@@ -112,23 +112,28 @@
 
 struct AsanChunk: ChunkBase {
   uptr Beg() { return reinterpret_cast<uptr>(this) + kChunkHeaderSize; }
-  uptr UsedSize(bool locked_version = false) {
+  uptr UsedSize() {
     if (user_requested_size != SizeClassMap::kMaxSize)
       return user_requested_size;
-    return *reinterpret_cast<uptr *>(
-               get_allocator().GetMetaData(AllocBeg(locked_version)));
+    return *(reinterpret_cast<uptr *>(this) - 1);
   }
-  void *AllocBeg(bool locked_version = false) {
-    if (from_memalign) {
-      if (locked_version)
-        return get_allocator().GetBlockBeginFastLocked(
-            reinterpret_cast<void *>(this));
-      return get_allocator().GetBlockBegin(reinterpret_cast<void *>(this));
+  void SetUsedSize(uptr size, void *unused_beg) {
+    if (size < SizeClassMap::kMaxSize) {
+      user_requested_size = size;
+      return;
     }
+    CHECK_GE(reinterpret_cast<uptr *>(this),
+             reinterpret_cast<uptr *>(unused_beg) + 1);
+    *(reinterpret_cast<uptr *>(this) - 1) = size;
+    user_requested_size = SizeClassMap::kMaxSize;
+  }
+  void *AllocBeg() {
+    if (from_memalign)
+      return get_allocator().GetBlockBegin(reinterpret_cast<void *>(this));
     return reinterpret_cast<void*>(Beg() - RZLog2Size(rz_log));
   }
-  bool AddrIsInside(uptr addr, bool locked_version = false) {
-    return (addr >= Beg()) && (addr < Beg() + UsedSize(locked_version));
+  bool AddrIsInside(uptr addr) {
+    return (addr >= Beg()) && (addr < Beg() + UsedSize());
   }
 };
 
@@ -308,7 +313,7 @@
     if (atomic_load(&ac->chunk_state, memory_order_acquire) ==
         CHUNK_ALLOCATED) {
       uptr beg = ac->Beg();
-      uptr end = ac->Beg() + ac->UsedSize(true);
+      uptr end = ac->Beg() + ac->UsedSize();
       uptr chunk_end = chunk + allocated_size;
       if (chunk < beg && beg < end && end <= chunk_end) {
         // Looks like a valid AsanChunk in use, poison redzones only.
@@ -522,15 +527,15 @@
       reinterpret_cast<uptr *>(alloc_beg)[0] = kAllocBegMagic;
       reinterpret_cast<uptr *>(alloc_beg)[1] = chunk_beg;
     }
+    CHECK(size);
     if (using_primary_allocator) {
-      CHECK(size);
-      m->user_requested_size = size;
       CHECK(allocator.FromPrimary(allocated));
+      m->user_requested_size = size;
     } else {
       CHECK(!allocator.FromPrimary(allocated));
-      m->user_requested_size = SizeClassMap::kMaxSize;
+      m->SetUsedSize(
+          size, reinterpret_cast<uptr *>(alloc_beg) + 2 /* magic, chunk_beg */);
       uptr *meta = reinterpret_cast<uptr *>(allocator.GetMetaData(allocated));
-      meta[0] = size;
       meta[1] = chunk_beg;
     }
     m->user_requested_alignment_log = user_requested_alignment_log;
@@ -1076,10 +1081,9 @@
                 __asan::CHUNK_ALLOCATED)
     return 0;
   uptr chunk = m->Beg();
-  if (m->AddrIsInside(addr, /*locked_version=*/true))
+  if (m->AddrIsInside(addr))
     return chunk;
-  if (IsSpecialCaseOfOperatorNew0(chunk, m->UsedSize(/*locked_version*/ true),
-                                  addr))
+  if (IsSpecialCaseOfOperatorNew0(chunk, m->UsedSize(), addr))
     return chunk;
   return 0;
 }
@@ -1132,7 +1136,7 @@
 
 uptr LsanMetadata::requested_size() const {
   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
-  return m->UsedSize(/*locked_version=*/true);
+  return m->UsedSize();
 }
 
 u32 LsanMetadata::stack_trace_id() const {