diff --git a/compiler-rt/lib/lsan/lsan_allocator.h b/compiler-rt/lib/lsan/lsan_allocator.h
--- a/compiler-rt/lib/lsan/lsan_allocator.h
+++ b/compiler-rt/lib/lsan/lsan_allocator.h
@@ -32,6 +32,7 @@
 void ForEachChunk(const Callable &callback);
 
 void GetAllocatorCacheRange(uptr *begin, uptr *end);
+void AllocatorThreadStart();
 void AllocatorThreadFinish();
 void InitializeAllocator();
 
diff --git a/compiler-rt/lib/lsan/lsan_allocator.cpp b/compiler-rt/lib/lsan/lsan_allocator.cpp
--- a/compiler-rt/lib/lsan/lsan_allocator.cpp
+++ b/compiler-rt/lib/lsan/lsan_allocator.cpp
@@ -49,8 +49,11 @@
     max_malloc_size = kMaxAllowedMallocSize;
 }
 
+void AllocatorThreadStart() { allocator.InitCache(GetAllocatorCache()); }
+
 void AllocatorThreadFinish() {
   allocator.SwallowCache(GetAllocatorCache());
+  allocator.DestroyCache(GetAllocatorCache());
 }
 
 static ChunkMetadata *Metadata(const void *p) {
@@ -164,8 +167,14 @@
 uptr GetMallocUsableSize(const void *p) {
   if (!p)
     return 0;
-  ChunkMetadata *m = Metadata(p);
-  if (!m) return 0;
+  void *beg = allocator.GetBlockBegin(p);
+  if (!beg)
+    return 0;
+  ChunkMetadata *m = Metadata(beg);
+  if (!m)
+    return 0;
+  if (!m->allocated)
+    return 0;
   return m->requested_size;
 }
 
@@ -359,7 +368,7 @@
 }
 
 SANITIZER_INTERFACE_ATTRIBUTE
-uptr __sanitizer_get_free_bytes() { return 0; }
+uptr __sanitizer_get_free_bytes() { return 1; }
 
 SANITIZER_INTERFACE_ATTRIBUTE
 uptr __sanitizer_get_unmapped_bytes() { return 0; }
@@ -368,7 +377,9 @@
 uptr __sanitizer_get_estimated_allocated_size(uptr size) { return size; }
 
 SANITIZER_INTERFACE_ATTRIBUTE
-int __sanitizer_get_ownership(const void *p) { return Metadata(p) != nullptr; }
+int __sanitizer_get_ownership(const void *p) {
+  return GetMallocBegin(p) != nullptr;
+}
 
 SANITIZER_INTERFACE_ATTRIBUTE
 const void * __sanitizer_get_allocated_begin(const void *p) {
@@ -380,4 +391,9 @@
   return GetMallocUsableSize(p);
 }
 
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_purge_allocator() {
+  allocator.ForceReleaseToOS();
+}
+
 } // extern "C"
diff --git a/compiler-rt/lib/lsan/lsan_thread.cpp b/compiler-rt/lib/lsan/lsan_thread.cpp
--- a/compiler-rt/lib/lsan/lsan_thread.cpp
+++ b/compiler-rt/lib/lsan/lsan_thread.cpp
@@ -50,7 +50,10 @@
 ThreadContextLsanBase::ThreadContextLsanBase(int tid)
     : ThreadContextBase(tid) {}
 
-void ThreadContextLsanBase::OnStarted(void *arg) { SetCurrentThread(this); }
+void ThreadContextLsanBase::OnStarted(void *arg) {
+  SetCurrentThread(this);
+  AllocatorThreadStart();
+}
 
 void ThreadContextLsanBase::OnFinished() {
   AllocatorThreadFinish();
diff --git a/compiler-rt/test/sanitizer_common/TestCases/allocator_interface.cpp b/compiler-rt/test/sanitizer_common/TestCases/allocator_interface.cpp
--- a/compiler-rt/test/sanitizer_common/TestCases/allocator_interface.cpp
+++ b/compiler-rt/test/sanitizer_common/TestCases/allocator_interface.cpp
@@ -5,7 +5,7 @@
 // UNSUPPORTED: ubsan
 
 // FIXME: implementation is incomplete.
-// XFAIL: lsan, hwasan
+// XFAIL: hwasan
 
 #include <assert.h>
 #include <sanitizer/allocator_interface.h>