diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 2c4dee518..21fa2939d 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -920,7 +920,7 @@ StorePathSet Store::exportReferences(const StorePathSet & storePaths, const Stor
 const Store::Stats & Store::getStats()
 {
     {
-        auto state_(state.lock());
+        auto state_(state.read());
         stats.pathInfoCacheSize = state_->pathInfoCache.size();
     }
     return stats;
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 7d5f533c5..8288cfdf0 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -201,7 +201,7 @@ protected:
         LRUCache<std::string, PathInfoCacheValue> pathInfoCache;
     };
 
-    Sync<State> state;
+    SharedSync<State> state;
 
     std::shared_ptr<NarInfoDiskCache> diskCache;
 
diff --git a/src/libutil/lru-cache.hh b/src/libutil/lru-cache.hh
index 0e19517ed..6e14cac35 100644
--- a/src/libutil/lru-cache.hh
+++ b/src/libutil/lru-cache.hh
@@ -89,7 +89,7 @@ public:
         return i->second.second;
     }
 
-    size_t size()
+    size_t size() const
     {
         return data.size();
     }