diff --git a/VolumeManager.cpp b/VolumeManager.cpp
index 2085ca8..4a649bb 100644
--- a/VolumeManager.cpp
+++ b/VolumeManager.cpp
@@ -350,6 +350,7 @@
 }
 
 void VolumeManager::addDiskSource(const std::shared_ptr<DiskSource>& diskSource) {
+    std::lock_guard<std::mutex> lock(mLock);
     mDiskSources.push_back(diskSource);
 }