diff --git a/src/d3d9/d3d9_texture.h b/src/d3d9/d3d9_texture.h
index 47f09a84..4b070a3c 100644
--- a/src/d3d9/d3d9_texture.h
+++ b/src/d3d9/d3d9_texture.h
@@ -77,6 +77,8 @@ namespace dxvk {
       if (unlikely(FilterType == D3DTEXF_NONE))
         return D3DERR_INVALIDCALL;
 
+      auto lock = this->m_parent->LockDevice();
+
       m_texture.SetMipFilter(FilterType);
       return D3D_OK;
     }
@@ -89,6 +91,8 @@ namespace dxvk {
       if (!m_texture.NeedsMipGen())
         return;
 
+      auto lock = this->m_parent->LockDevice();
+
       this->m_parent->MarkTextureMipsUnDirty(&m_texture);
       this->m_parent->EmitGenerateMips(&m_texture);
     }