diff --git a/src/brpc/mongo_service_adaptor.h b/src/brpc/mongo_service_adaptor.h
index 318e902ee2..d050fb6a11 100644
--- a/src/brpc/mongo_service_adaptor.h
+++ b/src/brpc/mongo_service_adaptor.h
@@ -46,6 +46,8 @@ class MongoContextMessage : public InputMessageBase {
 
 class MongoServiceAdaptor {
 public:
+    virtual ~MongoServiceAdaptor() = default;
+
     // Make an error msg when the cntl fails. If cntl fails, we must send mongo client a msg not 
     // only to indicate the error, but also to finish the round trip.
     virtual void SerializeError(int response_to, butil::IOBuf* out_buf) const = 0;
diff --git a/src/brpc/span.h b/src/brpc/span.h
index 4427340592..1ef3d03c73 100644
--- a/src/brpc/span.h
+++ b/src/brpc/span.h
@@ -206,6 +206,7 @@ void AnnotateSpan(const char* fmt, ...);
 
 class SpanFilter {
 public:
+    virtual ~SpanFilter() = default;
     virtual bool Keep(const BriefSpan&) = 0;
 };