diff --git a/src/pkg/net/rpc/client.go b/src/pkg/net/rpc/client.go
index 6fb414e089..abc1e59cd5 100644
--- a/src/pkg/net/rpc/client.go
+++ b/src/pkg/net/rpc/client.go
@@ -145,6 +145,7 @@ func (call *Call) done() {
 	default:
 		// We don't want to block here.  It is the caller's responsibility to make
 		// sure the channel has enough buffer space. See comment in Go().
+		log.Println("rpc: discarding Call reply due to insufficient Done chan capacity")
 	}
 }