diff --git a/aos/ipc_lib/signalfd.h b/aos/ipc_lib/signalfd.h
index 7d2021a..b3a9063 100644
--- a/aos/ipc_lib/signalfd.h
+++ b/aos/ipc_lib/signalfd.h
@@ -29,7 +29,8 @@
  private:
   int fd_ = -1;
 
-  sigset_t mask_;
+  // The signals we blocked in the constructor.
+  sigset_t blocked_mask_;
 };
 
 }  // namespace ipc_lib