diff --git a/src/platform/redox/socket.rs b/src/platform/redox/socket.rs
index f7ee9eef40..3ef263c0ec 100644
--- a/src/platform/redox/socket.rs
+++ b/src/platform/redox/socket.rs
@@ -789,7 +789,8 @@ impl PalSocket for Sys {
             + mhdr.msg_namelen as usize     // name_buffer
             + mem::size_of::<usize>()       // payload_len
             + whole_iov_size                // payload_data_buffer
-            + mhdr.msg_controllen as usize // ancillary_stream_buffer
+            + mem::size_of::<usize>()       // control_len
+            + mhdr.msg_controllen as usize  // ancillary_stream_buffer
         };
         msg_stream
             .try_reserve_exact(expected_stream_size)