diff --git a/src/unix/notbsd/mod.rs b/src/unix/notbsd/mod.rs
index 668c25f7fee22..34b213b5430cd 100644
--- a/src/unix/notbsd/mod.rs
+++ b/src/unix/notbsd/mod.rs
@@ -999,7 +999,7 @@ f! {
         if cmsg.is_null() {
             return CMSG_FIRSTHDR(mhdr);
         };
-        let pad = mem::align_of::<cmsghdr>() - 1;
+        let pad = mem::align_of::<usize>() - 1;
         let next = cmsg as usize + (*cmsg).cmsg_len as usize + pad & !pad;
         let max = (*mhdr).msg_control as usize
             + (*mhdr).msg_controllen as usize;