diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
index b542a3a021bf8cee34276bd5fa4e73f599cee759..f834627586272b80c4702b499553ac24c296c9dd 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -496,8 +496,7 @@ int os_rcv_fd(int fd, int *helper_pid_out)
 	n = recvmsg(fd, &msg, 0);
 	if(n < 0)
 		return -errno;
-
-	else if(n != sizeof(iov.iov_len))
+	else if(n != iov.iov_len)
 		*helper_pid_out = -1;
 
 	cmsg = CMSG_FIRSTHDR(&msg);