Re: [PATCH net-next v2 1/4] selftests: net: Move some UAPI header inclusions after libc ones
From: Matthieu Baerts <matttbe@kernel.org>
Date: 2026-01-26 18:14:05
Also in:
bpf, linux-kselftest, linux-security-module, lkml, mptcp, netdev
Hi Thomas, On 20/01/2026 15:10, Thomas Weißschuh wrote:
Interleaving inclusions of UAPI headers and libc headers is problematic. Both sets of headers define conflicting symbols. To enable their coexistence a compatibility-mechanism is in place. An upcoming change will define 'struct sockaddr' from linux/socket.h. However sys/socket.h from libc does not yet handle this case and a symbol conflict will arise. Furthermore libc-compat.h evaluates the state of the libc inclusions only once, at the point it is included first. If another problematic header from libc is included later, symbol conflicts arise. This will trigger other duplicate definitions when linux/libc-compat.h is added to linux/socket.h Move the inclusion of UAPI headers after the inclusion of the glibc ones, so the libc-compat.h continues to work correctly.
Thank you for looking at this! Here is my (late, sorry) review for the modifications related to MPTCP:
quoted hunk ↗ jump to hunk
diff --git a/tools/testing/selftests/net/mptcp/mptcp_diag.c b/tools/testing/selftests/net/mptcp/mptcp_diag.c index 8e0b1b8d84b6..af25ebfd2915 100644 --- a/tools/testing/selftests/net/mptcp/mptcp_diag.c +++ b/tools/testing/selftests/net/mptcp/mptcp_diag.c@@ -1,11 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2025, Kylin Software */ -#include <linux/sock_diag.h> -#include <linux/rtnetlink.h> -#include <linux/inet_diag.h> -#include <linux/netlink.h> -#include <linux/compiler.h> #include <sys/socket.h> #include <netinet/in.h> #include <linux/tcp.h>
There is a remaining one (linux/tcp.h) here that you might want to move below too.
quoted hunk ↗ jump to hunk
@@ -17,6 +12,12 @@ #include <errno.h> #include <stdio.h> +#include <linux/sock_diag.h> +#include <linux/rtnetlink.h> +#include <linux/inet_diag.h> +#include <linux/netlink.h> +#include <linux/compiler.h>
Note that I just noticed this is the only file from this directory where the "includes" are not sorted by type and alphabetical order, see pm_nl_ctl.c as an example. A bit of a detail, but if you plan to send a v2, do you mind doing that too here while at it, please? If not, I can look at that later, but better to avoid doing that in parallel. Cheers, Matt -- Sponsored by the NGI0 Core fund.