Patch "selftests: mptcp: pm: ensure unknown flags are ignored" has been added to the 6.1-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    selftests: mptcp: pm: ensure unknown flags are ignored

to the 6.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     selftests-mptcp-pm-ensure-unknown-flags-are-ignored.patch
and it can be found in the queue-6.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From matttbe@kernel.org Wed Feb 11 20:06:54 2026
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: Wed, 11 Feb 2026 20:06:19 +0100
Subject: selftests: mptcp: pm: ensure unknown flags are ignored
To: mptcp@lists.linux.dev, stable@vger.kernel.org, gregkh@linuxfoundation.org
Cc: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>, sashal@kernel.org, Mat Martineau <martineau@kernel.org>, Jakub Kicinski <kuba@kernel.org>
Message-ID: <20260211190617.77192-9-matttbe@kernel.org>

From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>

commit 29f4801e9c8dfd12bdcb33b61a6ac479c7162bd7 upstream.

This validates the previous commit: the userspace can set unknown flags
-- the 7th bit is currently unused -- without errors, but only the
supported ones are printed in the endpoints dumps.

The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests,
but it validates the previous fix for an issue introduced by this commit
ID.

Fixes: 01cacb00b35c ("mptcp: add netlink-based PM")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251205-net-mptcp-misc-fixes-6-19-rc1-v1-2-9e4781a6c1b8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ Conflicts in pm_netlink.sh, because some refactoring have been done
  later on: commit 0d16ed0c2e74 ("selftests: mptcp: add
  {get,format}_endpoint(s) helpers") and commit c99d57d0007a
  ("selftests: mptcp: use pm_nl endpoint ops") are not in this version.
  The same operation can still be done at the same place, without using
  the new helpers.
  Also, commit 1dc88d241f92 ("selftests: mptcp: pm_nl_ctl: always look
  for errors") is not in this version, and create a conflict in the
  context which is not related to the modification here. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 tools/testing/selftests/net/mptcp/pm_netlink.sh |    4 ++++
 tools/testing/selftests/net/mptcp/pm_nl_ctl.c   |   11 +++++++++++
 2 files changed, 15 insertions(+)

--- a/tools/testing/selftests/net/mptcp/pm_netlink.sh
+++ b/tools/testing/selftests/net/mptcp/pm_netlink.sh
@@ -124,6 +124,10 @@ id 8 flags signal 10.0.1.8" "id limit"
 ip netns exec $ns1 ./pm_nl_ctl flush
 check "ip netns exec $ns1 ./pm_nl_ctl dump" "" "flush addrs"
 
+ip netns exec $ns1 ./pm_nl_ctl add 10.0.1.1 flags unknown
+check "ip netns exec $ns1 ./pm_nl_ctl dump" "id 1 flags  10.0.1.1" "ignore unknown flags"
+ip netns exec $ns1 ./pm_nl_ctl flush
+
 ip netns exec $ns1 ./pm_nl_ctl limits 9 1
 check "ip netns exec $ns1 ./pm_nl_ctl limits" "$default_limits" "rcv addrs above hard limit"
 
--- a/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
+++ b/tools/testing/selftests/net/mptcp/pm_nl_ctl.c
@@ -29,6 +29,8 @@
 #define IPPROTO_MPTCP 262
 #endif
 
+#define MPTCP_PM_ADDR_FLAG_UNKNOWN _BITUL(7)
+
 static void syntax(char *argv[])
 {
 	fprintf(stderr, "%s add|ann|rem|csf|dsf|get|set|del|flush|dump|events|listen|accept [<args>]\n", argv[0]);
@@ -814,6 +816,8 @@ int add_addr(int fd, int pm_family, int
 					flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
 				else if (!strcmp(tok, "fullmesh"))
 					flags |= MPTCP_PM_ADDR_FLAG_FULLMESH;
+				else if (!strcmp(tok, "unknown"))
+					flags |= MPTCP_PM_ADDR_FLAG_UNKNOWN;
 				else
 					error(1, errno,
 					      "unknown flag %s", argv[arg]);
@@ -1018,6 +1022,13 @@ static void print_addr(struct rtattr *at
 				if (flags)
 					printf(",");
 			}
+
+			if (flags & MPTCP_PM_ADDR_FLAG_UNKNOWN) {
+				printf("unknown");
+				flags &= ~MPTCP_PM_ADDR_FLAG_UNKNOWN;
+				if (flags)
+					printf(",");
+			}
 
 			/* bump unknown flags, if any */
 			if (flags)


Patches currently in stable-queue which might be from matttbe@kernel.org are

queue-6.1/selftests-mptcp-join-fix-local-endp-not-being-tracked.patch
queue-6.1/mptcp-schedule-rtx-timer-only-after-pushing-data.patch
queue-6.1/mptcp-ensure-context-reset-on-disconnect.patch
queue-6.1/selftests-mptcp-pm-ensure-unknown-flags-are-ignored.patch
queue-6.1/selftests-mptcp-check-no-dup-close-events-after-error.patch
queue-6.1/selftests-mptcp-check-subflow-errors-in-close-events.patch