FAILED: patch "[PATCH] selftests: mptcp: join: check re-adding init endp with != id" failed to apply to 6.10-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.10.y
git checkout FETCH_HEAD
git cherry-pick -x 1c2326fcae4f0c5de8ad0d734ced43a8e5f17dac
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024083017-acclaim-eatery-5ccf@gregkh' --subject-prefix 'PATCH 6.10.y' HEAD^..

Possible dependencies:

1c2326fcae4f ("selftests: mptcp: join: check re-adding init endp with != id")
a13d5aad4dd9 ("selftests: mptcp: join: check re-using ID of unused ADD_ADDR")
b5e2fb832f48 ("selftests: mptcp: add explicit test case for remove/readd")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 1c2326fcae4f0c5de8ad0d734ced43a8e5f17dac Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <matttbe@kernel.org>
Date: Wed, 28 Aug 2024 08:14:30 +0200
Subject: [PATCH] selftests: mptcp: join: check re-adding init endp with != id

The initial subflow has a special local ID: 0. It is specific per
connection.

When a global endpoint is deleted and re-added later, it can have a
different ID, but the kernel should still use the ID 0 if it corresponds
to the initial address.

This test validates this behaviour: the endpoint linked to the initial
subflow is removed, and re-added with a different ID.

Note that removing the initial subflow will not decrement the 'subflows'
counters, which corresponds to the *additional* subflows. On the other
hand, when the same endpoint is re-added, it will increment this
counter, as it will be seen as an additional subflow this time.

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: 3ad14f54bd74 ("mptcp: more accurate MPC endpoint tracking")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 8b4529ff15e5..75458ade32c7 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -3627,11 +3627,12 @@ endpoint_tests()
 	# remove and re-add
 	if reset "delete re-add signal" &&
 	   mptcp_lib_kallsyms_has "subflow_rebuild_header$"; then
-		pm_nl_set_limits $ns1 0 2
-		pm_nl_set_limits $ns2 2 2
+		pm_nl_set_limits $ns1 0 3
+		pm_nl_set_limits $ns2 3 3
 		pm_nl_add_endpoint $ns1 10.0.2.1 id 1 flags signal
 		# broadcast IP: no packet for this address will be received on ns1
 		pm_nl_add_endpoint $ns1 224.0.0.1 id 2 flags signal
+		pm_nl_add_endpoint $ns1 10.0.1.1 id 42 flags signal
 		test_linkfail=4 speed=20 \
 			run_tests $ns1 $ns2 10.0.1.1 &
 		local tests_pid=$!
@@ -3653,11 +3654,21 @@ endpoint_tests()
 		wait_mpj $ns2
 		chk_subflow_nr "after re-add" 3
 		chk_mptcp_info subflows 2 subflows 2
+
+		pm_nl_del_endpoint $ns1 42 10.0.1.1
+		sleep 0.5
+		chk_subflow_nr "after delete ID 0" 2
+		chk_mptcp_info subflows 2 subflows 2
+
+		pm_nl_add_endpoint $ns1 10.0.1.1 id 99 flags signal
+		wait_mpj $ns2
+		chk_subflow_nr "after re-add" 3
+		chk_mptcp_info subflows 3 subflows 3
 		mptcp_lib_kill_wait $tests_pid
 
-		chk_join_nr 3 3 3
-		chk_add_nr 4 4
-		chk_rm_nr 2 1 invert
+		chk_join_nr 4 4 4
+		chk_add_nr 5 5
+		chk_rm_nr 3 2 invert
 	fi
 
 	# flush and re-add