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