From 06fd2bec7aebf393288e4b78924482fe170caabc Mon Sep 17 00:00:00 2001 From: Tao Cui Date: Tue, 2 Jun 2026 22:14:13 +1000 Subject: [PATCH] selftests: mptcp: add test for extra_subflows underflow on userspace PM Add a test to verify that when userspace PM fails to create a subflow (e.g. using an unreachable address), the extra_subflows counter is not decremented below zero. Fixes: 77e4b94a3de6 ("mptcp: update userspace pm infos") Cc: stable@vger.kernel.org Signed-off-by: Tao Cui Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-6-856831229976@kernel.org Signed-off-by: Jakub Kicinski --- tools/testing/selftests/net/mptcp/mptcp_join.sh | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh index 5acd12021e6e8..4b3f71e666092 100755 --- a/tools/testing/selftests/net/mptcp/mptcp_join.sh +++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh @@ -4100,6 +4100,10 @@ userspace_tests() chk_rm_nr 0 1 chk_mptcp_info subflows 0 subflows 0 chk_subflows_total 1 1 + # check counters are not affected by errors at creation time + userspace_pm_add_sf $ns2 10.0.12.2 10 2>/dev/null + chk_mptcp_info subflows 0 subflows 0 + chk_subflows_total 1 1 kill_events_pids mptcp_lib_kill_group_wait $tests_pid fi -- 2.47.3