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: 77e4b94a3d ("mptcp: update userspace pm infos")
Cc: stable@vger.kernel.org
Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260602-net-mptcp-misc-fixes-7-1-rc7-v2-6-856831229976@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
master
Tao Cui 2026-06-02 22:14:13 +10:00 committed by Jakub Kicinski
parent 14e9fea30b
commit 06fd2bec7a
1 changed files with 4 additions and 0 deletions

View File

@ -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