[PATCH net 06/10] selftests: mptcp: add test for extra_subflows underflow on userspace PM

[Matthieu Baerts (NGI0)]

From: Tao Cui <cuitao@xxxxxxxxxx>

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@xxxxxxxxxxxxxxx
Signed-off-by: Tao Cui <cuitao@xxxxxxxxxx>
Reviewed-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
To: Shuah Khan <shuah@xxxxxxxxxx>
Cc: linux-kselftest@xxxxxxxxxxxxxxx
---
 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 5acd12021e6e..4b3f71e66609 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

-- 
2.53.0